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Purpose Glioma patients, especially recurrent glioma, suffer from a poor prognosis. While advances to classify glioma on a molecular level improved prognostication at initial diagnosis, markers to prognosticate survival in the recurrent situation are still needed. As 18 kDa translocator protein (TSPO) was previously reported to be associated with aggressive histopathological glioma features, we correlated the TSPO positron emission tomography (PET) signal using [18F]GE180 in a large cohort of recurrent glioma patients with their clinical outcome. Methods In patients with [18F]GE180 PET at glioma recurrence, [18F]GE180 PET parameters (e.g., SUVmax) as well as other imaging features (e.g., MRI volume, [18F]FET PET parameters when available) were evaluated together with patient characteristics (age, sex, Karnofsky-Performance score) and neuropathological features (e.g. WHO 2021 grade, IDH-mutation status). Uni- and multivariate Cox regression and Kaplan–Meier survival analyses were performed to identify prognostic factors for post-recurrence survival (PRS) and time to treatment failure (TTF). Results Eighty-eight consecutive patients were evaluated. TSPO tracer uptake correlated with tumor grade at recurrence (p IDH-wild-type versus IDH-mutant tumors. Within the subgroup of IDH-mutant glioma (n = 46), patients with low SUVmax (median split, ≤ 1.60) had a significantly longer PRS (median 41.6 vs. 25.3 months, p = 0.031) and TTF (32.2 vs 8.7 months, p = 0.001). Also among IDH-wild-type glioblastoma (n = 42), patients with low SUVmax (≤ 1.89) had a significantly longer PRS (median not reached vs 8.2 months, p = 0.002). SUVmax remained an independent prognostic factor for PRS in the multivariate analysis including CNS WHO 2021 grade, IDH status, and age. Tumor volume defined by [18F]FET PET or contrast-enhanced MRI correlated weakly with TSPO tracer uptake. Treatment regimen did not differ among the median split subgroups. Conclusion Our data suggest that TSPO PET using [18F]GE180 can help to prognosticate recurrent glioma patients even among homogeneous molecular subgroups and may therefore serve as valuable non-invasive biomarker for individualized patient management. Graphical abstract

Purpose:To explore a prognostic or predictive role of MRI and O-(2–18F-fluoroethyl)-L-tyrosine (18FET) PET parameters for outcome in the randomized multicenter trial ARTE that compared bevacizumab plus radiotherapy with radiotherpay alone in elderly patients with glioblastoma.Patients and Methods:Patients with isocitrate dehydrogenase wild-type glioblastoma ages 65 years or older were included in this post hoc analysis. Tumor volumetric and apparent diffusion coefficient (ADC) analyses of serial MRI scans from 67 patients and serial 18FET-PET tumor-to-brain intensity ratios (TBRs) from 31 patients were analyzed blinded for treatment arm and outcome. Multivariate Cox regression analysis was done to account for established prognostic factors and treatment arm.Results:Overall survival benefit from bevacizumab plus radiotherapy compared with radiotherapy alone was observed for larger pretreatment MRI contrast-enhancing tumor [HR per cm3 0.94; 95% confidence interval (CI), 0.89–0.99] and for higher ADC (HR 0.18; CI, 0.05–0.66). Higher 18FET-TBR on pretreatment PET scans was associated with inferior overall survival in both arms. Response assessed by standard MRI-based Response Assessment in Neuro-Oncology criteria was associated with overall survival in the bevacizumab plus radiotherapy arm by trend only (P = 0.09). High 18FET-TBR of noncontrast-enhancing tumor portions during bevacizumab therapy was associated with inferior overall survival on multivariate analysis (HR 5.97; CI, 1.16–30.8).Conclusions:Large pretreatment contrast-enhancing tumor mass and higher ADCs identify patients who may experience a survival benefit from bevacizumab plus radiotherapy. Persistent 18FET-PET signal of no longer contrast-enhancing tumor after concomitant bevacizumab plus radiotherapy suggests pseudoresponse and predicts poor outcome.

