SURG-03. GENE EXPRESSION CHANGES ASSOCIATED WITH RECURRENCE AFTER GROSS TOTAL RESECTION OF NEWLY DIAGNOSED WHO GRADE 1 MENINGIOMA

Abstract Patients who undergo gross total resection (GTR) of Central Nervous System World Health Organization (WHO) grade 1 meningioma constitute a “low risk” group, but some low risk meningiomas can recur despite reassuring clinical and histological features. In this study, gene expression in newly diagnosed WHO grade 1 meningiomas that had undergone GTR were evaluated for their association with recurrence. This was a retrospective, international, multi-center cohort study that included WHO grade 1 meningiomas that underwent GTR as first treatment. Normalized gene expression values from a previously validated 34-gene panel were evaluated for their association with recurrence. Kaplan-Meier, multivariable Cox proportional hazard analyses, and K-means clustering were performed to assess the association of genes of interest with recurrence and identify molecular subgroups among clinically and histologically low risk meningiomas. 442 patients with WHO grade 1 meningiomas that underwent GTR and had available gene expression profiling data were included in the study. Median follow-up was 5.0 years (interquartile range 2.6-7.7 years), local recurrence occurred in 36 patients (8.1%), 5-year local freedom from recurrence (LFFR) was 90.5%, and median time to recurrence of 2.9 years (range 0.5-10.7 years). Eleven genes were associated with local recurrence, including lower expression of ARID1B, ESR1, LINC02593, PGR, and TMEM30B and higher expression of CDK6, CDKN2C, CKS2, KIF20A, PGK1, and TAGLN. K-means clustering based on these 11 genes distinguished 2 molecular groups of clinically and histologically low risk meningiomas with significant differences in LFFR (HR 2.5, 95% CI 1.2-5.1, p=0.016). In conclusion, gene expression profiling may help to identify newly diagnosed WHO grade 1 meningiomas that have an elevated risk of recurrence despite GTR.