CD22 and hematopoietic and lymphoid system neoplasm: Inotuzumab ozogamicin (Besponsa®) against CD22 with an acid-cleavable linker, approved for blood cancer in 2017, was internalized into cells and released a potent cytotoxic agent, N-acetyl-γ-calicheamicin, to the cytoplasm and the nucleus after lysosomal escape [25].