In summary, in Italy, trastuzumab is approved in neoadjuvant treatment for tumors >1 cm or node-positive BC patients and, in case of complete pathological response, in adjuvant therapy (NOAH trial); T-DM1 is approved and reimbursed as adjuvant therapy for residual disease after neoadjuvant treatment with trastuzumab (KATHERINE trial), whereas the double blockade with pertuzumab and trastuzumab is approved and reimbursed in Italy only in adjuvant setting for untreated high-risk (node-positive) HER2+ BC patients (APHINITY trial). This evidence concerns the gene ERBB2 and breast cancer.