CD33 and acute myeloid leukemia: These cells display prominently NK-like properties, with high cytotoxic activity; they kill primary AML and MDS cells with a high efficacy, through different targeting mechanisms; they target a population of leukemic cells, such as leukemia stem and progenitor cells characterized by a lower CD33 expression; and they also exhibit bone-marrow homing capacity mediated by chemokine receptors, CXCR4 and CCR5 [52].