Patent Application
20230348986
Analysis of cell-free nucleic acids, such as cell-free deoxyribonucleic acid (cfDNA) and cell-free ribonucleic acid (cfRNA) is an important marker for a range of conditions including determining the health of an ongoing pregnancy and cancer detection, allowing non-invasive monitoring of these and other conditions.
In an aspect, there are provided, methods for nucleic acid processing or analysis. In some cases, the method comprises (a) generating a mixture comprising (i) a first plurality of nucleic acid molecules derived from a biological sample of a subject, and (ii) a second plurality of nucleic acid molecules comprising sequences having at least one predetermined size; (b) subjecting the (i) first plurality of nucleic acid molecules, or derivative thereof; and (ii) second plurality of nucleic acid molecules or derivative thereof, to sequencing to generate a plurality of sequence reads; and (c) processing the plurality of sequence reads to identify (i) a first set of sequence reads corresponding to at least a subset of the first plurality of nucleic acid molecules, and (ii) a second set of sequence reads corresponding to at least a subset of the second plurality of nucleic acid molecules, which second set of sequence reads corresponds to the sequences having the at least one predetermined size; and (d) using the second set of sequence reads to identify one or more nucleic acid molecules of the first plurality of nucleic acid molecules as having the at least one predetermined size. In some cases, the method comprises subsequent to (a) using the first plurality of nucleic acid molecules and the second plurality of nucleic acid molecules to generate a third plurality of nucleic acid molecules. In some cases, generating the third plurality of nucleic acid molecules comprises ligating ends of a nucleic acid molecule of the first or second plurality of nucleic acid molecules, or a derivative thereof, to one another. In some cases, generating the third plurality of nucleic acid molecules comprises coupling an adapter to a 3′ end, a 5′ end or both a 5′ end and a 3′ end of a nucleic acid molecule of the first or second plurality of nucleic acid molecules, or a derivative thereof. In some cases, the method comprises subsequent to (b) subjecting a nucleic acid molecule of the first plurality of nucleic acid molecules or the second plurality of nucleic acid molecules, or a derivative thereof, to nucleic acid amplification to generate a plurality of amplification products, wherein (b) comprises subjecting the plurality of amplification products or derivatives thereof to sequencing to generate a plurality of sequence reads. In some cases, the nucleic acid amplification is effected by a polymerase having strand-displacement activity. In some cases, the nucleic acid amplification is effected by a polymerase that does not have strand-displacement activity. In some cases, the nucleic acid amplification comprises contacting the nucleic acid molecule of the first plurality of nucleic acid molecules or the second plurality of nucleic acid molecules, or a derivative thereof, to an amplification reaction mixture comprising random primers. In some cases, the nucleic acid amplification comprises contacting the nucleic acid molecule of the first plurality of nucleic acid molecules or the second plurality of nucleic acid molecules, or a derivative thereof, or a derivative thereof, to an amplification reaction mixture comprising one or more primers, each of which specifically hybridizes to a different target sequence via sequence complementarity. In some cases, the second plurality of nucleic acid molecules comprises (i) a 5′ common sequence, (ii) a 3′ common sequence, or (iii) a 5′ common sequence and a 3′ common sequence. In some cases, the second plurality of nucleic acid molecules comprises a fixed molar ratio of nucleic acid molecules of each predetermined size. In some cases, the method further comprises using the second set of sequence reads to normalize a molar ratio of the first plurality of nucleic acid molecules of each predetermined size. In some cases, (c) further comprises processing the plurality of sequence reads to determine a size for at least a subset of the first or second plurality of nucleic acid molecules. In some cases, the first or second plurality of nucleic acid molecules is single stranded. In some cases, the first plurality of nucleic acid molecules of the biological sample comprises cell-free deoxyribonucleic acid (DNA) or cell-free ribonucleic acid (RNA). In some cases, the first plurality of nucleic acid molecules of the biological sample is from a tumor. In some cases, the sequencing comprises a method selected from one or more of sequencing by synthesis, sequencing by ligation, nanopore sequencing, nanoball sequencing, ion detection, sequencing by hybridization, polymerized colony (POLONY) sequencing, nanogrid rolling circle sequencing (ROLONY), and ion torrent sequencing. In some cases, the biological sample comprises a bodily fluid. In some cases, the bodily fluid is urine, saliva, blood, serum, plasma, tears, sputum, cerebrospinal fluid, synovial fluid, mucus, bile, semen, lymph, amniotic fluid, menstrual fluid, or combinations thereof. In some cases, the biological sample is a cell-free biological sample. In some cases, the method further comprises, subsequent to (d) using the second set of sequence reads to normalize the one or more nucleic acid molecules of the first plurality of nucleic acid molecules having the at least one predetermined size. In some cases, the method further comprises processing the first set of sequence reads with a reference set of sequence reads to identify a change in the first set of sequence reads thereby determining that a subject has or is at risk of having a disease. In some cases, the disease is cancer. In some cases, the cancer is selected from the group consisting of colon cancer, non-small cell lung cancer, small cell lung cancer, breast cancer, hepatocellular carcinoma, liver cancer, skin cancer, malignant melanoma, endometrial cancer, esophageal cancer, gastric cancer, ovarian cancer, pancreatic cancer, brain cancer, leukemia, lymphoma, and myeloma. In some cases, the method further comprises using the first set of sequence reads to output an electronic report indicating that the subject has or is at risk of having a disease. In some cases, the method further comprises using the first set of sequence reads to provide a therapeutic intervention to the subject for a disease. In some cases, the method further comprises using the first set of sequence reads to treat the subject for the disease. In some cases, the subject is treated by administering a chemotherapy or immunotherapy to the subject. In some cases, the disease is cancer. In some cases, the method further comprises using the first set of sequence reads to monitor the subject for a progression or regression of the disease. In some cases, the second plurality of nucleic acid molecules comprises sequences having at least two predetermined sizes.
In another aspect, there are provided systems for nucleic acid processing or analysis. In some cases, systems comprise: (a) a computer configured to receive a user request to perform nucleic acid processing or analysis on a biological sample of a subject; (b) a mixing unit that generates a mixture comprising (i) a first plurality of nucleic acid molecules derived from the biological sample of the subject and (ii) a second plurality of nucleic acid molecules comprising sequences having at least one predetermined size; (c) a sequencing unit that subjects (i) the first plurality of nucleic acid molecules or derivative thereof and (ii) the second plurality of nucleic acid molecules or derivative thereof to sequencing to generate a plurality of sequence reads; (e) a processing unit that processes the plurality of sequence reads to identify (i) a first set of sequence reads corresponding to at least a subset of the first plurality of nucleic acid molecules, and (ii) a second set of sequence reads corresponding to at least a subset of the second plurality of nucleic acid molecules, which second set of sequence reads corresponds to the sequences having the at least one predetermined size; and using the second set of sequence reads to identify one or more nucleic acid molecules of the first plurality of nucleic acid molecules as having at least one predetermined size; and (f) a report generator that sends a report to a recipient, wherein the report contains the one or more nucleic acid molecules of the first plurality of nucleic acid molecules having the at least one predetermined size.
Another aspect of the present disclosure provides a non-transitory computer readable medium comprising machine executable code that, upon execution by one or more computer processors, implements any of the methods above or elsewhere herein.
Another aspect of the present disclosure provides a system comprising one or more computer processors and computer memory coupled thereto. The computer memory comprises machine executable code that, upon execution by the one or more computer processors, implements any of the methods above or elsewhere herein.
Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only illustrative embodiments of the present disclosure are shown and described. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.
All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. To the extent publications and patents or patent applications incorporated by reference contradict the disclosure contained in the specification, the specification is intended to supersede and/or take precedence over any such contradictory material.
The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings (also “Figure” and “FIG.” herein), of which:
While various embodiments of the invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions may occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed.
Whenever the term “at least,” “greater than,” or “greater than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “at least,” “greater than” or “greater than or equal to” applies to each of the numerical values in that series of numerical values. For example, greater than or equal to 1, 2, or 3 is equivalent to greater than or equal to 1, greater than or equal to 2, or greater than or equal to 3.
Whenever the term “no more than,” “less than,” or “less than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “no more than,” “less than,” or “less than or equal to” applies to each of the numerical values in that series of numerical values. For example, less than or equal to 3, 2, or 1 is equivalent to less than or equal to 3, less than or equal to 2, or less than or equal to 1.
As used herein, the term “about” or “approximately” means within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which may depend in part on how the value is measured or determined, i.e., the limitations of the measurement system. For example, “about” can mean within 1 or more than 1 standard deviation, per the practice in the art. As another example, “about” can mean a range of up to 20%, up to 10%, up to 5%, or up to 1% of a given value. With respect to biological systems or processes, the term “about” can mean within an order of magnitude, such as within 5-fold or within 2-fold of a value. Where particular values are described in the application and claims, unless otherwise stated, the term “about” means within an acceptable error range for the particular value.
As used herein, the terms “polynucleotide”, “nucleotide”, “nucleotide sequence”, “nucleic acid” and “oligonucleotide” generally refer to a polymeric form of nucleotides of any length, either deoxyribonucleotides or ribonucleotides, or analogs thereof. Polynucleotides may have any three-dimensional structure, and may perform any function, known or unknown. The following are non-limiting examples of polynucleotides: cell-free nucleic acids, cell-free DNA (cfDNA), circulating tumor DNA (ctDNA), coding or non-coding regions of a gene or gene fragment, loci (locus) defined from linkage analysis, exons, introns, messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA), short interfering RNA (siRNA), short-hairpin RNA (shRNA), micro-RNA (miRNA), ribozymes, cDNA, recombinant polynucleotides, branched polynucleotides, plasmids, vectors, isolated DNA of any sequence, isolated RNA of any sequence, nucleic acid probes, and primers. A polynucleotide may comprise one or more modified nucleotides, such as methylated nucleotides and nucleotide analogs. If present, modifications to the nucleotide structure may be imparted before or after assembly of the polymer. The sequence of nucleotides may be interrupted by non-nucleotide components. A polynucleotide may be further modified after polymerization, such as by conjugation with a labeling component.
The term “subject” as used herein, generally refers to an individual, such as a vertebrate. A vertebrate may be a mammal (e.g., a human). Mammals include, but are not limited to, murines, simians, humans, farm animals, sport animals, and pets. Tissues, cells, and their progeny of a biological entity obtained in vivo or cultured in vitro are also encompassed. The subject may be a patient. The subject may be symptomatic with respect to a disease (e.g., cancer). As an alternative, the subject may be asymptomatic with respect to the disease.
