This contributed towards the rationale for successful clinical studies where rapalogue treatment was combined with aromatase inhibitor (BOLERO-2) or tamoxifen (TAMRAD) therapy[26,27,43,44] which resulted in approval of the rapalogue everolimus (Afinitor, RAD001), in combination with the steroidal aromatase inhibitor exemestane (Aromasin), for treatment of post-menopausal women with advanced ER+/HER2- breast cancer progressing on a non-steroidal aromatase inhibitor. Here, CYP19A1 is linked to breast cancer.