The established risk factors for breast cancer include age, obesity, early menarche, late menopause, alcohol consumption, no breast feeding, estrogen use, and a BRCA genetic mutation (BRCA1 and BRCA2, which produce proteins that help repair damaged DNA; people who inherit harmful variants in one of these genes have increased risks of several cancers, especially breast cancer and ovarian cancer). Here, BRCA1 is linked to breast cancer.