TGFB1 and neoplasm: Mexo isolated from tumor cell supernatants or obtained from cancer patient plasma [112] contain inhibitory cytokines such as IL-10, TGF-β1 and prostaglandin E2 (PGE2), death receptor ligands such as Fas Ligand or TRAIL, enzymes involved in the adenosine pathway such CD39 and CD73, checkpoint receptor ligands such as PD-L1 [112,115].