Although pilocytic astrocytoma (PA) is the most common brain tumor diagnosed in children, few prognostic variables have been delineated that stratify the risk of clinical progression in patients with this tumor. In this study, the MIB-1 labeling index was compared with 2 other immunohistochemical markers of cell proliferation, phospho-histone H3 (PHH3) and mini-chromosomal maintenance protein 2 (MCM2) in 80 incompletely resected PAs to see whichwas best able to identify patients at risk for tumor progression. 0 6-Methylguanine-DNA methyltransferase (MGMT) protein expression, which has been predictive of progression-free survival (PFS) in high-grade gliomas in children, was also evaluated in these cases. The mean follow-up period was 7.81±3.9 years, and 42.8% of tumors have shown progression at the time of censoring. A MIB-1 labeling index ≥2.0 was associated with shortened PFS as a grouped variable by log-ranked analysis (P 5 .03) and byCox regression analysis as a continuous variable (P 5 .007). None of the other potential biomarkers was significantly predictive of PFS. Although the amount of MCM2 staining correlated with the MIB-1 labeling index (P < .001), MCM2 reactivity was not independently associated with outcome.We conclude that MIB-1 labeling remains the best predictor of PFS in pediatric PAs.
- 06-methylguanine-DNA methyltransferase
- Mini-chromosomal maintenance protein 2
- Phospho-histone H3
- Pilocytic astrocytoma
ASJC Scopus subject areas
- Clinical Neurology
- Cancer Research