A Methylation Profile of Circulating Cell Free DNA for the Early Detection of Gastric Cancer and the Effects after Surgical Resection

Circulating cell free DNA (cfDNA) has been suggested as a novel biomarker for the early detection of cancer. Therefore, we investigated whether the methylation pattern of promoters of critical genes in cfDNA can be a useful marker for the early detection of gastric cancer and the therapeutic effects of treatment. In this casecontrol study, the methylation status of 32 cancer associated genes from 41 gastric cancer patients and 104 healthy control subjects were measured by methylation-specific PCR. We found that 15 out of 32 cancer-associated genes were hypermethylated in cancer patients compared to those of the controls. Further, we found that a gene panel of PYCARD, APAF1, MINT1, and BRCA1 genes showed 97.6% sensitivity and 66.3% specificity for the presence of gastric cancer. Lastly, we found that 22 initially methylated genes became unmethylated after surgical resection of the tumor (p< 0.05). The aberrant methylation pattern of tumor suppressor genes can be reliable biomarkers for the early detection of gastric cancer and of the efficacy of surgical resection.