Everolimus is FDA approved for a series of indications including hormone receptor-positive, HER2-negative advanced breast cancer (in combination with aromatase inhibitors), neuroendocrine tumors (NET) of gastrointestinal (GI) or lung origin, advanced renal carcinoma, renal angiomyolipoma associated with tuberous sclerosis complex (TSC), subependymal giant cell astrocytoma (SEGA) associated with TSC [23]. This evidence concerns the gene CYP19A1 and breast cancer.