Evaluation of the contribution of methylenetetrahydrofolate reductase genotypes to Taiwan breast cancer

The aim of the present study was to evaluate the effects of the genotypic polymorphisms in methylenetetrahydrofolate reductase (MTHFR) and its interaction with early-onset breast cancer risk in Taiwan. Two well-known polymorphic variants of MTHFR, C677T (rs1801133) and A1298C (rs1801131), were analyzed and their joint effects with individual age- and estrogen-related factors on breast cancer risk were discussed. In total, 1,232 patients with breast cancer and 1,232 healthy controls were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The MTHFR C677T genotype, but not the A1298C, was differently distributed between cancer and control groups. The T allele of MTHFR C677T was significantly more frequently found in controls than in patients with cancer. In addition, females carrying MTHFR C677T CT or TT genotypes had a higher odds ratio of 1.21 (95% confidence interval=1.03-1.42, p=1.85E-5) for breast cancer, especially before the age of 45.4 years (odds ratio=1.51 and 95% confidence interval=1.20-1.90). Our results indicate that MTHFR C677T T allele was associated with increased risk of breast cancer in Taiwan, especially in cases who were 45.4 old or younger and with earlier menarche age (