It has been hypothesized that ER-negative and perhaps PR-negative breast tumors, which result from hypermethylation of the promoter region of ER and PR,8 are linked to low intake of B vitamins.7 We thus examined the association between vitamin B6 intake and breast cancer risk stratified by the ER and PR status of breast tumors (Table 5). Here, ESR1 is linked to breast carcinoma.