PURPOSE: Meningiomas are the most frequent primary intracranial tumors. Patient outcome varies widely from benign to highly aggressive, ultimately fatal courses. Reliable identification of risk of progression for individual patients is of pivotal importance. However, only biomarkers for highly aggressive tumors are established ( CDKN2A/B and TERT), whereas no molecularly based stratification exists for the broad spectrum of patients with low- and intermediate-risk meningioma.METHODS: DNA methylation data and copy-number information were generated for 3,031 meningiomas (2,868 patients), and mutation data for 858 samples. DNA methylation subgroups, copy-number variations (CNVs), mutations, and WHO grading were analyzed. Prediction power for outcome was assessed in a retrospective cohort of 514 patients, validated on a retrospective cohort of 184, and on a prospective cohort of 287 multicenter cases.RESULTS: Both CNV- and methylation family–based subgrouping independently resulted in increased prediction accuracy of risk of recurrence compared with the WHO classification (c-indexes WHO 2016, CNV, and methylation family 0.699, 0.706, and 0.721, respectively). Merging all risk stratification approaches into an integrated molecular-morphologic score resulted in further substantial increase in accuracy (c-index 0.744). This integrated score consistently provided superior accuracy in all three cohorts, significantly outperforming WHO grading (c-index difference P = .005). Besides the overall stratification advantage, the integrated score separates more precisely for risk of progression at the diagnostically challenging interface of WHO grade 1 and grade 2 tumors (hazard ratio 4.34 [2.48-7.57] and 3.34 [1.28-8.72] retrospective and prospective validation cohorts, respectively).CONCLUSION: Merging these layers of histologic and molecular data into an integrated, three-tiered score significantly improves the precision in meningioma stratification. Implementation into diagnostic routine informs clinical decision making for patients with meningioma on the basis of robust outcome prediction.

Purpose: Targeting immunosuppressive and pro-tumorigenic glioblastoma (GBM)-associated macrophages and microglial cells (GAM) has great potential to improve patient outcomes. Colony-stimulating factor-1 receptor (CSF1R) has emerged as a promising target for reprograming anti-inflammatory M2-like GAMs. However, treatment data on patient-derived, tumor-educated GAMs and their influence on the adaptive immunity are lacking. Experimental Design: CD11b+-GAMs freshly isolated from patient tumors were treated with CSF1R-targeting drugs PLX3397, BLZ945, and GW2580. Phenotypical changes upon treatment were assessed using RNA sequencing, flow cytometry, and cytokine quantification. Functional analyses included inducible nitric oxide synthase activity, phagocytosis, transmigration, and autologous tumor cell killing assays. Antitumor effects and changes in GAM activation were confirmed in a complex patient-derived 3D tumor organoid model serving as a tumor avatar. Results: The most effective reprogramming of GAMs was observed upon GW2580 treatment, which led to the downregulation of M2-related markers, IL6, IL10, ERK1/2, and MAPK signaling pathways, while M1-like markers, gene set enrichment indicating activated MHC-II presentation, phagocytosis, and T-cell killing were substantially increased. Moreover, treatment of patient-derived GBM organoids with GW2580 confirmed successful reprogramming, resulting in impaired tumor cell proliferation. In line with its failure in clinical trials, PLX3397 was ineffective in our analysis. Conclusions: This comparative analysis of CSF1R-targeting drugs on patient-derived GAMs and human GBM avatars identified GW2580 as the most powerful inhibitor with the ability to polarize immunosuppressive GAMs to a proinflammatory phenotype, supporting antitumor T-cell responses while also exerting a direct antitumor effect. These data indicate that GW2580 could be an important pillar in future therapies for GBM.

