However, despite impaired NK cell leukemia cytolytic activity, NK cells appear to maintain their intrinsic functionality, and that impaired NK cell function may be a result of mismatched NK cell receptor-ligand pairing on NK cells and leukemia cells, as well as secretion of immunosuppressive cytokines such as TGF-B by leukemia cells [81,82]. This evidence concerns the gene TGFB1 and leukemia.