The term “sample,” as used herein, generally refers to a sample derived from or obtained from a subject, such as a mammal (e.g., a human). The sample may be a biological sample. Samples may include, but are not limited to, hair, finger nails, skin, sweat, tears, ocular fluids, nasal swab or nasopharyngeal wash, sputum, throat swab, saliva, mucus, blood, serum, plasma, placental fluid, amniotic fluid, cord blood, emphatic fluids, cavity fluids, earwax, oil, glandular secretions, bile, lymph, pus, microbiota, meconium, breast milk, bone marrow, bone, CNS tissue, cerebrospinal fluid, adipose tissue, synovial fluid, stool, gastric fluid, urine, semen, vaginal secretions, stomach, small intestine, large intestine, rectum, pancreas, liver, kidney, bladder, lung, and other tissues and fluids derived from or obtained from a subject. The biological sample may be a cell-free (or cell free) biological sample.
The term “cell-free,” as used herein, generally refers to a sample derived from or obtained from a subject that is free from cells. Cell-free biological samples may include, but are not limited to, blood, serum, plasma, nasal swab or nasopharyngeal wash, saliva, urine, gastric fluid, tears, stool, mucus, sweat, earwax, oil, glandular secretion, bile, lymph, cerebrospinal fluid, tissue, semen, vaginal fluid, interstitial fluids, including interstitial fluids derived from tumor tissue, ocular fluids, spinal fluid, throat swab, breath, hair, finger nails, skin, biopsy, placental fluid, amniotic fluid, cord blood, emphatic fluids, cavity fluids, sputum, pus, microbiota, meconium, breast milk and/or other excretions.
Methods and systems for nucleic acid processing or analysis provided herein enable normalizing the amount of nucleic acid molecules having a given size in a sample by using synthetic nucleic acid standards that are added to the sample before library construction. When the library is processed to determine sizes of the nucleic acid molecules and the amount of nucleic acid molecules at each size the amount of these synthetic standards can be used to normalize the amount of sample nucleic acid molecules present. This can be especially helpful in cases when nucleic acid molecules of certain sizes are more prone to loss or degradation.
Provided herein are methods for nucleic acid processing or analysis, such as normalizing the amount of nucleic acid molecules of a certain size in a mixture of nucleic acids. Such methods of nucleic acid processing may comprise generating a mixture comprising a first plurality of nucleic acid molecules derived from a cell-free biological sample of a subject, and a second plurality of nucleic acid molecules comprising sequences having at least one predetermined size. Next, the first plurality of nucleic acid molecules or derivative thereof and second plurality of nucleic acid molecules or derivative thereof are subjected to sequencing to generate a plurality of sequence reads. Then the plurality of sequence reads are processed to identify a first set of sequence reads corresponding to at least a subset of the first plurality of nucleic acid molecules, and a second set of sequence reads corresponding to at least a subset of the second plurality of nucleic acid molecules, which second set of sequence reads corresponds to the sequences having the at least two predetermined sizes. Next, one or more nucleic acid molecules of the first plurality of nucleic acid molecules are identified as having at least one predetermined size using the second set of sequence reads. In some cases, the second plurality of nucleic acid molecules comprises sequences having at least two or more independent sizes.
In an aspect of methods of nucleic acid processing or analysis herein, methods may further comprise using the first plurality of nucleic acid molecules and the second plurality of nucleic acid molecules to generate a third plurality of nucleic acid molecules subsequent to generating the mixture comprising the first plurality of nucleic acid molecules and the second plurality of nucleic acid molecules. Generating the third plurality of nucleic acid molecules may comprise ligating ends of a nucleic acid molecule of the first or second plurality of nucleic acid molecules, or a derivative thereof, to one another. Alternatively, generating the third plurality of nucleic acid molecules comprises coupling an adapter to a 3′ end, a 5′ end or both a 5′ end and a 3′ end of a nucleic acid molecule of the or second plurality of nucleic acid molecules, or a derivative thereof.
In an aspect of methods of nucleic acid processing or analysis herein, methods may further comprise subjecting a nucleic acid molecule of the first plurality of nucleic acid molecules or the second plurality of nucleic acid molecules, or a derivative thereof, to nucleic acid amplification to generate a plurality of amplification products, wherein sequencing comprises subjecting the plurality of amplification products or derivatives thereof to sequencing to generate a plurality of sequence reads. Nucleic acid amplification may be effected by a polymerase having strand-displacement activity. Alternatively, or in combination, nucleic acid amplification may be effected by a polymerase that does not have strand-displacement activity. In some cases, the nucleic acid amplification comprises contacting the nucleic acid molecule of the first plurality of nucleic acid molecules or the second plurality of nucleic acid molecules, or a derivative thereof, to an amplification reaction mixture comprising random primers. In some cases, the nucleic acid amplification comprises contacting the nucleic acid molecule of the first plurality of nucleic acid molecules or the second plurality of nucleic acid molecules, or a derivative thereof, or a derivative thereof, to an amplification reaction mixture comprising one or more primers, each of which specifically hybridizes to a different target sequence via sequence complementarity.
In an aspect of methods of nucleic acid processing or analysis herein the second plurality of nucleic acid molecules comprises a 5′ common sequence, a 3′ common sequence, or a 5′ common sequence and a 3′ common sequence. In some cases, the common sequence comprises an adapter. In some cases, the common sequence comprises a restriction enzyme recognition site. In some cases, the common sequence comprises a probe binding site. In some cases, the common sequence comprises a primer binding site, such as a sequencing primer binding site.
In another aspect of methods of nucleic acid processing or analysis herein the second plurality of nucleic acid molecules comprises an equimolar amount of nucleic acid molecules of each predetermined size. In some cases, the second plurality of nucleic acids comprises an equimolar amount of nucleic acid molecules of one predetermined size. In some cases, the second plurality of nucleic acids comprises an equimolar amount of nucleic acid molecules of two predetermined sizes. In some cases, the second plurality of nucleic acids comprises an equimolar amount of nucleic acid molecules of three predetermined sizes. In some cases, the second plurality of nucleic acids comprises an equimolar amount of nucleic acid molecules of four predetermined sizes. In some cases, the second plurality of nucleic acids comprises an equimolar amount of nucleic acid molecules of five predetermined sizes. In some cases, the second plurality of nucleic acids comprises an equimolar amount of nucleic acid molecules of six predetermined sizes. In some cases, the second plurality of nucleic acids comprises an equimolar amount of nucleic acid molecules of seven predetermined sizes. In some cases, the second plurality of nucleic acids comprises an equimolar amount of nucleic acid molecules of eight predetermined sizes. In some cases, the second plurality of nucleic acids comprises an equimolar amount of nucleic acid molecules of nine predetermined sizes. In some cases, the second plurality of nucleic acids comprises an equimolar amount of nucleic acid molecules of ten predetermined sizes. In some cases, each nucleic acid molecule of the second plurality of nucleic acid molecules has a sequence specific for its predetermined size.
In another aspect of methods of nucleic acid processing or analysis provided herein processing the plurality of sequence reads may comprise processing the plurality of sequence reads to determine a size for at least a subset of the first or second plurality of nucleic acid molecules.
In an aspect of methods of nucleic acid processing or analysis provided herein, the first or second plurality of nucleic acid molecules may be single stranded. In some cases, the first or second plurality of nucleic acids is double stranded. In some cases, the first or second plurality of nucleic acid molecules is processed to obtain single stranded nucleic acids. In some cases, the first plurality of nucleic acid molecules of the cell-free biological sample comprises cell-free deoxyribonucleic acid (DNA) or cell-free ribonucleic acid (RNA). In some cases, the first plurality of nucleic acid molecules of the cell-free biological sample comprises cell-free deoxyribonucleic acid (DNA) and cell-free ribonucleic acid (RNA).
In an aspect of methods of nucleic acid processing or analysis provided herein, sequencing may comprise a method selected from one or more of sequencing by synthesis, sequencing by ligation, nanopore sequencing, nanoball sequencing, ion detection, sequencing by hybridization, polymerized colony (POLONY) sequencing, nanogrid rolling circle sequencing (ROLONY), and ion torrent sequencing. In some cases, sequencing comprises any sequencing method described herein.
In an aspect of methods of nucleic acid processing or analysis provided herein, the first plurality of nucleic acid molecules of the cell-free biological sample is from a tumor. In some cases, the first plurality of nucleic acid molecules of the cell-free biological sample is from a blood cancer.
In an aspect of methods of nucleic acid processing or analysis provided herein, the cell-free biological sample may comprise a bodily fluid. In some cases, the bodily fluid is urine, saliva, blood, serum, plasma, tears, sputum, cerebrospinal fluid, synovial fluid, mucus, bile, semen, lymph, amniotic fluid, menstrual fluid, or combinations thereof.
In an aspect of methods of nucleic acid processing or analysis provided herein, the method may further comprise using the second set of sequence reads to normalize the one or more nucleic acid molecules of the first plurality of nucleic acid molecules having the at least one predetermined size. In some cases, the second set of sequence reads shows a decrease in nucleic acid molecules having a first size compared with nucleic acid molecules having a second size and the amount of the first plurality of nucleic acid molecules having that predetermined size is adjusted to account for that decrease.
In an aspect of methods of nucleic acid processing or analysis provided herein, the method may comprise processing the first set of sequence reads with a reference set of sequence reads to identify a change in the first set of sequence reads thereby determining that a subject has or is at risk of having a disease. In some cases, the disease is cancer. In some cases, the cancer is selected from the group consisting of colon cancer, non-small cell lung cancer, small cell lung cancer, breast cancer, hepatocellular carcinoma, liver cancer, skin cancer, malignant melanoma, endometrial cancer, esophageal cancer, gastric cancer, ovarian cancer, pancreatic cancer, brain cancer, leukemia, lymphoma, and myeloma. In some cases, the cancer is any cancer disclosed herein.
In an aspect of methods of nucleic acid processing or analysis provided herein, the method may further comprise using the first set of sequence reads to output an electronic report indicating that the subject has or is at risk of having a disease. In some cases, the method may further comprise using the first set of sequence reads to provide a therapeutic intervention to the subject for a disease. In some cases, the method may further comprise using the first set of sequence reads to treat the subject for the disease. In some cases, the subject is treated by administering a chemotherapy or immunotherapy to the subject. In some cases, disease is cancer, such as any cancer described herein. In some cases, the method further comprises using the first set of sequence reads to monitor the subject for a progression or regression of the disease.
