Patent Grant
11661632
Lung cancer is the most common worldwide cause of cancer mortality. In the United States, lung cancer is the second most prevalent cancer in both men and women and will account for more than 174,000 new cases per year and more than 162,000 cancer deaths. In fact, lung cancer accounts for more deaths each year than from breast, prostate and colorectal cancers combined.
The high mortality (80-85% in five years), which has shown little or no improvement in the past 30 years, emphasizes the fact that new and effective tools to facilitate early diagnosis prior to metastasis to regional nodes or beyond the lung are needed.
High risk populations include smokers, former smokers, and individuals with markers associated with genetic predispositions. Because surgical removal of early stage tumors remains the most effective treatment for lung cancer, there has been great interest in screening high-risk patients with low dose spiral CT (LDCT). This strategy identifies non-calcified pulmonary nodules in approximately 30-70% of high risk individuals but only a small proportion of detected nodules are ultimately diagnosed as lung cancers (0.4 to 2.7%). Currently, the only way to differentiate subjects with lung nodules of benign etiology from subjects with malignant nodules is an invasive biopsy, surgery, or prolonged observation with repeated scanning Even using the best clinical algorithms, 20-55% of patients selected to undergo surgical lung biopsy for indeterminate lung nodules, are found to have benign disease and those that do not undergo immediate biopsy or resection require sequential imaging studies. The use of serial CT in this group of patients runs the risk of delaying potential curable therapy, along with the costs of repeat scans, the not-insignificant radiation doses, and the anxiety of the patient.
Ideally, a diagnostic test would be easily accessible, inexpensive, demonstrate high sensitivity and specificity, and result in improved patient outcomes (medically and financially). Others have shown that classifiers which utilize epithelial cells have high accuracy. However, harvesting these cells requires an invasive bronchoscopy. See, Silvestri et al, N Engl J Med. 2015 Jul. 16; 373(3): 243-251, which is incorporated herein by reference.
Efforts are in progress to develop non-invasive diagnostics using sputum, blood or serum and analyzing for products of tumor cells, methylated tumor DNA, single nucleotide polymorphism (SNPs) expressed messenger RNA or proteins. This broad array of molecular tests with potential utility for early diagnosis of lung cancer has been discussed in the literature. Although each of these approaches has its own merits, none has yet passed the exploratory stage in the effort to detect patients with early stage lung cancer, even in high-risk groups, or patients which have a preliminary diagnosis based on radiological and other clinical factors. A simple blood test, a routine event associated with regular clinical office visits, would be an ideal diagnostic test.
In one aspect, a composition or kit for diagnosing or evaluating a lung cancer in a mammalian subject includes ten (10) or more polynucleotides or oligonucleotides, wherein each polynucleotide or oligonucleotide hybridizes to a different gene, gene fragment, gene transcript or expression product in a patient sample. Each gene, gene fragment, gene transcript or expression product is selected from the genes of Table I or Table II. In one embodiment, at least one polynucleotide or oligonucleotide is attached to a detectable label. In one embodiment, the composition or kit includes polynucleotides or oligonucleotides which detect the gene, gene fragment, gene transcript or expression product of each of the 559 genes in Table I. In another embodiment, the composition or kit includes polynucleotides or oligonucleotides which detect the gene, gene fragment, gene transcript or expression product of each of the 100 genes in Table II.
In another aspect, a composition or kit for diagnosing or evaluating a lung cancer in a mammalian subject includes ten (10) or more ligands, wherein each ligand hybridizes to a different gene expression product in a patient sample. Each gene expression product is selected from the genes of Table I or Table II. In one embodiment, at least one ligand is attached to a detectable label. In one embodiment, the composition or kit includes ligands which detect the expression products of each of the 559 genes in Table I. In another embodiment, the composition or kit includes ligands which detect the expression products of each of the 100 genes in Table II.
The compositions described herein enable detection of changes in expression in the genes in the subject's gene expression profile from that of a reference gene expression profile. The various reference gene expression profiles are described below. In one embodiment, the composition provides the ability to distinguish a cancerous tumor from a non-cancerous nodule.
In another aspect, a method for diagnosing or evaluating a lung cancer in a mammalian subject involves identifying changes in the expression of three or more genes in the sample of a subject, said genes selected from the genes of Table I or Table II, and comparing that subject's gene expression levels with the levels of the same genes in a reference or control, wherein changes in expression of said gene expression correlates with a diagnosis or evaluation of a lung cancer. In one embodiment, the changes in expression of said gene expression provides the ability to distinguish a cancerous tumor from a non-cancerous nodule.
In another aspect, a method for diagnosing or evaluating a lung cancer in a mammalian subject involves identifying a gene expression profile in the blood of a subject, the gene expression profile comprising 10 or more gene expression products of 10 or more informative genes as described herein. The 10 or more informative genes are selected from the genes of Table I or Table II. In one embodiment, the gene expression profile contains all 559 genes of Table I. In another embodiment, the gene expression profile contains all 100 genes of Table II. The subject's gene expression profile is compared with a reference gene expression profile from a variety of sources described below. Changes in expression of the informative genes correlate with a diagnosis or evaluation of a lung cancer. In one embodiment, the changes in expression of said gene expression provides the ability to distinguish a cancerous tumor from a non-cancerous nodule.
In another aspect, a method of detecting lung cancer in a patient is provided. The method includes obtaining a sample from the patient; and detecting a change in expression in at least 10 genes selected from Table I or Table II in the patient sample as compared to a control by contacting the sample with a composition comprising oligonucleotides, polynucleotides or ligands specific for each different gene transcript or expression product of the at least 10 gene of Table I or Table II and detecting binding between the oligonucleotide, polynucleotide or ligand and the gene product or expression product.
In yet another aspect, a method of diagnosing lung cancer in a subject is provided. The method includes obtaining a blood sample from a subject; detecting a change in expression in at least 10 genes selected from Table I or Table II in the patient sample as compared to a control by contacting the sample with a composition comprising oligonucleotides, polynucleotides or ligands specific for each different gene transcript or expression product of the at least 10 gene of Table I or Table II and detecting binding between the oligonucleotide, polynucleotide or ligand and the gene product or expression product; and diagnosing the subject with cancer when changes in expression of the subject's genes from those of the reference are detected.
In another aspect, a method of diagnosing and treating lung cancer in a subject having a neoplastic growth is provided. The method includes obtaining a blood sample from a subject; detecting a change in expression in at least 10 genes selected from Table I or Table II in the patient sample as compared to a control by contacting the sample with a composition comprising oligonucleotides, polynucleotides or ligands specific for each different gene transcript or expression product of the at least 10 gene of Table I or Table II and detecting binding between the oligonucleotide, polynucleotide or ligand and the gene product or expression product; diagnosing the subject with cancer when changes in expression of the subject's genes from those of the reference are detected; and removing the neoplastic growth. Other appropriate treatments may also be provided.
Other aspects and advantages of these compositions and methods are described further in the following detailed description of the preferred embodiments thereof.
The methods and compositions described herein apply gene expression technology to blood screening for the detection and diagnosis of lung cancer. The compositions and methods described herein provide the ability to distinguish a cancerous tumor from a non-cancerous nodule, by determining a characteristic RNA expression profile of the genes of the blood of a mammalian, preferably human, subject. The profile is compared with the profile of one or more subjects of the same class (e.g., patients having lung cancer or a non-cancerous nodule) or a control to provide a useful diagnosis.
These methods of lung cancer screening employ compositions suitable for conducting a simple and cost-effective and non-invasive blood test using gene expression profiling that could alert the patient and physician to obtain further studies, such as a chest radiograph or CT scan, in much the same way that the prostate specific antigen is used to help diagnose and follow the progress of prostate cancer. The application of these profiles provides overlapping and confirmatory diagnoses of the type of lung disease, beginning with the initial test for malignant vs. non-malignant disease.
“Patient” or “subject” as used herein means a mammalian animal, including a human, a veterinary or farm animal, a domestic animal or pet, and animals normally used for clinical research. In one embodiment, the subject of these methods and compositions is a human.
“Control” or “Control subject” as used herein refers to the source of the reference gene expression profiles as well as the particular panel of control subjects described herein. In one embodiment, the control or reference level is from a single subject. In another embodiment, the control or reference level is from a population of individuals sharing a specific characteristic. In yet another embodiment, the control or reference level is an assigned value which correlates with the level of a specific control individual or population, although not necessarily measured at the time of assaying the test subject's sample. In one embodiment, the control subject or reference is from a patient (or population) having a non-cancerous nodule. In another embodiment, the control subject or reference is from a patient (or population) having a cancerous tumor. In other embodiments, the control subject can be a subject or population with lung cancer, such as a subject who is a current or former smoker with malignant disease, a subject with a solid lung tumor prior to surgery for removal of same; a subject with a solid lung tumor following surgical removal of said tumor; a subject with a solid lung tumor prior to therapy for same; and a subject with a solid lung tumor during or following therapy for same. In other embodiments, the controls for purposes of the compositions and methods described herein include any of the following classes of reference human subject with no lung cancer. Such non-healthy controls (NHC) include the classes of smoker with non-malignant disease, a former smoker with non-malignant disease (including patients with lung nodules), a non-smoker who has chronic obstructive pulmonary disease (COPD), and a former smoker with COPD. In still other embodiments, the control subject is a healthy non-smoker with no disease or a healthy smoker with no disease.
“Sample” as used herein means any biological fluid or tissue that contains immune cells and/or cancer cells. The most suitable sample for use in this invention includes whole blood. Other useful biological samples include, without limitation, peripheral blood mononuclear cells, plasma, saliva, urine, synovial fluid, bone marrow, cerebrospinal fluid, vaginal mucus, cervical mucus, nasal secretions, sputum, semen, amniotic fluid, bronchoscopy sample, bronchoalveolar lavage fluid, and other cellular exudates from a patient having cancer. Such samples may further be diluted with saline, buffer or a physiologically acceptable diluent. Alternatively, such samples are concentrated by conventional means.
As used herein, the term “cancer” refers to or describes the physiological condition in mammals that is typically characterized by unregulated cell growth. More specifically, as used herein, the term “cancer” means any lung cancer. In one embodiment, the lung cancer is non-small cell lung cancer (NSCLC). In a more specific embodiment, the lung cancer is lung adenocarcinoma (AC or LAC). In another more specific embodiment, the lung cancer is lung squamous cell carcinoma (SCC or LSCC). In another embodiment, the lung cancer is a stage I or stage II NSCLC. In still another embodiment, the lung cancer is a mixture of early and late stages and types of NSCLC.
