The CLEOPATRA trial confirmed that adding pertuzumab to trastuzumab and docetaxel significantly improved overall survival in patients with HER2-positive metastatic breast cancer who had not previously received chemotherapy or anti-HER2 therapy for metastatic disease, presenting a median investigator-assessed progression-free survival of 18.7 months [8]. This evidence concerns the gene ERBB2 and metastatic neoplasm.