title: Clinicopathologic aspects of 1p/19q loss and the diagnosis of oligodendroglioma.
abstract: BACKGROUND
  Significant interobserver variability exists with respect to the diagnosis of oligodendroglial neoplasms, especially their distinction from astrocytoma and mixed oligoastrocytoma. Combined loss of the short arm of chromosome 1 and the long arm of chromosome 19 has been shown to be both relatively specific to oligodendroglioma and, when present, a marker of improved prognosis in patients with these tumors. In addition, 1p/19q loss has been shown to be a marker of "classic" oligodendroglial histology. These findings raise questions as to the role of 1p/19q testing in clinical practice, both as a prognostic marker and as a potential diagnostic marker among infiltrating glial neoplasms.
  
  
  OBJECTIVE
  This review discusses the issues raised above and tries to clarify the current status of 1p/19q evaluation in the diagnosis of oligodendroglioma.
  
  
  METHODS
  Sources for this review include recent literature as well as the experience of 3 practicing neuropathologists.
  
  
  CONCLUSIONS
  1p/19q status is an important marker in oligodendroglioma. Loss of 1p/19q is associated with classic oligodendroglioma histology as well as improved prognosis. The combined 1p/19q marker will continue to be a clinically useful marker of prognosis and could potentially be incorporated into diagnostic criteria in the future.
authors.affiliation: M. D. Anderson Cancer Center, Department of Pathology and Brain Tumor Center, 1515 Holcombe Blvd, Houston, TX 60153, USA. kaldape@mdanderson.org
authors.forename: Kenneth
authors.initials: K
authors.lastname: Aldape
authors.forename: Peter C
authors.initials: PC
authors.lastname: Burger
authors.forename: Arie
authors.initials: A
authors.lastname: Perry
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics*; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000235:genetics*; D002872:Chromosome Deletion; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics; D002888:Chromosomes, Human, Pair 19 / Q000235:genetics; D006801:Humans; D009837:Oligodendroglioma / Q000175:diagnosis* / Q000235:genetics*; D011379:Prognosis
chemical_list: D014408:Biomarkers, Tumor