Aberrant promoter hypermethylation of p16, survivin, and retinoblastoma in gastric cancer.

Abstract

Gastric cancer is common and can be found throughout the world. Notoriously like other cancers, gastric cancer is a consequence of cellular regulation disorder. Epigenetics, including many oncogenes or tumour suppressor genes, can provide some clues for this kind of disorder. DNA methylation, especially promoter methylation, which causes the silence/decrease of tumour related genes, has become a focus in various tumour types. The aim of this study was to investigate promoter methylation of certain genes: p16, survivin, retinoblastoma (Rb), all of which have been regarded as genes related to gastric cancer. To detect the promoter methylation of p16, survivin, and Rb genes, peripheral blood samples from 106 gastric cancer patients as well as 18 healthy individuals were collected for Methylation-Specific Polymerase Chain Reaction (MSP) analysis. According to the statistical analysis, positive methylation ratio of p16 was 72.6 % (77 cases), 6 % had methylated survivin (7 cases), and positive methylation ratio of Rb was only 17.9 % (19 cases). The differences of promoter methylation of these genes between the patients group and control group were observed: P (P16) = 5.097E-08, P (survivin) = 0.262, and P (Rb) = 0.187. In the control group, methylated p16 was found in only one case that also had a methylated Rb. However, Survivin could not be found methylated in control cases. In this study, promoter methylation was observed for the p16 gene, which was considered an early potential marker in gastric cancer. This data supports that further investigations should study Rb and survivin as candidate markers for gastric cancer (Tab. 2, Fig. 1, Ref. 35).