In 2012 the FDA approved another monoclonal antibody, pertuzumab, which is now used in combination with trastuzumab and chemotherapy for metastatic and even early-stage of HER2+ breast cancer (Angelis et al. 2023; Kreutzfeldt et al. 2020; SmPC Herceptin; SmPC Perjeta). This evidence concerns the gene ERBB2 and breast cancer.