In summary, the KIR AA genotype confers differential protection against ALL, AML, CML and NHL; whereas the C2 ligand enhances KIR AA protection against CML, the C1 and Bw4 ligands enhance KIR AA protection against ALL, and the KIR AA genotype alone protects from AML and NHL. Here, KIR3DL1 is linked to non-Hodgkin lymphoma.