<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>A disorder in which tumors of the pancreatic islet cells produce large amounts of gastrin (a hormone), leading to excess acid in the stomach and, possibly, a peptic ulcer (ulcer of the stomach or the upper part of the small intestine).</n0:def-definition><n0:def-source>NCI-GLOSS</n0:def-source></n0:ComplexDefinition>
<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>A syndrome characterized by the presence of a gastrin-secreting tumor, usually in the pancreas or duodenum, resulting in increased gastric acidity and formation of gastric ulcers. Signs and symptoms include abdominal pain and diarrhea. It may be sporadic or a manifestation of multiple endocrine neoplasia type 1.</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>