KIR3DL1 and acute myeloid leukemia: One of the first clinical observations that demonstrated the relevant role of NK cells in the fight against cancer was the appreciation that in patients with acute myeloid leukemia (AML) that were subjected to an allogeneic HSCT, the success of it was greater when donor subsets of NK cells possessed a KIR repertoire that do not interact with HLA class I molecules in the recipient.