For example, Trastuzumab deruxtecan (T-DXd) is a human epidermal growth factor 2 (HER2) -directed antibody-drug conjugated compound that can be used in breast and stomach cancers with high HER2 expression and in non-small cell lung cancers with HER2 mutations (26). The gene discussed is ERBB2; the disease is non-small cell lung carcinoma.