Note S1, Figure S1-S4, Table S1-S3

Purpose In surgery for intramedullary spinal cord tumors (imSCT), distortion of the anatomy challenges the visual identification of dorsal columns (DC) for midline myelotomy. Dorsal column mapping (DCM) and spinal cord stimulation (SCS) can identify DC neurophysiologically. We compare application and feasibility of both methods. Methods Patients with surgically treated imSCT were prospectively included between 04/2017 and 06/2019. The anatomical midline (AM) was marked. SSEPs at the DC after stimulation of tibial/median nerve with an 8-channel DCM electrode and cortical SSEP phase reversal at C3/C4 after SCS using a bipolar concentric probe were recorded. Procedural and technical aspects were compared. Standardized neurological examinations were performed preoperatively, 1 week postoperatively and after more than 12 months. Results The DCM electrode detected the midline in 9/13 patients with handling limitations in the remaining patients. SCS was applicable in all patients with determination of the midline in 9/13. If both recordings could be acquired (6/13), concordance was 100%. If baseline SSEPs were poor, both methods were limited. SCS was less time-consuming (p = 0.001), cheaper, and easier to handle. In 92% of cases, the AM and neurophysiologic midlines were concordant. After myelotomy, 3 patients experienced > 50% reduction in amplitude of SSEPs. Despite early postoperative worsening of DC function, long-term follow-up showed significant recovery and improvement in quality of life. Conclusion DCM and SCS may help confirm and correct the AM for myelotomy in imSCT, leading to a favorable long-term neurological outcome in this cohort. SCS evolved to be superior concerning applicability, cost-effectiveness, and time expenditure.

Introduction The cIMPACT-NOW update 6 first introduced glioblastoma diagnosis based on the combination of IDH-wildtype (IDHwt) status and TERT promotor mutation (pTERTmut). In glioblastoma as defined by histopathology according to the WHO 2016 classification, MGMT promotor status is associated with outcome. Whether this is also true in glioblastoma defined by molecular markers is yet unclear. Methods We searched the institutional database for patients with: (1) glioblastoma defined by histopathology; and (2) IDHwt astrocytoma with pTERTmut. MGMT promotor methylation was analysed using methylation-specific PCR and Sanger sequencing of CpG sites within the MGMT promotor region. Results We identified 224 patients with glioblastoma diagnosed based on histopathology, and 54 patients with IDHwt astrocytoma with pTERTmut (19 astrocytomas WHO grade II and 38 astrocytomas WHO grade III). There was no difference in the number of MGMT methylated tumors between the two cohorts as determined per PCR, and also neither the number nor the pattern of methylated CpG sites differed as determined per Sanger sequencing. Progression-free (PFS) and overall survival (OS) was similar between the two cohorts when treated with radio- or chemotherapy. In both cohorts, higher numbers of methylated CpG sites were associated with favourable outcome. Conclusions Extent and pattern of methylated CpG sites are similar in glioblastoma and IDHwt astrocytoma with pTERTmut. In both tumor entities, higher numbers of methylated CpG sites appear associated with more favourable outcome. Evaluation in larger prospective cohorts is warranted.

Purpose: To explore a prognostic or predictive role of MRI and O-(2–18F-fluoroethyl)-L-tyrosine (18FET) PET parameters for outcome in the randomized multicenter trial ARTE that compared bevacizumab plus radiotherapy with radiotherpay alone in elderly patients with glioblastoma. Patients and Methods: Patients with isocitrate dehydrogenase wild-type glioblastoma ages 65 years or older were included in this post hoc analysis. Tumor volumetric and apparent diffusion coefficient (ADC) analyses of serial MRI scans from 67 patients and serial 18FET-PET tumor-to-brain intensity ratios (TBRs) from 31 patients were analyzed blinded for treatment arm and outcome. Multivariate Cox regression analysis was done to account for established prognostic factors and treatment arm. Results: Overall survival benefit from bevacizumab plus radiotherapy compared with radiotherapy alone was observed for larger pretreatment MRI contrast-enhancing tumor [HR per cm3 0.94; 95% confidence interval (CI), 0.89–0.99] and for higher ADC (HR 0.18; CI, 0.05–0.66). Higher 18FET-TBR on pretreatment PET scans was associated with inferior overall survival in both arms. Response assessed by standard MRI-based Response Assessment in Neuro-Oncology criteria was associated with overall survival in the bevacizumab plus radiotherapy arm by trend only (P = 0.09). High 18FET-TBR of noncontrast-enhancing tumor portions during bevacizumab therapy was associated with inferior overall survival on multivariate analysis (HR 5.97; CI, 1.16–30.8). Conclusions: Large pretreatment contrast-enhancing tumor mass and higher ADCs identify patients who may experience a survival benefit from bevacizumab plus radiotherapy. Persistent 18FET-PET signal of no longer contrast-enhancing tumor after concomitant bevacizumab plus radiotherapy suggests pseudoresponse and predicts poor outcome.

