FAS and neoplasm: Several different immunosuppressive mediators (e.g., TGF-β, IL-10, prostaglandins, soluble FAS, adenosine, and reactive oxygen species (ROS)) and ligands were secreted or expressed in the TME by tumor cells, cancer-associated fibroblasts (CAFs), myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), neutrophils, mast cells, or Tregs [235].