GNAS and Ewing sarcoma: NPY blocked, via Gi-coupled-Y1R, cAMP formation in Ewing sarcoma cells [142], and the peptide, through the inhibitory guanine nucleotide regulatory protein of adenylate cyclase, also blocked the dopamine-induced cAMP formation in Ewing sarcoma cells (WE-68), but not basal cAMP formation [143].