An example method is diagrammed in
In an aspect, there are provided systems for nucleic acid processing or analysis comprising. Systems herein may comprise a computer configured to receive a user request to perform nucleic acid processing or analysis on a cell-free biological sample of a subject. The system may further comprise a mixing unit that generates a mixture comprising a first plurality of nucleic acid molecules derived from the cell-free biological sample of the subject and a second plurality of nucleic acid molecules comprising sequences having at least one predetermined size. The system may also comprise a sequencing unit that subjects the first plurality of nucleic acid molecules and second plurality of nucleic acid molecules or derivatives thereof to sequencing to generate a plurality of sequence reads. The system may also comprise a processing unit that processes the plurality of sequence reads to identify a first set of sequence reads corresponding to at least a subset of the first plurality of nucleic acid molecules, and a second set of sequence reads corresponding to at least a subset of the second plurality of nucleic acid molecules, which second set of sequence reads corresponds to the sequences having the at least one predetermined size; and using the second set of sequence reads to identify one or more nucleic acid molecules of the first plurality of nucleic acid molecules as having at least one predetermined size. In addition, the system may comprise a report generator that sends a report to a recipient, wherein the report contains the one or more nucleic acid molecules of the first plurality of nucleic acid molecules having the at least one predetermined size. In some cases, the second plurality of nucleic acid molecules comprises sequences having at least two or more independent sizes.
Computer systems are provided herein that are programmed to implement methods of the disclosure.
The computer system 101 includes a central processing unit (CPU, also “processor” and “computer processor” herein) 105, which can be a single core or multi core processor, or a plurality of processors for parallel processing. The computer system 101 also includes memory or memory location 110 (e.g., random-access memory, read-only memory, flash memory), electronic storage unit 115 (e.g., hard disk), communication interface 120 (e.g., network adapter) for communicating with one or more other systems, and peripheral devices 125, such as cache, other memory, data storage and/or electronic display adapters. The memory 110, storage unit 115, interface 120 and peripheral devices 125 are in communication with the CPU 105 through a communication bus (solid lines), such as a motherboard. The storage unit 115 can be a data storage unit (or data repository) for storing data. The computer system 101 can be operatively coupled to a computer network (“network”) 130 with the aid of the communication interface 120. The network 130 can be the Internet, an internet and/or extranet, or an intranet and/or extranet that is in communication with the Internet. The network 130 in some cases is a telecommunication and/or data network. The network 130 can include one or more computer servers, which can enable distributed computing, such as cloud computing. The network 130, in some cases with the aid of the computer system 101, can implement a peer-to-peer network, which may enable devices coupled to the computer system 101 to behave as a client or a server.
The CPU 105 can execute a sequence of machine-readable instructions, which can be embodied in a program or software. The instructions may be stored in a memory location, such as the memory 110. The instructions can be directed to the CPU 105, which can subsequently program or otherwise configure the CPU 105 to implement methods of the present disclosure. Examples of operations performed by the CPU 105 can include fetch, decode, execute, and writeback.
The CPU 105 can be part of a circuit, such as an integrated circuit. One or more other components of the system 101 can be included in the circuit. In some cases, the circuit is an application specific integrated circuit (ASIC).
The storage unit 115 can store files, such as drivers, libraries and saved programs. The storage unit 115 can store user data, e.g., user preferences and user programs. The computer system 101 in some cases can include one or more additional data storage units that are external to the computer system 101, such as located on a remote server that is in communication with the computer system 101 through an intranet or the Internet.
The computer system 101 can communicate with one or more remote computer systems through the network 130. For instance, the computer system 101 can communicate with a remote computer system of a user (e.g., a laboratory technician or a healthcare provider). Examples of remote computer systems include personal computers (e.g., portable PC), slate or tablet PC's (e.g., Apple® iPad, Samsung® Galaxy Tab), telephones, Smart phones (e.g., Apple® iPhone, Android-enabled device, Blackberry®), or personal digital assistants. The user can access the computer system 101 via the network 130.
Methods as described herein can be implemented by way of machine (e.g., computer processor) executable code stored on an electronic storage location of the computer system 101, such as, for example, on the memory 110 or electronic storage unit 115. The machine executable or machine readable code can be provided in the form of software. During use, the code can be executed by the processor 105. In some cases, the code can be retrieved from the storage unit 115 and stored on the memory 110 for ready access by the processor 105. In some situations, the electronic storage unit 115 can be precluded, and machine-executable instructions are stored on memory 110.
The code can be pre-compiled and configured for use with a machine having a processer adapted to execute the code, or can be compiled during runtime. The code can be supplied in a programming language that can be selected to enable the code to execute in a pre-compiled or as-compiled fashion.
Aspects of the systems and methods provided herein, such as the computer system 101, can be embodied in programming. Various aspects of the technology may be thought of as “products” or “articles of manufacture” typically in the form of machine (or processor) executable code and/or associated data that is carried on or embodied in a type of machine readable medium. Machine-executable code can be stored on an electronic storage unit, such as memory (e.g., read-only memory, random-access memory, flash memory) or a hard disk. “Storage” type media can include any or all of the tangible memory of the computers, processors or the like, or associated modules thereof, such as various semiconductor memories, tape drives, disk drives and the like, which may provide non-transitory storage at any time for the software programming. All or portions of the software may at times be communicated through the Internet or various other telecommunication networks. Such communications, for example, may enable loading of the software from one computer or processor into another, for example, from a management server or host computer into the computer platform of an application server. Thus, another type of media that may bear the software elements includes optical, electrical and electromagnetic waves, such as used across physical interfaces between local devices, through wired and optical landline networks and over various air-links. The physical elements that carry such waves, such as wired or wireless links, optical links or the like, also may be considered as media bearing the software. As used herein, unless restricted to non-transitory, tangible “storage” media, terms such as computer or machine “readable medium” refer to any medium that participates in providing instructions to a processor for execution.
Hence, a machine readable medium, such as computer-executable code, may take many forms, including but not limited to, a tangible storage medium, a carrier wave medium or physical transmission medium. Non-volatile storage media include, for example, optical or magnetic disks, such as any of the storage devices in any computer(s) or the like, such as may be used to implement the databases, etc. shown in the drawings. Volatile storage media include dynamic memory, such as main memory of such a computer platform. Tangible transmission media include coaxial cables; copper wire and fiber optics, including the wires that comprise a bus within a computer system. Carrier-wave transmission media may take the form of electric or electromagnetic signals, or acoustic or light waves such as those generated during radio frequency (RF) and infrared (IR) data communications. Common forms of computer-readable media therefore include for example: a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD or DVD-ROM, any other optical medium, punch cards paper tape, any other physical storage medium with patterns of holes, a RAM, a ROM, a PROM and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave transporting data or instructions, cables or links transporting such a carrier wave, or any other medium from which a computer may read programming code and/or data. Many of these forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to a processor for execution.
The computer system 101 can include or be in communication with an electronic display 135 that comprises a user interface (UI) 140 for providing, for example, normalized results according to methods of the present disclosure. Examples of UI's include, without limitation, a graphical user interface (GUI) and web-based user interface.
Methods and systems of the present disclosure can be implemented by way of one or more algorithms. An algorithm can be implemented by way of software upon execution by the central processing unit 105. The algorithm can be, for example, a trained algorithm (or trained machine learning algorithm), such as, for example, a support vector machine or neural network.
Methods herein may comprise amplification of polynucleotides present in a sample from a subject. Methods of amplification used herein may comprise rolling-circle amplification. Alternatively or in combination, methods of amplification used herein may comprise PCR. In some cases, methods of amplification herein comprise linear amplification. In some cases, amplification is not targeted to one gene or set of genes and the entire nucleic acid sample is amplified. In some cases, the method comprises circularizing individual polynucleotides of the plurality to form a plurality of circular polynucleotides, each of which having a junction between the 5′ end and the 3′ end and amplifying the circular polynucleotides of to produce amplified polynucleotides. In additional cases, methods of amplification comprise shearing the amplified polynucleotides to produce sheared polynucleotides, each sheared polynucleotide comprising one or more shear points at a 5′ end and/or 3′ end. In some cases, the method comprises enriching for a target sequence or a plurality of target sequences. In some cases, the method does not comprise enriching for a target sequence. In some cases, the method does not comprise aligning or mapping a cfDNA polynucleotide sequence to a reference genome.
In general, joining ends of a polynucleotide to one-another to form a circular polynucleotide (either directly, or with one or more intermediate adapter oligonucleotides) produces a junction having a junction sequence. Where the 5′ end and 3′ end of a polynucleotide are joined via an adapter polynucleotide, the term “junction” can refer to a junction between the polynucleotide and the adapter (e.g. one of the 5′ end junction or the 3′ end junction), or to the junction between the 5′ end and the 3′ end of the polynucleotide as formed by and including the adapter polynucleotide. Where the 5′ end and the 3′ end of a polynucleotide are joined without an intervening adapter (e.g. the 5′ end and 3′ end of a single-stranded DNA), the term “junction” refers to the point at which these two ends are joined. A junction may be identified by the sequence of nucleotides comprising the junction (also referred to as the “junction sequence”).
In some embodiments, samples comprise polynucleotides having a mixture of ends formed by natural degradation processes (such as cell lysis, cell death, and other processes by which polynucleotides such as DNA and RNA are released from a cell to its surrounding environment in which it may be further degraded, e.g., cell-free polynucleotides, e.g., cell-free DNA and cell-free RNA). Where polynucleotide ends are joined without an intervening adapter, a junction sequence may be identified by alignment to a reference sequence. For example, where the order of two component sequences appears to be reversed with respect to the reference sequence, the point at which the reversal appears to occur may be an indication of a junction at that point. Where polynucleotide ends are joined via one or more adapter sequences, a junction may be identified by proximity to the known adapter sequence, or by alignment as above if a sequencing read is of sufficient length to obtain sequence from both the 5′ and 3′ ends of the circularized polynucleotide.
In some embodiments, circularizing individual polynucleotides is effected by subjecting the plurality of polynucleotides to a ligation reaction. The ligation reaction may comprise a ligase enzyme. In some embodiments, the ligase enzyme is degraded prior to amplifying. Degradation of ligase prior to amplifying can increase the recovery rate of amplifiable polynucleotides. In some embodiments, the plurality of circularized polynucleotides is not purified or isolated prior to amplification. In some embodiments, uncircularized, linear polynucleotides are degraded prior to amplifying.
Polynucleotides (e.g., polynucleotides from a sample) may be enriched prior to circularization. This may be performed using target specific primers. Alternatively, this may be performed using capture sequences, such as pull-down probes or capture sequences attached to a substrate (e.g., pull-down probes or capture sequences attached to an array or beads). Bait sets may be used to enrich for target-specific sequences before circularization.
