PATH-36. GENOMIC MARKERS OF RECURRENCE RISK IN ATYPICAL MENINGIOMA FOLLOWING GROSS TOTAL RESECTION

Abstract Atypical meningiomas (CNS WHO grade 2) show an intermediate risk of recurrence/progression, and molecular parameters informing management following gross total resection (GTR) remain to be established. We performed comprehensive genomic analysis in 63 patients who underwent GTR atypical meningioma. Median age was 59.8 years, 41 (65.1%) were female, 8/62 (12.9%) radiation therapy resection. Follow-up available for all (median 10 years), with recurrence/progression 17 (5-year PFS: 84.2%; 10-year 71.0%). Tumors evaluated by next generation sequencing (n=61), chromosomal microarray (n=63), DNA methylation profiling (n=62), H3K27me3 immunohistochemistry (n=62). Next using a CLIA-certified 50-gene Neuro-Oncology specific panel identified pathogenic alterations NF2 (n=31; 50.8%), SMARCB1 (n=5; 8.2%), AKT1 (n=2; 3.3%), TERT (n=1, 1.6%), SMO (n=1), SUFU TP53 PTEN (n=1). There trend toward decreased PFS (p=0.078) which not statistically significant. Copy number variants (CNVs) OncoScan (ThermoFisher). The most frequent CNVs loss -22 (n=45; 71.4%), -1p (n=30, 47.6%), -14 (n=21, 33.3%), -6q (n=18, 28.6%), -10q (n=15, 23.8%), -X (n=13, 20.6%), -18 (n=11, 17.4%). associated included (p=0.015), -7p (p=0.007), (p=0.0007), (p=0.0376). the Illumina MethylationEPIC array (n=62) DKFZ classifier (v12.3). Based on highest score, tumors matched benign (n=32; 51.6%) or (n=29; 46.7%) meningioma subclasses showed non-contributory profiles (n=1; 1.6%). Methylation class (benign vs. intermediate) no association (p=0.96). H3K27 trimethylation (H3K27me3) unequivocally lost 4 (6.5%) tumors, insufficient analysis. Overall, our study supports CNV GTR, can implemented existing, clinically validated technologies. Molecular predictors could guide use radiotherapy these patients.