<prompt> Tumor of which of the following type of cells result in Zollinger Ellison syndrome?ECL cellsChief cellsG cellsS cells  <response>: Zollinger Ellison syndrome is a malignancy of the gastrin secreting G cells present in the antral mucosa of the stomach. Parietal cells secrete acid and intrinsic factor, chief cells secretes pepsinogen, ECL cells synthesize histamine, and secretin is synthesized by the S cells of the duodenum. Ref: LANGES Gastrointestinal Physiology By Kim E Barrett chapter 3. 