title: Study of the MIB-1 labeling index as a predictor of tumor progression in pilocytic astrocytomas in children and adolescents.
abstract: OBJECTIVE
  The pilocytic astrocytoma (PA) is the most common childhood brain tumor. This report examines the MIB-1 labeling index (LI) as a predictor of progression-free survival (PFS) among childhood PAs.
  
  
  METHODS
  Consecutive PAs were examined to determine whether the MIB-1 LI was associated with tumor progression. Other variables evaluated included tumor location, use of adjuvant therapy, extent of resection, and age at diagnosis.
  
  
  RESULTS
  One hundred forty-one children were identified (mean +/- SD age, 7.6 +/- 4.7 years; range, 0.43 to 18.56 years); 118 children had adequate tissue for MIB-1 immunohistochemistry. The 5-year PFS was 61.25%. By log-rank analysis, an MIB-1 LI of more than 2.0 was associated with shortened PFS (P =.035). Patients with PAs who underwent complete surgical resection, had tumors located in the cerebellum, and were treated with surgery only also had more prolonged PFS (P =.001 for all). Tumors in the optic pathways were associated with a shorter PFS (P =.001). Restricting the evaluation of MIB-1 LI to only incompletely resected tumors revealed an insignificant trend of MIB-1 LI of more than 2.0 having a shortened PFS. Multivariate analysis demonstrated completely resected tumors and tumors located in the cerebellum as less likely to progress (P =.001 and.019, respectively).
  
  
  CONCLUSIONS
  Children with PAs with an MIB-1 LI of more than 2.0 have a shortened PFS. PAs that are completely resected and are located in the cerebellum have a prolonged PFS. This initial study suggests that the MIB-1 LI identifies a more aggressive subset of PAs. Further work should focus on elucidating features of pilocytic astocytomas that will identify prospectively children at risk for progression.
authors.affiliation: Department of Pediatrics, University of Texas Southwestern Medical School at Dallas, Dallas, TX 75390-9063, USA. daniel.bowers@ utsouthwestern.edu.
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Bowers
authors.forename: Lynn
authors.initials: L
authors.lastname: Gargan
authors.forename: Payal
authors.initials: P
authors.lastname: Kapur
authors.forename: Joan S
authors.initials: JS
authors.lastname: Reisch
authors.forename: Arlynn F
authors.initials: AF
authors.lastname: Mulne
authors.forename: Kenneth N
authors.initials: KN
authors.lastname: Shapiro
authors.forename: Roy D
authors.initials: RD
authors.lastname: Elterman
authors.forename: Naomi J
authors.initials: NJ
authors.lastname: Winick
authors.forename: Linda R
authors.initials: LR
authors.lastname: Margraf
mesh_terms: D000293:Adolescent; D001254:Astrocytoma / Q000378:metabolism* / Q000473:pathology*; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology*; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005260:Female; D006801:Humans; D007223:Infant; D019394:Ki-67 Antigen / Q000378:metabolism*; D008297:Male; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D016019:Survival Analysis
chemical_list: D019394:Ki-67 Antigen