Interestingly, while T-DM1 is still the mainstay of treatment in residual disease after neoadjuvant therapy in HER2+ breast cancer, the DESTINY-Breast05 trial is investigating whether a novel antibody-drug conjugate, trastuzumab deruxtecan (T-DXd), may have superior survival outcomes [54]. The gene discussed is ERBB2; the disease is breast cancer.