These peptides include neurotensin,277–279 glucagon-like peptide-1 (GLP-1),280 neuropeptide Y (NPY), peptide YY, gastric inhibitory peptide (GIP) and cholecystokinin.281 A positive correlation between obesity and PDAC risk is well established, but the mechanism(s) involved remain incompletely understood. The gene discussed is GLP1R; the disease is obesity due to melanocortin 4 receptor deficiency.