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BioMed Research International
Volume 2013 (2013), Article ID 192548, 5 pages
http://dx.doi.org/10.1155/2013/192548
Research Article

Expression of Bmi-1 in Pediatric Brain Tumors as a New Independent Prognostic Marker of Patient Survival

1Department of Genetics, Faculty of Biological Science, Shahid Beheshti University (GC), Tehran 1983963113, Iran
2Laser and Plasma Research Institute, Shahid Beheshti University (GC), Tehran 1983963113, Iran
3Department of Pediatrics, Shahid Beheshti University of Medical Sciences, Mofid Children’s Hospital, Tehran, Iran
4Pediatrics Infectious Research Center (PIRC), Shahid Beheshti University of Medical Sciences, Tehran, Iran

Received 2 April 2013; Accepted 18 June 2013

Academic Editor: Natasa Tosic

Copyright © 2013 Shirin Farivar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objectives. The B-cell-specific moloney leukemia virus insertion site 1 (the Bmi-1) gene is an important member in the family of polycomb group (PcG) genes that plays an oncogenic role in several types of cancer, but it’s expression as a prognostic marker in pediatric brain tumors has not been indicated. Materials and Methods. The Bmi-1 gene expression, clinic pathological and prognostic significance in a series of pediatric brain tumors were examined by real-time PCR method in 56 pediatric brain tumors. Results. The Bmi-1 gene expression in various types of pediatric brain tumors compared to that in normal brain tissue was 4.85-fold. The relative expression varied from 8.64-fold in ependymomas to 2.89-fold in other types. Expression level in high-grade tumors compared to that in low-grade tumors was 2.5 times. In univariate survival analysis of the pediatric brain tumors, a significant association of high expression of the Bmi-1 with patient survival was demonstrated. In multivariate analysis, the Bmi-1 high expression provided significant independent prognostic factors. Conclusion. Increased expression of the Bmi-1 in pediatric brain tumors may be important in the acquisition of an aggressive phenotype. In addition, it can be used as a strong and independent molecular marker of prognosis in pediatric brain tumors.