The Methylenetetrahydrofolate Reductase C677T Polymorphism and Breast Cancer Risk in Asian Populations

Background: Methylenetetrahydrofolate (MTHFR) is the key enzyme of the folate metabolic pathway and several studies have pointed to association between the MTHFR C677T polymorphism and breast cancer risk. Although significant association was observed in some studies, in others no clear link could be established. Objective: A meta-analysis of published Asian case control studies was therefor carried out to shed further light on any C677T breast cancer association. Materials and Methods: PubMed, Springer Link, Google Scholar and Elsevier databases were searched for case control studies of associations between MTHFR C677T polymorphism and breast cancer risk. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. A total of 36 studies including 8,040 cases and 10,008 controls were included in the present meta-analysis. Results: Overall, a significantly elevated breast cancer risk was associated with the T allele and TT genotype in homozygote comparison and dominant genetic models when all studies were pooled into the metaanalysis (T vs C (allele contrast model): OR=1,23, 95% CI=1.13-1.37, p=0.000; TT vs CC(homozygote model): OR=1.38, 95 %CI=1.16-1.63, p=0.0003; TT+CT vs CC (dominant model): OR=1.12, 95 %CI=1.01-1.23, p=0.02). Conclusions: The present meta analysis strongly suggested a significant association between the MTHFR C677T polymorphism and risk of breast cancer in Asian populations.