Association between dietary intake of folate, Vitamin B6, B12 & MTHFR, MTR Genotype and breast cancer risk

Objective: we conducted a case-control study to investigate the association between dietary folate, vitamin b6 and vitamin b12 intake, mthfr and mtr genotype, and breast cancer risk. methods: 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 b6 and vitamin b12 were calculated by each food item from questionnaire. results: subjects with breast cancer tended to have more first-degree relatives (χ²=30.77, p < 0.001) and have high intake of folate (t=2.42, p=0.008) and vitamin b6 (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 b6 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). conclusion: this case-control study found a significant association between mthfr c667t polymorphism, folate intake and vitamin b6 and breast cancer risk, and a significant interaction was observed between mthfr c667t polymorphism and folate intake on the risk of breast cancer.