The interaction between NK activating receptors, including NKG2D, NKG2C, DNAM-1, NCRs (NKp46, NKp44, and NKp30), and NKp80, with their corresponding ligands on tumor cells results in the activation of NK cells, leading to enhanced NK cell cytotoxicity (3–5). This evidence concerns the gene KLRF1 and neoplasm.