title: Genetic characterization of skull base chondrosarcomas.
abstract: OBJECTIVE
  Although chondrosarcomas rarely arise in the skull base, chondrosarcomas and chordomas are the 2 major malignant bone neoplasms occurring at this location. The distinction of these 2 tumors is important, but this distinction is occasionally problematic because of radiological and histological overlap. Unlike chordoma and extracranial chondrosarcoma, no case series presenting a whole-genome analysis of skull base chondrosarcomas (SBCSs) has been reported. The goal of this study is to clarify the genetic characteristics of SBCSs and contrast them with those of chordomas.
  
  
  METHODS
  The authors analyzed 7 SBCS specimens for chromosomal copy number alterations (CNAs) using comparative genomic hybridization (CGH). They also examined IDH1 and IDH2 mutations and brachyury expression.
  
  
  RESULTS
  In CGH analyses, the authors detected CNAs in 6 of the 7 cases, including chromosomal gains of 8q21.1, 19, 2q22-q32, 5qcen-q14, 8q21-q22, and 15qcen-q14. Mutation of IDH1 was found with a high frequency (5 of 7 cases, 71.4%), of which R132S was most frequently mutated. No IDH2 mutations were found, and immunohistochemical staining for brachyury was negative in all cases.
  
  
  CONCLUSIONS
  To the best of the authors' knowledge, this is the first whole-genome study of an SBSC case series. Their findings suggest that these tumors are molecularly consistent with a subset of conventional central chondrosarcomas and different from skull base chordomas.
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kanamori
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Kitamura
authors.affiliation: Pathology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Tokuhiro
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Hikaru
authors.initials: H
authors.lastname: Sasaki
mesh_terms: D000328:Adult; D000368:Aged; D002813:Chondrosarcoma / Q000235:genetics* / Q000378:metabolism; D055028:Comparative Genomic Hybridization; D005260:Female; D005326:Fetal Proteins / Q000096:biosynthesis; D006801:Humans; D007521:Isocitrate Dehydrogenase / Q000235:genetics; D008875:Middle Aged; D009154:Mutation; D019292:Skull Base Neoplasms / Q000235:genetics* / Q000378:metabolism; D020825:T-Box Domain Proteins / Q000096:biosynthesis; D055815:Young Adult; D000098908:Brachyury Protein
chemical_list: D005326:Fetal Proteins; D007521:Isocitrate Dehydrogenase; D020825:T-Box Domain Proteins; D000098908:Brachyury Protein; C538784:IDH2 protein, human; C543588:IDH1 protein, human
keywords: AML = acute myeloid leukemia; CGH = comparative genomic hybridization; CNA = copy number alteration; DIG = digoxigenin; DOP-PCR = degenerate oligonucleotide primed-polymerase chain reaction; EMA = epithelial membrane antigen; IDH1; IDH2; PFS = progression-free survival; SBCS = skull base chondrosarcoma; brachyury; chordoma; comparative genomic hybridization; oncology; skull base chondrosarcomas