The phase II FAKTION trial recruited women with HR+/HER2− relapsed breast cancer progressing after or during AI and with no prior CDK4/6i; patients received the AKT inhibitor capivasertib plus fulvestrant, and a significant PFS and OS benefit occurred in those carrying mutations in PTEN, AKT1, or PIK3CA genes [132]. The gene discussed is CDK4; the disease is breast cancer.