P2RX7 and neoplasm: ATP plays a dual role in the TME by exhibiting anti- or pro-tumor effects depending on its extracellular concentration, the presence of purinergic receptors, and the combined activity of ectonucleotidases, such as ecto-nucleoside-triphosphate-diphosphohydrolases (E-NTPDases) and CD73, which metabolize ATP to ADO in the extracellular space (Allard et al., 2016, 2017).