Expression of TGF-alpha in neuroendocrine tumours of the distal colon and rectum.
OBJECTIVE
Transforming growth factor alpha (TGF-alpha) has been localized in neuroendocrine L-cells of the colon and rectum in previous studies. We examined whether neuroendocrine tumours with L-cell differentiation express TGF-alpha.


METHODS
Immunohistochemistry was performed for proglucagon- and pro-pancreatic polypeptide derivatives, as well as for TGF-alpha, and epidermal growth factor receptor (EGFR) using paraffin sections from 16 neuroendocrine tumours of the colon and rectum. Also, in situ hybridization for TGF-alpha and proglucagon was carried out.


RESULTS
A strong expression of TGF-alpha at the protein level can be shown for neuroendocrine tumours of the hindgut. In one third of our cases we found a strong hybridization signal and in two thirds a moderate signal for TGF-alpha. The immunohistological phenotype concerning gut hormones is highly heterogeneous. Glucagon-like peptide 2 (GLP2) in our series was the most sensitive immunohistological hormone marker.


CONCLUSIONS
The immunophenotype of colorectal neuroendocrine tumours regarding hormone markers is heterogeneous. The expression of TGF-alpha corresponds to the immunohistological profile of normal L-cells. TGF-alpha, especially in the neuroendocrine L-cells, most probably acts as a multifunctional trophic factor responsible for cellular integrity and survival, and not as an oncogenic growth factor.
Back
Walter
W
Pathologisches Institut, Universitätsklinikum Mannheim, Fakultät für Klinische Medizin Mannheim der Universität Heidelberg, Mannheim, Germany. walter.back@path.ma.uni-heidelberg.de
Rohr
Gerhard
G
Bleyl
Uwe
U
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D019858:Enteroendocrine Cells / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D005934:Glucagon / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D010191:Pancreatic Polypeptide / Q000378:metabolism; D052336:Proglucagon; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D012004:Rectal Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D016211:Transforming Growth Factor alpha / Q000235:genetics* / Q000378:metabolism*
D011498:Protein Precursors; D016211:Transforming Growth Factor alpha; D052336:Proglucagon; D010191:Pancreatic Polypeptide; D005934:Glucagon; D066246:ErbB Receptors