QUESTION The role of temozolomide chemotherapy alone in isocitrate dehydrogenase (IDH)-mutant astrocytomas has not been conclusively determined. Recent studies have linked temozolomide therapy with induction of hypermutation and poor clinical course in some IDH-mutant gliomas. METHODS In this retrospective, single-center study, 183 patients with astrocytoma, IDH-mutant, CNS WHO grade 2 or 3 diagnosed between 2003 and 2019 were included. Patients initially monitored by means of a wait-and-scan strategy, or treated with radiotherapy alone, or receiving temozolomide alone, after histological sampling through biopsy or tumor resection, were studied. Progression-free and overall survival was analysed. A matched-pair analysis accounting for post-surgical tumor volume was conducted. RESULTS Initial T2 tumor volume and WHO grade were associated with survival in univariate analyses (p < 0.01). The proportion of WHO grade 2 gliomas was highest in the wait-and-scan cohort (p < 0.01). Tumor volumes were largest in the temozolomide cohort (p < 0.01). Radiotherapy was associated with longer progression-free survival than temozolomide (6.2 vs 3.4 years, p = 0.02) and wait-and-scan strategies (6.2 vs 4 years, p = 0.03). Patients treated with radiotherapy showed longer overall survival than patients treated with temozolomide (14.4 vs 10.7 years, p = 0.02). Survival was longer in patients initially monitored by means of a wait-and-scan strategy than in patients treated with temozolomide (not reached vs 10.7 years, p < 0.0001). The same association was seen in a subgroup analysis of WHO grade 2 astrocytomas (p = 0.02) and by trend in a matched pair analysis (p = 0.09). CONCLUSION The results suggest superiority for progression-free survival of radiotherapy alone over temozolomide alone or wait-and-scan strategies and for overall survival of radiotherapy alone and wait-and-scan therapies over temozolomide in IDH-mutant WHO grade 2 and 3. Recent study results indicating that temozolomide might compromise prognosis in some patients with IDH-mutant gliomas might be supported by our data.

Purpose Glioma patients, especially recurrent glioma, suffer from a poor prognosis. While advances to classify glioma on a molecular level improved prognostication at initial diagnosis, markers to prognosticate survival in the recurrent situation are still needed. As 18 kDa translocator protein (TSPO) was previously reported to be associated with aggressive histopathological glioma features, we correlated the TSPO positron emission tomography (PET) signal in a large cohort of recurrent glioma patients with their clinical outcome. Methods In patients with TSPO PET at glioma recurrence, TSPO PET parameters (e.g. SUVmax) as well as other imaging features (e.g. MRI volume, [18F]FET PET parameters when available) were evaluated together with patient characteristics (age, sex, Karnofsky-Performance score) and neuropathological features (e.g. WHO grade, IDH-mutation status). Uni- and multivariate Cox regression and Kaplan-Meier survival analyses were performed to identify prognostic factors for post-recurrence survival (PRS) and time to treatment failure (TTF). Results 88 consecutive patients were evaluated. TSPO tracer uptake correlated with tumor grade at recurrence (p IDH-wildtype versus IDH-mutant tumors. Within the subgroup of IDH-mutant glioma (n = 46), patients with low SUVmax (median split, ≤ 1.60) had a significantly longer PRS (median 41.6 vs. 25.3 months, p = 0.031) and TTF (32.2 vs 8.7 months, p = 0.001). Also among IDH-wildtype tumors (n = 42), patients with low SUVmax (≤ 1.89) had a significantly longer PRS (median not reached vs 8.2 months, p = 0.002). SUVmax remained an independent prognostic factor for PRS in the multivariate analysis including CNS WHO grade, IDH status and age. Tumor volume defined by [18F]FET PET or contrast-enhanced MRI correlated weakly with TSPO tracer uptake. Treatment regimen did not differ among the median split subgroups. Conclusion Our data suggest that TSPO PET can help to prognosticate recurrent glioma patients even among homogeneous molecular subgroups and may therefore serve as valuable non-invasive biomarker for individualized patient management.

Background The optimal timing for the surgical treatment of additional unruptured aneurysms in patients with multiple aneurysms and aneurysmal subarachnoid hemorrhage (aSAH) is unknown. Therefore, we analyzed the results of early versus delayed microsurgical treatment of unruptured aneurysms when multiple aneurysms were present in the setting of aSAH. Methods The medical records from a consecutive, single-surgeon, 19-year experience of all patients with aSAH and additional unruptured aneurysms treated with a second surgery were reviewed retrospectively. Early treatment was defined as treatment within 30 days and delayed treatment as treatment more than 30 days after the initial surgery for aSAH. Results A total of 85 patients with aSAH and multiple aneurysms were identified. Early (n = 55; 65%) or delayed (n = 30; 35%) clipping was performed for additional unruptured aneurysms. Intraoperative rupture (P = 0.028), higher Fisher grade (P = 0.046), multiple additional unruptured aneurysms (P = 0.04), and large aneurysm size of either the ruptured aneurysm (P = 0.034) or unruptured aneurysm (P = 0.022) were significant factors favoring early treatment. Significant differences were not observed with respect to outcome (modified Rankin scale), unfavorable modified Rankin scale changes between the first surgery and last follow-up, aneurysm occlusion, and shunt-dependent hydrocephalus. No ruptures of untreated aneurysms during the follow-up course were observed. Conclusions Both early and delayed surgical treatment of unruptured aneurysms in the setting of aSAH are safe. Factors prompting earlier intervention might include multiple additional aneurysms, larger aneurysms, and intraoperative aneurysm rupture, which could suggest a destabilized arterial wall. Delayed treatment is advisable for patients with a poor clinical presentation, greater underlying brain injury, and a swollen brain requiring decompressive craniectomy to allow time for recovery.

