ERBB2 and breast cancer: Cleavable linkers have been used in many ADCs, such as hydrazone linkers in gemtuzumab ozogamicin targeting CD33 for patients with AML, dipeptide (VC) MMAE linkers in brentuximab vedotin (SGN-35) targeting CD30 for patients with Hodgkin lymphoma, and SMCC linkers in trastuzumab emtansine targeting HER2 for HER2-positive breast cancers [101, 102].