Effector CTLs can exert antigen-driven anti-tumor responses through granule exocytosis mediated by perforin and the granule-associated enzymes (granzymes), through Fas ligand (FasL) induced apoptosis, or indirectly through secreted cytokines such as interferon γ (IFNγ) [11, 12]. This evidence concerns the gene IFNG and neoplasm.