MTHFR and breast carcinoma: Previous studies have suggested an inverse association between high consumption of folate intake and methyl-related B vitamins and risk of breast cancer in different populations.15, 16 However, the results of studies regarding the protective effects of folate and B vitamins intake against breast cancer risk remains inconsistent.15-17 Therefore, 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.