Polymorphisms of 5,10-methylenetetrahydrofolate reductase and risk of gastric cancer in a Chinese population: a case-control study.

Low dietary folate intake has been associated with increased risk of gastric cancer. The 5,10-methylenetetrahydrofolate reductase (MTHFR) involved in folate metabolism has 2 variants, C677T and A1298C, that result in decreased MTHFR activity and lower plasma folate levels. Therefore, we hypothesized that these 2 variants play a role in gastric carcinogenesis. We tested this hypothesis in a Chinese population-based case-control study of 187 histopathologically confirmed gastric cancer cases and 166 healthy controls frequency-matched by age (+/-5 years), gender and residential area. The 677TT genotype was associated with increased risk for gastric cancer [adjusted odds ratio (OR) = 1.87, 95% confidence interval (CI) = 1.00-3.48] compared to the 677CC genotype. This association was more pronounced for gastric cardia cancer (adjusted OR = 2.47, 95% CI = 1.14-5.32). However, no evidence was found for risk associated with the MTHFR A1298C polymorphism. Our findings support the hypothesis that MTHFR C677T variants contribute to gastric carcinogenesis, particularly in gastric cardia. Larger studies incorporating dietary folate intake and serum levels are needed to confirm our findings. Copyright 2001 Wiley-Liss, Inc.