Dietary intake of folate, vitamin B6, and vitamin B12, genetic polymorphism of related enzymes, and risk of breast cancer: a case-control study in Brazilian women

MTHFR polymorphisms and dietary intake of folate, vitamin B6, and vitamin B12 had no overall association with breast cancer risk. However, increased risk was observed in total women with the MTR 2756GG genotype and in premenopausal women with high folate intake. These findings, as well as significant interactions between MTHFR polymorphisms and B vitamins, warrant further investigation.