MTHFR and cancer: Varied activity of folate metabolic enzyme which induced by genetic polymorphisms may have impact on the methylation status and carcinogenesis.13,14 The relationship between DNA methylation of P16, MGMT and hMLH1 genes and MTHFR polymorphisms with the cancer risk has been pointed in several studies.13,15-17 However, the evidences of DNA methylation with gastric cancer risk and relation to MTHFR are still lacking.