PURPOSE To assess the relationship between F-18-fluoro-ethyl-tyrosine positron emission tomography (FET-PET) parameters of relapsing oligodendroglioma and progression-free survival. MATERIAL AND METHODS The relationship of clinical parameters, FET-PET parameters (SUV$_{max}$, TBR$_{max}$, BTV$_{,}$ time-activity curves) and progression-free survival was analyzed using univariate and multivariate analysis in 42 adult patients with relapsing oligodendroglioma. Kaplan-Meier analysis was used to assess survival. RESULTS Patients who did not undergo surgical resection of their relapsing tumor had significantly lower PFS if the tumor exhibited an SUV$_{max}$ above 3.40 than those with an SUV$_{max}$ below 3.40 (13.1 ± 2.3 months vs. 47.3 ± 6.0 months, respectively, p

OBJECTIVEIn patients with suspected diffusely infiltrating low-grade gliomas (LGG), the prognosis is dependent especially on extent of resection and precision of tissue sampling. Unfortunately, visible 5-aminolevulinic acid (5-ALA) fluorescence is usually only present in high-grade gliomas (HGGs), and most LGGs cannot be visualized. Recently, spectroscopic probes were introduced allowing in vivo quantitative analysis of intratumoral 5-ALA–induced protoporphyrin IX (PpIX) accumulation. The aim of this study was to intraoperatively investigate the value of visible 5-ALA fluorescence and quantitative PpIX analysis in suspected diffusely infiltrating LGG.METHODSPatients with radiologically suspected diffusely infiltrating LGG were prospectively recruited, and 5-ALA was preoperatively administered. During resection, visual fluorescence and absolute tissue PpIX concentration (CPpIX) measured by a spectroscopic handheld probe were determined in different intratumoral areas. Subsequently, corresponding tissue samples were safely collected for histopathological analysis. Tumor diagnosis was established according to the World Health Organization 2016 criteria. Additionally, the tumor grade and percentage of tumor cells were investigated in each sample.RESULTSAll together, 69 samples were collected from 22 patients with histopathologically confirmed diffusely infiltrating glioma. Visible fluorescence was detected in focal areas in most HGGs (79%), but in none of the 8 LGGs. The mean CPpIX was significantly higher in fluorescing samples than in nonfluorescing samples (0.693 μg/ml and 0.008 μg/ml, respectively; p < 0.001). A significantly higher mean percentage of tumor cells was found in samples with visible fluorescence compared to samples with no fluorescence (62% and 34%, respectively; p = 0.005), and significant correlation of CPpIX and percentage of tumor cells was found (r = 0.362, p = 0.002). Moreover, high-grade histology was significantly more common in fluorescing samples than in nonfluorescing samples (p = 0.001), whereas no statistically significant difference in mean CPpIX was noted between HGG and LGG samples. Correlation between maximum CPpIX and overall tumor grade was highly significant (p = 0.005). Finally, 14 (40%) of 35 tumor samples with no visible fluorescence and 16 (50%) of 32 LGG samples showed significantly increased CPpIX (cutoff value: 0.005 μg/ml).CONCLUSIONSVisible 5-ALA fluorescence is able to detect focal intratumoral areas of malignant transformation, and additional quantitative PpIX analysis is especially useful to visualize mainly LGG tissue that usually remains undetected by conventional fluorescence. Thus, both techniques will support the neurosurgeon in achieving maximal safe resection and increased precision of tissue sampling during surgery for suspected LGG.Clinical trial registration no.: NCT01116661 (clinicaltrials.gov)

