In the SOLAR-1 Phase III clinical trial, patients with PIK3CA-mutated ER+/HER2− breast cancer had almost a doubling in PFS in response to the p110α-selective PI3K inhibitor alpelisib (BYL719) (Piqray®) in combination with fulvestrant compared to patients treated with fulvestrant with placebo [21]. The gene discussed is ESR1; the disease is breast carcinoma.