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Background Brain tumors, whether primary or secondary, have limited therapeutic options despite advances in understanding driver gene mutations and heterogeneity within tumor cells. The cellular and molecular composition of brain tumor stroma, an important modifier of tumor growth, has been less investigated to date. Only few studies have focused on the vasculature of human brain tumors despite the fact that the blood-brain barrier (BBB) represents the major obstacle for efficient drug delivery. Methods In this study, we employed RNA sequencing to characterize transcriptional alterations of endothelial cells (EC) isolated from primary and secondary human brain tumors. We used an immunoprecipitation approach to enrich for EC from normal brain, glioblastoma (GBM), and lung cancer brain metastasis (BM). Results Analysis of the endothelial transcriptome showed deregulation of genes implicated in cell proliferation, angiogenesis, and deposition of extracellular matrix (ECM) in the vasculature of GBM and BM. Deregulation of genes defining the BBB dysfunction module was found in both tumor types. We identified deregulated expression of genes in vessel-associated fibroblasts in GBM. Conclusion We characterize alterations in BBB genes in GBM and BM vasculature and identify proteins that might be exploited for developing drug delivery platforms. In addition, our analysis on vessel-associated fibroblasts in GBM shows that the cellular composition of brain tumor stroma merits further investigation.

OBJECTIVE To avoid craniospinal irradiation (CSI) in children younger than four years with non-metastatic medulloblastoma by chemotherapy, intraventricular methotrexate and risk-adapted local radiotherapy. PATIENTS AND METHODS Eighty-seven patients received systemic chemotherapy and intraventricular methotrexate. Until 2006, CSI was reserved for non-response or progression. After 2006, local radiotherapy was introduced for non-responders or classic (CMB), anaplastic or large-cell medulloblastoma (LCA). Infantile SHH-activated medulloblastomas (SHH_INF) were subdivided by DNA-methylation profiling. Survival in SHH_INF subtypes were also assessed in a validation cohort (n=71). RESULTS Patients with desmoplastic medulloblastoma (DMB) or medulloblastoma with extensive nodularity (MBEN) (n=42) had 93% 5-year PFS, 100% 5-year OS and 93% 5-year CSI-free survival. Patients with CMB/LCA (n=45) had 37% 5y-PFS, 62% 5y-OS and 39% 5y-CSI-free survival. Local radiotherapy did not improve survival in CMB/LCA patients. All DMB/MBEN assessed by DNA methylation profiling belonged to the SHH_INF subgroup. Group 3 patients (5y-PFS 36% [n=14]) relapsed more frequently than SHH_INF (5y-PFS 93% [n=28]) or Group 4 patients (5y-PFS 83% [n=6], p CONCLUSION Systemic chemotherapy and intraventricular methotrexate led to favorable survival in both iSHH-subtypes of SHH-activated DMB/MBEN with acceptable neurotoxicity. Survival in non-WNT/non-SHH CMB/LCA patients was not improved by local radiotherapy. Survival was more favorable in patients with Group 4 than in patients with Group 3 medulloblastoma.

BACKGROUND Although the vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR) system has become a prime target for antiangiogenic treatment, its biological role in glioblastoma beyond angiogenesis has remained controversial. METHODS Using neutralizing antibodies to VEGF or placental growth factor (PlGF) or the tyrosine kinase inhibitor, cediranib, or lentiviral gene silencing, we delineated autocrine signaling in glioma cell lines. The in vivo effects of VEGFR1 and VEGFR2 depletion were evaluated in orthotopic glioma xenograft models. RESULTS VEGFR1 and VEGFR2 modulated glioma cell clonogenicity, viability, and invasiveness in vitro in an autocrine, cell-line-specific manner. VEGFR1 silencing promoted mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling, whereas VEGFR2 silencing resulted in cell-type dependent activation of the protein kinase B (PKB)/AKT and MAPK/ERK pathways. These responses may represent specific escape mechanisms from VEGFR inhibition. The survival of orthotopic glioma-bearing mice was prolonged upon VEGFR1 silencing in the LNT-229, LN-308, and U87MG models and upon VEGFR2 silencing in LN-308 and U87MG. Disruption of VEGFR1 and VEGFR2 signaling was associated with decreased tumor size, increased tumor necrosis, or loss of matrix metalloproteinase 9 (MMP9) immunoreactivity. Neutralizing VEGF and PlGF by specific antibodies was superior to either antibody treatment alone in the VEGFR1-dependent LNT-229 model. CONCLUSIONS Differential dependence on autocrine signaling through VEGFR1 and VEGFR2 suggests a need for biomarker-stratified VEGF(R)-based therapeutic approaches to glioblastoma.

