Regarding the respective role of adenosine receptors, it has been demonstrated that among the four subtypes, adenosine binding to A2AR and A2BR causes an increase in intracellular cyclic adenosine monophosphate (cAMP) and consequently the functional inhibition of immune cells, while A1R and A3R activation leads to tumor growth, cell proliferation and survival in some cases (88–90). This evidence concerns the gene ADORA2A and neoplasm.