Abstract
INTRODUCTION
Ganglioglioma (GG) is a rare mixed glioneuronal neoplasm accounting for 0.5–5% of all pediatric central nervous system tumors. BRAF V600E mutation has been previously reported in GG but its incidence and impact remain unknown. This retrospective study evaluates the incidence of BRAF mutation in GG and its prognostic implication. PATIENTS AND
METHODS
Retrospective review of 55 patients under the age of 21 years diagnosed with GG at our institution from 1992 to 2012 was performed. Patient demographics, clinical history, radiological features, treatment data and molecular analysis data were collected and analyzed. Molecular testing using next generation gene sequencing and /or immunohistochemistry (IHC) to identify BRAFV600E mutation was performed in available tumor specimens. Kaplan-Meier survival and Cox-regression analyses were performed to assess the overall survival (OS) and progression-free survival (PFS).
RESULTS
55 patients with GG were identified; tumor tissue was available for 21 patients for molecular analysis. Two specimens were inadequate for analysis, 19 patients specimens were tested for BRAF mutation, 3 using sequencing and 16 using IHC. BRAF V600E was detected in nine patients specimens (47%). BRAF mutation was equally distributed among both genders. No association was found with tumor location, size, metastatic status or imaging characteristics. There was no difference in outcome between patients with BRAF mutated tumors versus non mutated tumors, with the 10 years PFS and OS 77.8% versus 51.4% and 88.9% versus 100% (p=0.26, p= 0.29), respectively. Unfortunately, the study number is small to draw statistical conclusion.
CONCLUSION
We present one of the largest retrospective studies in pediatric GG. Though limited sample numbers were probed for BRAF mutation in our study, our data suggests similar incidence as reported in the literature. Prospective studies should continue to evaluate this molecular event, and newer generation of BRAF inhibitors should be profiled which could improve clinical outcome.