A series of drugs including monoclonal antibodies (e.g. trastuzumab and pertuzumab), tyrosine kinase inhibitors (e.g. lapatinib, neratinib, and tucatinib) and antibody-drug conjugates (e.g. trastuzumab emtansine and trastuzumab deruxtecan) have significantly improved cure rates in early-stage HER2-positive breast cancer patients, prolonging the survival of patients in advanced metastatic stages. Here, ERBB2 is linked to breast cancer.