FAS and neoplasm: Various immune cells, such as the tumor-associated macrophage (TAM), dendritic cell (DC), regulatory T cell (Treg), myeloid-derived suppressor cell (MDSC), and tumor exhibited ligands, such as the natural killer group 2 member D ligand (NKG2DL), natural cytotoxicity receptors (NCR) ligand, TNF-related apoptosis-inducing ligand-receptor (TRAIL-R), and FAS, have been involved in this process.