FASLG and neoplasm: Exosomes released by tumor cells express immunosuppressive molecules such as Fas-ligand (FasL) [42], tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), programmed death-ligand 1 (PD-L1), and interleukin 10 (IL-10), neo-angiogenesis factors, as well as microenvironment conditioning factors, e.g., transforming growth factor β1 (TGF-β1), prostaglandin E2 (PGE2), and ectoenzymes engaged in the adenosine pathway (CD39 and CD73) [43–45].