In some cases, circularizing in comprises the operation of joining and adapter polynucleotide to the 5′ end, the 3′ end, or both the 5′ end and the 3′ end of a polynucleotide in the plurality of polynucleotides. As previously described, where the 5′ end and/or 3′ end of a polynucleotide are joined via an adapter polynucleotide, the term “junction” can refer to the junction between the polynucleotide and the adapter (e.g., one of the 5′ end junction or the 3′ end junction), or to the junction between the 5′ end and the 3′ end of the polynucleotide as formed by and including the adapter polynucleotide.
The circularized polynucleotides can be amplified, for example, after degradation of the ligase enzyme, to yield amplified polynucleotides. Amplifying the circular polynucleotides can be effected by a polymerase. In some cases, the polymerase is a polymerase having strand-displacement activity. In some cases, the polymerase is a Phi29 DNA polymerase. Alternatively, the polymerase is a polymerase that does not have strand-displacement activity. In some cases, the polymerase is a T4 DNA polymerase or a T7 DNA polymerase. Alternately or in combination, the polymerase is a Taq polymerase, or polymerase in the Taq polymerase family. In some cases, amplification comprises rolling circle amplification (RCA). The amplified polynucleotides resulting from RCA can comprise linear concatemers, or polynucleotides comprising more than one copy of a target sequence (e.g., subunit sequence) from a template polynucleotide. In some embodiments, amplifying comprises subjecting the circular polynucleotides to an amplification reaction mixture comprising random primers. In some embodiments, amplifying comprises subjecting the circular polynucleotides to an amplification reaction mixture comprising targeted primers. Alternatively, the circular polynucleotides may be amplified in an untargeted manner and enriched for one or more target sequences after amplification. In some cases, amplifying comprises subjecting the circular polynucleotides to an amplification reaction mixture comprising one or more primers, each of which specifically hybridizes to a different target sequence via sequence complementarity. In some cases, amplifying comprises subjecting the circular polynucleotides to an amplification reaction mixture comprising inverse primers.
The amplified polynucleotides are sheared, in some cases, to produce sheared polynucleotides that are shorter in length relative to the unsheared polynucleotides. Two or more sheared polynucleotides originating from the same linear concatemer may have the same junction sequence but can have different 5′ and/or 3′ ends (e.g., shear ends).
Amplified polynucleotides can be sheared using any variety of methods, such as, but not limited to, physical fragmentation, enzymatic methods, and chemical fragmentation. Non-limiting examples of physical fragmentation methods that can be employed for the fragmentation of amplified polynucleotides include acoustic shearing, sonication, and hydrodynamic shearing. In some cases, acoustic shearing and sonication may be used. Non-limiting examples of enzymatic fragmentation methods that can be employed for the fragmentation of amplified polynucleotides include use of enzymes such as DNase I and other restriction endonucleases, including non-specific nucleases, and transposases. Non-limiting examples of chemical fragmentation methods that can be employed for the fragmentation of amplified polynucleotides include use of heat and divalent metal cations.
Sheared polynucleotides (also referred to as fragmented polynucleotides) which are shorter in length compared to the unsheared polynucleotides may be desired to match the capabilities of the sequencing instrument used for producing sequencing reads, also referred to as sequence reads. For example, amplified polynucleotides may be fragmented, for example sheared, to the optimal length determined by the downstream sequencing platform. Various sequencing instruments, further described herein, can accommodate nucleic acids of different lengths. In some cases, amplified polynucleotides are sheared in the process of attaching adapters useful in downstream sequencing platforms, for example in flow cell attachment or sequencing primer binding. In some cases, sheared polynucleotides are subject to amplification to produce amplification products of the sheared polynucleotides prior to sequencing. Additional amplification can be desirable, for example, to generate a sufficient amount of polynucleotides for downstream analysis, for example, sequencing analysis. The resulting amplification products can comprise multiple copies of individual sheared polynucleotides.
Cell-free polynucleotides from a sample may be any of a variety of polynucleotides, including but not limited to, DNA, RNA, ribosomal RNA (rRNA), transfer RNA (tRNA), micro RNA (miRNA), messenger RNA (mRNA), fragments of any of these, or combinations of any two or more of these. In some embodiments, samples comprise DNA. In some embodiments, samples comprise cell-free genomic DNA. In some embodiments, the samples comprise DNA generated by amplification, such as by primer extension reactions using any suitable combination of primers and a DNA polymerase, including but not limited to polymerase chain reaction (PCR), reverse transcription, and combinations thereof. Where the template for the primer extension reaction is RNA, the product of reverse transcription is referred to as complementary DNA (cDNA). Primers useful in primer extension reactions can comprise sequences specific to one or more targets, random sequences, partially random sequences, and combinations thereof. In general, sample polynucleotides comprise any polynucleotide present in a sample, which may or may not include target polynucleotides. The polynucleotides may be single-stranded, double-stranded, or a combination of these. In some embodiments, polynucleotides subjected to a method of the disclosure are single-stranded polynucleotides, which may or may not be in the presence of double-stranded polynucleotides. In some embodiments, the polynucleotides are single-stranded DNA. Single-stranded DNA (ssDNA) may be ssDNA that is isolated in a single-stranded form, or DNA that is isolated in double-stranded form and subsequently made single-stranded for the purpose of one or more steps in a method of the disclosure.
In some embodiments, polynucleotides are subjected to subsequent steps (e.g. circularization and amplification) without an extraction step, and/or without a purification step. For example, a fluid sample may be treated to remove cells without an extraction step to produce a purified liquid sample and a cell sample, followed by isolation of DNA from the purified fluid sample. A variety of procedures for isolation of polynucleotides are available, such as by precipitation or non-specific binding to a substrate followed by washing the substrate to release bound polynucleotides. Where polynucleotides are isolated from a sample without a cellular extraction step, polynucleotides will largely be extracellular or “cell-free” polynucleotides, such as cell-free DNA and cell-free RNA, which may correspond to dead or damaged cells. The identity of such cells may be used to characterize the cells or population of cells from which they are derived, such as tumor cells (e.g. in cancer detection), fetal cells (e.g. in prenatal diagnostic), cells from transplanted tissue (e.g. in early detection of transplant failure), or members of a microbial community.
If a sample is treated to extract polynucleotides, such as from cells in a sample, a variety of extraction methods are available. For example, nucleic acids can be purified by organic extraction with phenol, phenol/chloroform/isoamyl alcohol, or similar formulations, including TRIzol and TriReagent. Other non-limiting examples of extraction techniques include: (1) organic extraction followed by ethanol precipitation, e.g., using a phenol/chloroform organic reagent (Ausubel et al., 1993, which is entirely incorporated herein by reference), with or without the use of an automated nucleic acid extractor, e.g., the Model 341 DNA Extractor available from Applied Biosystems (Foster City, Calif.); (2) stationary phase adsorption methods (U.S. Pat. No. 5,234,809; Walsh et al., 1991, each of which is entirely incorporated herein by reference); and (3) salt-induced nucleic acid precipitation methods (Miller et al., (1988), which is entirely incorporated herein by reference), such precipitation methods may be referred to as “salting-out” methods. Another example of nucleic acid isolation and/or purification includes the use of magnetic particles to which nucleic acids can specifically or non-specifically bind, followed by isolation of the beads using a magnet, and washing and eluting the nucleic acids from the beads (see e.g. U.S. Pat. No. 5,705,628, which is entirely incorporated herein by reference). In some embodiments, the above isolation methods may be preceded by an enzyme digestion step to help eliminate unwanted protein from the sample, e.g., digestion with proteinase K, or other like proteases. See, e.g., U.S. Pat. No. 7,001,724, which is entirely incorporated herein by reference. If desired, RNase inhibitors may be added to the lysis buffer. For certain cell or sample types, it may be desirable to add a protein denaturation/digestion step to the protocol. Purification methods may be directed to isolate DNA, RNA, or both. When both DNA and RNA are isolated together during or subsequent to an extraction procedure, further steps may be employed to purify one or both separately from the other. Sub-fractions of extracted nucleic acids can also be generated, for example, purification by size, sequence, or other physical or chemical characteristic. In addition to an initial nucleic acid isolation step, purification of nucleic acids can be performed after any step in the disclosed methods, such as to remove excess or unwanted reagents, reactants, or products. A variety of methods for determining the amount and/or purity of nucleic acids in a sample are available, such as by absorbance (e.g. absorbance of light at 260 nm, 280 nm, and a ratio of these) and detection of a label (e.g. fluorescent dyes and intercalating agents, such as SYBR green, SYBR blue, DAPI, propidium iodine, Hoechst stain, SYBR gold, ethidium bromide).
Where desired, polynucleotides from a sample may be fragmented prior to further processing. Fragmentation may be accomplished by any of a variety of methods, including chemical, enzymatic, and mechanical fragmentation. In some embodiments, the fragments have an average or median length from about 10 to about 1,000 nucleotides in length, such as between 10-800, 10-500, 50-500, 90-200, or 50-150 nucleotides. In some embodiments, the fragments have an average or median length of about or less than about 100, 200, 300, 500, 600, 800, 1000, or 1500 nucleotides. In some embodiments, the fragments range from about 90-200 nucleotides, and/or have an average length of about 150 nucleotides. In some embodiments, the fragmentation is accomplished mechanically comprising subjecting sample polynucleotides to acoustic sonication. In some embodiments, the fragmentation comprises treating the sample polynucleotides with one or more enzymes under conditions suitable for the one or more enzymes to generate double-stranded nucleic acid breaks. Examples of enzymes useful in the generation of polynucleotide fragments include sequence specific and non-sequence specific nucleases. Non-limiting examples of nucleases include DNase I, Fragmentase, restriction endonucleases, variants thereof, and combinations thereof. For example, digestion with DNase I can induce random double-stranded breaks in DNA in the absence of Mg++ and in the presence of Mn++. In some embodiments, fragmentation comprises treating the sample polynucleotides with one or more restriction endonucleases. Fragmentation can produce fragments having 5′ overhangs, 3′ overhangs, blunt ends, or a combination thereof. In some embodiments, such as when fragmentation comprises the use of one or more restriction endonucleases, cleavage of sample polynucleotides leaves overhangs having a predictable sequence. Fragmented polynucleotides may be subjected to a step of size selecting the fragments via standard methods such as column purification, bead purification, or isolation from an agarose gel.
