On the other hand, trastuzumab deruxtecan (T-DXd), an ADC, has shown efficacy in HER2+, HER2-low, and HER2-ultralow metastatic breast cancer (60, 61) as well as in HER2+ and HER2-low endometrial, cervical, ovarian, and bladder cancers (62). The gene discussed is ERBB2; the disease is urinary bladder cancer.