Polymorphisms of 5,10-methylenetetrahydrofolate reductase and risk of stomach cancer in a Korean population.

BACKGROUND: Methylentetrahydrofolate reductase plays a central role in converting folate to methyl donor for DNA methylation. Genetic variations in folate metabolism are believed to contribute to the risk of acute lymphoblastic leukemia, colon, esophageal and stomach cancer, as well as cardiovascular and cerebrovascular diseases. MTHFR C677T and A1298C polymorphisms are known to be risk factors for gastric cancer in the Chinese population. Therefore, we hypothesized that the MTHFR polymorphisms are associated with the risk of stomach cancer in Korean subjects. PATIENTS AND METHODS: We conducted a Korean population-based case-control study to examine the relationship between genetic polymorphisms in MTHFR and risk of stomach cancer. The study subjects were 133 patients with stomach cancer and 445 population controls, matched according to sex and age. Genomic DNA was extracted from blood samples of the controls and from surgically resected "normal" tissues adjacent to the tumor of stomach cancer patients. MTHFR genotypes at the C677T and A1298C sites were analyzed by PCR-based RFLP methods. RESULTS: We found no evidence for an association between the MTHFR C677T and A1298C polymorphisms and stomach cancer in any of the subjects. The adjusted odds ratios and 95% confidence intervals for MTHFR C677T were 0.924 (0.581-1.469) for 677CT versus 677CC wild-type and 1.147 (0.850-1.549) for 677TT versus 677CC, and for MTHFR A1298C, they were 1.114 (0.695-1.783) for 1298AC versus 1298AA wild-type and 0.834 (0.284-2.450) for 1298CC versus 1298AA. CONCLUSION: These results suggest that the MTHFR C677T and A1298C polymorphisms by themselves do not play an important role in the etiology of stomach cancer in the Korean population.