Positive association between MTHFR C677T polymorphism and oral cancer risk: a meta-analysis.

Methylenetetrahydrofolate reductase (MTHFR) is a central enzyme involved in regulating the metabolic function of folate, which plays a pivotal role in DNA synthesis, repair, and methylation. The role of MTHFR C677T polymorphism in oral cancer risk has been reported with conflicting evidence. We conducted this study to appropriately estimate the effect size. We searched eligible studies in medicine-specific databases (PubMed, EMBASE, and Web of Knowledge) using (polymorphism) OR (polymorphisms) AND (methylenetetrahydrofolate reductase) OR (MTHFR) AND (oral cancer). A total of seven studies were summarized. This meta-analysis of the combined data showed a marginal association of MTHFR C677T polymorphism with oral cancer risk [odds ratio (OR) = 0.86, 95% confidence interval (CI) = 0.73-1.00 for CT vs. CC]. We also found decreased oral cancer risk in Asian population and hospital-based studies. Moreover, heavy drinkers were found to have a significantly higher risk of developing such cancer as compared to the non-heavy drinkers. These results suggest that MTHFR C677T polymorphism may play a role in oral cancer carcinogenesis in Asian population and heavy drinkers.