title: Evaluation of cell proliferation, epidermal growth factor receptor, and bcl-2 immunoexpression as prognostic factors for patients with World Health Organization grade 2 oligodendroglioma.
abstract: BACKGROUND
  Prognostic factors in oligodendrogliomas are an area of controversy in neuropathology. Although grading and the study of some morphologic variables may be of value as prognostic parameters, the variability of postoperative disease free survival in patients with World Health Organization Grade 2 oligodendroglioma indicates that the biologic behavior of this entity remains unknown. The objective of the current study was to evaluate immunoexpression of the proliferation index (PI), epidermal growth factor receptor (EGFR), and bcl-2 as prognostic factors in patients with Grade 2 oligodendroglioma.
  
  
  METHODS
  In a series of 19 cases of pure Grade 2 oligodendroglioma, we assessed the mitotic count, labeling index for MIB-1 and PCNA, and immunoreactivity for EGFR and bcl-2 with semiquantitative parameters and compared these with postoperative disease free survival. Statistical analyses using the Cox-Mantel nonparametric test and Spearman correlation coefficient were used to evaluate the data.
  
  
  RESULTS
  Disease free survival was significantly shorter when the MIB-1 PI was > 5% (P = 0.0096) and the PCNA PI was > 9% (P = 0.00011) and when mitoses were observed (P = 0.00004). The paired variables also were found to correlate: MIB-1 versus PCNA (P = 0.04), MIB-1 versus mitotic count (P = 0.0184), and PCNA versus mitotic count (P = 0.0079). In all cases, there was immunoreactivity for EGFR; conversely, all cases were negative for bcl-2 in the cells with an oligodendrocyte phenotype.
  
  
  CONCLUSIONS
  The PI was found to correlate with the postoperative disease free survival in patients with Grade 2 oligodendroglioma; therefore, the authors suggest a possible subdivision of Grade 2 oligodendrogliomas into two groups based on the mitotic count and PI.
authors.affiliation: Serviço de Anatomia Patológica, Hospital de Clínicas UFPR, Curitiba, Brazil.
authors.forename: J S
authors.initials: JS
authors.lastname: Reis-Filho
authors.forename: L N
authors.initials: LN
authors.lastname: Faoro
authors.forename: C
authors.initials: C
authors.lastname: Carrilho
authors.forename: L F
authors.initials: LF
authors.lastname: Bleggi-Torres
authors.forename: F C
authors.initials: FC
authors.lastname: Schmitt
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D001932:Brain Neoplasms / Q000737:chemistry / Q000401:mortality / Q000473:pathology*; D018572:Disease-Free Survival; D066246:ErbB Receptors / Q000032:analysis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008875:Middle Aged; D008940:Mitotic Index; D009837:Oligodendroglioma / Q000737:chemistry / Q000401:mortality / Q000473:pathology*; D011379:Prognosis; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis*; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D018809:Proliferating Cell Nuclear Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D066246:ErbB Receptors