The term “tumor,” as used herein, refers to all neoplastic cell growth and proliferation, whether malignant or benign, and all pre-cancerous and cancerous cells and tissues. The term “nodule” refers to an abnormal buildup of tissue which is benign. The term “cancerous tumor” refers to a malignant tumor.
By “diagnosis” or “evaluation” it is meant a diagnosis of a lung cancer, a diagnosis of a stage of lung cancer, a diagnosis of a type or classification of a lung cancer, a diagnosis or detection of a recurrence of a lung cancer, a diagnosis or detection of a regression of a lung cancer, a prognosis of a lung cancer, or an evaluation of the response of a lung cancer to a surgical or non-surgical therapy. In one embodiment, “diagnosis” or “evaluation” refers to distinguishing between a cancerous tumor and a benign pulmonary nodule.
As used herein, “sensitivity” (also called the true positive rate), measures the proportion of positives that are correctly identified as such (e.g., the percentage of sick people who are correctly identified as having the condition).
As used herein, “specificity” (also called the true negative rate) measures the proportion of negatives that are correctly identified as such (e.g., the percentage of healthy people who are correctly identified as not having the condition).
By “change in expression” is meant an upregulation of one or more selected genes in comparison to the reference or control; a downregulation of one or more selected genes in comparison to the reference or control; or a combination of certain upregulated genes and down regulated genes.
By “therapeutic reagent” or “regimen” is meant any type of treatment employed in the treatment of cancers with or without solid tumors, including, without limitation, chemotherapeutic pharmaceuticals, biological response modifiers, radiation, diet, vitamin therapy, hormone therapies, gene therapy, surgical resection, etc.
By “informative genes” as used herein is meant those genes the expression of which changes (either in an up-regulated or down-regulated manner) characteristically in the presence of lung cancer. A statistically significant number of such informative genes thus form suitable gene expression profiles for use in the methods and compositions. Such genes are shown in Table I and Table II below. Such genes make up the “expression profile”.
The term “statistically significant number of genes” in the context of this invention differs depending on the degree of change in gene expression observed. The degree of change in gene expression varies with the type of cancer and with the size or spread of the cancer or solid tumor. The degree of change also varies with the immune response of the individual and is subject to variation with each individual. For example, in one embodiment of this invention, a large change, e.g., 2-3 fold increase or decrease in a small number of genes, e.g., in about 10 to 20 genes, is statistically significant. In another embodiment, a smaller relative change in about 15 more genes is statistically significant.
Thus, the methods and compositions described herein contemplate examination of the expression profile of a “statistically significant number of genes” ranging from 5 to about 559 genes in a single profile. In one embodiment, the genes are selected from Table I. In another embodiment, the genes are selected from Table II. In one embodiment, the gene profile is formed by a statistically significant number of 5 or more genes. In one embodiment, the gene profile is formed by a statistically significant number of 10 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 15 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 20 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 25 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 30 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 35 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 40 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 45 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 50 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 60 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 65 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 70 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 75 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 80 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 85 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 90 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 95 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 100 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 200 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 300 or more genes. In another embodiment, the gene profile is formed by a statistically significant number of 350 or more genes. In still another embodiment, the gene profile is formed by 400 or more genes. In still another embodiment, the gene profile is formed by 539 genes. In still another embodiment, the gene profile is formed by 559 genes. In still other embodiments, the gene profiles examined as part of these methods contain, as statistically significant numbers of genes, from 10 to 559 genes, and any numbers therebetween. In another embodiment, the gene profile is formed by 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, 352, 353, 354, 355, 356, 357, 358, 359, 360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 377, 378, 379, 380, 381, 382, 383, 384, 385, 386, 387, 388, 389, 390, 391, 392, 393, 394, 395, 396, 397, 398, 399, 400, 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417, 418, 419, 420, 421, 422, 423, 424, 425, 426, 427, 428, 429, 430, 431, 432, 433, 434, 435, 436, 437, 438, 439, 440, 441, 442, 443, 444, 445, 446, 447, 448, 449, 450, 451, 452, 453, 454, 455, 456, 457, 458, 459, 460, 461, 462, 463, 464, 465, 466, 467, 468, 469, 470, 471, 472, 473, 474, 475, 476, 477, 478, 479, 480, 481, 482, 483, 484, 485, 486, 487, 488, 489, 490, 491, 492, 493, 494, 495, 496, 497, 498, 499, 500, 501, 502, 503, 504, 505, 506, 507, 508, 509, 510, 511, 512, 513, 514, 515, 516, 517, 518, 519, 520, 521, 522, 523, 524, 525, 526, 527, 528, 529, 530, 531, 532, 533, 534, 535, 536, 537, 538, 539, 540, 541, 542, 543, 544, 545, 546, 547, 548, 549, 550, 551, 552, 553, 554, 555, 556, 557, 558, or all 559 genes of Table I. In another embodiment, the gene profile is formed by 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or all 100 genes of Table II.
Table I and Table II below refer to a collection of known genes useful in discriminating between a subject having a lung cancer, e.g., NSCLC, and subjects having benign (non-malignant) lung nodules. The sequences of the genes identified in Table I and Table II are publicly available. One skilled in the art may readily reproduce the compositions and methods described herein by use of the sequences of the genes, all of which are publicly available from conventional sources, such as GenBank. The GenBank accession number for each gene is provided.
The term “microarray” refers to an ordered arrangement of hybridizable array elements, preferably polynucleotide or oligonucleotide probes, on a substrate.
The term “polynucleotide,” when used in singular or plural form, generally refers to any polyribonucleotide or polydeoxribonucleotide, which may be unmodified RNA or DNA or modified RNA or DNA. Thus, for instance, polynucleotides as defined herein include, without limitation, single- and double-stranded DNA, DNA including single- and double-stranded regions, single- and double-stranded RNA, and RNA including single- and double-stranded regions, hybrid molecules comprising DNA and RNA that may be single-stranded or, more typically, double-stranded or include single- and double-stranded regions. In addition, the term “polynucleotide” as used herein refers to triple-stranded regions comprising RNA or DNA or both RNA and DNA. The strands in such regions may be from the same molecule or from different molecules. The regions may include all of one or more of the molecules, but more typically involve only a region of some of the molecules. One of the molecules of a triple-helical region often is an oligonucleotide. The term “polynucleotide” specifically includes cDNAs. The term includes DNAs (including cDNAs) and RNAs that contain one or more modified bases. Thus, DNAs or RNAs with backbones modified for stability or for other reasons are “polynucleotides” as that term is intended herein. Moreover, DNAs or RNAs comprising unusual bases, such as inosine, or modified bases, such as tritiated bases, are included within the term “polynucleotides” as defined herein. In general, the term “polynucleotide” embraces all chemically, enzymatically and/or metabolically modified forms of unmodified polynucleotides, as well as the chemical forms of DNA and RNA characteristic of viruses and cells, including simple and complex cells.
The term “oligonucleotide” refers to a relatively short polynucleotide, including, without limitation, single-stranded deoxyribonucleotides, single- or double-stranded ribonucleotides, RNA:DNA hybrids and double-stranded DNAs. Oligonucleotides, such as single-stranded DNA probe oligonucleotides, are often synthesized by chemical methods, for example using automated oligonucleotide synthesizers that are commercially available. However, oligonucleotides can be made by a variety of other methods, including in vitro recombinant DNA-mediated techniques and by expression of DNAs in cells and organisms.
The terms “differentially expressed gene”, “differential gene expression” and their synonyms, which are used interchangeably, refer to a gene whose expression is activated to a higher or lower level in a subject suffering from a disease, specifically cancer, such as lung cancer, relative to its expression in a control subject, such as a subject having a benign nodule. The terms also include genes whose expression is activated to a higher or lower level at different stages of the same disease. It is also understood that a differentially expressed gene may be either activated or inhibited at the nucleic acid level or protein level, or may be subject to alternative splicing to result in a different polypeptide product. Such differences may be evidenced by a change in mRNA levels, surface expression, secretion or other partitioning of a polypeptide, for example. Differential gene expression may include a comparison of expression between two or more genes or their gene products, or a comparison of the ratios of the expression between two or more genes or their gene products, or even a comparison of two differently processed products of the same gene, which differ between normal subjects, non-health controls and subjects suffering from a disease, specifically cancer, or between various stages of the same disease. Differential expression includes both quantitative, as well as qualitative, differences in the temporal or cellular expression pattern in a gene or its expression products among, for example, normal and diseased cells, or among cells which have undergone different disease events or disease stages. For the purpose of this invention, “differential gene expression” is considered to be present when there is a statistically significant (p<0.05) difference in gene expression between the subject and control samples.
The term “over-expression” with regard to an RNA transcript is used to refer to the level of the transcript determined by normalization to the level of reference mRNAs, which might be all measured transcripts in the specimen or a particular reference set of mRNAs.
The phrase “gene amplification” refers to a process by which multiple copies of a gene or gene fragment are formed in a particular cell or cell line. The duplicated region (a stretch of amplified DNA) is often referred to as “amplicon.” Usually, the amount of the messenger RNA (mRNA) produced, i.e., the level of gene expression, also increases in the proportion of the number of copies made of the particular gene expressed.
In the context of the compositions and methods described herein, reference to “10 or more”, “at least 10” etc. of the genes listed in Table I or Table II means any one or any and all combinations of the genes listed. For example, suitable gene expression profiles include profiles containing any number between at least 5 through 559 genes from Table I. In another example, suitable gene expression profiles include profiles containing any number between at least 5 through 100 genes from Table II. In one embodiment, gene profiles formed by genes selected from a table are used in rank order, e.g., genes ranked in the top of the list demonstrated more significant discriminatory results in the tests, and thus may be more significant in a profile than lower ranked genes. However, in other embodiments the genes forming a useful gene profile do not have to be in rank order and may be any gene from the table. As used herein, the term “100 Classifier” or “100 Biomarker Classifier” refers to the 100 genes of Table II. As used herein, the term “559 Classifier” or “559 Biomarker Classifier” refers to the 559 genes of Table I. However, subsets of the genes of Table I or Table II, as described herein, are also useful, and, in another embodiment, the terms may refer to those subsets as well.
As used herein, “labels” or “reporter molecules” are chemical or biochemical moieties useful for labeling a nucleic acid (including a single nucleotide), polynucleotide, oligonucleotide, or protein ligand, e.g., amino acid or antibody. “Labels” and “reporter molecules” include fluorescent agents, chemiluminescent agents, chromogenic agents, quenching agents, radionucleotides, enzymes, substrates, cofactors, inhibitors, magnetic particles, and other moieties known in the art. “Labels” or “reporter molecules” are capable of generating a measurable signal and may be covalently or noncovalently joined or bound to an oligonucleotide or nucleotide (e.g., a non-natural nucleotide) or ligand.
