Based on randomized evidence showing significant progression-free and numerical clinically meaningful overall survival benefit when the oral PI3K—selective inhibitor alpelisib is combined with fulvestrant in patients with PIK3CA-mutated HR + /HER2- advanced or metastatic BC who progressed during or after endocrine therapy, this treatment combination has been approved from regulatory authorities [8, 9]. This evidence concerns the gene ERBB2 and breast cancer.