<prompt> Most common functional pancreatic endocrine tumor associated with MEN 1 is:Zollinger-Ellison syndromeInsulinomaGlucagonomaVIPoma  <response>: Functional pancreatic endocrine tumor in MEN 1 : 54 develope Zollinger-Ellison syndrome, 18 insulinomas, 3 glucagonomas, 3 VIPomas. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 3060 