Xenin-immunoreactive cells and extractable xenin in neuroendocrine tumors of duodenal origin.

Abstract

BACKGROUND & AIMS:

Xenin is a 25-amino acid peptide produced by specific endocrine cells of the duodenal mucosa. We investigated whether xenin is expressed in neuroendocrine tumors.

METHODS:

Seventy-two foregut and midgut neuroendocrine tumors were examined by means of immunohistochemistry, confocal laser microscopy with an antibody against the C-terminus of xenin, and high-pressure liquid chromatography after acidic extraction, assessed by radioimmunoassay.

RESULTS:

We found xenin-immunoreactive cells in 23 of 26 duodenal neuroendocrine tumors, including gastrinomas, somatostatinomas, and nonfunctioning and enterochromaffin cell tumors. In these tumors, up to 20% of the endocrine cells were xenin immunoreactive, and xenin immunoreactivity was concentrated in secretory granules. Xenin was coexpressed with chromogranin A. We found no xenin expression in gastrin-, somatostatin-, and serotonin-immunoreactive cells. High-pressure liquid chromatography after acidic extraction revealed 497 +/- 285 pmol of xenin per gram of tissue in 5 duodenal gastrinomas. The other neuroendocrine tumors, such as bronchial carcinoids, gastric enterochromaffin-like cell carcinoids, gastric and ileal enterochromaffin cell carcinoids, insulinomas, and gastrinomas of pancreatic origin, did not contain immunoreactive xenin.

CONCLUSIONS:

Xenin is a peptide marker specific to neuroendocrine tumors of the duodenum. This finding may be useful in tumor classification and in the differential diagnosis of neuroendocrine tumors of the upper gut.

• Authors: Gerhard E Feurle, Martin Anlauf, Gerd Hamscher, Rudolf Arnold, Günter Klöppel, Eberhard Weihe
• Journal: Gastroenterology (Gastroenterology) Vol. 123 Issue 5 Pg. 1616-26 (Nov 2002) ISSN: 0016-5085 [Print] United States
• PMID: 12404236 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Peptides
• xenin 25
• Neurotensin

Topics

• Chromatography, High Pressure Liquid
• Duodenal Neoplasms (metabolism)
• Gastrinoma (metabolism)
• Humans
• Immunohistochemistry
• Neuroendocrine Tumors (metabolism)
• Neurotensin
• Peptides (isolation & purification, metabolism)
• Somatostatinoma (metabolism)