PIK3CA plays important role in breast cancer treatment, the FDA on May 2019 approved alpelisib (Piqray tablets) to be used in combination with fulvestrant (endocrine therapy) for the treatment of postmenopausal women, and men, with HR+, HER2-, PIK3CA-mutated, advanced or metastatic breast cancer. Here, ERBB2 is linked to breast carcinoma.