Patent Application
20210071259
The present invention relates to a method of assisting the detection of head and neck cancer.
Head and neck cancer refers to cancer that occurs in a body region below the brain and above the clavicles. Vital functions such as breathing and eating, and socially important daily life functions such as speaking, tasting, and hearing are predominantly related to the head and neck region. Thus, a therapy to treat cancer while keeping the balance between curability and QOL is needed because any lesion in the head and neck region may directly affect QOL. Additionally, aesthetic considerations are also necessary because the head and neck region is involved in maintenance of facial morphology and/or in expression of feelings.
As methods to detect such cancer including head and neck cancer, methods in which the abundance of microRNA (hereinafter referred to as “miRNA”) in blood is used as an index are proposed (Patent Documents 1 to 5).
As described above, various miRNAs have been proposed as indexes for the detection of cancer including head and neck cancer and, needless to say, it is advantageous if head and neck cancer can be detected with higher accuracy.
Thus, an object of the present invention is to provide a method of assisting the detection of head and neck cancer which assists in highly accurate detection of head and neck cancer.
As a result of intensive study, the inventors newly found miRNAs, isoform miRNAs (isomiRs), precursor miRNAs. transfer RNA fragments (tRFs), and non-coding RNA fragments (LincRNAs, MiscRNAs) which increase or decrease in abundance in head and neck cancer. and discovered that use of those RNA molecules as indexes enables highly accurate detection of head and neck cancer, and thereby completed the present invention.
That is, the present invention provides the followings.
By the method of the present invention, head and neck cancer can be highly accurately and yet conveniently detected. Thus, the method of the present invention will greatly contribute to the detection of head and neck cancer.
As described above, the abundance of a specified miRNAs, isomiRs, precursor miRNAs, transfer RNA fragments (tRFs), or non-coding RNA fragments (LincRNAs or MiscRNA) (hereinafter sometimes referred to as “miRNAs or the like” for convenience) contained in a test sample isolated from a living body is used as an index in the method of the present invention. The nucleotide sequence of these miRNAs or the like themselves are as shown in Sequence Listing. The list of miRNAs or the like used in the method of the present invention is presented in Tables 1-1 to 1-7 below.
Among those miRNAs or the like, miRNAs or the like whose nucleotide sequences are represented by SEQ ID NOs: 1 to 162 (for example, “a miRNA or the like whose nucleotide sequence is represented by SEQ ID NO: 1” is hereinafter sometimes referred to simply as “a miRNA or the like represented by SEQ ID NO: 1” or “one represented by SEQ ID NO: 1” for convenience) are present in serum or exosomes.
In many of those miRNAs or the like, the logarithm of the ratio of the abundance in serum or exosomes from patients with head and neck cancer to the abundance in serum or exosomes from healthy subjects (represented by “log FC” which means the logarithm of FC (fold change) to base 2) is not less than 1.00 in absolute value, showing a statistical significance (t-test; p<0.05).
The abundance of miRNAs or the like represented by SEQ ID NOs: 1 to 71 and 118 to 136 is higher in patients with head and neck cancer than in healthy subjects, while the abundance of miRNAs or the like represented by SEQ ID NOs: 72 to 117 and 137 to 162 is lower in patients with head and neck cancer than in healthy subjects.
By a method in which among those, any of the combinations of the miRNAs represented by SEQ ID NOs: 11 and 30, SEQ ID NOs: 11 and 26, SEQ ID NOs: 11 and 117, SEQ ID NOs: 30 and 118, and SEQ ID NOs: 157 and 162 is used as an index, even early tongue cancer can be detected, as specifically described in Examples below.
The accuracy of each cancer marker is indicated using the area under the ROC curve (AUC: Area Under Curve) as an index, and cancer markers with an AUC value of 0.7 or higher are generally considered effective. AUC values of 0.90 or higher, 0.97 or higher, 0.99 or higher, and 1.00 correspond to cancer markers with high accuracy, very high accuracy, quite high accuracy, and complete accuracy (with no false-positive and false-negative events), respectively. Thus, the AUC value of each cancer marker is likewise preferably 0.90, more preferably not less than 0.97, still more preferably not less than 0.99, and most preferably 1.00 in the present invention. The ones whose nucleotide sequences are represented by SEQ ID NOs: 162, 160, 145, 143, 146, 140, and 141 are preferable due to an AUC value of 0.97 or higher; among those, ones represented by SEQ ID NOs: 162 and 160 are more preferable due to an AUC value of 0.98 or higher.
