title: MIB-1 counting methods in meningiomas and agreement among pathologists.
abstract: OBJECTIVE
  To evaluate the correlation of MIB-1 labeling index (LI) obtained by 2 counting methods with histologic grade and investigate interobserver variability between these methods.
  
  
  METHODS
  A total of 65 meningiomas were analyzed for proliferation with 2 counting methods by 2 pathologists using MIB-1 antibody. In the first method, the most densely staining areas were counted (HL method). In the second method, randomly selected areas were counted (RS method).
  
  
  RESULTS
  MIB-1 values correlated well with histologic grade in both methods. As expected, the tumors with recurrence had significantly higher LIs than the nonrecurrent tumors in each method. However, there was a statistically significant difference in the mean MIB-1 values of between the HL and RS methods. When MIB-1 LI was compared between 2 pathologists, perfect agreement in the HL method and substantial agreement in the RS method were achieved.
  
  
  CONCLUSIONS
  Our results showed that values of MIB LIs differ with different counting methods. Nonetheless, both methods showed good correlation with World Health Organization grades. Therefore standardization of 1 counting method is of great importance for determining a reliable and specific cutoff value in assessing the risk of recurrence in meningiomas.
authors.affiliation: Department of Pathology, Izmir Ataturk Education and Research Hospital, Izmir, Turkey. rezankoa@yahoo.com
authors.forename: Turkan
authors.initials: T
authors.lastname: Rezanko
authors.forename: Asli Kahraman
authors.initials: AK
authors.lastname: Akkalp
authors.forename: Mine
authors.initials: M
authors.lastname: Tunakan
authors.forename: Aysegul Akder
authors.initials: AA
authors.lastname: Sari
mesh_terms: D000974:Antibodies, Antinuclear; D000911:Antibodies, Monoclonal; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis*; D008577:Meningeal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008579:Meningioma / Q000175:diagnosis* / Q000473:pathology; D009364:Neoplasm Recurrence, Local; D015588:Observer Variation; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000974:Antibodies, Antinuclear; D000911:Antibodies, Monoclonal; D019394:Ki-67 Antigen; C440408:MIB-1 antibody