In some cases, methods herein comprise digesting polynucleotides, including DNA and cfDNA with a nuclease, such as a DNase, that cleaves DNA including cfDNA that is free of DNA-binding proteins. Some such methods provide information for mapping protein binding sites on DNA including cfDNA. In these methods, DNA including cfDNA is isolated to preserve DNA-protein interactions and then treated with a DNase, such as DNase Ito cleave DNA including cfDNA at the protein free region of the DNA fragments. Cleaved DNA including cfDNA is further purified to remove protein using any DNA extraction methods provided herein and then used in any library preparation methods provided herein including but not limited to circularization, single stranded DNA library preparation, and double stranded DNA library preparation. In some cases DNase I treatment of DNA comprises isolation of DNA, treating the DNA with DNase I, removing protein from the treated DNA with a buffer, treating the DNA with T4 DNA polymerase to create blunt ends, purification of DNA using phenol extraction and ethanol precipitation, ligating linkers to the DNA prior to library preparation. In some cases, the method further comprises digesting the isolated biotinylated DNA with a restriction enzyme resulting in only the border of the DNase hypersensitive site prior to library preparation and sequencing, as described in Crawford et al. Genome Res. 2006. 16(1) 123-31, which is entirely incorporated herein by reference.
In some cases, methods herein comprise preparation of a DNA library from polynucleotides. For example, methods herein comprise preparation of a single stranded DNA library. Any suitable method of preparing a single stranded DNA library is contemplated for use in methods herein. For example, the method of preparing a single stranded DNA library comprises denaturing the DNA sample to create a plurality of ssDNA; ligating an adapter to the 3′ end of the ssDNA molecules; synthesizing a second strand using a primer complementary to the adapter; ligating a double stranded adapter to the extension products; amplifying the second strand using primers targeting the first and second adapters (for example, using PCR); and sequencing the library on a sequencer. An additional method of single stranded library preparation comprises denaturing the DNA sample to create a plurality of ssDNA; ligating an adapter to the 3′ end of the ssDNA molecules; synthesizing the second strand by using a primer complementary to the adapter; ligating a double stranded adapter to the extension products; amplifying the second strand (for example, by PCR) the second strand using primers targeting the first and second adapters; in some cases enriching for the regions of interest using hybridization with capture probes; amplifying (for example, by PCR) the captured products; and sequencing the library on a sequencer.
Further examples of single stranded library preparation include a method comprising the steps of treating the DNA with a heat labile phosphatase to remove residual phosphate groups from the 5′ and 3′ ends of the DNA strands; removal of deoxyuracils derived from cytosine deamination from the DNA strands; ligation of a 5′ -phosphorylated adapter oligonucleotide having about 10 nucleotides and a long 3′ biotinylated spacer arm to the 3′ ends of the DNA strands; immobilization of adapter-ligated molecules on streptavidin beads; copying the template strand using a 5′-tailed primer complementary to the adapter using Bst polymerase; washing away excess primers; removal of 3′ overhangs using T4 DNA polymerase; joining a second adapter to the newly synthesized strands using blunt-end ligation; washing away excess adapter; releasing library molecules by heat denaturation; adding full-length adapter sequences including bar codes through amplification using tailed primers; and sequencing the library, as described in Gansauge et al. 2013. Nature Protocols. 8(4) 737-748, which is entirely incorporated herein by reference.
In additional embodiments, methods herein comprise preparation of a double stranded DNA library. Any suitable method of preparing a double stranded DNA library is contemplated for use in methods herein. For example, the method of preparing a double stranded DNA library comprises ligating sequencing adapters to the 5′ and 3′ ends of a plurality of DNA fragments and sequencing the library on a sequencer. An additional method of double stranded DNA library preparation comprises ligating adapters to the 5′ and 3′ ends of a plurality of DNA fragments; attaching the full adapter sequences to the ligated fragments through PCR using primers that are complementary to the ligated adapters; and sequencing the library on a sequencer. A further method comprises ligating adapters to the 5′ and 3′ ends of a plurality of DNA fragments; amplifying the ligated product through PCR that are complementary to the ligated adapters; in some cases enriching for the regions of interest through hybridization with capture probes; PCR amplifying the captured products; and sequencing the library on a sequencer. An additional method of double stranded library preparation comprises ligating adapters to the 5′ and 3′ ends of a plurality of DNA fragments; amplifying the ligated product through PCR using primers that are complementary to the ligated adapters; circularizing the double stranded PCR products or denature and circularize the single stranded PCR products; in some cases enriching for the regions of interest by PCR using primers targeting specific genes; and sequencing the library on a sequencer.
Further examples of double stranded library preparation include the Safe-Sequencing System described in Kinde et al. (Kinde et al. 2011. Proc. Natl. Acad. Sci., USA, 108(23) 9530-9535, which is entirely incorporated herein by reference) which comprises assignment of a unique identifier (UID) to each template molecule; amplification of each uniquely tagged template molecule to create UID families; and redundant sequencing of the amplification products. An additional example comprises the circulating single-molecule amplification and resequencing technology (cSMART) described in Lv et al. (Lv et al. 2015. Clin. Chem., 61(1) 172-181, which is entirely incorporated herein by reference) which tags single molecules with unique barcodes, circularizes, targets alleles for replication by inverse PCR, then sequencing the prepared library and counts the alleles present.
In some library preparation approaches provided herein, certain nucleic acid molecules (e.g., cfDNA polynucleotides) are selected or enriched from a plurality of nucleic acid molecules (e.g., total cfDNA). Certain nucleic acid molecules or target sequences may be selected or enriched when they are more likely to result in informative results. For example, certain nucleic acid molecules or target sequences may be selected when they correspond to cfDNA sequences having altered size differences in subjects who have cancer (e.g., early stage cancer) as compared to healthy subjects. Certain nucleic acid molecules may be selected or enriched by amplification with target specific primers. Certain nucleic acid molecules may be selected or enriched by binding target nucleic acid molecules to probes. For example, such nucleic acid molecules are selected or enriched using bait sets.
In additional library preparation methods, cfDNA fragments having certain features are selected using an antibody. In some cases, cfDNA fragments that are methylated or hypermethylated are selected using an antibody. Selected cfDNA fragments are then used in any library preparation method described herein, including circularization, single stranded DNA library preparation, and double stranded DNA library preparation. Sequencing such isolated cfDNA fragments provides information as to the features present in the cfDNA, including modifications such as methylation or hypermethylation.
According to some embodiments, polynucleotides among the plurality of polynucleotides from a sample are circularized. Circularization can include joining the 5′ end of a polynucleotide to the 3′ end of the same polynucleotide, to the 3′ end of another polynucleotide in the sample, or to the 3′ end of a polynucleotide from a different source (e.g. an artificial polynucleotide, such as an oligonucleotide adapter). In some embodiments, the 5′ end of a polynucleotide is joined to the 3′ end of the same polynucleotide (also referred to as “self-joining”). In some embodiment, conditions of the circularization reaction are selected to favor self-joining of polynucleotides within a particular range of lengths, so as to produce a population of circularized polynucleotides of a particular average length. For example, circularization reaction conditions may be selected to favor self-joining of polynucleotides shorter than about 5000, 2500, 1000, 750, 500, 400, 300, 200, 150, 100, 50, or fewer nucleotides in length. In some embodiments, fragments having lengths between 50-5000 nucleotides, 100-2500 nucleotides, or 150-500 nucleotides are favored, such that the average length of circularized polynucleotides falls within the respective range. In some embodiments, 80% or more of the circularized fragments are between 50-500 nucleotides in length, such as between 50-200 nucleotides in length. Reaction conditions that may be optimized include the length of time allotted for a joining reaction, the concentration of various reagents, and the concentration of polynucleotides to be joined. In some embodiments, a circularization reaction preserves the distribution of fragment lengths present in a sample prior to circularization. For example, one or more of the mean, median, mode, and standard deviation of fragment lengths in a sample before circularization and of circularized polynucleotides are within 75%, 80%, 85%, 90%, 95%, or more of one another.
In some cases, rather than preferentially forming self-joining circularization products, one or more adapter oligonucleotides are used, such that the 5′ end and 3′ end of a polynucleotide in the sample are joined by way of one or more intervening adapter oligonucleotides to form a circular polynucleotide. For example, the 5′ end of a polynucleotide can be joined to the 3′ end of an adapter, and the 5′ end of the same adapter can be joined to the 3′ end of the same polynucleotide. An adapter oligonucleotide includes any oligonucleotide having a sequence, at least a portion of which is known, that can be joined to a sample polynucleotide. Adapter oligonucleotides can comprise DNA, RNA, nucleotide analogues, non-canonical nucleotides, labeled nucleotides, modified nucleotides, or combinations thereof. Adapter oligonucleotides can be single-stranded, double-stranded, or partial duplex. In general, a partial-duplex adapter comprises one or more single-stranded regions and one or more double-stranded regions. Double-stranded adapters can comprise two separate oligonucleotides hybridized to one another (also referred to as an “oligonucleotide duplex”), and hybridization may leave one or more blunt ends, one or more 3′ overhangs, one or more 5′ overhangs, one or more bulges resulting from mismatched and/or unpaired nucleotides, or any combination of these. When two hybridized regions of an adapter are separated from one another by a non-hybridized region, a “bubble” structure results. Adapters of different kinds can be used in combination, such as adapters of different sequences. Different adapters can be joined to sample polynucleotides in sequential reactions or simultaneously. In some embodiments, identical adapters are added to both ends of a target polynucleotide. For example, first and second adapters can be added to the same reaction. Adapters can be manipulated prior to combining with sample polynucleotides. For example, terminal phosphates can be added or removed.