Furthermore, because the FC (fold change) in the abundance of an isomiR represented by either SEQ ID NO: 115 or SEQ ID NO: 116 is changed before and after surgery for tongue cancer, the isomiRs can be used to assess the success or failure of the surgery.
The test sample is not specifically limited, provided that the test sample is a body fluid containing miRNAs or the like; typically, it is preferable to use a blood sample (including plasma, serum, and whole blood). For the ones or the like present in serum, it is simple and preferable to use serum or plasma as a test sample. For the miRNAs or the like present in exosomes, it is preferable to use serum or plasma as a test sample, from which exosomes are isolated to extract total RNA and to measure the abundance of each miRNA or the like. The method of extracting total RNA in serum or plasma is well known and is specifically described in Examples below. The method of extracting total RNA from exosomes in serum or plasma is itself known and is specifically described in more detail in Examples below.
The abundance of each miRNA or the like is preferably measured (quantified) using a next-generation sequencer. Any instrument may be used and is not limited to a specific type of instrument, provided that the instrument determines sequences, similarly to next-generation sequencers. In the method of the present invention, as specifically described in Examples below. use of a next-generation sequencer is preferred over quantitative reverse-transcription PCR (qRT-PCR), which is widely used for quantification of miRNAs, to perform measurements from the viewpoint of accuracy because miRNAs or the like to be quantified include, for example, isomiRs, in which only one or more nucleotides are deleted from or added to the 5′ and/or 3′ ends of the original mature miRNAs thereof, and which should be distinguished from the original miRNAs when measured. Briefly, though details will be described specifically in Examples below, the quantification method can be performed as follows. When the RNA content in serum or plasma is constant, among reads measured in a next-generation sequencing analysis of the RNA content, the number of reads for each isomiR or mature miRNA per million reads is considered as the measurement value, where the total counts of reads with human-derived sequences are normalized to one million reads. When the RNA content in serum or plasma is variable in comparison with healthy subjects due to a disease, miRNAs showing little abundance variation in serum and plasma may be used. In cases where the abundance of miRNAs or the like in serum or plasma is measured, at least one miRNA selected from the group consisting of let-7g-5p, miR-425-3p, and miR-425-5p is preferably used as an internal control, which are miRNAs showing little abundance variation in serum and plasma.
The cut-off value for the abundance of each miRNA or the like for use in evaluation is preferably determined based on the presence or absence of a statistically significant difference (t-test; p<0.05, preferably p<0.01, more preferably p<0.001) from healthy subjects with regard to the abundance of the miRNA or the like. Specifically, the value of log2 read counts (the cut-off value) can be preferably determined for each miRNA or the like, for example, at which the false-positive rate is optimal (the lowest); for example, the cut-off values (the values of log2 read counts) for several miRNAs or the like are as indicated in Table 2. The cut-off values indicated in Table 2 are only examples, and other values may be employed as cut-off values as long as those values are appropriate to determine statistically significant difference. Additionally, the optimal cut-off values vary among different populations of patients and healthy subjects from which data is collected. However, the cut-off values indicated in Table 2 or 3 with an interval of usually ±20%, particularly ±10%, may be set as cut-off values.
Each of the above miRNAs or the like is statistically significantly different in abundance between patients with head and neck cancer and healthy subjects, and may thus be used alone as an index. However, a combination of multiple miRNAs or the like may also be used as an index, which can assist in more accurate detection of head and neck cancer.
Moreover, a method of detecting the abundance of miRNAs or the like in a test sample from human suspected of having or affected with head and neck cancer is also provided.
