Impact of Morphology, MIB-1, p53 and MGMT on Outcome in Pilocytic Astrocytomas
Article first published online: 21 SEP 2009
© 2009 The Authors; Journal Compilation © 2009 International Society of Neuropathology
Volume 20, Issue 3, pages 581–588, May 2010
How to Cite
Horbinski, C., Hamilton, R. L., Lovell, C., Burnham, J. and Pollack, I. F. (2010), Impact of Morphology, MIB-1, p53 and MGMT on Outcome in Pilocytic Astrocytomas. Brain Pathology, 20: 581–588. doi: 10.1111/j.1750-3639.2009.00336.x
- Issue published online: 12 APR 2010
- Article first published online: 21 SEP 2009
- Received 5 August 2009; accepted 7 September 2009.
- pilocytic astrocytoma;
Pilocytic astrocytoma (PA) is the most common glioma in the pediatric population. PAs can exhibit variable behavior that does not always correlate with location, yet at present there is no way to predict which tumors will be more aggressive. To address this problem, an institutional cohort of 147 PAs (118 with outcome data) from both cerebellar and noncerebellar locations (spine, diencephalon, midbrain, brainstem and cortex) was utilized. Parameters included quantification of characteristic morphologic variables as well as genes previously shown to be of relevance in high-grade gliomas, including MIB-1, p53 and MGMT. In this cohort, the classic biphasic appearance was most common in cerebellar tumors, whereas noncerebellar tumors were predominantly microcystic. Associations with outcome suggest that the presence of degenerative atypia may be a favorable factor in PAs. Oligodendroglial morphology and the absence of leptomeningeal invasion are adverse histologic factors, but only in cerebellar tumors. Conversely, MIB-1 proliferation index and p53 and MGMT expression do not correlate with outcome. Morphologic biomarkers thus do exist for PAs, but the utility of each biomarker varies according to location. These results suggest that PAs differ fundamentally according to location; therefore, biological behavior may not simply depend on extent of resection.