Association between dietary intake of folate, Vitamin B[6], B[12] and MTHFR, MTR Genotype and breast cancer risk

ABSTRACT

We conducted a case-control study to investigate the association between dietary folate, vitamin B[6] and vitamin B[12] intake, MTHFR and MTR genotype, and breast cancer risk. Genotyping for MTHFR C677T and A1298C and MTR A2756G polymorphisms were performed using polymerase chain reaction-restriction fragment length polymorphism analysis [PCR-RFLP] method. The intake of folate, vitamin B[6] and vitamin B[12] were calculated by each food item from questionnaire. Subjects with breast cancer tended to have more first-degree relatives [X[2]=30.77, P < 0.001] and have high intake of folate [t=2.42, P=0.008] and Vitamin B[6] [t=2.94, P=0.002]. Compared to the reference group, women with MTHFR 677 TT genotype and T allele had a significantly increased risk of breast cancer, with ORs [95%CI] of 1.8[1.08-2.27] and 1.39[1.02-1.92], respectively. For those who had folate intake < 450 ug/day, MTHFR 667TT genotype was associated with a higher risk of breast cancer [OR=2.45, 95% CI=1.09- 5.82, P=0.02]. Similarly, subjects with Vitamin B[6] intake < 0.84 mg/day and MTHFR 667T allele genotype was correlated with a marginally increased risk of breast cancer. A significant interaction was observed between MTHFR C667T polymorphism and folate intake on the risk of breast cancer [P for interaction was 0.025]. This case-control study found a significant association between MTHFR C667T polymorphism, folate intake and vitamin B[6] and breast cancer risk, and a significant interaction was observed between MTHFR C667T polymorphism and folate intake on the risk of breast cancer