title: Malignant pheochromocytomas/paragangliomas harbor mutations in transport and cell adhesion genes.
abstract: One out of ten patients with pheochromocytoma (PCC) and paraganglioma (PGL) develop malignant disease. Today there are no reliable pathological methods to predict malignancy at the time of diagnosis. Tumors harboring mutations in the succinate dehydrogenase subunit B (SDHB) gene often metastasize but the sequential genetic events resulting in malignant progression are not fully understood. The aim of this study was to identify somatic mutations that contribute to the malignant transformation of PCC/PGL. We performed pair-wise (tumor-normal) whole-exome sequencing to analyze the somatic mutational landscape in five malignant and four benign primary PCC/sympathetic PGL (sPGL), including two biological replicates from each specimen. In total, 225 unique somatic mutations were identified in 215 genes, with an average mutation rate of 0.54 mutations/megabase. Malignant tumors had a significantly higher number of mutations compared to benign tumors (p < 0.001). Three novel genes were identified as recurrently mutated; MYCN, MYO5B and VCL, and mutations in these genes were exclusively found in malignant sPGL tumors. Mutations in the MYO5B gene could be verified in two publicly available data sets. A gene ontology analysis of mutated genes showed enrichment of cellular functions related to cytoskeletal protein binding, myosin complex and motor activity, many of which had functions in Rab and Rac/Rho GTPase pathways. In conclusion, we have identified recurrent mutations in genes related to intracellular transport and cell adhesion, and we have confirmed MYO5B to be recurrently mutated in PCC/PGL cases with malignant potential. Our study suggests that deregulated Rab and Rac/Rho pathways may be important in PCC/PGL tumorigenesis.
authors.affiliation: Department of Clinical Genetics, Institution of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Annica
authors.initials: A
authors.lastname: Wilzén
authors.affiliation: Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Rehammar
authors.affiliation: Section for Endocrine Surgery and Abdominal Sarcoma, Department of Surgery, Sahlgrenska University Hospital, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Andreas
authors.initials: A
authors.lastname: Muth
authors.affiliation: Sahlgrenska Cancer Center, Institute of Biomedicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Ola
authors.initials: O
authors.lastname: Nilsson
authors.affiliation: Department of Clinical Genetics, Institution of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Tajana
authors.initials: T
authors.lastname: Tešan Tomić
authors.affiliation: Section for Endocrine Surgery and Abdominal Sarcoma, Department of Surgery, Sahlgrenska University Hospital, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Bo
authors.initials: B
authors.lastname: Wängberg
authors.affiliation: Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Kristiansson
authors.affiliation: Department of Clinical Genetics, Institution of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Frida
authors.initials: F
authors.lastname: Abel
mesh_terms: D000328:Adult; D000368:Aged; D002448:Cell Adhesion / Q000235:genetics; D004252:DNA Mutational Analysis / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D018995:Myosin Heavy Chains / Q000235:genetics*; D024701:Myosin Type V / Q000235:genetics*; D000071447:N-Myc Proto-Oncogene Protein; D009361:Neoplasm Invasiveness / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics*; D015513:Oncogene Proteins / Q000235:genetics*; D010673:Pheochromocytoma / Q000235:genetics* / Q000473:pathology; D021381:Protein Transport / Q000235:genetics; D016596:Vinculin / Q000235:genetics*
chemical_list: C459801:MYCN protein, human; C505832:MYO5B protein, human; D000071447:N-Myc Proto-Oncogene Protein; D009687:Nuclear Proteins; D015513:Oncogene Proteins; C488955:VCL protein, human; D016596:Vinculin; D024701:Myosin Type V; D018995:Myosin Heavy Chains
keywords: HRAS; massively parallel sequencing; neuroendocrine tumor