Unless defined otherwise in this specification, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs and by reference to published texts, which provide one skilled in the art with a general guide to many of the terms used in the present application.
The inventors have shown that the gene expression profiles of the whole blood of lung cancer patients differ significantly from those seen in patients having non-cancerous lung nodules. For example, changes in the gene expression products of the genes of Table I and/or Table II can be observed and detected by the methods of this invention in the normal circulating blood of patients with early stage solid lung tumors.
The gene expression profiles described herein provide new diagnostic markers for the early detection of lung cancer and could prevent patients from undergoing unnecessary procedures relating to surgery or biopsy for a benign nodule. Since the risks are very low, the benefit to risk ratio is very high. In one embodiment, the methods and compositions described herein may be used in conjunction with clinical risk factors to help physicians make more accurate decisions about how to manage patients with lung nodules. Another advantage of this invention is that diagnosis may occur early since diagnosis is not dependent upon detecting circulating tumor cells which are present in only vanishing small numbers in early stage lung cancers.
In one aspect, a composition is provided for classifying a nodule as cancerous or benign in a mammalian subject. In one embodiment, the composition includes at least 10 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In another embodiment, the composition includes at least 100 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I. In one embodiment, the polynucleotide or oligonucleotide or ligand hybridizes to an mRNA.
In one embodiment, a novel gene expression profile or signature can identify and distinguish patients having cancerous tumors from patients having benign nodules. See for example the genes identified in Table I and Table II which may form a suitable gene expression profile. In another embodiment, a portion of the genes of Table I form a suitable profile. In yet another embodiment, a portion of the genes of Table II form a suitable profile. As discussed herein, these profiles are used to distinguish between cancerous and non-cancerous tumors by generating a discriminant score based on differences in gene expression profiles as exemplified below. The validity of these signatures was established on samples collected at different locations by different groups in a cohort of patients with undiagnosed lung nodules. See Example 7 and
In one embodiment, the composition includes 10 to 559 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I. In another embodiment, the composition includes 10 to 100 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table II. In another embodiment, the composition includes 10 to 559 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I. In another embodiment, the composition includes 10 to 100 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table II. In another embodiment, the composition includes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, 352, 353, 354, 355, 356, 357, 358, 359, 360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 377, 378, 379, 380, 381, 382, 383, 384, 385, 386, 387, 388, 389, 390, 391, 392, 393, 394, 395, 396, 397, 398, 399, 400, 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417, 418, 419, 420, 421, 422, 423, 424, 425, 426, 427, 428, 429, 430, 431, 432, 433, 434, 435, 436, 437, 438, 439, 440, 441, 442, 443, 444, 445, 446, 447, 448, 449, 450, 451, 452, 453, 454, 455, 456, 457, 458, 459, 460, 461, 462, 463, 464, 465, 466, 467, 468, 469, 470, 471, 472, 473, 474, 475, 476, 477, 478, 479, 480, 481, 482, 483, 484, 485, 486, 487, 488, 489, 490, 491, 492, 493, 494, 495, 496, 497, 498, 499, 500, 501, 502, 503, 504, 505, 506, 507, 508, 509, 510, 511, 512, 513, 514, 515, 516, 517, 518, 519, 520, 521, 522, 523, 524, 525, 526, 527, 528, 529, 530, 531, 532, 533, 534, 535, 536, 537, 538, 539, 540, 541, 542, 543, 544, 545, 546, 547, 548, 549, 550, 551, 552, 553, 554, 555, 556, 557, 558, or 559 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I. In another embodiment, the composition includes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table II. In one embodiment, the composition includes at least 3 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 5 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 10 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 15 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 20 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 25 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 30 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 35 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 40 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 45 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 50 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 55 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 60 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 65 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 70 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 75 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 80 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 85 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 90 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 95 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 100 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I or Table II. In one embodiment, the composition includes at least 150 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I. In one embodiment, the composition includes at least 200 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I. In one embodiment, the composition includes at least 250 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I. In one embodiment, the composition includes at least 300 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I. In one embodiment, the composition includes at least 350 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I. In one embodiment, the composition includes at least 400 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I. In one embodiment, the composition includes at least 450 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I. In one embodiment, the composition includes at least 500 polynucleotides or oligonucleotides or ligands, wherein each polynucleotide or oligonucleotide or ligand hybridizes to a different gene, gene fragment, gene transcript or expression product in a sample selected from the genes of Table I. In one embodiment, the composition includes polynucleotides or oligonucleotides or ligands capable of hybridizing to each different gene, gene fragment, gene transcript or expression product listed in Table I. In another embodiment, the composition includes polynucleotides or oligonucleotides or ligands capable of hybridizing to each different gene, gene fragment, gene transcript or expression product listed in Table II.
In yet another embodiment, the expression profile is formed by the first 3 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 5 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 10 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 15 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 20 genes in rank order of Table I or Table II. In another embodiment, the expression profile is formed by the first 25 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 30 genes in rank order of Table I or Table II. In another embodiment, the expression profile is formed by the first 35 genes in rank order of Table I or Table II. In another embodiment, the expression profile is formed by the first 40 genes in rank order of Table I or Table II. In another embodiment, the expression profile is formed by the first 45 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 50 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 55 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 60 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 65 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 70 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 75 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 80 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 85 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 90 genes in rank order of Table I or Table II. In yet another embodiment, the expression profile is formed by the first 95 genes in rank order of Table I or Table II. In another embodiment, the expression profile is formed by the first 100 genes in rank order of Table I or Table II. In another embodiment, the expression profile is formed by the first 150 genes in rank order of Table I. In another embodiment, the expression profile is formed by the first 200 genes in rank order of Table I. In another embodiment, the expression profile is formed by the first 250 genes in rank order of Table I. In another embodiment, the expression profile is formed by the first 300 genes in rank order of Table I. In another embodiment, the expression profile is formed by the first 350 genes in rank order of Table I. In another embodiment, the expression profile is formed by the first 400 genes in rank order of Table I. In yet another embodiment, the expression profile is formed by the first 539 genes in rank order of Table I.
As discussed below, the compositions described herein can be used with the gene expression profiling methods which are known in the art. Thus, the compositions can be adapted accordingly to suit the method for which they are intended to be used. In one embodiment, at least one polynucleotide or oligonucleotide or ligand is attached to a detectable label. In certain embodiments, each polynucleotide or oligonucleotide is attached to a different detectable label, each capable of being detected independently. Such reagents are useful in assays such as the nCounter, as described below.
In another embodiment, the composition comprises a capture oligonucleotide or ligand, which hybridizes to at least one polynucleotide or oligonucleotide or ligand. In one embodiment, such capture oligonucleotide or ligand may include a nucleic acid sequence which is specific for a portion of the oligonucleotide or polynucleotide or ligand which is specific for the gene of interest. The capture ligand may be a peptide or polypeptide which is specific for the ligand to the gene of interest. In one embodiment, the capture ligand is an antibody, as in a sandwich ELISA.
The capture oligonucleotide also includes a moiety which allows for binding with a substrate. Such substrate includes, without limitation, a plate, bead, slide, well, chip or chamber. In one embodiment, the composition includes a capture oligonucleotide for each different polynucleotide or oligonucleotide which is specific to a gene of interest. Each capture oligonucleotide may contain the same moiety which allows for binding with the same substrate. In one embodiment, the binding moiety is biotin.
Thus, a composition for such diagnosis or evaluation in a mammalian subject as described herein can be a kit or a reagent. For example, one embodiment of a composition includes a substrate upon which the ligands used to detect and quantitate mRNA are immobilized. The reagent, in one embodiment, is an amplification nucleic acid primer (such as an RNA primer) or primer pair that amplifies and detects a nucleic acid sequence of the mRNA. In another embodiment, the reagent is a polynucleotide probe that hybridizes to the target sequence. In another embodiment, the target sequences are illustrated in Table III. In another embodiment, the reagent is an antibody or fragment of an antibody. The reagent can include multiple said primers, probes or antibodies, each specific for at least one gene, gene fragment or expression product of Table I or Table II. Optionally, the reagent can be associated with a conventional detectable label.
In another embodiment, the composition is a kit containing the relevant multiple polynucleotides or oligonucleotide probes or ligands, optional detectable labels for same, immobilization substrates, optional substrates for enzymatic labels, as well as other laboratory items. In still another embodiment, at least one polynucleotide or oligonucleotide or ligand is associated with a detectable label. In certain embodiments, the reagent is immobilized on a substrate. Exemplary substrates include a microarray, chip, microfluidics card, or chamber.
In one embodiment, the composition is a kit designed for use with the nCounter Nanostring system, as further discussed below.
Methods of gene expression profiling that were used in generating the profiles useful in the compositions and methods described herein or in performing the diagnostic steps using the compositions described herein are known and well summarized in U.S. Pat. No. 7,081,340. Such methods of gene expression profiling include methods based on hybridization analysis of polynucleotides, methods based on sequencing of polynucleotides, and proteomics-based methods. The most commonly used methods known in the art for the quantification of mRNA expression in a sample include northern blotting and in situ hybridization; RNAse protection assays; nCounter® Analysis; and PCR-based methods, such as RT-PCR. Alternatively, antibodies may be employed that can recognize specific duplexes, including DNA duplexes, RNA duplexes, and DNA-RNA hybrid duplexes or DNA-protein duplexes. Representative methods for sequencing-based gene expression analysis include Serial Analysis of Gene Expression (SAGE), and gene expression analysis by massively parallel signature sequencing (MPSS).
In certain embodiments, the compositions described herein are adapted for use in the methods of gene expression profiling described herein, and those known in the art.
A. Patient Sample
The “sample” or “biological sample” as used herein means any biological fluid or tissue that contains immune cells and/or cancer cells. In one embodiment, a suitable sample is whole blood. In another embodiment, the sample may be venous blood. In another embodiment, the sample may be arterial blood. In another embodiment, a suitable sample for use in the methods described herein includes peripheral blood, more specifically peripheral blood mononuclear cells. Other useful biological samples include, without limitation, plasma or serum. In still other embodiment, the sample is saliva, urine, synovial fluid, bone marrow, cerebrospinal fluid, vaginal mucus, cervical mucus, nasal secretions, sputum, semen, amniotic fluid, bronchoalveolar lavage fluid, and other cellular exudates from a subject suspected of having a lung disease. Such samples may further be diluted with saline, buffer or a physiologically acceptable diluent. Alternatively, such samples are concentrated by conventional means. It should be understood that the use or reference throughout this specification to any one biological sample is exemplary only. For example, where in the specification the sample is referred to as whole blood, it is understood that other samples, e.g., serum, plasma, etc., may also be employed in another embodiment.
