[1742] Analysis of IDH Mutation, 1p19q Deletion, and PTEN Loss in Low Grade Diffuse Gliomas

Nesrin Sabha, Christiane B Knobbe, Soha Al Omar, Andreas Von Deimling, Tak Mak, Arie Perry, Gelareh Zadeh, Abhijit Guha, Sidney E Croul. Hospital for Sick Children, Toronto, ON, Canada; University of Toronto, Toronto, ON, Canada; University of Heidelberg, Heidelberg, Germany; UCSF, San Francisco, CA

Background: Astrocytomas grade II and III have unpredictable rates of biological and clinical progression, making management decisions difficult. Currently, several clinical and radiological characteristics are utilized to predict progression and survival, but collectively are suboptimal.
Design: In our study, we analyzed a large set of non-enhancing hemispheric grade II-II gliomas for IDH mutations (mIDH), 1p19q co-deletion, PTEN deletion, and EGFR amplification to determine if these singly or in combination offer advantages over tumor grading for prediction of overall survival (OS) and /or progression free survival (PFS).
Results: In this cohort, neither pathologic diagnosis nor gradewere predictive of OS or PFS. The greatest individual predictor was mIDH when both immunohistochemical and sequencing based assays were considered. mIDH was a predictor of longer OS and PFS for the entire group of tumours. 1p19q deletion alone was predictive of OS but not of PFS. With multifactorial analysis, Pathology again was not a significant predictor of OS or PFS. However, mIDH, 1p19 deletion, and, PTEN deletion were all found to be significant variables. Use of Cox regression analysis to construct groups of high and low risk based on IDH, 1p19q, and PTEN status resulted in a model with greatest predictive value for OS and PFS.
Conclusions: This data leads us to conclude that this combination of tests may be particularly effective in discriminating good prognosis from poor prognosis hemispheric gliomas. We would further propose that such a scheme merits testing on larger prospective cohorts. Should such confirm our findings, routine clinical analysis of hemispheric gliomas for mIDH, 1p 19q co-deletion and PTEN loss would be justified.
Category: Neuropathology

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 244, Wednesday Afternoon

 

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