ERBB2 and breast cancer: Lapatinib stands as the leading HER2 TKI in clinical practice, in a Phase III trial, its combination showcased superior progression-free time when compared to the sole utilization of capecitabine (8.4 months vs. 4.4 months; P < .001).[122,124] T-DM1 is currently the only approved antibody–drug conjugate for advanced HER2-positive breast cancer,[125] consisting of trastuzumab linked to a potent anti-microtubule agent DM1 through a nonreducible thioether linkage (SMCC).[126] T-DM1 interacts with the HER2 receptor, causing internalization and subsequent release of DM1 inside the cell.