Table 2: Univariate survival analysis (Kaplan-Meier): survival times according to clinicopathological features and the Bmi-1 gene expression.

CaseMean survival time 
(months ± s.e.)
Chi-square value

Bmi-1 expression5.870.015
 High expression24
 Low expression32
Sex0.0380.845
 Male30
 Female26
Embryonal/gliomas1.880.17
 Embryonal16
 Gliomas40
Tumor grade6.410.011
 High grade26
 Low grade30
Tumor type1.430.21
 Medulloblastoma11
 Astrocytomas19
 Ependymomas16
 Other10