In one embodiment, the biological sample is whole blood, and the method employs the PaxGene Blood RNA Workflow system (Qiagen). That system involves blood collection (e.g., single blood draws) and RNA stabilization, followed by transport and storage, followed by purification of Total RNA and Molecular RNA testing. This system provides immediate RNA stabilization and consistent blood draw volumes. The blood can be drawn at a physician's office or clinic, and the specimen transported and stored in the same tube. Short term RNA stability is 3 days at between 18-25° C. or 5 days at between 2-8° C. Long term RNA stability is 4 years at −20 to −70° C. This sample collection system enables the user to reliably obtain data on gene expression in whole blood. In one embodiment, the biological sample is whole blood. While the PAXgene system has more noise than the use of PBMC as a biological sample source, the benefits of PAXgene sample collection outweighs the problems. Noise can be subtracted bioinformatically by the person of skill in the art.
In one embodiment, the biological samples may be collected using the proprietary PaxGene Blood RNA System (PreAnalytiX, a Qiagen, BD company). The PAXgene Blood RNA System comprises two integrated components: PAXgene Blood RNA Tube and the PAXgene Blood RNA Kit. Blood samples are drawn directly into PAXgene Blood RNA Tubes via standard phlebotomy technique. These tubes contain a proprietary reagent that immediately stabilizes intracellular RNA, minimizing the ex-vivo degradation or up-regulation of RNA transcripts. The ability to eliminate freezing, batch samples, and to minimize the urgency to process samples following collection, greatly enhances lab efficiency and reduces costs. Thereafter, the miRNA is detected and/or measured using a variety of assays.
B. Nanostring Analysis
A sensitive and flexible quantitative method that is suitable for use with the compositions and methods described herein is the nCounter® Analysis system (NanoString Technologies, Inc., Seattle Wash.). The nCounter Analysis System utilizes a digital color-coded barcode technology that is based on direct multiplexed measurement of gene expression and offers high levels of precision and sensitivity (<1 copy per cell). The technology uses molecular “barcodes” and single molecule imaging to detect and count hundreds of unique transcripts in a single reaction. Each color-coded barcode is attached to a single target-specific probe (i.e., polynucleotide, oligonucleotide or ligand) corresponding to a gene of interest, i.e., a gene of Table I. Mixed together with controls, they form a multiplexed CodeSet. In one embodiment, the CodeSet includes all 559 genes of Table I. In another embodiment, the CodeSet includes all 100 genes of Table II. In another embodiment, the CodeSet includes at least 3 genes of Table I or Table II. In another embodiment, the CodeSet includes at least 5 genes of Table I or Table II. In another embodiment, the CodeSet includes at least 10 genes of Table I or Table II. In another embodiment, the CodeSet includes at least 15 genes of Table I or Table II. In another embodiment, the CodeSet includes at least 20 genes of Table I or Table II. In another embodiment, the CodeSet includes at least 25 genes of Table I or Table II. In another embodiment, the CodeSet includes at least 30 genes of Table I or Table II. In yet another embodiment, the CodeSet includes at least 40 genes of Table I or Table II. In yet another embodiment, the CodeSet includes at least 50 genes of Table I or Table II. In another embodiment, the CodeSet includes at least 60 genes of Table I or Table II. In another embodiment, the CodeSet includes at least 70 genes of Table I or Table II. In yet another embodiment, the CodeSet includes at least 80 genes of Table I or Table II. In yet another embodiment, the CodeSet includes at least 90 genes of Table I or Table II. In another embodiment, the CodeSet includes at least 100 genes of Table I. In another embodiment, the CodeSet includes at least 200 genes of Table I. In another embodiment, the CodeSet includes at least 300 genes of Table I. In yet another embodiment, the CodeSet includes at least 400 genes of Table I. In yet another embodiment, the CodeSet includes at least 500 genes of Table I. In yet another embodiment, the CodeSet is formed by the first 539 genes in rank order of Table I. In yet another embodiment, the CodeSet includes any subset of genes of Table I, as described herein. In another embodiment, the CodeSet includes any subset of genes of Table II, as described herein.
The NanoString platform employs two ˜50 base probes per mRNA that hybridizes in solution. The Reporter Probe carries the signal; the Capture Probe allows the complex to be immobilized for data collection. The probes are mixed with the patient sample. After hybridization, the excess probes are removed and the probe/target complexes aligned and immobilized to a substrate, e.g., in the nCounter Cartridge.
The target sequences utilized in the Examples below for each of the genes of Table I and Table II are shown in Table III below, and are reproduced in the sequence listing. These sequences are portions of the published sequences of these genes. Suitable alternatives may be readily designed by one of skill in the art.
Sample Cartridges are placed in the Digital Analyzer for data collection. Color codes on the surface of the cartridge are counted and tabulated for each target molecule.
A benefit of the use of the NanoString nCounter system is that no amplification of mRNA is necessary in order to perform the detection and quantification. However, in alternate embodiments, other suitable quantitative methods are used. See, e.g., Geiss et al, Direct multiplexed measurement of gene expression with color-coded probe pairs, Nat Biotechnol. 2008 March; 26(3):317-25. doi: 10.1038/nbt1385. Epub 2008 Feb. 17, which is incorporated herein by reference in its entirety.
C. Polymerase Chain Reaction (PCR) Techniques
Another suitable quantitative method is RT-PCR, which can be used to compare mRNA levels in different sample populations, in normal and tumor tissues, to characterize patterns of gene expression, to discriminate between closely related mRNAs, and to analyze RNA structure. The first step is the isolation of mRNA from a target sample (e.g., typically total RNA isolated from human PBMC). mRNA can be extracted, for example, from frozen or archived paraffin-embedded and fixed (e.g. formalin-fixed) tissue samples.
General methods for mRNA extraction are well known in the art, such standard textbooks of molecular biology. In particular, RNA isolation can be performed using a purification kit, buffer set and protease from commercial manufacturers, according to the manufacturer's instructions. Exemplary commercial products include TRI-REAGENT, Qiagen RNeasy mini-columns, MASTERPURE Complete DNA and RNA Purification Kit (EPICENTRE®, Madison, Wis.), Paraffin Block RNA Isolation Kit (Ambion, Inc.) and RNA Stat-60 (Tel-Test). Conventional techniques such as cesium chloride density gradient centrifugation may also be employed.
The first step in gene expression profiling by RT-PCR is the reverse transcription of the RNA template into cDNA, followed by its exponential amplification in a PCR reaction. The two most commonly used reverse transcriptases are avilo myeloblastosis virus reverse transcriptase (AMV-RT) and Moloney murine leukemia virus reverse transcriptase (MMLV-RT). The reverse transcription step is typically primed using specific primers, random hexamers, or oligo-dT primers, depending on the circumstances and the goal of expression profiling. See, e.g., manufacturer's instructions accompanying the product GENEAMP RNA PCR kit (Perkin Elmer, Calif., USA). The derived cDNA can then be used as a template in the subsequent RT-PCR reaction.
The PCR step generally uses a thermostable DNA-dependent DNA polymerase, such as the Taq DNA polymerase, which has a 5′-3′ nuclease activity but lacks a 3′-5′ proofreading endonuclease activity. Thus, TAQMAN® PCR typically utilizes the 5′-nuclease activity of Taq or Tth polymerase to hydrolyze a hybridization probe bound to its target amplicon, but any enzyme with equivalent 5′ nuclease activity can be used. Two oligonucleotide primers are used to generate an amplicon typical of a PCR reaction. In one embodiment, the target sequence is shown in Table III. A third oligonucleotide, or probe, is designed to detect nucleotide sequence located between the two PCR primers. The probe is non-extendible by Taq DNA polymerase enzyme, and is labeled with a reporter fluorescent dye and a quencher fluorescent dye. Any laser-induced emission from the reporter dye is quenched by the quenching dye when the two dyes are located close together as they are on the probe. During the amplification reaction, the Taq DNA polymerase enzyme cleaves the probe in a template-dependent manner. The resultant probe fragments disassociate in solution, and signal from the released reporter dye is free from the quenching effect of the second fluorophore. One molecule of reporter dye is liberated for each new molecule synthesized, and detection of the unquenched reporter dye provides the basis for quantitative interpretation of the data.
TaqMan® RT-PCR can be performed using commercially available equipment. In a preferred embodiment, the 5′ nuclease procedure is run on a real-time quantitative PCR device such as the ABI PRISM 7900® Sequence Detection System®. The system amplifies samples in a 96-well format on a thermocycler. During amplification, laser-induced fluorescent signal is collected in real-time through fiber optic cables for all 96 wells, and detected at the CCD. The system includes software for running the instrument and for analyzing the data. 5′-Nuclease assay data are initially expressed as Ct, or the threshold cycle. As discussed above, fluorescence values are recorded during every cycle and represent the amount of product amplified to that point in the amplification reaction. The point when the fluorescent signal is first recorded as statistically significant is the threshold cycle (Ct).
To minimize errors and the effect of sample-to-sample variation, RT-PCR is usually performed using an internal standard. The ideal internal standard is expressed at a constant level among different tissues, and is unaffected by the experimental treatment. RNAs most frequently used to normalize patterns of gene expression are mRNAs for the housekeeping genes glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) and β-actin.
Real time PCR is comparable both with quantitative competitive PCR, where internal competitor for each target sequence is used for normalization, and with quantitative comparative PCR using a normalization gene contained within the sample, or a housekeeping gene for RT-PCR.
In another PCR method, i.e., the MassARRAY-based gene expression profiling method (Sequenom, Inc., San Diego, Calif.), following the isolation of RNA and reverse transcription, the obtained cDNA is spiked with a synthetic DNA molecule (competitor), which matches the targeted cDNA region in all positions, except a single base, and serves as an internal standard. The cDNA/competitor mixture is PCR amplified and is subjected to a post-PCR shrimp alkaline phosphatase (SAP) enzyme treatment, which results in the dephosphorylation of the remaining nucleotides. After inactivation of the alkaline phosphatase, the PCR products from the competitor and cDNA are subjected to primer extension, which generates distinct mass signals for the competitor- and cDNA-derived PCR products. After purification, these products are dispensed on a chip array, which is pre-loaded with components needed for analysis with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis. The cDNA present in the reaction is then quantified by analyzing the ratios of the peak areas in the mass spectrum generated.
