Mechanistically, this is mediated via exocytosis of cytotoxic granules from NK cells, containing perforin and granzymes, as well as via induction of the TNF superfamily (Fas ligand and TRAIL) signaling pathways in the tumor cells.20 However, some tumors escape T-cell as well as NK-cell recognition and/or their killing machinery using mechanisms that are incompletely understood.21, 22. The gene discussed is FASLG; the disease is neoplasm.