title: SDHB immunohistochemistry: a useful tool in the diagnosis of Carney-Stratakis and Carney triad gastrointestinal stromal tumors.
abstract: Mutations in the tumor suppressor genes SDHB, SDHC, and SDHD (or collectively SDHx) cause the inherited paraganglioma syndromes, characterized by pheochromocytomas and paragangliomas. However, other tumors have been associated with SDHx mutations, such as gastrointestinal stromal tumors (GISTs) specifically in the context of Carney-Stratakis syndrome. Previously, we have shown that SDHB immunohistochemistry is a reliable technique for the identification of pheochromocytomas and paragangliomas caused by SDHx mutations. We hypothesized that GISTs in patients with SDHx mutations would be negative immunohistochemically for SDHB as well. Four GISTs from patients with Carney-Stratakis syndrome and six from patients with Carney triad were investigated by SDHB immunohistochemistry. Five GISTs with KIT or PDGFRA gene mutations were used as controls. In addition, SDHB immunohistochemistry was performed on 42 apparently sporadic GISTs. In cases in which the SDHB immunohistochemistry was negative, mutational analysis of SDHB, SDHC, and SDHD was performed. All GISTs from patients with Carney-Stratakis syndrome and Carney triad were negative for SDHB immunohistochemically. In one patient with Carney-Stratakis syndrome, a germline SDHB mutation was found (p.Ser92Thr). The five GISTs with a KIT or PDGFRA gene mutation were all immunohistochemically positive for SDHB. Of the 42 sporadic tumors, one GIST was SDHB-negative. Mutational analysis of this tumor did not reveal an SDHx mutation. All SDHB-negative GISTs were located in the stomach, had an epithelioid morphology, and had no KIT or PDGFRA mutations. We show that Carney-Stratakis syndrome- and Carney-triad-associated GISTs are negative by immunohistochemistry for SDHB in contrast to KIT- or PDGFRA-mutated GISTs and a majority of sporadic GISTs. We suggest that GISTs of epithelioid cell morphology are tested for SDHB immunohistochemically. In case of negative SDHB staining in GISTs, Carney-Stratakis syndrome or Carney triad should be considered and appropriate clinical surveillance should be instituted.
authors.affiliation: Department of Pathology, Josephine Nefkens Institute, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. j.gaal@erasmusmc.nl
authors.forename: José
authors.initials: J
authors.lastname: Gaal
authors.forename: Constantine A
authors.initials: CA
authors.lastname: Stratakis
authors.forename: J Aidan
authors.initials: JA
authors.lastname: Carney
authors.forename: Evan R
authors.initials: ER
authors.lastname: Ball
authors.forename: Esther
authors.initials: E
authors.lastname: Korpershoek
authors.forename: Maya B
authors.initials: MB
authors.lastname: Lodish
authors.forename: Isaac
authors.initials: I
authors.lastname: Levy
authors.forename: Paraskevi
authors.initials: P
authors.lastname: Xekouki
authors.forename: Francien H
authors.initials: FH
authors.lastname: van Nederveen
authors.forename: Michael A
authors.initials: MA
authors.lastname: den Bakker
authors.forename: Maureen
authors.initials: M
authors.lastname: O'Sullivan
authors.forename: Winand N M
authors.initials: WN
authors.lastname: Dinjens
authors.forename: Ronald R
authors.initials: RR
authors.lastname: de Krijger
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D056733:Carney Complex / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D004252:DNA Mutational Analysis; D015622:Epithelioid Cells / Q000378:metabolism / Q000473:pathology; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D009154:Mutation; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000378:metabolism; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics / Q000378:metabolism; D013385:Succinate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D013577:Syndrome
chemical_list: D014408:Biomarkers, Tumor; C108095:SDHB protein, human; D013385:Succinate Dehydrogenase; D019009:Proto-Oncogene Proteins c-kit; D020796:Receptor, Platelet-Derived Growth Factor alpha