The addition of bevacizumab to temozolomide-based chemoradiotherapy (TMZ/RT→TMZ) prolonged progression-free survival (PFS), but not overall survival (OS) in patients with newly diagnosed glioblastoma in two double-blind phase III trials. Elderly and frail patients are underrepresented in most clinical trials, but early reports of bevacizumab in glioblastoma suggested preferential benefit in this population. ARTE was a 2:1 randomized, multi-center, open-label trial of hypofractionated RT (40 Gy in 15 fractions) in combination with bevacizumab (10 mg/kg x 14 days) (arm A, N=50) versus RT alone (arm B, N=25) in patients with newly diagnosed glioblastoma aged >65 years. The primary endpoint was median OS. Quality of life (QoL) was monitored by the EORTC QLQ-C30/BN20 modules. Response was assessed by RANO criteria. Exploratory studies included 18F-fluoro-ethyltyrosine positron emission tomography (FET-PET, N=34), as well as whole methylome (N=57) and nanostring gene expression (N=54) analyses. Median PFS was longer in arm A versus arm B (7.6 vs. 4.8 months, p=0.003), but OS was similar (12.1 vs 12.2 months, p=0.8). Clinical deterioration was delayed and more patients came off steroids in arm A versus arm B. Longer PFS in arm A versus arm B was confined to the receptor tyrosine kinase (RTK) I methylation subtype and to the proneural gene expression subtype, but was not observed for patients with RTK II, classical or mesenchymal subtype glioblastoma. Applying a Cox model to OS that controlled for established prognostic factors, we detected an association with age and KPS. Exploration of imaging predictors of OS in this model identified the presence of non-enhancing tumor detected by FET-PET (HR 0.31, p=0.02) as an important prognostic factor. Efficacy outcomes and exploratory analyses of ARTE do not support the notion that bevacizumab generally prolongs survival in elderly glioblastoma patients. However, novel molecular and imaging biomarkers may identify patients with preferential benefit from bevacizumab.

Background: The vascular endothelial growth factor antibody, bevacizumab (Avastin®), received approval for the treatment of recurrent glioblastoma in Switzerland in 2009. Here we explored the hypothesis that the approval of bevacizumab improved outcome in glioblastoma on a population level. Methods: The prognostic significance of epidemiological and clinical data, as well as molecular markers for glioblastoma patients diagnosed from 2010–2014 in the Canton of Zurich was analyzed using the log rank test and the Cox proportional hazards model. Data were compared to the years 2005–2009. Results: 310 glioblastoma patients were identified in the years 2010–2014. Median overall survival (OS) in this cohort was 13.1 months for all patients (independent of the isocitrate dehydrogenase (IDH) mutation status) and 13.5 months for patients with IDH wildtype (wt) tumors, compared with 11.3 months for all patients (p=0.554) and 11.3 months for IDH wt patients (p=0.675) before (2005–2009). In the present study, in the subgroup of IDH wt patients (n=247), 111 patients received bevacizumab at any time, half of them at time of first recurrence. Multivariate analysis demonstrated young age, high Karnofsky performance score, greater extent of resection, methylated O6-methylguanine DNA methyltransferase (MGMT) promoter, or first-line chemoradiotherapy, but not bevacizumab exposure, to be independently associated with survival. Conclusions: Despite a strong increase in bevacizumab use in the Canton of Zurich, Switzerland, on a population level, OS has moderately, but not significantly improved from 2005–2009 to 2010–2014. Our data do not support the notion that the minor increase in survival was directly linked to the availability of bevacizumab.