Kinesins play an important role in many physiological functions including intracellular vesicle transport and mitosis. The emerging role of kinesins in different cancers led us to investigate the expression and functional role of kinesins in meningioma. Therefore, we re-analyzed our previous microarray dataset of benign, atypical, and anaplastic meningiomas (n = 62) and got evidence for differential expression of five kinesins (KIFC1, KIF4A, KIF11, KIF14 and KIF20A). Further validation in an extended study sample (n = 208) revealed a significant upregulation of these genes in WHO°I to °III meningiomas (WHO°I n = 61, WHO°II n = 88, and WHO°III n = 59), which was most pronounced in clinically more aggressive tumors of the same WHO grade. Immunohistochemical staining confirmed a WHO grade-associated upregulated protein expression in meningioma tissues. Furthermore, high mRNA expression levels of KIFC1, KIF11, KIF14 and KIF20A were associated with shorter progression-free survival. On a functional level, knockdown of kinesins in Ben-Men-1 cells and in the newly established anaplastic meningioma cell line NCH93 resulted in a significantly inhibited tumor cell proliferation upon siRNA-mediated downregulation of KIF11 in both cell lines by up to 95% and 71%, respectively. Taken together, in this study we were able to identify the prognostic and functional role of several kinesin family members of which KIF11 exhibits the most promising properties as a novel prognostic marker and therapeutic target, which may offer new treatment options for aggressive meningiomas.

Intraventricular meningiomas (IVMs) account for less than 5% of all intracranial meningiomas; hence their molecular phenotype remains unknown. In this study, we were interested whether genetic alterations in IVMs differ from meningiomas in other locations and analyzed our institutional series with respect to clinical and molecular characteristics. A total of 25 patients with surgical removal of an IVM at our department between 1986 and 2018 were identified from our institutional database. Median progression-free survival (PFS) was 79 months (range of 2–319 months) and PFS at 5 years was 86%. Corresponding tumor tissue was available for 18 patients including one matching recurrence and was subjected to targeted panel sequencing of 130 selected genes frequently mutated in brain cancers by applying a custom hybrid capture approach on a NextSeq500 instrument. Loss of chromosome 22q and 1p occurred frequently in 89 and 44% of cases. Deleterious NF2 mutations were found in 44% of IVMs (n = 8/18). In non-NF2-mutated IVMs, previously reported genetic alterations including TRAF7, AKT1, SMO, KLF4, PIK3CA, and TERT were lacking, suggesting alternative genes in the pathogenesis of non-NF2 IVMs. In silico analysis revealed possible damaging mutations of APC, GABRA6, GSE1, KDR, and two SMO missense mutations differing from previously reported ones. Interestingly, all WHO°II IVMs (n = 3) harbored SMARCB1 and SMARCA4 mutations, indicating a role of the SWI/SNF chromatin remodeling complex in aggressive IVMs.

Purpose: Clinically aggressive meningiomas (MGMs) are rare but treatment-resistant tumors in need for more effective therapies. Since tumor-infiltrating T-lymphocytes (TILs) are essential for successful immunotherapy, we assessed TIL numbers and their activation status in primary (p-) and recurrent (r‑)MGMs and their impact on survival. Experimental Design: Presence of TILs was analyzed in 202 clinically well-annotated cases (n = 123 pMGMs and n = 79 rMGMs) focusing on higher-grade MGMs (n = 97 WHO°II, n = 62 WHO°III). TILs were quantified by a semi-automated analysis on whole tissue sections stained by multi-color immunofluorescence for CD3, CD8, FOXP3, and PD-1. Results: Median T-cell infiltration accounted for 0.59% TILs per total cell count. Although there were no significant WHO°-dependent changes regarding helper (CD3⁺CD8^-FOXP3^-) and cytotoxic (CD3⁺CD8⁺FOXP3^-) TILs in pMGMs, higher numbers of cytotoxic TILs were associated with an improved progression-free survival (PFS) independent of prognostic confounders. rMGMs were characterized by lower numbers of TILs in general, helper and cytotoxic TILs. When investigating their activation status, proportion of PD-1⁺CD8⁺ TILs within the TIL population was significantly decreased with higher WHO grade and in rMGMs. Furthermore, lower proportions of PD‑1⁺CD8⁺ TILs were associated with inferior PFS in multivariate analyses, arguing for PD-1 as activation rather than exhaustion marker. Conclusion: We identified higher numbers of CD3⁺CD8⁺FOXP3^- TILs and proportions of PD-1-expressing CD3⁺CD8⁺FOXP3^- TILs as novel biomarkers for better survival. These findings might facilitate the selection of patients who may benefit from immunotherapy and argue in favor of an intervention in primary rather than recurrent tumors.