Analysis of all subunits, SDHA, SDHB, SDHC, SDHD, of the succinate dehydrogenase complex in KIT/PDGFRA wild-type GIST

• Published in: European journal of human genetics : EJHG Vol. 22; no. 1; pp. 32 - 39
• Main Authors: Pantaleo, Maria A, Astolfi, Annalisa, Urbini, Milena, Nannini, Margherita, Paterini, Paola, Indio, Valentina, Saponara, Maristella, Formica, Serena, Ceccarelli, Claudio, Casadio, Rita, Rossi, Giulio, Bertolini, Federica, Santini, Donatella, Pirini, Maria G, Fiorentino, Michelangelo, Basso, Umberto, Biasco, Guido
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 01.01.2014
• Subjects: Adolescent; Adult; Aged; Cancer; Dehydrogenase; Dehydrogenases; Deoxyribonucleic acid; Diagnosis; DNA; DNA Mutational Analysis; Electron Transport Complex II - biosynthesis; Electron Transport Complex II - genetics; Female; Gastrointestinal Stromal Tumors - genetics; Gastrointestinal Stromal Tumors - pathology; Gene Expression Regulation - genetics; Genes; Genetic Association Studies; Genetics; Genomes; Germ-Line Mutation; Humans; Immunohistochemistry; Insulin; Insulin-like growth factors; Male; Membrane Proteins - biosynthesis; Membrane Proteins - genetics; Metastases; Metastasis; Middle Aged; Mutation; Pediatrics; Peripheral blood; Protein expression; Proto-Oncogene Proteins c-kit - genetics; Proto-Oncogene Proteins c-kit - metabolism; Receptor, Platelet-Derived Growth Factor alpha - genetics; Rodents; Succinate dehydrogenase; Succinate Dehydrogenase - biosynthesis; Succinate Dehydrogenase - genetics; Tumors; Italy
• ISSN: 1018-4813; 1476-5438
• DOI: 10.1038/ejhg.2013.80

Mutations of genes encoding the subunits of the succinate dehydrogenase (SDH) complex were described in KIT/PDGFRA wild-type GIST separately in different reports. In this study, we simultaneously sequenced the genome of all subunits, SDHA, SDHB, SDHC, and SDHD in a larger series of KIT/PDGFRA wild-type GIST in order to evaluate the frequency of the mutations and explore their biological role. SDHA, SDHB, SDHC, and SDHD were sequenced on the available samples obtained from 34 KIT/PDGFRA wild-type GISTs. Of these, in 10 cases, both tumor and peripheral blood (PB) were available, in 19 cases only tumor, and in 5 cases only PB. Overall, 9 of the 34 patients with KIT/PDGFRA wild-type GIST carried mutations in one of the four subunits of the SDH complex (six patients in SDHA, two in SDHB, one in SDHC). WB and immunohistochemistry analysis showed that patients with KIT/PDGFRA wild-type GIST who harbored SDHA mutations exhibited a significant downregulation of both SDHA and SDHB protein expression, with respect to the other GIST lacking SDH mutations and to KIT/PDGFRA-mutated GIST. Clinically, four out of six patients with SDHA mutations presented with metastatic disease at diagnosis with a very slow, indolent course. Patients with KIT/PDGFRA wild-type GIST may harbor germline and/or de novo mutations of SDH complex with prevalence for mutations within SDHA, which is associated with a downregulation of SDHA and SDHB protein expression. The presence of germline mutations may suggest that these patients should be followed up for the risk of development of other cancers.