Detection of gene promoter hypermethylation in the tumor and serum of patients with gastric carcinoma.

PURPOSE: Aberrant promoter methylation, an alternative mechanism for gene silencing, is frequently detected in gastric cancer. We studied the feasibility of detecting aberrant methylation in serum of gastric cancer patients. EXPERIMENTAL DESIGN: Patients (54) with gastric adenocarcinoma were studied. The tumor and the paired serum were examined for aberrant methylation in DAP-kinase, E-cadherin, GSTP1, p15, and p16 by methylation-specific PCR. Serum from 30 age-matched noncancer patients was used as control. RESULTS: Promoter methylation in DAP-kinase, E-cadherin, GSTP1, p15, and p16 were detected in 70.3, 75.9, 18.5, 68.5, and 66.7% of primary tumor. In serum of gastric cancer patients, methylation in DAP-kinase, E-cadherin, GSTP1, p15, and p16 were detected in 48.1, 57.4, 14.8, 55.6, and 51.9%, respectively. None of the control serum showed aberrant methylation. Aberrant methylation in serum DNA was all accompanied with methylation in the corresponding tumor samples. In general, >60% of serum from cancers with aberrant methylation demonstrated these epigenetic alterations. CONCLUSION: Our findings suggest that aberrant promoter methylation in serum can be detected in a substantial proportion of gastric cancer patients, and this strategy should be evaluated in the screening and surveillance of gastric cancer.