That is, a method of detecting the abundance of at least one of miRNAs, isoform miRNAs (isomiRs), precursor miRNAs, transfer RNA fragments (tRFs), or non-coding RNA fragments (LincRNAs or MiscRNAs) whose nucleotide sequence is represented by any one of SEQ ID NOs: 162, 160, 145, 143, 146, 140, 141, 1 to 139, 142, 144, 147 to 159, and 161 in a test sample from human suspected of having or affected with head and neck cancer is also provided, wherein the method includes the steps of:
collecting a blood sample from human; and
measuring the abundance of the miRNA(s), isoform miRNA(s) (isomiR(s)), precursor miRNA(s), transfer RNA fragment(s) (tRF(s)), or non-coding RNA fragment(s) (LincRNA(s) or MiscRNA(s)) in the blood sample by means of a next-generation sequencer or qRT-PCR,
wherein the abundance of at least one of the miRNAs, isomiRs, precursor miRNAs, transfer RNA fragments, or non-coding RNA fragments whose nucleotide sequence is represented by any one of SEQ ID NOs: 1 to 71 and 118 to 136 is higher than that in healthy subjects, or the abundance of at least one of the miRNAs, isomiRs, precursor miRNAs, transfer RNA fragments, or non-coding RNA fragments whose nucleotide sequence is represented by any one of SEQ ID NOs: 72 to 117 and 137 to 162 is lower than that in healthy subjects.
In the present invention, the term head and neck cancer includes, for example, tongue cancer (oral cavity cancer), maxillary sinus cancer, nasopharyngeal cancer, oropharyngeal cancer, hypopharyngeal cancer, laryngeal cancer, thyroid cancer, salivary gland cancer, and metastatic cervical carcinoma from unknown primary.
Additionally, in cases where the detection of head and neck cancer is successfully achieved by the above-described method of the present invention, an effective amount of an anti-head and neck cancer drug can be administered to patients in whom head and neck cancer is detected, to treat the head and neck cancer. Examples of the anti-head and neck cancer drug can include cisplatin (CDDP), 5-FU (5-fluorouracil), and docetaxel.
The present invention will be specifically described below by way of examples and comparative examples. Naturally, the present invention is not limited by the examples below.
Plasma samples from 24 patients with head and neck cancer and from 10 healthy subjects were used.
Extraction of RNA in serum was performed using the miRNeasy Mini kit (QIAGEN).
Exosomes in serum were collected as follows.
Exosome isolation was performed with the Total Exosome Isolation (from serum) from Thermo Fisher Scientific, Inc. Extraction of RNA from the collected exosomes was performed using the miRNeasy Mini kit (QIAGEN).
(4) Quantification of miRNAs or the Like
The quantification of miRNAs or the like was performed as follows.
In cases where miRNAs or the like from, for example, two groups are quantified, extracellular vesicles (including exosomes) isolated by the same method are used to purify RNAs through the same method, from which cDNA libraries are prepared and then analyzed by next-generation sequencing. The next-generation sequencing analysis is not limited by a particular instrument, provided that the instrument determines sequences.
Specifically, the cut-off value and the AUC were calculated from measurement results as follows. The logistic regression analysis was carried out using the JMP Genomics 8 to draw the ROC curve and to calculate the AUC. Moreover, the value corresponding to a point on the ROC curve which was closest to the upper left corner of the ROC graph (sensitivity: 1.0, specificity: 1.0) was defined as the cut-off value.
The results are presented in Tables 2-1 to 2-10.
As seen in these results, the abundance of the miRNAs or the like represented by SEQ ID NOs: 1 to 71 and 118 to 136 was significantly higher in the patients with head and neck cancer than that in the healthy subjects, and the miRNAs or the like represented by SEQ ID NOs: 72 to 117 and 137 to 162 was significantly lower in the patients with head and neck cancer than in the healthy subjects. It was indicated that head and neck cancer was able to be detected with high accuracy by the method of the present invention (Examples Ito 116, 122 to 165, and 167 to 168).
Moreover, the result presented in Table 2-9 showed that the FC (fold change) in the abundance of the isomiR represented by either SEQ ID NO: 115 or SEQ ID NO: 116 was changed before and after surgery for tongue cancer, indicating that the isomiRs can be used to assess the success or failure of the surgery. Furthermore, the result presented in Table 2-10 showed that the combinations of the miRNAs represented by SEQ ID NOs: 11 and 30, SEQ ID NOs: 11 and 26, SEQ ID NOs: 11 and 117, SEQ ID NOs: 30 and 118, and SEQ ID NOs: 157 and 162 had an AUC value ranging from 0.91406 to 0.97628, indicating that even early tongue cancer can be detected by using any of the combinations.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-238856 | Dec 2017 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/045994 | 12/13/2018 | WO | 00 |
