title: Gastrointestinal stromal tumors regularly express synaptic vesicle proteins: evidence of a neuroendocrine phenotype.
abstract: Gastrointestinal stromal tumors (GISTs) are thought to originate from the interstitial cells of Cajal, which share many properties with neurons of the gastrointestinal tract. Recently, we demonstrated expression of the hormone ghrelin in GIST. The aim of the present study was therefore to evaluate a possible neuroendocrine phenotype of GIST. Specimens from 41 GISTs were examined for the expression of 12 different synaptic vesicle proteins. Expression of synaptic-like microvesicle proteins, e.g., Synaptic vesicle protein 2 (SV2), synaptobrevin, synapsin 1, and amphiphysin was demonstrated in a majority of GISTs by immunohistochemistry, western blotting, and quantitative reversetranscriptase PCR. One-third of the tumors also expressed the large dense core vesicle protein vesicular monoamine transporter 1. Presence of microvesicles and dense core vesicles in GIST was confirmed by electron microscopy. The expression of synaptic-like microvesicle proteins in GIST was not related to risk profile or to KIT/platelet derived growth factor alpha (PDGFRA) mutational status. Thus, GISTs regularly express a subset of synaptic-like microvesicle proteins necessary for the regulated secretion of neurotransmitters and hormones. Expression of synaptic-like micro-vesicle proteins, ghrelin and peptide hormone receptors in GIST indicate a neuroendocrine phenotype and suggest novel possibilities to treat therapy-resistant GIST.
authors.affiliation: Department of Surgery and Pathology, Sahlgrenska Academy at the University of Göteborg, Sahlgrenska University Hospital, Göteborg, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Bümming
authors.forename: Ola
authors.initials: O
authors.lastname: Nilsson
authors.forename: Håkan
authors.initials: H
authors.lastname: Ahlman
authors.forename: Anna
authors.initials: A
authors.lastname: Welbencer
authors.forename: Mattias K
authors.initials: MK
authors.lastname: Andersson
authors.forename: Katarina
authors.initials: K
authors.lastname: Sjölund
authors.forename: Bengt
authors.initials: B
authors.lastname: Nilsson
mesh_terms: D000368:Aged; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism*; D009490:Neurosecretory Systems / Q000378:metabolism / Q000473:pathology*; D010641:Phenotype; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics; D022142:Secretory Vesicles / Q000378:metabolism; D016704:Synapsins / Q000235:genetics / Q000378:metabolism; D013572:Synaptic Vesicles / Q000378:metabolism*; D050987:Vesicle-Associated Membrane Protein 1 / Q000235:genetics / Q000378:metabolism
chemical_list: D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D016704:Synapsins; C494704:VAMP1 protein, human; D050987:Vesicle-Associated Membrane Protein 1; C075637:amphiphysin; C076414:SV2A protein, human; D020796:Receptor, Platelet-Derived Growth Factor alpha