title: Gastrointestinal stromal tumors express the orexigen ghrelin.
abstract: Expression of the neuroendocrine marker synaptic vesicle protein 2 (SV2) has been reported in a few cases of gastrointestinal stromal tumors (GISTs). The goal of the present study was to assess the relevance of this finding and identify a possible hormone production in these tumors. We chose to study the orexigen ghrelin and its receptor, since these patients are seldom cachexic, even in advanced disease stages. We investigated ghrelin expression by means of immunohistochemistry on frozen or paraffin-embedded sections from 22 GISTs from a well-characterized patient material. Expression of the growth hormone secretagogue receptor, the ghrelin receptor, was investigated in a subset of lesions. In six tumors, mRNA levels of ghrelin, the ghrelin receptor, and SV2 were analyzed by real-time quantitative PCR. Totally 17 out of 22 tumors showed immunoreactivity for ghrelin. Five out of ten tumors were immunoreactive for the ghrelin receptor, and all of these co-expressed ghrelin. All tumors expressed ghrelin, ghrelin receptor, and SV2 mRNA. GISTs frequently express SV2, ghrelin, and its receptor, indicating the presence of autocrine/paracrine loops.
authors.affiliation: Department of Medical Sciences, University Hospital, 75185 Uppsala, Sweden.
authors.forename: Sara
authors.initials: S
authors.lastname: Ekeblad
authors.forename: Bengt
authors.initials: B
authors.lastname: Nilsson
authors.forename: Margareta Halin
authors.initials: MH
authors.lastname: Lejonklou
authors.forename: Térèse
authors.initials: T
authors.lastname: Johansson
authors.forename: Peter
authors.initials: P
authors.lastname: Stålberg
authors.forename: Ola
authors.initials: O
authors.lastname: Nilsson
authors.forename: Håkan
authors.initials: H
authors.lastname: Ahlman
authors.forename: Britt
authors.initials: B
authors.lastname: Skogseid
mesh_terms: D004252:DNA Mutational Analysis; D005091:Exons; D046152:Gastrointestinal Stromal Tumors / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D054439:Ghrelin; D006801:Humans; D007150:Immunohistochemistry; D008940:Mitotic Index; D036361:Peptide Hormones / Q000235:genetics*; D016133:Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
chemical_list: D054439:Ghrelin; D036361:Peptide Hormones