NK cells can eliminate cancer cells through complex mechanisms: releasing cytotoxic granules containing perforin, granzymes, and granulysin; generating cytokines (such as IFN-γ and TNF-α) to activate antitumor immunity; and death ligands, such as Fas ligand (FasL) and TNF-related apoptosis-inducing ligand (TRAIL) (54). This evidence concerns the gene FASLG and cancer.