P2RX7 and cancer: ATP contributes to EMT induction and invasion in the following 3 aspects: (1) eATP acts as an extracellular messenger molecule by binding and activating various purinergic receptors, leading to PR-mediated specific signaling for EMT induction; (2) eATP is internalized via macropinocytosis and significantly enhances the iATP level in cancer cells.