Purpose The role of temozolomide chemotherapy alone in isocitrate dehydrogenase (IDH)-mutant astrocytomas has not been conclusively determined. Radiotherapy might be superior to temozolomide. Recent studies have linked temozolomide with induction of hypermutation and poor clinical course in some IDH-mutant gliomas. Methods In this retrospective study, 183 patients with astrocytoma, IDH-mutant, CNS WHO grade 2 or 3 and diagnosed between 2001 and 2019 were included. Patients initially monitored by wait-and-scan strategies or treated with radiotherapy or temozolomide alone were studied. Patient data were correlated with outcome. Matched pair and subgroup analyses were conducted. Results Radiotherapy was associated with longer progression-free survival than temozolomide (6.2 vs 3.4 years, p = 0.02) and wait-and-scan strategies (6.2 vs 4 years, p = 0.03). Patients treated with radiotherapy lived longer than patients treated with temozolomide (14.4 vs 10.7 years, p = 0.02). Survival was longer in the wait-and-scan cohort than in the temozolomide cohort (not reached vs 10.7 years, p Conclusion The results suggest superiority of radiotherapy over temozolomide and wait-and-scan strategies regarding progression-free survival and superiority of radiotherapy over temozolomide regarding overall survival. Our results are consistent with the notion that early temozolomide might compromise outcome in some patients.

BackgroundAn integrated diagnosis consisting of histology and molecular markers is the basis of the current WHO classification system of gliomas. In patients with suspected newly diagnosed or recurrent glioma, stereotactic biopsy is an alternative in cases in which microsurgical resection is deemed to not be safely feasible or indicated. In this retrospective study, we aimed to analyze both the diagnostic yield and the safety of a standardized biopsy technique.Material and MethodsThe institutional database was screened for frame-based biopsy procedures (January 2016 until March 2021). Only patients with a suspected diagnosis of glioma based on imaging were included. All tumors were classified according to the current WHO grading system. The clinical parameters, procedural complications, histology, and molecular signature of the tissues obtained were assessed.ResultsBetween January 2016 and March 2021, 1,214 patients underwent a stereotactic biopsy: 617 (50.8%) for a newly diagnosed lesion and 597 (49.2%) for a suspected recurrence. The median age was 56.9 years (range 5 months−94.4 years). Magnetic resonance imaging (MRI)-guidance was used in 99.3% of cases and additional positron emission tomography (PET)-guidance in 34.3% of cases. In total, stereotactic serial biopsy provided an integrated diagnosis in 96.3% of all procedures. The most frequent diagnoses were isocitrate dehydrogenase (IDH) wildtype glioblastoma (n = 596; 49.2%), oligodendroglioma grade 2 (n = 109; 9%), astrocytoma grade 3 (n = 108; 8.9%), oligodendroglioma grade 3 (n = 76; 6.3%), and astrocytoma grade 2 (n = 66; 5.4%). A detailed determination was successful for IDH 1/2 mutation in 99.4% of cases, for 1p/19q codeletion in 97.4% of cases, for TERT mutation in 98.9% of cases, and for MGMT promoter methylation in 99.1% of cases. Next-generation sequencing was evaluable in 64/67 (95.5%) of cases and DNA methylome analysis in 41/44 (93.2%) of cases. Thirteen (1.1%) cases showed glial tumors that could not be further specified. Seventy-three tumors were different non-glioma entities, e.g., of infectious or inflammatory nature. Seventy-five out of 597 suspected recurrences turned out to be post-therapeutic changes only. The rate of post-procedural complications with clinical symptoms of the Common Terminology Criteria for Adverse Events (CTCAE) grade 3 or higher was 1.2% in overall patients and 2.6% in the subgroup of brainstem biopsies. There was no fatal outcome in the entire series.ConclusionImage-guided stereotactic serial biopsy enables obtaining reliable histopathological and molecular diagnoses with a very low complication rate even in tumors with critical localization. Thus, in patients not undergoing microsurgical resection, this is a valuable tool for precision medicine of patients with glioma.

Neural stem cells within the subventricular zone were identified as cells of origin driving growth of high-grade gliomas, and anatomical involvement of the subventricular zone has been associated with an inferior clinical outcome. Whether the association between poor outcome and subventricular zone involvement also applies to glioma of lower grades is unclear. We therefore analysed a retrospective cohort of 182 patients with glioma grade 2 (according to the WHO 2016 classification) including 78 individuals (43%) with subventricular zone involvement. Patients with and without subventricular zone involvement did not differ in regard to demographics, histopathology, and molecular markers. Notably, subventricular zone involvement was a negative prognostic marker for malignant progression and overall survival on uni- and multivariate analysis. When patients were stratified according to the cIMPACT-NOW update 6, subventricular zone involvement was negatively associated with outcome in IDH-wildtype astrocytomas and 1p19q-codeleted oligodendrogliomas but not in IDH-mutant astrocytomas. Collectively, subventricular zone involvement may represent a risk factor for worse outcome in glioma WHO grade 2 depending on the molecular tumor signature. The present data confirm the relevance of molecular glioma classifications as proposed by the cIMPACT-NOW update 6. These findings warrant evaluation in prospective cohorts.

