title: [Ultrastructural features and platelet-derived growth factor receptor A gene mutations in CD117-negative gastrointestinal stromal tumor].
abstract: OBJECTIVE
  To explore the ultrastructural features and mutation status of platelet-derived growth factor receptors A (PDGFRA) and c-kit in gastrointestinal stromal tumors that were immunohistochemically negative for CD117 antigen.
  
  
  METHODS
  Six cases of gastrointestinal stromal tumors that were CD117 immunostain negative were studied by electron microscopy. Direct PCR sequencing was used to investigate the mutation status of c-kit gene exons 9, 11, 13, 17 and PDGFRA gene exons 12 and 18.
  
  
  RESULTS
  The ultrastructural features of all 6 cases were similar to those of the interstitial cell of Cajal (ICC). None of the 6 cases were found to have c-kit gene mutations. However, three tumors were found to harbor PDGFRA exon 18 activating mutations, including two tumors having an Asp-->Val842 missense mutation and one having an Arg-->Ser841 missense mutation.
  
  
  CONCLUSIONS
  PDGFRA mutations may provide an important alternative molecular mechanism for the development of gastrointestinal stromal tumor.
authors.affiliation: Department of Pathology, Peking University Health Science Center, Beijing 100083, China.
authors.forename: Yi-ning
authors.initials: YN
authors.lastname: Xiang
authors.forename: Dong-xia
authors.initials: DX
authors.lastname: Gao
authors.forename: Hui-ying
authors.initials: HY
authors.lastname: He
authors.forename: Yu-ping
authors.initials: YP
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
mesh_terms: D000328:Adult; D000368:Aged; D004252:DNA Mutational Analysis; D005091:Exons; D005260:Female; D005500:Follow-Up Studies; D046152:Gastrointestinal Stromal Tumors / Q000235:genetics* / Q000276:immunology / Q000648:ultrastructure; D006801:Humans; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D011379:Prognosis; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis* / Q000235:genetics; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics*
chemical_list: D019009:Proto-Oncogene Proteins c-kit; D020796:Receptor, Platelet-Derived Growth Factor alpha