Still other embodiments of PCR-based techniques which are known to the art and may be used for gene expression profiling include, e.g., differential display, amplified fragment length polymorphism (iAFLP), and BeadArray™ technology (Illumina, San Diego, Calif.) using the commercially available Luminex100 LabMAP system and multiple color-coded microspheres (Luminex Corp., Austin, Tex.) in a rapid assay for gene expression; and high coverage expression profiling (HiCEP) analysis.
D. Microarrays
Differential gene expression can also be identified, or confirmed using the microarray technique. Thus, the expression profile of lung cancer-associated genes can be measured in either fresh or paraffin-embedded tissue, using microarray technology. In this method, polynucleotide sequences of interest (including cDNAs and oligonucleotides) are plated, or arrayed, on a microchip substrate. The arrayed sequences are then hybridized with specific DNA probes from cells or tissues of interest. Just as in the other methods and compositions herein, the source of mRNA is total RNA isolated from whole blood of controls and patient subjects.
In one embodiment of the microarray technique, PCR amplified inserts of cDNA clones are applied to a substrate in a dense array. In one embodiment, all 559 nucleotide sequences from Table III are applied to the substrate. The microarrayed genes, immobilized on the microchip, are suitable for hybridization under stringent conditions. Fluorescently labeled cDNA probes may be generated through incorporation of fluorescent nucleotides by reverse transcription of RNA extracted from tissues of interest. Labeled cDNA probes applied to the chip hybridize with specificity to each spot of DNA on the array. After stringent washing to remove non-specifically bound probes, the chip is scanned by confocal laser microscopy or by another detection method, such as a CCD camera. Quantitation of hybridization of each arrayed element allows for assessment of corresponding mRNA abundance. With dual color fluorescence, separately labeled cDNA probes generated from two sources of RNA are hybridized pairwise to the array. The relative abundance of the transcripts from the two sources corresponding to each specified gene is thus determined simultaneously. The miniaturized scale of the hybridization affords a convenient and rapid evaluation of the expression pattern for large numbers of genes. Such methods have been shown to have the sensitivity required to detect rare transcripts, which are expressed at a few copies per cell, and to reproducibly detect at least approximately two-fold differences in the expression levels. Microarray analysis can be performed by commercially available equipment, following manufacturer's protocols.
Other useful methods summarized by U.S. Pat. No. 7,081,340, and incorporated by reference herein include Serial Analysis of Gene Expression (SAGE) and Massively Parallel Signature Sequencing (MPSS). Briefly, serial analysis of gene expression (SAGE) is a method that allows the simultaneous and quantitative analysis of a large number of gene transcripts, without the need of providing an individual hybridization probe for each transcript. First, a short sequence tag (about 10 to 14 bp) is generated that contains sufficient information to uniquely identify a transcript, provided that the tag is obtained from a unique position within each transcript. Then, many transcripts are linked together to form long serial molecules, that can be sequenced, revealing the identity of the multiple tags simultaneously. The expression pattern of any population of transcripts can be quantitatively evaluated by determining the abundance of individual tags, and identifying the gene corresponding to each tag. For more details see, e.g. Velculescu et al., Science 270:484 487 (1995); and Velculescu et al., Cell 88:243 51 (1997), both of which are incorporated herein by reference.
Gene Expression Analysis by Massively Parallel Signature Sequencing (MPSS), described by Brenner et al., Nature Biotechnology 18:630 634 (2000) (which is incorporated herein by reference), is a sequencing approach that combines non-gel-based signature sequencing with in vitro cloning of millions of templates on separate 5 μm diameter microbeads. First, a microbead library of DNA templates is constructed by in vitro cloning. This is followed by the assembly of a planar array of the template-containing microbeads in a flow cell at a high density (typically greater than 3×106 microbeads/cm2). The free ends of the cloned templates on each microbead are analyzed simultaneously, using a fluorescence-based signature sequencing method that does not require DNA fragment separation. This method has been shown to simultaneously and accurately provide, in a single operation, hundreds of thousands of gene signature sequences from a yeast cDNA library.
E. Immunohistochemistry
Immunohistochemistry methods are also suitable for detecting the expression levels of the gene expression products of the informative genes described for use in the methods and compositions herein. Antibodies or antisera, preferably polyclonal antisera, and most preferably monoclonal antibodies, or other protein-binding ligands specific for each marker are used to detect expression. The antibodies can be detected by direct labeling of the antibodies themselves, for example, with radioactive labels, fluorescent labels, hapten labels such as, biotin, or an enzyme such as horse radish peroxidase or alkaline phosphatase. Alternatively, unlabeled primary antibody is used in conjunction with a labeled secondary antibody, comprising antisera, polyclonal antisera or a monoclonal antibody specific for the primary antibody. Protocols and kits for immunohistochemical analyses are well known in the art and are commercially available.
The methods for diagnosing lung cancer described herein which utilize defined gene expression profiles permit the development of simplified diagnostic tools for diagnosing lung cancer, e.g., NSCLC vs. non-cancerous nodule. Thus, a composition for diagnosing lung cancer in a mammalian subject as described herein can be a kit or a reagent. For example, one embodiment of a composition includes a substrate upon which said polynucleotides or oligonucleotides or ligands or ligands are immobilized. In another embodiment, the composition is a kit containing the relevant 5 or more polynucleotides or oligonucleotides or ligands, optional detectable labels for same, immobilization substrates, optional substrates for enzymatic labels, as well as other laboratory items. In still another embodiment, at least one polynucleotide or oligonucleotide or ligand is associated with a detectable label.
In one embodiment, a composition for diagnosing lung cancer in a mammalian subject includes 5 or more PCR primer-probe sets. Each primer-probe set amplifies a different polynucleotide sequence from a gene expression product of 5 or more informative genes found in the blood of the subject. These informative genes are selected to form a gene expression profile or signature which is distinguishable between a subject having lung cancer and a subject having a non-cancerous nodule. Changes in expression in the genes in the gene expression profile from that of a reference gene expression profile are correlated with a lung cancer, such as non-small cell lung cancer (NSCLC).
In one embodiment of this composition, the informative genes are selected from among the genes identified in Table I. In another embodiment of this composition, the informative genes are selected from among the genes identified in Table II. This collection of genes is those for which the gene product expression is altered (i.e., increased or decreased) versus the same gene product expression in the blood of a reference control (i.e., a patient having a non-cancerous nodule). In one embodiment, polynucleotide or oligonucleotide or ligands, i.e., probes, are generated to 5 or more informative genes from Table I or Table II for use in the composition (the CodeSet). An example of such a composition contains probes to a targeted portion of the 559 genes of Table I. In another embodiment, probes are generated to all 559 genes from Table I for use in the composition. In another embodiment, probes are generated to the first 539 genes from Table I for use in the composition. In another embodiment, probes are generated to the first 3 genes from Table I or Table II for use in the composition. In another embodiment, probes are generated to the first 5 genes from Table I or Table II for use in the composition. In another embodiment, probes are generated to the first 10 genes from Table I or Table II for use in the composition. In another embodiment, probes are generated to the first 15 genes from Table I or Table II for use in the composition. In another embodiment, probes are generated to the first 20 genes from Table I or Table II for use in the composition. In another embodiment, probes are generated to the first 25 genes from Table I or Table II for use in the composition. In yet another embodiment, probes are generated to the first 30 genes from Table I or Table II for use in the composition. In yet another embodiment, probes are generated to the first 35 genes from Table I or Table II for use in the composition. In yet another embodiment, probes are generated to the first 40 genes from Table I or Table II for use in the composition. In yet another embodiment, probes are generated to the first 45 genes from Table I or Table II for use in the composition. In yet another embodiment, probes are generated to the first 50 genes from Table I or Table II for use in the composition. In yet another embodiment, probes are generated to the first 60 genes from Table I or Table II for use in the composition. In yet another embodiment, probes are generated to the first 65 genes from Table I or Table II for use in the composition. In yet another embodiment, probes are generated to the first 70 genes from Table I or Table II for use in the composition. In yet another embodiment, probes are generated to the first 75 genes from Table I or Table II for use in the composition. In yet another embodiment, probes are generated to the first 80 genes from Table I or Table II for use in the composition. In yet another embodiment, probes are generated to the first 85 genes from Table I or Table II for use in the composition. In yet another embodiment, probes are generated to the first 90 genes from Table I or Table II for use in the composition. In yet another embodiment, probes are generated to the first 95 genes from Table I or Table II for use in the composition. In another embodiment, probes are generated to the first 100 genes from Table I or Table II for use in the composition. In another embodiment, probes are generated to the first 200 genes from Table I for use in the composition. In yet another embodiment, probes are generated to 300 genes from Table I for use in the composition. Still other embodiments employ probes to a targeted portion of other combinations of the genes in Table I or Table II. The selected genes from the Table need not be in rank order; rather any combination that clearly shows a difference in expression between the reference control to the diseased patient is useful in such a composition.
In one embodiment of the compositions described above, the reference control is a non-healthy control (NHC) as described above. In other embodiments, the reference control may be any class of controls as described above in “Definitions”.
The compositions based on the genes selected from Table I or Table II described herein, optionally associated with detectable labels, can be presented in the format of a microfluidics card, a chip or chamber, or a kit adapted for use with the Nanostring, PCR, RT-PCR or Q PCR techniques described above. In one aspect, such a format is a diagnostic assay using TAQMAN® Quantitative PCR low density arrays. In another aspect, such a format is a diagnostic assay using the Nanostring nCounter platform.
For use in the above-noted compositions the PCR primers and probes are preferably designed based upon intron sequences present in the gene(s) to be amplified selected from the gene expression profile. Exemplary target sequences are shown in Table III. The design of the primer and probe sequences is within the skill of the art once the particular gene target is selected. The particular methods selected for the primer and probe design and the particular primer and probe sequences are not limiting features of these compositions. A ready explanation of primer and probe design techniques available to those of skill in the art is summarized in U.S. Pat. No. 7,081,340, with reference to publically available tools such as DNA BLAST software, the Repeat Masker program (Baylor College of Medicine), Primer Express (Applied Biosystems); MGB assay-by-design (Applied Biosystems); Primer3 (Steve Rozen and Helen J. Skaletsky (2000) Primer3 on the WWW for general users and for biologist programmers.
In general, optimal PCR primers and probes used in the compositions described herein are generally 17-30 bases in length, and contain about 20-80%, such as, for example, about 50-60% G+C bases. Melting temperatures of between 50 and 80° C., e.g. about 50 to 70° C. are typically preferred.
