The results of the reported effects of chronic hypergastrinemia on gastric ECL cells and other gastric mucosal cells from both groups of ZES patients (i.e., sporadic ZES and MEN1/ZES) show a number of close similarities, as well as some differences with the results from studies of the gastric mucosal effects of chronic hypergastrinemic in animals, as well as seen with chronic use of PPIs in humans and other common chronic hypergastrinemia disorders in man such as chronic atrophic gastritis/pernicious anemia (CAG/PA). Here, MEN1 is linked to Zollinger-Ellison syndrome.