ERBB2 and breast cancer: There are multiple HER2-targeted therapies approved for the treatment of HER2+ breast cancer, including the monoclonal antibody therapies (mAbs) trastuzumab and pertuzumab, the tyrosine kinase inhibitors (TKIs) lapatinib, tucatinib and neratinib, and the antibody drug conjugates (ADCs) T-DM1 and T-DXd [2].