Finally, we can argue that the role of NK cells in CML control seems important after imatinib discontinuation,9, 10, 30 but currently, precise mechanisms associated with disease control are still unclear and KIR genotype, as reflects of NK cell ability to exert a cytotoxicity against tumor cells is only partial.7 This evidence concerns the gene KIR3DL1 and chronic myelogenous leukemia, BCR-ABL1 positive.