<prompt> Zollinger Ellison syndrome is caused by ?Gastrin secreting tumorSomatostatin secreting tumorCCK secreting tumorAdrenalin secreting tumor  <response>: Ans. is a i.e., Gastrin secreting tumor Zollinger-Ellison syndrome is caused by gastrin-secreting tumors. These gastrinomas are most commonly found in the small intestine or pancreas. 