Where adapter oligonucleotides are used, the adapter oligonucleotides can contain one or more of a variety of sequence elements, including but not limited to, one or more amplification primer annealing sequences or complements thereof, one or more sequencing primer annealing sequences or complements thereof, one or more barcode sequences, one or more common sequences shared among multiple different adapters or subsets of different adapters, one or more restriction enzyme recognition sites, one or more overhangs complementary to one or more target polynucleotide overhangs, one or more probe binding sites (e.g. for attachment to a sequencing platform, such as a flow cell for massive parallel sequencing, such as flow cells as developed by Illumina, Inc.), one or more random or near-random sequences (e.g. one or more nucleotides selected at random from a set of two or more different nucleotides at one or more positions, with each of the different nucleotides selected at one or more positions represented in a pool of adapters comprising the random sequence), and combinations thereof. In some cases, the adapters may be used to purify those circles that contain the adapters, for example by using beads (particularly magnetic beads for ease of handling) that are coated with oligonucleotides comprising a complementary sequence to the adapter, that can “capture” the closed circles with the correct adapters by hybridization thereto, wash away those circles that do not contain the adapters and any unligated components, and then release the captured circles from the beads. In addition, in some cases, the complex of the hybridized capture probe and the target circle can be directly used to generate concatemers, such as by direct rolling circle amplification (RCA). In some embodiments, the adapters in the circles can also be used as a sequencing primer. Two or more sequence elements can be non-adjacent to one another (e.g. separated by one or more nucleotides), adjacent to one another, partially overlapping, or completely overlapping. For example, an amplification primer annealing sequence can also serve as a sequencing primer annealing sequence. Sequence elements can be located at or near the 3′ end, at or near the 5′ end, or in the interior of the adapter oligonucleotide. A sequence element may be of any suitable length, such as about or less than about 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50 or more nucleotides in length. Adapter oligonucleotides can have any suitable length, at least sufficient to accommodate the one or more sequence elements of which they are comprised. In some embodiments, adapters are about or less than about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 90, 100, 200, or more nucleotides in length. In some embodiments, an adapter oligonucleotide is in the range of about 12 to 40 nucleotides in length, such as about 15 to 35 nucleotides in length.
In some embodiments, the adapter oligonucleotides joined to fragmented polynucleotides from one sample comprise one or more sequences common to all adapter oligonucleotides and a barcode that is unique to the adapters joined to polynucleotides of that particular sample, such that the barcode sequence can be used to distinguish polynucleotides originating from one sample or adapter joining reaction from polynucleotides originating from another sample or adapter joining reaction. In some embodiments, an adapter oligonucleotide comprises a 5′ overhang, a 3′ overhang, or both that is complementary to one or more target polynucleotide overhangs. Complementary overhangs can be one or more nucleotides in length, including but not limited to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or more nucleotides in length. Complementary overhangs may comprise a fixed sequence. Complementary overhangs of an adapter oligonucleotide may comprise a random sequence of one or more nucleotides, such that one or more nucleotides are selected at random from a set of two or more different nucleotides at one or more positions, with each of the different nucleotides selected at one or more positions represented in a pool of adapters with complementary overhangs comprising the random sequence. In some embodiments, an adapter overhang is complementary to a target polynucleotide overhang produced by restriction endonuclease digestion. In some embodiments, an adapter overhang consists of an adenine or a thymine.
A variety of methods for circularizing polynucleotides are available. In some embodiments, circularization comprises an enzymatic reaction, such as use of a ligase (e.g. an RNA or DNA ligase). A variety of ligases are available, including, but not limited to, Circligase™ (Epicentre; Madison, WI), RNA ligase, T4 RNA Ligase 1 (ssRNA Ligase, which works on both DNA and RNA). In addition, T4 DNA ligase can also ligate ssDNA if no dsDNA templates are present, although this is generally a slow reaction. Other non-limiting examples of ligases include NAD-dependent ligases including Taq DNA ligase, Thermus filiformis DNA ligase, Escherichia coli DNA ligase, Tth DNA ligase, Thermus scotoductus DNA ligase (I and II), thermostable ligase, Ampligase thermostable DNA ligase, VanC-type ligase, 9° N DNA Ligase, Tsp DNA ligase, and novel ligases discovered by bioprospecting; ATP-dependent ligases including T4 RNA ligase, T4 DNA ligase, T3 DNA ligase, T7 DNA ligase, Pfu DNA ligase, DNA ligase 1, DNA ligase III, DNA ligase IV, and novel ligases discovered by bioprospecting; and wild-type, mutant isoforms, and genetically engineered variants thereof Where self-joining is desired, the concentration of polynucleotides and enzyme can be adjusted to facilitate the formation of intramolecular circles rather than intermolecular structures. Reaction temperatures and times can be adjusted as well. In some embodiments, 60° C. is used to facilitate intramolecular circles. In some embodiments, reaction times are between 12-16 hours. Reaction conditions may be those specified by the manufacturer of the selected enzyme. In some embodiments, an exonuclease step can be included to digest any unligated nucleic acids after the circularization reaction. That is, closed circles do not contain a free 5′ or 3′ end, and thus the introduction of a 5′ or 3′ exonuclease will not digest the closed circles but will digest the unligated components. This may find particular use in multiplex systems.
In general, joining ends of a polynucleotide to one-another to form a circular polynucleotide (either directly, or with one or more intermediate adapter oligonucleotides) produces a junction having a junction sequence. Where the 5′ end and 3′ end of a polynucleotide are joined via an adapter polynucleotide, the term “junction” can refer to a junction between the polynucleotide and the adapter (e.g. one of the 5′ end junction or the 3′ end junction), or to the junction between the 5′ end and the 3′ end of the polynucleotide as formed by and including the adapter polynucleotide. Where the 5′ end and the 3′ end of a polynucleotide are joined without an intervening adapter (e.g. the 5′ end and 3′ end of a single-stranded DNA), the term “junction” refers to the point at which these two ends are joined. A junction may be identified by the sequence of nucleotides comprising the junction (also referred to as the “junction sequence”). In some embodiments, samples comprise polynucleotides having a mixture of ends formed by natural degradation processes (such as cell lysis, cell death, and other processes by which DNA is released from a cell to its surrounding environment in which it may be further degraded, such as in cell-free polynucleotides, such as cell-free DNA and cell-free RNA), fragmentation that is a byproduct of sample processing (such as fixing, staining, and/or storage procedures), and fragmentation by methods that cleave DNA without restriction to specific target sequences (e.g. mechanical fragmentation, such as by sonication; non-sequence specific nuclease treatment, such as DNase I, fragmentase). Where samples comprise polynucleotides having a mixture of ends, the likelihood that two polynucleotides will have the same 5′ end or 3′ end is low, and the likelihood that two polynucleotides will independently have both the same 5′ end and 3′ end is extremely low. Accordingly, in some embodiments, junctions may be used to distinguish different polynucleotides, even where the two polynucleotides comprise a portion having the same target sequence. Where polynucleotide ends are joined without an intervening adapter, a junction sequence may be identified by alignment to a reference sequence. For example, where the order of two component sequences appears to be reversed with respect to the reference sequence, the point at which the reversal appears to occur may be an indication of a junction at that point. Where polynucleotide ends are joined via one or more adapter sequences, a junction may be identified by proximity to the known adapter sequence, or by alignment as above if a sequencing read is of sufficient length to obtain sequence from both the 5′ and 3′ ends of the circularized polynucleotide. In some embodiments, the formation of a particular junction is a sufficiently rare event such that it is unique among the circularized polynucleotides of a sample.
According to some embodiments, linear and/or circularized polynucleotides (or amplification products thereof, which may have been enriched in some cases) are subjected to a sequencing reaction to generate sequencing reads. Sequencing reads produced by such methods may be used in accordance with other methods disclosed herein. A variety of sequencing methodologies are available, particularly high-throughput sequencing methodologies. Examples include, without limitation, sequencing systems manufactured by Illumina (sequencing systems such as HiSeq® and MiSeq®), Life Technologies (Ion Torrent®, SOLiD®, etc.), Roche's 454 Life Sciences systems, Pacific Biosciences systems, etc. In some embodiments, sequencing comprises use of HiSeq® and MiSeq® systems to produce reads of about or more than about 50, 75, 100, 125, 150, 175, 200, 250, 300, or more nucleotides in length. In some embodiments, sequencing comprises a sequencing by synthesis process, where individual nucleotides are identified iteratively, as they are added to the growing primer extension product. Pyrosequencing is an example of a sequence by synthesis process that identifies the incorporation of a nucleotide by assaying the resulting synthesis mixture for the presence of by-products of the sequencing reaction, namely pyrophosphate. In particular, a primer/template/polymerase complex is contacted with a single type of nucleotide. If that nucleotide is incorporated, the polymerization reaction cleaves the nucleoside triphosphate between the α and β phosphates of the triphosphate chain, releasing pyrophosphate. The presence of released pyrophosphate is then identified using a chemiluminescent enzyme reporter system that converts the pyrophosphate, with AMP, into ATP, then measures ATP using a luciferase enzyme to produce measurable light signals. Where light is detected, the base is incorporated, where no light is detected, the base is not incorporated. Following appropriate washing steps, the various bases are cyclically contacted with the complex to sequentially identify subsequent bases in the template sequence. See, e.g., U.S. Pat. No. 6,210,891, which is entirely incorporated herein by reference.
In related sequencing processes, the primer/template/polymerase complex is immobilized upon a substrate and the complex is contacted with labeled nucleotides. The immobilization of the complex may be through the primer sequence, the template sequence and/or the polymerase enzyme, and may be covalent or noncovalent. For example, immobilization of the complex can be via a linkage between the polymerase or the primer and the substrate surface. In alternate configurations, the nucleotides are provided with and without removable terminator groups. Upon incorporation, the label is coupled with the complex and is thus detectable. In the case of terminator bearing nucleotides, all four different nucleotides, bearing individually identifiable labels, are contacted with the complex. Incorporation of the labeled nucleotide arrests extension, by virtue of the presence of the terminator, and adds the label to the complex, allowing identification of the incorporated nucleotide. The label and terminator are then removed from the incorporated nucleotide, and following appropriate washing steps, the process is repeated. In the case of non-terminated nucleotides, a single type of labeled nucleotide is added to the complex to determine whether it will be incorporated, as with pyrosequencing. Following removal of the label group on the nucleotide and appropriate washing steps, the various different nucleotides are cycled through the reaction mixture in the same process. See, e.g., U.S. Pat. No. 6,833,246, incorporated herein by reference in its entirety for all purposes. For example, the Illumina Genome Analyzer System is based on technology described in WO 98/44151, wherein DNA molecules are bound to a sequencing platform (flow cell) via an anchor probe binding site (otherwise referred to as a flow cell binding site) and amplified in situ on a glass slide. A solid surface on which DNA molecules are amplified may comprise a plurality of first and second bound oligonucleotides, the first complementary to a sequence near or at one end of a target polynucleotide and the second complementary to a sequence near or at the other end of a target polynucleotide. This arrangement permits bridge amplification, such as described in US20140121116. The DNA molecules are then annealed to a sequencing primer and sequenced in parallel base-by-base using a reversible terminator approach. Hybridization of a sequencing primer may be preceded by cleavage of one strand of a double-stranded bridge polynucleotide at a cleavage site in one of the bound oligonucleotides anchoring the bridge, thus leaving one single strand not bound to the solid substrate that may be removed by denaturing, and the other strand bound and available for hybridization to a sequencing primer. In some cases, the Illumina Genome Analyzer System utilizes flow-cells with 8 channels, generating sequencing reads of 18 to 36 bases in length, generating >1.3 Gbp of high quality data per run (see www.illumina.com).
