title: World Health Organization Grade II gliomas and subventricular zone: anatomic, genetic, and clinical considerations.
abstract: BACKGROUND
  Recent studies suggest a possible origin of human gliomas from subventricular zone (SVZ) stem cells.
  
  
  OBJECTIVE
  To evaluate the relationship of World Health Organization grade II gliomas (GIIGs) with the SVZ and to investigate the presence of different genetic patterns, depending on their relationship with the SVZ.
  
  
  METHODS
  Forty-three consecutive patients were operated on for GIIG. Preoperative fluid-attenuated inversion recovery-weighted magnetic resonance images were reviewed to assess the presence of cortical involvement and the relationship between gliomas and the SVZ. Patients were divided into 2 groups: group 1, tumors in contact with the SVZ; and group 2, tumors not in contact with the SVZ. Preoperative and postoperative tumor volumes were calculated. Genetic analysis was performed to study 1p19q allelic loss.
  
  
  RESULTS
  Twenty-four patients were in group 1 and 19 in group 2. All tumors were in contact with the cortex. Preoperative volume was significantly larger in group 1 than in group 2 (P = .003). The proportion of total and subtotal resections was higher in group 2 (P = .01). Insular tumors never showed 1p19q codeletions. Noninsular tumors exhibited a significantly different incidence of complete 1p19q codeletion, with allelic loss more common in group 1 (P = .03).
  
  
  CONCLUSIONS
  GIIGs showed a constant relationship with the cortex and a larger volume when they came in contact with the ventricles. A distinct genetic pattern was found in noninsular SVZ GIIGs. This parameter can be considered for therapeutic management.
authors.affiliation: Department of Neurosurgery, The Newcastle Upon Tyne Hospitals, Newcastle, United Kingdom.
authors.forename: Francesco
authors.initials: F
authors.lastname: Vergani
authors.forename: Juan
authors.initials: J
authors.lastname: Martino
authors.forename: Catherine
authors.initials: C
authors.lastname: Gozé
authors.forename: Valérie
authors.initials: V
authors.lastname: Rigau
authors.forename: Hugues
authors.initials: H
authors.lastname: Duffau
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D002552:Cerebral Ventricles / Q000473:pathology* / Q000502:physiology; D005260:Female; D005910:Glioma / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D013234:Stem Cells / Q000473:pathology* / Q000502:physiology; D014944:World Health Organization; D055815:Young Adult