ADORA3 and cancer: Adenosine is a signaling molecule thatis the endogenous agonistto four adenosine receptors (ARs): the A1, A2A, A2B, and A3 adenosine receptors (A1AR, A2AAR, A2BAR, and A3AR) thatare members of the larger G protein-coupled receptor (GPCR) family.1−3 Activation of the ARs via binding of adenosine induces a cascadeof intracellular signaling pathways that in turn modulate the cellularresponse to physiological and pathophysiological conditions, examplesbeing inflammation, autoimmune disorders, and cancers.4−6