KIR2DL1 and neoplasm: NK cells licensed through stronger KIR2DL2/L3 alleles have higher cytotoxicity than those with weaker alleles against tumor cells with missing ligands, a finding in line with our previous observation that KIR2DL1+ NK cells licensed through stronger KIR2DL1-R245 have higher cytotoxicity than KIR2DL1-C245 19, 20.