The cytotoxicity of NK cells is dependent upon the release of perforin and granzymes, the secretion of tumor necrosis factor alpha (TNF-α) and the expression of apoptosis-inducing ligands such as Fas ligand (FasL) and TNF-related apoptosis-inducing ligand (TRAIL) which result in the apoptosis of tumor cells via ligand-receptor reactions. This evidence concerns the gene TNF and neoplasm.