FAS and neoplasm: TNF family members, such as FasL or TNF-related apoptosis-inducing ligands (TRAILs), are expressed by some NK cells, which, upon interaction with their corresponding receptors (Fas and TRAILs), induce apoptosis of tumor cells by limiting tumor angiogenesis and enhancing adaptive immunity through the release of many effector molecules with anticancer properties, such as IFN-γ [25,29].