title: Succinate dehydrogenase-deficient GISTs are characterized by IGF1R overexpression.
abstract: Succinate dehydrogenase-deficient gastrointestinal stromal tumors (GISTs) demonstrate unique pathological and clinical features, including the absence of activating mutations of KIT and PDGFRA, and primary resistance to imatinib. They arise exclusively in the stomach and account for 5-7.5% of all adult stomach GISTs and the great majority of these tumors in childhood. Insulin-like growth factor 1 receptor (IGF1R) overexpression has been associated with wild-type and pediatric GISTs. We propose that IGF1R overexpression is a feature of succinate dehydrogenase-deficient GISTs as a group. We assessed succinate dehydrogenase complex subunit B (SDHB) and IGF1R expression by immunohistochemistry in eight known succinate dehydrogenase-deficient GISTs, three GISTs arising in the setting of neurofibromatosis type 1 syndrome and 40 unselected GISTs. Selected KIT and PDGFRA exons were amplified and sequenced from formalin-fixed paraffin-embedded tumor samples. All eight succinate dehydrogenase-deficient tumors were wild-type for KIT and PDGFRA, succinate dehydrogenase B negative and demonstrated IGF1R overexpression. The three neurofibromatosis-related tumors were succinate dehydrogenase B positive and IGF1R negative. Of the 40 unselected upper GISTs, five were wild-type for KIT and PDGFRA in the selected exons. Two of the wild-type GISTs were succinate dehydrogenase B negative and showed IGF1R overexpression and three were succinate dehydrogenase B positive and IGF1R negative. We conclude that IGF1R overexpression is a feature of succinate dehydrogenase deficient GIST as a group, rather than pediatric or wild-type GIST per se. Therefore, IGF1R inhibition represents a potential rational therapeutic approach in this recently recognized subgroup of GIST.
authors.affiliation: Department of Anatomical Pathology, SydPath, St Vincent's Hospital, Sydney, NSW, Australia.
authors.forename: Angela
authors.initials: A
authors.lastname: Chou
authors.forename: Jason
authors.initials: J
authors.lastname: Chen
authors.forename: Adele
authors.initials: A
authors.lastname: Clarkson
authors.forename: Jaswinder S
authors.initials: JS
authors.lastname: Samra
authors.forename: Roderick J
authors.initials: RJ
authors.lastname: Clifton-Bligh
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Hugh
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Gill
mesh_terms: D000293:Adolescent; D000328:Adult; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D046152:Gastrointestinal Stromal Tumors / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics / Q000378:metabolism; D013385:Succinate Dehydrogenase / Q000172:deficiency* / Q000235:genetics; D055815:Young Adult
chemical_list: D004273:DNA, Neoplasm; D013385:Succinate Dehydrogenase; D019009:Proto-Oncogene Proteins c-kit; D017526:Receptor, IGF Type 1; D020796:Receptor, Platelet-Derived Growth Factor alpha