In another aspect, a composition for diagnosing lung cancer in a mammalian subject contains a plurality of polynucleotides immobilized on a substrate, wherein the plurality of genomic probes hybridize to 100 or more gene expression products of 100 or more informative genes selected from a gene expression profile in the blood of the subject, the gene expression profile comprising genes selected from Table I. In another embodiment, a composition for diagnosing lung cancer in a mammalian subject contains a plurality of polynucleotides immobilized on a substrate, wherein the plurality of genomic probes hybridize to 10 or more gene expression products of 10 or more informative genes selected from a gene expression profile in the blood of the subject, the gene expression profile comprising genes selected from Table I or Table II. This type of composition relies on recognition of the same gene profiles as described above for the Nanostring compositions but employs the techniques of a cDNA array. Hybridization of the immobilized polynucleotides in the composition to the gene expression products present in the blood of the patient subject is employed to quantitate the expression of the informative genes selected from among the genes identified in Tables I or Table II to generate a gene expression profile for the patient, which is then compared to that of a reference sample. As described above, depending upon the identification of the profile (i.e., that of genes of Table I or subsets thereof, that of genes of Table II or subsets thereof), this composition enables the diagnosis and prognosis of NSCLC lung cancers. Again, the selection of the polynucleotide sequences, their length and labels used in the composition are routine determinations made by one of skill in the art in view of the teachings of which genes can form the gene expression profiles suitable for the diagnosis and prognosis of lung cancers.
In yet another aspect, a composition or kit useful in the methods described herein contain a plurality of ligands that bind to 100 or more gene expression products of 100 or more informative genes selected from a gene expression profile in the blood of the subject. In another embodiment, a composition or kit useful in the methods described herein contain a plurality of ligands that bind to 10 or more gene expression products of 10 or more informative genes selected from a gene expression profile in the blood of the subject. The gene expression profile contains the genes of Table I or Table II, as described above for the other compositions. This composition enables detection of the proteins expressed by the genes in the indicated Tables. While preferably the ligands are antibodies to the proteins encoded by the genes in the profile, it would be evident to one of skill in the art that various forms of antibody, e.g., polyclonal, monoclonal, recombinant, chimeric, as well as fragments and components (e.g., CDRs, single chain variable regions, etc.) may be used in place of antibodies. Such ligands may be immobilized on suitable substrates for contact with the subject's blood and analyzed in a conventional fashion. In certain embodiments, the ligands are associated with detectable labels. These compositions also enable detection of changes in proteins encoded by the genes in the gene expression profile from those of a reference gene expression profile. Such changes correlate with lung cancer in a manner similar to that for the PCR and polynucleotide-containing compositions described above.
For all of the above forms of diagnostic/prognostic compositions, the gene expression profile can, in one embodiment, include at least the first 25 of the informative genes of Table I or Table II. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 10 or more of the informative genes of Table I or Table II. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 15 or more of the informative genes of Table I or Table II. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 20 or more of the informative genes of Table I or Table II. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 30 or more of the informative genes of Table I or Table II. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 40 or more of the informative genes of Table I or Table II. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 50 or more of the informative genes of Table I or Table II. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 60 or more of the informative genes of Table I or Table II. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 70 or more of the informative genes of Table I or Table II. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 80 or more of the informative genes of Table I or Table II. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 90 or more of the informative genes of Table I or Table II. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include all 100 of the informative genes of Table II. In one embodiment, for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include at least the first 100 of the informative genes of Table I. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 200 or more of the informative genes of Table I. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 300 or more of the informative genes of Table I. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 400 or more of the informative genes of Table I. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 500 or more of the informative genes of Table I. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include 539 or more of the informative genes of Table I. In another embodiment for all of the above forms of diagnostic/prognostic compositions, the gene expression profile can include all 559 of the informative genes of Table I.
These compositions may be used to diagnose lung cancers, such as stage I or stage II NSCLC. Further these compositions are useful to provide a supplemental or original diagnosis in a subject having lung nodules of unknown etiology.
All of the above-described compositions provide a variety of diagnostic tools which permit a blood-based, non-invasive assessment of disease status in a subject. Use of these compositions in diagnostic tests, which may be coupled with other screening tests, such as a chest X-ray or CT scan, increase diagnostic accuracy and/or direct additional testing.
Thus, in one aspect, a method is provided for diagnosing lung cancer in a mammalian subject. This method involves identifying a gene expression profile in the blood of a mammalian, preferably human, subject. In one embodiment, the gene expression profile includes 100 or more gene expression products of 100 or more informative genes having increased or decreased expression in lung cancer. The gene expression profiles are formed by selection of 100 or more informative genes from the genes of Table I. In another embodiment, the gene expression profile includes 10 or more gene expression products of 10 or more informative genes having increased or decreased expression in lung cancer. The gene expression profiles are formed by selection of 10 or more informative genes from the genes of Table I. In another embodiment, the gene expression profiles are formed by selection of 10 or more informative genes from the genes of Table II. In another embodiment, the gene expression profile includes 10 or more gene expression products of 5 or more informative genes having increased or decreased expression in lung cancer. The gene expression profiles are formed by selection of 5 or more informative genes from the genes of Table I. In another embodiment, the gene expression profiles are formed by selection of 5 or more informative genes from the genes of Table II. Comparison of a subject's gene expression profile with a reference gene expression profile permits identification of changes in expression of the informative genes that correlate with a lung cancer (e.g., NSCLC). This method may be performed using any of the compositions described above. In one embodiment, the method enables the diagnosis of a cancerous tumor from a benign nodule.
In another aspect, use of any of the compositions described herein is provided for diagnosing lung cancer in a subject.
The diagnostic compositions and methods described herein provide a variety of advantages over current diagnostic methods. Among such advantages are the following. As exemplified herein, subjects with cancerous tumors are distinguished from those with benign nodules. These methods and compositions provide a solution to the practical diagnostic problem of whether a patient who presents at a lung clinic with a small nodule has malignant disease. Patients with an intermediate-risk nodule would clearly benefit from a non-invasive test that would move the patient into either a very low-likelihood or a very high-likelihood category of disease risk. An accurate estimate of malignancy based on a genomic profile (i.e. estimating a given patient has a 90% probability of having cancer versus estimating the patient has only a 5% chance of having cancer) would result in fewer surgeries for benign disease, more early stage tumors removed at a curable stage, fewer follow-up CT scans, and reduction of the significant psychological costs of worrying about a nodule. The economic impact would also likely be significant, such as reducing the current estimated cost of additional health care associated with CT screening for lung cancer, i.e., $116,000 per quality adjusted life-year gained. A non-invasive blood genomics test that has a sufficient sensitivity and specificity would significantly alter the post-test probability of malignancy and thus, the subsequent clinical care.
A desirable advantage of these methods over existing methods is that they are able to characterize the disease state from a minimally-invasive procedure, i.e., by taking a blood sample. In contrast, current practice for classification of cancer tumors from gene expression profiles depends on a tissue sample, usually a sample from a tumor. In the case of very small tumors a biopsy is problematic and clearly if no tumor is known or visible, a sample from it is impossible. No purification of tumor is required, as is the case when tumor samples are analyzed. A recently published method depends on brushing epithelial cells from the lung during bronchoscopy, a method which is also considerably more invasive than taking a blood sample. Blood samples have an additional advantage, which is that the material is easily prepared and stabilized for later analysis, which is important when messenger RNA is to be analyzed.
The 559 classifier described herein showed a ROC-AUC of 0.81 over all tested samples. In one embodiment, when the sensitivity is about 90%, the specificity is about 46%. When the nodule classification accuracy is assessed by size without using a specific threshold for sensitivity, as nodules size and the cancer risk factor increases, the number of benign nodules classified as cancer increases. In one embodiment, the accuracy of the gene classifier is about 89% for nodules ≤8 mm. In another embodiment, the accuracy of the gene classifier is about 75% for nodules >8 to about ≤12 mm. In yet another embodiment, the accuracy of the gene classifier is about 68% for nodules >12 to about ≤16 mm. In another embodiment, the accuracy of the gene classifier is about 53% for >16 mm. See examples below.
In one embodiment, for nodules about <10 mm, the specificity is about 54% and the ROC-AUC to 0.85 at about 90% sensitivity. In another embodiment, for larger nodules, about >10 mm, the specificity is about 24% and the ROC-AUC about 0.71 at about 90% sensitivity.
The 100 Classifier described herein showed a ROC-AUC of 0.82 over all tested samples. In one embodiment, when the sensitivity is about 90%, the specificity is about 62%. In another embodiment, when the sensitivity is about 79%, the specificity is about 68%. In one embodiment, when the sensitivity is about 71%, the specificity is about 75%. See examples below.
These compositions and methods allow for more accurate diagnosis and treatment of lung cancer. Thus, in one embodiment, the methods described include treatment of the lung cancer. Treatment may removal of the neoplastic growth, chemotherapy and/or any other treatment known in the art or described herein.
In one embodiment, a method for diagnosing the existence or evaluating a lung cancer in a mammalian subject is provided, which includes identifying changes in the expression of 5, 10, 15 or more genes in the sample of said subject, said genes selected from the genes of Table I or the genes of Table II. The subject's gene expression levels are compare with the levels of the same genes in a reference or control, wherein changes in expression of the subject's genes from those of the reference correlates with a diagnosis or evaluation of a lung cancer.
In one embodiment, the diagnosis or evaluation comprise one or more of a diagnosis of a lung cancer, a diagnosis of a benign nodule, a diagnosis of a stage of lung cancer, a diagnosis of a type or classification of a lung cancer, a diagnosis or detection of a recurrence of a lung cancer, a diagnosis or detection of a regression of a lung cancer, a prognosis of a lung cancer, or an evaluation of the response of a lung cancer to a surgical or non-surgical therapy. In another embodiment, the changes comprise an upregulation of one or more selected genes in comparison to said reference or control or a downregulation of one or more selected genes in comparison to said reference or control.
In one embodiment, the method includes the size of a lung nodule in the subject. The specificity and sensitivity may be variable based on the size of the nodule. In one embodiment, the specificity is about 46% at about 90% sensitivity. In another embodiment, the specificity is about 54% at about 90% sensitivity for nodules <10 mm. In yet another embodiment, the accuracy is about 88% for nodules ≤8 mm, about 75% for nodules >8 mm and ≤12 mm, about 68% for nodules >12 mm and ≤16 mm, and about 53% for nodules >16 mm.
