Cancer detection methods
View Patent ↗The present application provides methods for the detection and diagnosis of cancer. In one aspect, the application provides methods for detecting the presence of cancer in an individual by detecting the methylation state of a region in the promoter of the ZNF154 gene. Methods are provided for detection and diagnosis of cancer from circulating tumor DNA which are minimally invasive and have diagnostic utility across different types and sub-types of cancer. In a further aspect, bioinformatics methods are provided to analyze the methylation state of the ZNF154 promoter and relate the methylation state to the likelihood of cancer in the individual.
1. A computer-implemented method for classifying DNA methylation of a cancer biomarker in a human individual, comprising:
treating cell free genomic DNA from a plasma sample from the individual with bisulfite to produce bisulfite-treated genomic DNA;
PCR amplification of a target nucleic acid molecule comprising the nucleotides 58,220,424 to 58,220,670 of chromosome 19 according to the human genome version GRCh37/hg19 from the bisulfite-treated genomic DNA to produce amplicons;
sequencing the amplicons to produce a plurality of sequence reads;
receiving the plurality of sequence reads on the computer
identifying the methylation status of 20 CpG sites within the nucleotides 58,220,424 to 58,220,670 of chromosome 19 of the genomic DNA from the sequence reads using the computer; and
classifying DNA methylation of the cancer biomarker as hypermethylated or not based on the identified methylation status of the 20 CpG sites;
wherein classification of the cancer biomarker as hypermethylated indicates that the plasma sample is from a subject with the cancer;
wherein classification of the cancer biomarker as not hypermethylated indicates that the plasma sample is from a subject without the cancer; and
wherein the cancer is selected from lung cancer, stomach cancer, colon cancer, breast cancer, uterine cancer, bladder, head and neck, kidney, liver, ovarian, pancreas, prostate, and rectum cancer.
2. The computer-implemented method of claim 1 , wherein classifying DNA methylation of the cancer biomarker based on the identified methylation status of the 20 CpG sites comprises:
identifying frequencies of sequence reads in the plurality where 0 or 20 of the 20 CpG sites within the nucleotides 58,220,424 to 58,220,670 of chromosome 19 of the genomic DNA are methylated CpG sites; and
calculating a ratio X:
X=N 20 /( N 0 +N 20 )
wherein N 0 and N 20 are the frequencies of sequence reads in the plurality where 0 or 20 of the 20 CpG sites within the nucleotides 58,220,424 to 58,220,670 of chromosome 19 of the genomic DNA are methylated, respectively; and
wherein an increase in the ratio X as compared with a control classifies the cancer biomarker as hypermethylated; and
wherein no increase in the ratio X as compared with the control classifies the cancer biomarker as not hypermethylated.
3. The computer-implemented method of claim 1 , wherein classifying DNA methylation of the cancer biomarker based on the identified methylation status of the 20 CpG sites comprises:
identifying the frequencies of sequence reads in the plurality where 0, 1, 2, 3, 4, 5, or 20 of the 20 CpG sites within the nucleotides 58,220,424 to 58,220,670 of chromosome 19 of the genomic DNA are methylated CpG sites; and
calculating a ratio Y:
Y=N 20 /( N 0 +N 1 +N 2 +N 3 +N 4 +N 5 +N 20 )
wherein N 0 , N 1 , N 2 , N 3 , N 4 , N 5 , and N 20 , are the frequencies of sequence reads in the plurality where 0, 1, 2, 3, 4, 5 or 20 of the 20 CpG sites within the nucleotides 58,220,424 to 58,220,670 of chromosome 19 of the genomic DNA are methylated, respectively; and
wherein an increase in the ratio Y as compared with a control classifies the cancer biomarker as hypermethylated; and
wherein no increase in the ratio Y as compared with the control classifies the cancer biomarker as not hypermethylated.
4. The method of claim 1 , wherein the cytosines of the 20 CpG sites are located at nucleotides 58220424, 58220440, 58220443, 58220446, 58220460, 58220466, 58220479, 58220482, 58220494, 58220500, 58220513, 58220516, 58220535, 58220567, 58220572, 58220595, 58220627, 58220657, 58220662, and 58220669 of chromosome 19.
5. The method of claim 1 , wherein the control is a threshold value that distinguishes between individuals with and without cancer.
6. The method of claim 1 , wherein genomic DNA corresponding to the amplicons comprises or consists the nucleotide sequence set forth as SEQ ID NO: 5.