This biased agonism can be observed in both the recombinant cells used in this mutagenesis study and natively expressing insulinoma cells that display key features of β islets, where both exendin-4 and oxyntomodulin were biased away from GLP-1 in promotion of cellular proliferation and reducing apoptosis, compared to cAMP signaling (Figure S2). The gene discussed is GLP1R; the disease is pancreatic insulinoma.