Louise ‘s study showed that for patients < 50 years of age, any OC use before age 20 can increase breast cancer events by approximately threefold, but in patients ≥50 years of age with estrogen receptor-positive tumors, previous OC use at any age can significantly decrease the risk of breast cancer events among patients [66], which may account for the increasing risk between endometriosis and breast cancer for some people. Here, ESR1 is linked to breast cancer.