BACKGROUND Lower grade gliomas show heterogenous appearance on T2-weighted MRI. Some tumors grow diffusely along axonal structures whereas others distort adjacent brain tissue through local mass effect. The diagnostic, therapeutic and prognostic implication of differential growth patterns on MRI remain unknown and are difficult to assess quantitatively. METHODS A web-based application allowing for image preprocessing and providing a comprehensive edge detection tool by means of quantifying tumor border delineation on T2-weighted images based on the canny edge detection algorithm was developed. A sigma value between 1 and 100 determined the threshold where tumor borders where not detected anymore, with 1 equating to the lowest threshold and thus detection of all edges contained in the image. Two experienced faculty members assigned sigma values to axial T2 images of a random sample of 20 WHO grade 2 astrocytomas, IDH-mutant and 1p/19q-non-codeleted. The sigma values were then compared with a binary, subjective rating by the same faculty staff according to the perceived predominant growth pattern (diffuse versus circumscript) of each glioma. RESULTS When subjectively categorizing tumors binarily (diffuse versus circumscript), there was moderate interrater variability between observers (cohen’s kappa=0.6). Raters agreed in 16 of 20 cases, terming 7 gliomas unanimously diffuse and 9 gliomas circumscript. In 4 cases, the raters opinions diverged. The sigma values differed significantly between diffuse and circumscript tumors in both raters (rater 1, p=0.002; rater 2, p=0.018). For rater 1, the mean sigma difference between diffuse and circumscript tumors was 10.7 and 9.3 for rater 2. The mean overall sigma value was 13.3 for rater 1 and 18.7 for rater 2 (p=0.005). CONCLUSION Edge detection algorithms can be efficiently applied on MRI scans and are highly accurate in differentiating diffuse from circumscript gliomas. Objectification demands defining imaging criteria for diffuse and circumscript appearance of lower grade gliomas on MRI.

Introduction The role of chemotherapy alone in newly diagnosed WHO grade 2 oligodendroglioma after biopsy, incomplete or gross total resection remains controversial. We here analyze the clinical outcome of four patient cohorts being treated with either procarbazine, CCNU and vincristine (PCV) or temozolomide (TMZ) after biopsy, resection only, or wait-and-scan after biopsy. Methods Patients (n = 142) with molecularly defined oligodendroglioma (WHO 2016) were assigned to four cohorts: W&S, wait-and-scan after stereotactic biopsy (n = 59); RES, surgical resection only (n = 27); TMZ, temozolomide after biopsy (n = 26) or PCV (n = 30) after biopsy. Presurgical MRI T2 tumor volumes were obtained by manual segmentation. Progression-free survival (PFS), post-recurrence PFS (PR-PFS) and rate of histological progression to grade 3 were analyzed. Results PFS was longest after PCV (9.1 years), compared to 5.1 years after W&S, 4.4 years after RES and 3.6 years after TMZ. The rate of histological progression from grade 2 to 3 within 10 years was 9% for the PCV, 29% for the W&S, 67% for the RES and 75% for the TMZ group (p = 0.01). In the W&S group, patients treated with PCV at first relapse had a longer PFS from intervention than those treated with TMZ (7.2 vs 4.0 years, p = 0.04). Multivariate analysis identified smaller tumor volume prior to any intervention (p = 0.02) to be prognostic for PFS. Conclusions PCV chemotherapy alone is an effective treatment for WHO grade 2 oligodendroglioma, with long PFS and low rate of histological progression.

BACKGROUND Current treatment guidelines for oligodendrogliomas (OD) recommend watch-and-wait strategies after gross total resection and radiation with subsequent chemotherapy (procarbazine, CCNU and vincristine (PCV)) after incomplete resection. The value of chemotherapy alone as an option to delay the risk of late cognitive deficits is not well defined yet. Here, we retrospectively investigated long-term outcome in OD WHO II with respect to initial therapy and tumor volume in magnetic resonance imaging (MRI). METHODS A total of 142 patients with OD WHO (World Health Organization) II according to WHO 2016 were retrospectively included. Patients either had watch and wait (W&W) after histological sampling through stereotactic biopsy (n=59) or tumor resection (n=27) or else stereotactic biopsy with subsequent temozolomide (TMZ) (n=26) or PCV (n=30). Pre- and post-therapeutic T2 tumor volumes were obtained. Progression-free survival (PFS), post-recurrence PFS (PR-PFS) and rate of secondary malignization after 10 years (MR-10yrs) were correlated with clinical and volumetric data. RESULTS PFS was significantly longer in the PCV cohort compared to TMZ (9.1 vs. 3.6 years, p = 0.04), even after matching patients according to age and initial tumor volume (9.1 vs 4.7 yrs, p = 0.03). PFS in the W&W cohort was 5.1 years and 4.4 years in those receiving tumor resection only. MR-10yrs was 4% in PCV cohort, 18% in the W&W cohort and 52% in the resection only cohort (p = 0.01). In the W&W cohort, patients treated with PCV at first relapse had a longer PR-PFS than those treated with TMZ (in years, 7.2 vs 4.0, p = 0.04). Multivariate analysis confirmed initial PCV therapy (p = 0.01) and initial T2 tumor volume (p = 0.02) to be prognostic. CONCLUSION In oligodendrogliomas WHO II PCV chemotherapy alone is superior in terms of PFS and rate of secondary malignization compared to TMZ chemotherapy alone or tumor resection only.

