In the context of breast cancer, several randomized clinical trials over the past three decades have demonstrated that selective estrogen receptor modulators (SERMs) such as tamoxifen and raloxifene, as well as aromatase inhibitors (AIs) including exemestane and anastrozole, can significantly reduce the incidence of hormone receptor-positive breast cancer in high-risk populations [6,7,8,9,10,11,12]. Here, ESR1 is linked to breast cancer.