In another embodiment, the reference or control comprises three or more genes of Table I sample of at least one reference subject. The reference subject may be selected from the group consisting of: (a) a smoker with malignant disease, (b) a smoker with non-malignant disease, (c) a former smoker with non-malignant disease, (d) a healthy non-smoker with no disease, (e) a non-smoker who has chronic obstructive pulmonary disease (COPD), (f) a former smoker with COPD, (g) a subject with a solid lung tumor prior to surgery for removal of same; (h) a subject with a solid lung tumor following surgical removal of said tumor; (i) a subject with a solid lung tumor prior to therapy for same; and (j) a subject with a solid lung tumor during or following therapy for same. In one embodiment, the reference or control subject (a)-(j) is the same test subject at a temporally earlier timepoint.
The sample is selected from those described herein. In one embodiment, the sample is peripheral blood. The nucleic acids in the sample are, in some embodiments, stabilized prior to identifying changes in the gene expression levels. Such stabilization may be accomplished, e.g., using the Pax Gene system, described herein.
In one embodiment, the method of detecting lung cancer in a patient includes
a. obtaining a sample from the patient; and
b. detecting a change in expression in at least 10 genes selected from Table I or Table II in the patient sample as compared to a control by contacting the sample with a composition comprising oligonucleotides, polynucleotides or ligands specific for each different gene transcript or expression product of the at least 10 gene of Table I or Table II and detecting binding between the oligonucleotide, polynucleotide or ligand and the gene product or expression product.
In another embodiment, the method of diagnosing lung cancer in a subject includes
a. obtaining a blood sample from a subject;
b. detecting a change in expression in at least 10 genes selected from Table I or Table II in the patient sample as compared to a control by contacting the sample with a composition comprising oligonucleotides, polynucleotides or ligands specific for each different gene transcript or expression product of the at least 100 gene of Table I or Table II and detecting binding between the oligonucleotide, polynucleotide or ligand and the gene product or expression product; and
c. diagnosing the subject with cancer when changes in expression of the subject's genes from those of the reference are detected.
In yet another embodiment, the method includes
a. obtaining a blood sample from a subject;
b. detecting a change in expression in at least 10 genes selected from Table I or Table II in the patient sample as compared to a control by contacting the sample with a composition comprising oligonucleotides, polynucleotides or ligands specific for each different gene transcript or expression product of the at least 10 genes of Table I or Table II and detecting binding between the oligonucleotide, polynucleotide or ligand and the gene product or expression product;
c. diagnosing the subject with cancer when changes in expression of the subject's genes from those of the reference are detected; and
d. removing the neoplastic growth.
The invention is now described with reference to the following examples. These examples are provided for the purpose of illustration only and the invention should in no way be construed as being limited to these examples but rather should be construed to encompass any and all variations that become evident as a result of the teaching provided herein.
For development of the gene classifier described herein, blood samples and clinical information were collected from 150 subjects, 73 having a diagnosis of lung cancer and 77 having a diagnosis of benign nodule. Patient characteristics are shown in
Patients with lung cancer included newly diagnosed male and female patients with early stage lung cancer. They were in moderately good health (ambulatory), although with medical illness. They were excluded if they have had previous cancers, chemotherapy, radiation, or cancer surgery. They must have had a lung cancer diagnosis within preceding 6 months, histologic confirmation, and no systemic therapy, such as chemotherapy, radiation therapy or cancer surgery as biomarker levels may change with therapy. Thus the majority of the cancer patients were early stage (i.e., Stage I and Stage II).
The “control” cohort was derived from patients with benign lung nodules (e.g. ground glass opacities, single nodules, granulomas or hamartomas). These patients were evaluated at pulmonary clinics, or underwent thoracic surgery for a lung nodule. All samples were collected prior to surgery.
Further blood samples and clinical information were collected from 120 subjects, 60 having a diagnosis of lung cancer and 60 having a diagnosis of benign nodule. Patients with lung cancer included newly diagnosed male and female patients with early stage lung cancer. They were in moderately good health (ambulatory), although with medical illness. They were excluded if they have had previous cancers, chemotherapy, radiation, or cancer surgery. They must have had a lung cancer diagnosis within preceding 6 months, histologic confirmation, and no systemic therapy, such as chemotherapy, radiation therapy or cancer surgery as biomarker levels may change with therapy. Thus the majority of the cancer patients were early stage (i.e., Stage I and Stage II).
The “control” cohort was derived from patients with benign lung nodules (e.g. granulomas or hamartomas). These patients were evaluated at pulmonary clinics, or underwent thoracic surgery for a lung nodule. All samples were collected prior to surgery.
Blood samples were collected in the clinic by the tissue acquisition technician. Blood samples were drawn directly into PAXgene Blood RNA Tubes via standard phlebotomy technique. These tubes contain a proprietary reagent that immediately stabilizes intracellular RNA, minimizing the ex-vivo degradation or up-regulation of RNA transcripts. The ability to eliminate freezing, batch samples, and to minimize the urgency to process samples following collection, greatly enhances lab efficiency and reduces costs.
PAXgene RNA is prepared using a standard commercially available kit from Qiagen™ that allows purification of mRNA. The resulting RNA is used for mRNA profiling. The RNA quality is determined using a Bioanalyzer. Only samples with RNA Integrity numbers >3 were used.
Briefly, RNA is isolated as follows. Turn shaker-incubator on and set to 55° C. before beginning. Unless otherwise noted, all steps in this protocol including centrifugation steps, should be carried out at room temp (15-25° C.). This protocol assumes samples are stores at −80° C. Unfrozen samples that have been left a RT per the Qiagen protocol of a minimum of 2 hours should be processed in the same way.
Thaw Paxgene tubes upright in a plastic rack. Invert tubes at least 10 times to mix before starting isolation. Prepare all necessary tubes. For each sample, the following are needed: 2 numbered 1.5 ml Eppendorf tubes; 1 Eppendorf tube with the sample information (this is the final tube); 1 Lilac Paxgene spin column; 1 Red Paxgene Spin column; and 5 Processing tubes.
Centrifuge the PAXgene Blood RNA Tube for 10 minutes at 5000×g using a swing-out rotor in Qiagen centrifuge. (Sigma 4-15° C. Centrifuge., Rotor: Sigma Nr. 11140, 7/01, 5500/min, Holder: Sigma 13115, 286 g 14/D, Inside tube holder: 18010, 125 g). Note: After thawed, ensure that the blood sample has been incubated in the PAXgene Blood RNA Tube for a minimum of 2 hours at room temperature (15-25° C.), in order to achieve complete lysis of blood cells.
Under the hood—remove the supernatant by decanting into bleach. When the supernatant is decanted, take care not to disturb the pellet, and dry the rim of the tube with a clean paper towel. Discard the decanted supernatant by placing the clotted blood into a bag and then into the infectious waste and discard the fluid portion down the sink and wash down with a lot of water. Add 4 ml RNase-free water to the pellet, and close the tube using a fresh secondary Hemogard closure.
Vortex until the pellet is visibly dissolved. Weigh the tubes in the centrifuge holder again to ensure they are balanced, and centrifuge for 10 minutes at 5000×g using a swing-out rotor Qiagen centrifuge Small debris remaining in the supernatant after vortexing but before centrifugation will not affect the procedure.
Remove and discard the entire supernatant. Leave tube upside-down for 1 min to drain off all supernatant. Incomplete removal of the supernatant will inhibit lysis and dilute the lysate, and therefore affect the conditions for binding RNA to the PAXgene membrane.
Add 350 μl Buffer BM1 and pipet up and down lyse the pellet.
Pipet the re-suspended sample into a labeled 1.5 ml microcentrifuge tube. Add 300 μl Buffer BM2. Then add 40 μl proteinase K. Mix by vortexing for 5 seconds, and incubate for 10 minutes at 55° C. using a shaker-incubator at the highest possible speed, 800 rpm on Eppendorf thermomixer. (If using a shaking water bath instead of a thermomixer, quickly vortex the samples every 2-3 minutes during the incubation. Keep the vortexer next to the incubator).
Pipet the lysate directly into a PAXgene Shredder spin column (lilac tube) placed in a 2 ml processing tube, and centrifuge for 3 minutes at 24 C at 18,500×g in the TOMY Microtwin centrifuge. Carefully pipet the lysate into the spin column and visually check that the lysate is completely transferred to the spin column. To prevent damage to columns and tubes, do not exceed 20,000×g.
Carefully transfer the entire supernatant of the flow-through fraction to a fresh 1.5 ml microcentrifuge tube without disturbing the pellet in the processing tube. Discard the pellet in the processing tube.
Add 700 μl isopropanol (100%) to the supernatant. Mix by vortexing.
Pipet 690 μl sample into the PAXgene RNA spin column (red) placed in a 2 ml processing tube, and centrifuge for 1 minute at 10,000×g. Place the spin column in a new 2 ml processing tube, and discard the old processing tube containing flow-through.
Pipet the remaining sample into the PAXgene RNA spin column (red), and centrifuge for 1 minute at 18,500×g. Place the spin column in a new 2 ml processing tube, and discard the old processing tube containing flow-through. Carefully pipet the sample into the spin column and visually check that the sample is completely transferred to the spin column.
Pipet 350 μl Buffer BM3 into the PAXgene RNA spin column. Centrifuge for 15 sec at 10,000×g. Place the spin column in a new 2 ml processing tube, and discard the old processing tube containing flow-through.
Prepare DNase I incubation mix for step 13. Add 10 μl DNase I stock solution to 70 μl Buffer RDD in a 1.5 ml microcentrifuge tube. Mix by gently flicking the tube, and centrifuge briefly to collect residual liquid from the sides of the tube.
Pipet the DNase I incubation mix (80 μl) directly onto the PAXgene RNA spin column membrane, and place on the benchtop (20-30° C.) for 15 minutes. Ensure that the DNase I incubation mix is placed directly onto the membrane. DNase digestion will be incomplete if part of the mix is applied to and remains on the walls or the O-ring of the spin column.
Pipet 350 μl Buffer BM3 into the PAXgene RNA spin column, and centrifuge for 15 sec at 18,500×g. Place the spin column in a new 2 ml processing tube, and discard the old processing tube containing flow-through.
Pipet 500 μl Buffer BM4 to the PAXgene RNA spin column, and centrifuge for 15 sec at 10,000×g. Place the spin column in a new 2 ml processing tube, and discard the old processing tube containing flow-through.
Add another 500 μl Buffer BM4 to the PAXgene RNA spin column. Centrifuge for 2 minutes at 18,500×g.
Discard the tube containing the flow-through, and place the PAXgene RNA spin column in a new 2 ml processing tube. Centrifuge for 1 minute at 18,500×g.
