In CAPItello-291, capivasertib–fulvestrant significantly improved progression-free survival (PFS) versus placebo–fulvestrant in the overall and PIK3CA/AKT1/PTEN-altered population with hormone receptor-positive (HR-positive)/human epidermal growth factor receptor 2-negative (HER2-negative) advanced breast cancer. Here, AKT1 is linked to breast cancer.