ESR1 and breast cancer: The literature (cohort studies) on folate intake and risk of breast cancer subtypes defined by ER and PR status is less extensive[8,12,13,30,34,36,37]; some reported null results [8,36], whereas the Nurses’ Health Study[37], the Vitamins And Lifestyle study [12], and the EPIC study (in premenopausal women only) [34] found that high folate intake was associated with lowered risk of ER- breast cancer.