studied the expression of 13 peptide receptors on the surface of insulinoma cells and found that GLP-1R, cholecystokinin-2, and vasoactive intestinal peptide-1 receptors had the highest incidence in insulinoma, but the density of the latter two was far lower than that of GLP-1R (24). The gene discussed is GLP1R; the disease is pancreatic insulinoma.