BACKGROUND Magnetic resonance imaging (MRI) based characterization has previously shown heterogeneity in tumor appearance according to IDH mutation status. We have recently investigated the relevance of contrast enhancement to be dependent on IDH mutation status in glioma WHO II and III. Here, we aimed at further characterizing tumor growth patterns and their prognostic value in these tumors. METHODS MRI and clinical data of patients with newly diagnosed glioma WHO II and III from two different centers were retrospectively reviewed. Radiological data such as localization, presence of contrast enhancement, T2-volume as well as tumor growth pattern (“diffuse” vs. “circumscript”) were obtained. Progression-free (PFS) and overall survival (OS) were determined and correlated with clinical, radiological and molecular characteristics using univariate and multivariate regression analyses. RESULTS 390 patients were included, 69% thereof having an IDH mutation. The median T2-volume was 46.0 ml, IDH mutant tumors being larger (50.7 ml) than IDH wildtype tumors (36.0 ml), p = 0.01. A total of 172 tumors were classified as “circumscript” and 218 as “diffuse”; the majority of IDH wildtype tumors (71%) were well delineated compared to 51% in the IDH mutant group (p< 0.0001). Apart from clinical parameters such as younger age, lower KPS, complete resection and delayed treatment, “circumscript” tumor growth pattern was associated with improved survival in the entire group (p = 0.016). When analyzed according to IDH mutation status, “circumscript” tumor growth pattern was significantly associated with OS and PFS (p = 0.006 and p = 0.002) in the IDH wildtype, but not in the IDH mutant group (p = 0.34 and p = 0.81). CONCLUSION IDH wildtype tumors present more often with a ”circumscript” growth pattern on initial T2 MRI. However, this “circumscript” growth pattern was associated with improved survival only in the IDH wiltdtype but not in the IDH mutant group.

BACKGROUND The subventricular zone represents a niche of adult neural stem cells. Involvement of the subventricular zone is associated with decreased survival in malignant glioma. We aimed to determine whether a similar association applies to low-grade gliomas. METHODS A retrospective institutional database search was performed for patients with glioma WHO grade II according to the 2016 classification. Demographic data, histology and molecular signature, imaging, and therapy were recorded and outcome was analysed for tumors with and without infiltration of the subventricular zone. RESULTS 182 patients with glioma WHO grade II were identified, including 97 oligodendrogliomas and 85 astrocytomas. 78 of 182 patients (43%) presented with subventricular zone involvement. Demographics, histopathology, and molecular signature did not differ between patients with and without subventricular zone involvement. First-line management included surgery, chemotherapy, radiotherapy, brachytherapy, and wait-and-scan approaches. Median follow-up was 43 months. Median time to malignant progression was 122 months; median overall survival was not reached. Subventricular zone involvement was a negative prognostic marker for time to malignant progression (p = 0.002) and overall survival (p = 0.023) in the entire cohort as well as in the subgroup of patients who were managed with wait-and-scan approaches. Among patients in which early therapy was provided, subventricular zone involvement was not prognostic for overall survival but for time to malignant progression. In multivariate analysis, subventricular zone involvement was associated with worse prognosis independent of molecular markers or treatment approaches including use of resection. CONCLUSION Subventricular zone involvement represents a key risk factor for worse outcome in glioma WHO grade II. Early first-line therapy may improve outcome in such patients.

To assess the relationship between F-18-fluoro-ethyl-tyrosine positron emission tomography (FET-PET) parameters of relapsing oligodendroglioma and progression-free survival.The relationship of clinical parameters, FET-PET parameters (SUVPatients who did not undergo surgical resection of their relapsing tumor had significantly lower PFS if the tumor exhibited an SUVFET-PET may provide added value for the prognostication of relapsing oligodendroglioma in addition to clinical parameters.

