The MONALEESA‐7 and ‐2 phase 3 randomized trials demonstrated a statistically significant progression‐free survival (PFS) and overall survival (OS) benefit with initial ribociclib + endocrine therapy (ET) versus placebo + ET in pre‐ and postmenopausal patients with hormone receptor–positive (HR+)/human epidermal growth factor receptor 2–negative (HER2−) advanced breast cancer (ABC), respectively. This evidence concerns the gene ERBB2 and breast cancer.