Discard the tube containing the flow-through. Place the PAXgene RNA spin column in a labeled 1.5 ml microcentrifuge tube (final tube), and pipet 40 μl Buffer BR5 directly onto the PAXgene RNA spin column membrane. Centrifuge for 1 minute at 10,000×g to elute the RNA. It is important to wet the entire membrane with Buffer BR5 in order to achieve maximum elution efficiency.
Repeat the elution step as described, using 40 μl Buffer BR5 and the same microcentrifuge tube. Centrifuge for 1 minute at 20,000×g to elute the RNA.
Incubate the eluate for 5 minutes at 65° C. in the shaker-incubator without shaking. After incubation, chill immediately on ice. This incubation at 65° C. denatures the RNA for downstream applications. Do not exceed the incubation time or temperature.
If the RNA samples will not be used immediately, store at −20° C. or −70° C. Since the RNA remains denatured after repeated freezing and thawing, it is not necessary to repeat the incubation at 65° C.
To provide a biomarker signature that can be used in clinical practice to diagnose lung cancer, a gene expression profile with the smallest number of genes that maintain satisfactory accuracy is provided by the use of 100 more of the genes identified in Table I as well as by the use of 10 or more of the genes identified in Table II. These gene profiles or signatures permit simpler and more practical tests that are easy to use in a standard clinical laboratory. Because the number of discriminating genes is small enough, NanoString nCounter® platforms are developed using these gene expression profiles.
A. Nanostring nCounter® Platform Gene Expression Assay Protocol
Total RNA was isolated from whole blood using the Paxgene Blood miRNA Kit, as described above, and samples were checked for RNA quality. Samples were analyzed with the Agilent 2100 Bioanalyzer on a RNA Nano chip, using the RIN score and electropherogram picture as indicators for good sample integrity. Samples were also quantitated on the Nanodrop (ND-1000 Spectrophotometer) where 260/280 and 260/230 readings were recorded and evaluated for Nanostring-compatibility. From the concentrations taken by Nanodrop, total RNA samples were normalized to contain 100 ng in 5 μL, using Nuclease-free water as diluent, into Nanostring-provided tube strips. An 8 μL aliquot of a mixture of the Nanostring nCounter Reporter CodeSet and Hybridization Buffer (70 μL Hybridization Buffer, 42 μL Reporter CodeSet per 12 assays) and 2 μL of Capture ProbeSet was added to each 5 μL RNA sample. Samples were hybridized for 19 hours at 65° C. in the Thermocycler (Eppendorf). During hybridization, Reporter Probes, which have fluorescent barcodes specific to each mRNA of interest to the user, and biotinylated Capture Probes bound to their associated target mRNA to create target-probe complexes. After hybridization was complete, samples were then transferred to the nCounter Prep Station for processing using the Standard Protocol setting (Run Time: 2 hr35 min). The Prep Station robot, during the Standard Protocol, washed samples to remove excess Reporter and Capture Probes. Samples were moved to a streptavidin-coated cartridge where purified target-probe complexes were immobilized in preparation for imaging by the nCounter Digital Analyzer. Upon completion, the cartridge was sealed and placed in the Digital Analyzer using a Field of View (FOV) setting at 555. A fluorescent microscope tabulated the raw counts for each unique barcode associated with a target mRNA. Data collected was stored in .csv files and then transferred to the Bioinformatics Facility for analysis according to the manufacturer's instructions.
Support Vector Machine (SVM) can be applied to gene expression datasets for gene function discovery and classification. SVM has been found to be most efficient at distinguishing the more closely related cases and controls that reside in the margins. Primarily SVM-RFE (48, 54) was used to develop gene expression classifiers which distinguish clinically defined classes of patients from clinically defined classes of controls (smokers, non-smokers, COPD, granuloma, etc). SVM-RFE is a SVM based model utilized in the art that removes genes, recursively based on their contribution to the discrimination, between the two classes being analyzed. The lowest scoring genes by coefficient weights were removed and the remaining genes were scored again and the procedure was repeated until only a few genes remained. This method has been used in several studies to perform classification and gene selection tasks. However, choosing appropriate values of the algorithm parameters (penalty parameter, kernel-function, etc.) can often influence performance.
SVM-RCE is a related SVM based model, in that it, like SVM-RFE assesses the relative contributions of the genes to the classifier. SVM-RCE assesses the contributions of groups of correlated genes instead of individual genes. Additionally, although both methods remove the least important genes at each step, SVM-RCE scores and removes clusters of genes, while SVM-RFE scores and removes a single or small numbers of genes at each round of the algorithm.
The SVM-RCE method is briefly described here. Low expressing genes (average expression less than 2× background) were removed, quantile normalization performed, and then “outlier” arrays whose median expression values differ by more than 3 sigma from the median of the dataset were removed. The remaining samples were subject to SVM-RCE using ten repetitions of 10-fold cross-validation of the algorithm. The genes were reduced by t-test (applied on the training set) to an experimentally determined optimal value which produces highest accuracy in the final result. These starting genes were clustered by K-means into clusters of correlated genes whose average size is 3-5 genes. SVM classification scoring was carried out on each cluster using 3-fold resampling repeated 5 times, and the worst scoring clusters eliminated. Accuracy is determined on the surviving pool of genes using the left-out 10% of samples (testing set) and the top-scoring 100 genes were recorded. The procedure was repeated from the clustering step to an end point of 2 clusters. The optimal gene panel was taken to be the minimal number of genes which gives the maximal accuracy starting with the most frequently selected gene. The identity of the individual genes in this panel is not fixed, since the order reflects the number of times a given gene was selected in the top 100 informative genes and this order is subject to some variation.
A. Biomarker Selection.
Genes which score highest (by SVM) in discriminating cancerous tumors from benign nodules were examined for their utility for clinical tests. Factors considered include, higher differences in expression levels between classes, and low variability within classes. When selecting biomarkers for validation an effort was made to select genes with distinct expression profiles to avoid selection of correlated genes and to identify genes with differential expression levels that were robust by alternative techniques including PCR and/or immuno-histochemistry.
B. Validation.
Three methods of validation were considered.
Cross-Validation: To minimize over-fitting within a dataset, K-fold cross-validation (K usually equal to 10) was used, when the dataset is split on K parts randomly and K−1 parts were used for training and 1 for testing. Thus, for K=10 the algorithm was trained on a random selection of 90% of the patients and 90% of the controls and then tested on the remaining 10%. This was repeated until all of the samples have been employed as test subjects and the cumulated classifier makes use of all of the samples, but no sample is tested using a training set of which it is a part. To reduce the randomization impact, K-fold separation was performed M times producing different combinations of patients and controls in each of K folds each time. Therefore, for individual dataset M*K rounds of permuted selection of training and testing sets were used for each set of genes.
Independent Validation: To estimate the reproducibility of the data and the generality of the classifier, one needs to examine the classifier that was built using one dataset and tested using another dataset to estimate the performance of the classifier. To estimate the performance, validation on the second set was performed using the classifier developed with the original dataset.
Resampling (permutation): To demonstrate dependence of the classifier on the disease state, patients and controls from the dataset were chosen at random (permuted) and the classification was repeated. The accuracy of classification using randomized samples was compared to the accuracy of the developed classifier to determine the p value for the classifier, i.e., the possibility that the classifier might have been chosen by chance. In order to test the generality of a classifier developed in this manner, it was used to classify independent sets of samples that were not used in developing the classifier. The cross-validation accuracies of the permuted and original classifier were compared on independent test sets to confirm its validity in classifying new samples.
C. Classifier Performance
Performance of each classifier was estimated by different methods and several performance measurements were used for comparing classifiers between each other. These measurements include accuracy, area under ROC curve, sensitivity, specificity, true positive rate and true negative rate. Based on the required properties of the classification of interest, different performance measurements can be used to pick the optimal classifier, e.g. classifier to use in screening of the whole population would require better specificity to compensate for small (˜1%) prevalence of the disease and therefore avoid large number of false positive hits, while a diagnostic classifier of patients in hospital should be more sensitive.
For diagnosing cancerous tumors from benign nodules, higher sensitivity is more desirable than specificity, as the patients are already at high risk.
Peripheral blood samples were all collected in PAXgene RNA stabilizations tubes and RNA was extracted according to the manufacturer. Samples were tested on a Nanostring nCounter™ (as described above) against a custom panel of 559 probes (Table III). In addition, they were tested against a 100 probe subset of 559 marker panel.
For the 559 Classifier, 432 were selected based on previous microarray data, 107 probes were selected from Nanostring studies and 20 were housekeeping genes. We analyzed 610 PAXgene RNA samples (278 cancers, 332 controls) derived from 5 collection sites. For QC, a Universal RNA standard (Agilent) was included in each batch of 36 samples tested. Probe expression values were normalized using the 20 housekeeping genes as well as spike-in positive and negative controls supplied by Nanostring (included in classifier). Zscores were calculated for probe count values and served as the input to a Support Vector Machine (SVM) classifier using a polynomial kernel. Classification performance was evaluated by 10-fold cross-validation of the samples.
A. 559 Classifier
As shown in
When nodule classification accuracy is assessed by size without using a specific threshold for sensitivity, we find that as nodules size and the cancer risk factor increases, the number of benign nodules classified as cancer increases.
A second set of nodules was tested and the accuracy of the classifier for size groups was determined by sample group (cancer vs benign nodule). Similarly, as nodule size and the cancer risk factor increases, the number of benign nodules classified as cancer increases (
Since classification accuracy was found to be negatively correlated with benign nodule size, we reanalyzed the data using only nodules <10 mm (n=244) (
B. 100 Marker Classifier
We now reanalyzed the data from the 633 samples analyzed by W559 on the Nanostring platform in order to identify the minimal number of probes required to maintain performance attained with the whole panel. We used SVM-RFE for probe selection as previously described. We used 75% of the data for the training set with SVM-RFE and the tested the performance of top 100 probes (Table II) selected by this process on an independent testing set composed of 25% of the samples. Samples were randomly selected for training and testing sets Table VI below. The accuracy obtained on the testing set is shown in
Each and every patent, patent application, and publication, including the priority application, U.S. Provisional Patent Application No. 62/352,865, filed Jun. 21, 2017, and publically available gene sequence cited throughout the disclosure is expressly incorporated herein by reference in its entirety. While this invention has been disclosed with reference to specific embodiments, it is apparent that other embodiments and variations of this invention are devised by others skilled in the art without departing from the true spirit and scope of the invention. The appended claims include such embodiments and equivalent variations.
This invention was made with government support under Grant No. CA010815 awarded by the National Institutes of Health. The government has certain rights in the invention.
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| PCT/US2017/038571 | 6/21/2017 | WO |
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| WO2017/223216 | 12/28/2017 | WO | A |
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