TGFB1 and cancer: One of the TGF-β signaling pathways and induced processes described in cancer cells is the exocytosis of cytosolic ATP-containing vesicles, releasing ATP to the extracellular environment and creating an autocrine/paracrine signaling loop through extracellular binding and activating of purinergic receptors (PR) located on plasma membrane of cancer cells (13, 14).