Methylenetetrahydrofolate Reductase and Methionine Synthase Polymorphism and Risk of Non-Hodgkin’s Lymphoma.

Methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MTR) are key enzymes in folate metabolism, which is essential for DNA methylation and synthesis. It is known that polymorphisms in its genes have been associated with some forms of cancer including lymphoma. Previous studies have shown MTHFR 677TT was associated with decreased risk of non-Hodgkin’s lymphoma(NHL). However, recent two reports have shown MTHFR 677TT was associated with increased risk. To evaluate the association between the MTHFR C677T and MTR A2756G polymorphisms and risk of non-Hodgkin’s lymphoma, large-scale population-based case-control study was conducted in Chonnam University Hwasun Hospital between March 1997 and June 2005. Three hundreds sixty-five patients with histologically comfirmed lymphoma and 1,162 controls were evaluated. Genotyping was done using PCR-RFLP. The cases consisted of 203 diffuse large B-cell lymphomas(DLBCL), 77 T-cell lymphomas, 62 other B-cell lymphomas, and 23 unclassifiable lymphomas. The MTHFR 677CT and 677TT genotypes were inversely associated with NHL and DLBCL, respectively. Using subjects with the MTHFR 677CC as reference group, the odds ratio of MTHFR 677CT and 677TT were (0.70, 95% CI 0.54–0.90) and (0.46, 95% CI 0.32–0.68) for NHL. The association was more evident for DLBCL (OR 0.56, 95% CI 0.40–0.78 for 677CT; OR 0.40, 95% CI 0.24–0.65 for 677TT). Dose-response effect was evident for the MTHFR T-allele (p < 0.01). There was no significant association of MTR A2756G with NHL. These results suggest that the MTHFR polymorphism may play an important role in the pathogenesis of NHL, particularly DLBCL.