In yet a further sequence by synthesis process, the incorporation of differently labeled nucleotides is observed in real time as template dependent synthesis is carried out. In particular, an individual immobilized primer/template/polymerase complex is observed as fluorescently labeled nucleotides are incorporated, permitting real time identification of each added base as it is added. In this process, label groups are attached to a portion of the nucleotide that is cleaved during incorporation. For example, by attaching the label group to a portion of the phosphate chain removed during incorporation, i.e., a β, γ, or other terminal phosphate group on a nucleoside polyphosphate, the label is not incorporated into the nascent strand, and instead, natural DNA is produced. Observation of individual molecules may involve the optical confinement of the complex within a very small illumination volume. By optically confining the complex, one creates a monitored region in which randomly diffusing nucleotides are present for a very short period of time, while incorporated nucleotides are retained within the observation volume for longer as they are being incorporated. This results in a characteristic signal associated with the incorporation event, which is also characterized by a signal profile that is characteristic of the base being added. In related aspects, interacting label components, such as fluorescent resonant energy transfer (FRET) dye pairs, are provided upon the polymerase or other portion of the complex and the incorporating nucleotide, such that the incorporation event puts the labeling components in interactive proximity, and a characteristic signal results, that is again, also characteristic of the base being incorporated (See, e.g., U.S. Pat. Nos. 6,917,726, 7,033,764, 7,052,847, 7,056,676, 7,170,050, 7,361,466, and 7,416,844; and US 20070134128, each of which is entirely incorporated herein by reference).
In some embodiments, the nucleic acids in the sample can be sequenced by ligation. This method may use a DNA ligase enzyme to identify the target sequence, for example, as used in the polony method and in the SOLiD technology (Applied Biosystems, now Invitrogen). In general, a pool of all possible oligonucleotides of a fixed length is provided, labeled according to the sequenced position. Oligonucleotides are annealed and ligated; the preferential ligation by DNA ligase for matching sequences results in a signal corresponding to the complementary sequence at that position.
Sequencing methods herein provide information useful in methods herein. In some cases, sequencing provides a sequence of a polymorphic region. Additionally, sequencing provides a length of a polynucleotide, such as a DNA including cfDNA. Further, sequencing provides a sequence of a breakpoint or end of a DNA such as a cfDNA. Sequencing further provides a sequence of a border of a protein binding site or a border of a DNase hypersensitive site.
In embodiments of the various methods described herein, the sample may be from a subject. A subject may be any animal, including but not limited to, a cow, a pig, a mouse, a rat, a chicken, a cat, a dog, etc., and is usually a mammal, such as a human. Sample polynucleotides may be isolated from a subject, such as a tissue sample, bodily fluid sample, or organ sample, including, for example, biopsy, blood sample, or fluid sample containing nucleic acids (e.g. saliva). In some cases, the sample does not comprise intact cells, is treated to remove cells, or polynucleotides are isolated without a cellular extractions step (e.g. to isolate cell-free polynucleotides, such as cell-free DNA). Other examples of sample sources include those from blood, urine, feces, nares, the lungs, the gut, other bodily fluids or excretions, materials derived therefrom, or combinations thereof. In some embodiments, the sample is a blood sample or a portion thereof (e.g. blood plasma or serum). Serum and plasma may be of particular interest, due to the relative enrichment for tumor DNA associated with the higher rate of malignant cell death among such tissues. In some embodiments, a sample from a single individual is divided into multiple separate samples (e.g. 2, 3, 4, 5, 6, 7, 8, 9, 10, or more separate samples) that are subjected to methods of the disclosure independently, such as analysis in duplicate, triplicate, quadruplicate, or more. Where a sample is from a subject, the reference sequence may also be derived of the subject, such as a consensus sequence from the sample under analysis or the sequence of polynucleotides from another sample or tissue of the same subject. For example, a blood sample may be analyzed for ctDNA mutations, while cellular DNA from another sample (e.g. buccal or skin sample) is analyzed to determine the reference sequence.
Polynucleotides may be extracted from a sample according to any suitable method. A variety of kits are available for extraction of polynucleotides, selection of which may depend on the type of sample, or the type of nucleic acid to be isolated. Examples of extraction methods are provided herein, such as those described with respect to any of the various aspects disclosed herein. In one example, the sample may be a blood sample, such as a sample collected in an EDTA tube (e.g. BD Vacutainer). Plasma can be separated from the peripheral blood cells by centrifugation (e.g. 10 minutes at 1900×g at 4° C.). Plasma separation performed in this way on a 6 mL blood sample may yield 2.5 to 3 mL of plasma. Circulating cell-free DNA can be extracted from a plasma sample, such as by using a QIAmp Circulating Nucleic Acid Kit (Qiagene), according the manufacturer's protocol. DNA may then be quantified (e.g. on an Agilent 2100 Bioanalyzer with High Sensitivity DNA kit (Agilent)). As an example, yield of circulating DNA from such a plasma sample from a healthy person may range from 1 ng to 10 ng per mL of plasma, with significantly more in cancer patient samples.
In some embodiments, the plurality of polynucleotides comprises cell-free polynucleotides, such as cell-free DNA (cfDNA), cell-free RNA (cfRNA), circulating tumor DNA (ctDNA), or circulating tumor RNA (ctRNA). Cell-free DNA circulates in both healthy and diseased individuals. Cell-free RNA circulates in both healthy and diseased individuals. cfDNA from tumors (ctDNA) is not confined to any specific cancer type, but appears to be a common finding across different malignancies. According to some measurements, the free circulating DNA concentration in plasma is about 14-18 ng/ml in control subjects and about 180-318 ng/ml in patients with neoplasias. Apoptotic and necrotic cell death contribute to cell-free circulating DNA in bodily fluids. For example, significantly increased circulating DNA levels have been observed in plasma of prostate cancer patients and other prostate diseases, such as Benign Prostate Hyperplasia and Prostatits. In addition, circulating tumor DNA is present in fluids originating from the organs where the primary tumor occurs. Thus, breast cancer detection can be achieved in ductal lavages; colorectal cancer detection in stool; lung cancer detection in sputum, and prostate cancer detection in urine or ejaculate. Cell-free DNA may be obtained from a variety of sources. One common source is blood samples of a subject. However, cfDNA or other fragmented DNA may be derived from a variety of other sources. For example, urine and stool samples can be a source of cfDNA, including ctDNA. Cell-free RNA may be obtained from a variety of sources.
In some embodiments, polynucleotides are subjected to subsequent steps (e.g. circularization and amplification) without an extraction step, and/or without a purification step. For example, a fluid sample may be treated to remove cells without an extraction step to produce a purified liquid sample and a cell sample, followed by isolation of DNA from the purified fluid sample. A variety of procedures for isolation of polynucleotides are available, such as by precipitation or non-specific binding to a substrate followed by washing the substrate to release bound polynucleotides. Where polynucleotides are isolated from a sample without a cellular extraction step, polynucleotides will largely be extracellular or “cell-free” polynucleotides. For example, cell-free polynucleotides may include cell-free DNA (also called “circulating” DNA). In some embodiments, the circulating DNA is circulating tumor DNA (ctDNA) from tumor cells, such as from a body fluid or excretion (e.g. blood sample). Cell-free polynucleotides may include cell-free RNA (also called “circulating” RNA). In some embodiments, the circulating RNA is circulating tumor RNA (ctRNA) from tumor cells. Tumors frequently show apoptosis or necrosis, such that tumor nucleic acids are released into the body, including the blood stream of a subject, through a variety of mechanisms, in different forms and at different levels. In some cases, the size of the ctDNA can range between higher concentrations of smaller fragments, generally 70 to 200 nucleotides in length, to lower concentrations of large fragments of up to thousands kilobases.
Methods herein may provide for detection of cancer, for example, in some cases, early stage cancer can be detected. Staging of cancer may be dependent on cancer type where each cancer type has its own classification system. Examples of cancer staging or classification systems are described in more detail below.
