However, the recently conducted DESTINY-Breast04 trial, Trastuzumab Deruxtecan (T-DXd) in Previously Treated HER2-Low Advanced Breast Cancer, led by Modi et al., reported that T-DXd resulted in significantly longer progression-free and overall survival than the physician’s choice of chemotherapy in patients with HER2-low metastatic breast cancer [60]. The gene discussed is ERBB2; the disease is breast cancer.