P2RY2 and synovial sarcoma: Expression of the P2X7 receptor (P2X7R) and the P2Y2 receptor (P2Y2R) for extracellular adenosine 5ʹ-triphosphate are upregulated under proinflammatory conditions,55–60 including in salivary glands of SS patients,61 mouse models of SS,62,63 and activated immune cells.64