Methods provided herein may allow for early detection cancer or for detection of non-metastatic cancer. Examples of cancers that may be detected in accordance with a method disclosed herein include, without limitation, Acanthoma, Acinic cell carcinoma, Acoustic neuroma, Acral lentiginous melanoma, Acrospiroma, Acute eosinophilic leukemia, Acute lymphoblastic leukemia, Acute megakaryoblastic leukemia, Acute monocytic leukemia, Acute myeloblastic leukemia with maturation, Acute myeloid dendritic cell leukemia, Acute myeloid leukemia, Acute promyelocytic leukemia, Adamantinoma, Adenocarcinoma, Adenoid cystic carcinoma, Adenoma, Adenomatoid odontogenic tumor, Adrenocortical carcinoma, Adult T-cell leukemia, Aggressive NK-cell leukemia, AIDS-Related Cancers, AIDS-related lymphoma, Alveolar soft part sarcoma, Ameloblastic fibroma, Anal cancer, Anaplastic large cell lymphoma, Anaplastic thyroid cancer, Angioimmunoblastic T-cell lymphoma, Angiomyolipoma, Angiosarcoma, Appendix cancer, Astrocytoma, Atypical teratoid rhabdoid tumor, Basal cell carcinoma, Basal-like carcinoma, B-cell leukemia, B-cell lymphoma, Bellini duct carcinoma, Biliary tract cancer, Bladder cancer, Blastoma, Bone Cancer, Bone tumor, Brain Stem Glioma, Brain Tumor, Breast Cancer, Brenner tumor, Bronchial Tumor, Bronchioloalveolar carcinoma, Brown tumor, Burkitt's lymphoma, Cancer of Unknown Primary Site, Carcinoid Tumor, Carcinoma, Carcinoma in situ, Carcinoma of the penis, Carcinoma of Unknown Primary Site, Carcinosarcoma, Castleman's Disease, Central Nervous System Embryonal Tumor, Cerebellar Astrocytoma, Cerebral Astrocytoma, Cervical Cancer, Cholangiocarcinoma, Chondroma, Chondrosarcoma, Chordoma, Choriocarcinoma, Choroid plexus papilloma, Chronic Lymphocytic Leukemia, Chronic monocytic leukemia, Chronic myelogenous leukemia, Chronic Myeloproliferative Disorder, Chronic neutrophilic leukemia, Clear-cell tumor, Colon Cancer, Colorectal cancer, Craniopharyngioma, Cutaneous T-cell lymphoma, Degos disease, Dermatofibrosarcoma protuberans, Dermoid cyst, Desmoplastic small round cell tumor, Diffuse large B cell lymphoma, Dysembryoplastic neuroepithelial tumor, Embryonal carcinoma, Endodermal sinus tumor, Endometrial cancer, Endometrial Uterine Cancer, Endometrioid tumor, Enteropathy-associated T-cell lymphoma, Ependymoblastoma, Ependymoma, Epithelioid sarcoma, Erythroleukemia, Esophageal cancer, Esthesioneuroblastoma, Ewing Family of Tumor, Ewing Family Sarcoma, Ewing's sarcoma, Extracranial Germ Cell Tumor, Extragonadal Germ Cell Tumor, Extrahepatic Bile Duct Cancer, Extramammary Paget's disease, Fallopian tube cancer, Fetus in fetu, Fibroma, Fibrosarcoma, Follicular lymphoma, Follicular thyroid cancer, Gallbladder Cancer, Gallbladder cancer, Ganglioglioma, Ganglioneuroma, Gastric Cancer, Gastric lymphoma, Gastrointestinal cancer, Gastrointestinal Carcinoid Tumor, Gastrointestinal Stromal Tumor, Gastrointestinal stromal tumor, Germ cell tumor, Germinoma, Gestational choriocarcinoma, Gestational Trophoblastic Tumor, Giant cell tumor of bone, Glioblastoma multiforme, Glioma, Gliomatosis cerebri, Glomus tumor, Glucagonoma, Gonadoblastoma, Granulosa cell tumor, Hairy Cell Leukemia, Hairy cell leukemia, Head and Neck Cancer, Head and neck cancer, Heart cancer, Hemangioblastoma, Hemangiopericytoma, Hemangiosarcoma, Hematological malignancy, Hepatocellular carcinoma, Hepatosplenic T-cell lymphoma, Hereditary breast-ovarian cancer syndrome, Hodgkin Lymphoma, Hodgkin's lymphoma, Hypopharyngeal Cancer, Hypothalamic Glioma, Inflammatory breast cancer, Intraocular Melanoma, Islet cell carcinoma, Islet Cell Tumor, Juvenile myelomonocytic leukemia, Kaposi Sarcoma, Kaposi's sarcoma, Kidney Cancer, Klatskin tumor, Krukenberg tumor, Laryngeal Cancer, Laryngeal cancer, Lentigo maligna melanoma, Leukemia, Leukemia, Lip and Oral Cavity Cancer, Liposarcoma, Lung cancer, Luteoma, Lymphangioma, Lymphangiosarcoma, Lymphoepithelioma, Lymphoid leukemia, Lymphoma, Macroglobulinemia, Malignant Fibrous Histiocytoma, Malignant fibrous histiocytoma, Malignant Fibrous Histiocytoma of Bone, Malignant Glioma, Malignant Mesothelioma, Malignant peripheral nerve sheath tumor, Malignant rhabdoid tumor, Malignant triton tumor, MALT lymphoma, Mantle cell lymphoma, Mast cell leukemia, Mediastinal germ cell tumor, Mediastinal tumor, Medullary thyroid cancer, Medulloblastoma, Medulloblastoma, Medulloepithelioma, Melanoma, Melanoma, Meningioma, Merkel Cell Carcinoma, Mesothelioma, Mesothelioma, Metastatic Squamous Neck Cancer with Occult Primary, Metastatic urothelial carcinoma, Mixed Mullerian tumor, Monocytic leukemia, Mouth Cancer, Mucinous tumor, Multiple Endocrine Neoplasia Syndrome, Multiple Myeloma, Multiple myeloma, Mycosis Fungoides, Mycosis fungoides, Myelodysplastic Disease, Myelodysplastic Syndromes, Myeloid leukemia, Myeloid sarcoma, Myeloproliferative Disease, Myxoma, Nasal Cavity Cancer, Nasopharyngeal Cancer, Nasopharyngeal carcinoma, Neoplasm, Neurinoma, Neuroblastoma, Neuroblastoma, Neurofibroma, Neuroma, Nodular melanoma, Non-Hodgkin Lymphoma, Non-Hodgkin lymphoma, Nonmelanoma Skin Cancer, Non-Small Cell Lung Cancer, Ocular oncology, Oligoastrocytoma, Oligodendroglioma, Oncocytoma, Optic nerve sheath meningioma, Oral Cancer, Oral cancer, Oropharyngeal Cancer, Osteosarcoma, Osteosarcoma, Ovarian Cancer, Ovarian cancer, Ovarian Epithelial Cancer, Ovarian Germ Cell Tumor, Ovarian Low Malignant Potential Tumor, Paget's disease of the breast, Pancoast tumor, Pancreatic Cancer, Pancreatic cancer, Papillary thyroid cancer, Papillomatosis, Paraganglioma, Paranasal Sinus Cancer, Parathyroid Cancer, Penile Cancer, Perivascular epithelioid cell tumor, Pharyngeal Cancer, Pheochromocytoma, Pineal Parenchymal Tumor of Intermediate Differentiation, Pineoblastoma, Pituicytoma, Pituitary adenoma, Pituitary tumor, Plasma Cell Neoplasm, Pleuropulmonary blastoma, Polyembryoma, Precursor T-lymphoblastic lymphoma, Primary central nervous system lymphoma, Primary effusion lymphoma, Primary Hepatocellular Cancer, Primary Liver Cancer, Primary peritoneal cancer, Primitive neuroectodermal tumor, Prostate cancer, Pseudomyxoma peritonei, Rectal Cancer, Renal cell carcinoma, Respiratory Tract Carcinoma Involving the NUT Gene on Chromosome 15, Retinoblastoma, Rhabdomyoma, Rhabdomyosarcoma, Richter's transformation, Sacrococcygeal teratoma, Salivary Gland Cancer, Sarcoma, Schwannomatosis, Sebaceous gland carcinoma, Secondary neoplasm, Seminoma, Serous tumor, Sertoli-Leydig cell tumor, Sex cord-stromal tumor, Sezary Syndrome, Signet ring cell carcinoma, Skin Cancer, Small blue round cell tumor, Small cell carcinoma, Small Cell Lung Cancer, Small cell lymphoma, Small intestine cancer, Soft tissue sarcoma, Somatostatinoma, Soot wart, Spinal Cord Tumor, Spinal tumor, Splenic marginal zone lymphoma, Squamous cell carcinoma, Stomach cancer, Superficial spreading melanoma, Supratentorial Primitive Neuroectodermal Tumor, Surface epithelial-stromal tumor, Synovial sarcoma, T-cell acute lymphoblastic leukemia, T-cell large granular lymphocyte leukemia, T-cell leukemia, T-cell lymphoma, T-cell prolymphocytic leukemia, Teratoma, Terminal lymphatic cancer, Testicular cancer, Thecoma, Throat Cancer, Thymic Carcinoma, Thymoma, Thyroid cancer, Transitional Cell Cancer of Renal Pelvis and Ureter, Transitional cell carcinoma, Urachal cancer, Urethral cancer, Urogenital neoplasm, Uterine sarcoma, Uveal melanoma, Vaginal Cancer, Verner Morrison syndrome, Verrucous carcinoma, Visual Pathway Glioma, Vulvar Cancer, Waldenstrom's macroglobulinemia, Warthin's tumor, Wilms' tumor, and combinations thereof.
While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. It is not intended that the invention be limited by the specific examples provided within the specification. While the invention has been described with reference to the aforementioned specification, the descriptions and illustrations of the embodiments herein are not meant to be construed in a limiting sense. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. Furthermore, it shall be understood that all aspects of the invention are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is therefore contemplated that the invention shall also cover any such alternatives, modifications, variations or equivalents. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.
The following example is illustrative of certain embodiments herein and is not intended to limit the scope of the present disclosure.
Double stranded DNA molecules are synthesized having a size of 60 bp and 160 bp. Each construct contains two 20 bp common sequences, one at 5′ end, one at 3′ ends. Each construct also contains a 8 bp long random sequences in the middle as a unique molecular barcode. Each construct is resuspended in buffer, and the concentration of each DNA construct solution is measured by ddPCR. The 4 different constructs are mixed at 1:1 ratio based on the ddPCR results.
Circularization of Single Strand cfDNA:
The pooled DNA constructs are mixed with 12 μl of purified cfDNA samples. Then the mixed DNA fragments are denatured by heating at 95° C. for 30 seconds and chilling on ice for 2 minutes. Then, 8 μl of ligation mix containing 2 μl of 10× CircLigase buffer, 4 μl of 5M Betaine, 1 μl of 50 mM MnCl2, and 1 μl of CircLigase II is added to the denatured DNA samples and the reactions are incubated at 60° C. for one hour.
Rolling Cycle Amplification of Circular Target Polynucleotides:
For each reaction, 5 μl of isothermal amplification buffer, 0.75 uL of dNTP mix (25 mM each), 2 μl of 10 μM gene specific primers and primers targeting the common sequences of the synthetic DNA construct, and 20.25 μl of water are added. The reaction is heated at 80° C. for 1 minute and incubated at 63° C. for 5 minutes before cooling down to 4° C. Next, 15 units of Bst 2.0 warm start DNA polymerase is added to each reaction, and incubated in a thermal cycler with the following program: 4 cycles of 60° C. for 30 seconds; 70° C. for 4.5 minutes; 94° C. for 20 seconds; and 58° C. for 10 seconds.
2nd Round of PCR and Sequencing:
Rolling cycle amplification products are purified by addition of 45 μl Ampure beads, following the manufacturer's instructions for the remaining wash steps. The samples are eluted in a volume of elution buffer. The purified RCA products are further amplified by PCR with primers containing sequencing adaptors. The resulting amplification products are then sequenced by NGS.
NGS Data Analysis:
The FASTQ files are aligned to a reference file containing the target sequence. Reads are identified that map to the synthetic DNA constructs. The ratio between reads mapped to each size is calculated.
The cfDNA fragment size is calculated based on sequencing data. The ratio of cfDNA fragment size peak at 60 vs 160 is normalized based by the ratio of the synthetic DNA construct at size 60 vs 160 bp.
While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments described herein may be employed. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.
This application is a continuation of PCT International Application No. PCT/US2021/058614, filed Nov. 9, 2021, which claims the benefit of U.S. Provisional Application No. 63/112,491, filed Nov. 11, 2020, each of which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63112491 | Nov 2020 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2021/058614 | Nov 2021 | US |
| Child | 18315025 | US |
