The phase III SOLAR-1 clinical trial of alpelisib plus fulvestrant in HR-positive/HER2-negative MBC showed better PFS in the alpelisib–fulvestrant group in the cohort of patients with PIK3CA-mutated cancer (hazard ratio, 0.65; 95% CI, 0.50–0.85; p < 0.001) (NCT02437318) [79]. This evidence concerns the gene ERBB2 and cancer.