Global DNA hypomethylation and biomarkers for clinical indications in cancer
The present invention provides methods of determination of a global DNA methylation index (GDMI) in a sample from a subject, using a variety of methods which can detect global, genome-wide, and gene-specific DNA methylation to create methylation portraits that can be used for early detection, diagnosis, and clinical management in the personalized medicine space. Further, the invention provides methods of diagnosis of cancer, including gastric cancer and hepatocellular cancer in a subject, by comparing the GDMI in a sample obtained from a subject to the methylation index of standard controls. These methods allow diagnosis of gastric carcinoma and liver cancer in patients who may be asymptomatic or have inconclusive pathology, and allowing earlier treatment of the subject.
1. A method for identifying a subject as having hepatocellular carcinoma (HCC) comprising:
a) obtaining a biological sample of hepatocytes comprising DNA from the subject;
b) performing bisulfite modification to the DNA in a);
c) performing quantitative real-time methylation specific PCR (QMSP) on bisulfite modified DNA from the sample using PCR primers and probes specific for the promoter region of the genes of interest, wherein the genes of interest consist of RASSF1A, SSBP2, and B4GALT1;
d) determining the promoter methylation level of the promoter regions of the genes of interest in the DNA from the hepatocyte tissue sample of the subject;
e) providing a reference non-neoplastic hepatocyte tissue sample;
f) comparing the level of methylation of the promoter region of the genes of interest from the hepatocyte tissue sample of the subject, to the level of methylation of the promoter region of the genes of interest in a reference non-neoplastic-hepatocyte tissue sample; and
g) identifying said human subject as having HCC when the level of methylation of the promoter region of the genes of interest in the hepatocyte tissue sample of the subject, is greater than the level of methylation of the promoter region of the genes of interest in a reference non-neoplastic hepatocyte tissue sample.
2. The method of claim 1 , wherein the subject is infected with Hepatitis B virus (HBV) or Hepatitis C virus (HCV).