NK cells exert direct and indirect antitumor activity and kill target tumor cells via release of granules containing perforin and granzyme, secretion of cytokines such as IFNγ and other effector molecules, ligation and activation of death receptors, and antibody-dependent cellular toxicity (ADCC) mediated through CD16 when combined with anti-tumor antibodies. This evidence concerns the gene PRF1 and neoplasm.