ERBB2 and breast cancer: Tyrosine kinase inhibitors (e.g., lapatinib) block HER2’s intracellular signalling activity [56], while antibody–drug conjugates such as T-DM1 (trastuzumab emtansine) is an antibody–drug conjugate (ADC) used in cancer therapy, specifically for HER2-positive breast cancer, which deliver targeted chemotherapy [57].