CD22 and acute lymphoblastic leukemia: Since then, several ADC, such as Brentuximab vedotin for relapsed Hodgkin’s lymphoma (HL), systemic anaplastic large cell lymphoma (sALCL), Trastuzumab emtansine for HER2-positive metastatic breast cancer, and Inotuzumab ozogamicin for relapsed CD22-positive B-cell precursor acute lymphoblastic leukemia (ALL), have been applied in clinical practice.