To explore a prognostic or predictive role of MRI and O-(2-Patients with isocitrate dehydrogenase wild-type glioblastoma ages 65 years or older were included in thisOverall survival benefit from bevacizumab plus radiotherapy compared with radiotherapy alone was observed for larger pretreatment MRI contrast-enhancing tumor [HR per cmLarge pretreatment contrast-enhancing tumor mass and higher ADCs identify patients who may experience a survival benefit from bevacizumab plus radiotherapy. Persistent

Objective To evaluate the diagnostic accuracy and safety of extended stereotactic brain biopsy (ESBB) in a single center cohort with suspected primary angiitis of the central nervous system (PACNS). Methods A standardized stereotactic biopsy targeting MRI-positive lesions and collecting samples from the meninges and the cortex as well as from the white matter was performed in 23 patients with clinically suspected PACNS between 2010 and 2017. The relationship between biopsy yield and clinical characteristics, cerebrospinal fluid parameters, MR-imaging, time point of biopsy and exact localization of biopsy as well as number of tissue samples were examined. Results PACNS was confirmed in 7 of 23 patients (30.4%). Alternative diagnoses were identified in 7 patients (30%). A shorter time period between the onset or worsening of symptoms (p = 0.018) and ESBB significantly increased the diagnostic yield. We observed only minor and transient postoperative complications in 3 patients (13.0%). ESBB led to a direct change of the therapeutic regime in 13 of 23 patients (56.5%). Careful neuropathological analysis furthermore revealed that cortical samples were crucial in obtaining a diagnosis. Conclusion ESBB is a safe approach with good feasibility, even in critically ill patients, and high diagnostic accuracy in patients with suspected PACNS changing future therapies in 13 of 23 patients (56.5%). Early biopsy after symptom onset/worsening is crucial and (sub)acute MRI-lesions should be targeted with a particular need for biopsy samples from the cortical layer.

INTRODUCTION The cIMPACT-NOW update 6 introduced glioblastoma diagnosis based on the combination of IDH-wildtype (IDHwt) status and TERT promotor mutation (pTERTmut). In glioblastoma as defined by histopathology according to the WHO 2016 classification, MGMT promotor status is associated with outcome. Whether this is also true in glioblastoma defined by molecular markers is yet unclear. METHODS We searched the institutional database for patients with: 1.) glioblastoma defined by histopathology; and 2.) IDHwt astrocytoma with pTERTmut. MGMT promotor methylation was analysed using methylation-specific PCR and Sanger sequencing of CpG sites within the MGMT promotor region. RESULTS We identified 224 patients with glioblastoma diagnosed based on histopathology, and 71 patients with IDHwt astrocytoma with pTERTmut (32 astrocytomas WHO grade II and 39 astrocytomas WHO grade III). There was no difference in the number of MGMT methylated tumors between the two groups as determined per PCR, and also neither the number nor the pattern of methylated CpG sites differed as determined per Sanger sequencing. Progression-free (PFS) and overall survival (OS) was similar between the two groups. Surgery was associated with improved overall survival in IDHwt astrocytoma with pTERTmut. In patients treated with radiochemotherapy or radiotherapy, higher numbers of methylated CpG sites were associated with favourable outcome in both groups. CONCLUSION Extent and pattern of methylated CpG sites are similar in glioblastoma and IDHwt astrocytoma with pTERTmut. In both groups, higher numbers of methylated CpG sites are associated with favourable outcome when radio/chemotherapy is administered. Surgery may form the basis for favourable outcome.

Background. The dichotomy between glioblastoma cell migration and proliferation is regulated by various parameters including oxygen tension. In glioblastoma stem-like cells, hypoxia induces downregulation of pentose phosphate pathway (PPP) enzymes and a flux shift towards glycolysis. We investigated whether the 2 parallel glucose metabolic pathways are intrinsically linked with cell function and whether these pathways are mechanistically involved in regulating functional programs. Methods. Enzyme expression, migration, and proliferation under hypoxia were studied in multiple cell types. Rapidly and slowly dividing or migrating glioblastoma cells were separated, and enzyme profiles were compared. Glucose-6-phosphate dehydrogenase (G6PD) and Aldolase C (ALDOC), the most strongly inversely regulated PPP and glycolysis enzymes, were knocked down by short hairpin RNA. Results. Hypoxia caused downregulation of PPP enzymes and upregulation of glycolysis enzymes in a broad spectrum of cancer and nonneoplastic cells and consistently stimulated migration while reducing proliferation. PPP enzyme expression was increased in rapidly dividing glioblastoma cells, whereas glycolysis enzymes were decreased. Conversely, glycolysis enzymes were elevated in migrating cells, whereas PPP enzymes were diminished. Knockdown of G6PD reduced glioblastoma cell proliferation, whereas ALDOC knockdown decreased migration. Enzyme inhibitors had similar effects. G6PD knockdown in a highly proliferative but non-invasive glioblastoma cell line resulted in prolonged survival of mice with intracerebral xenografts, whereas ALDOC knockdown shortened survival. In a highly invasive glioblastoma xenograft model, tumor burden was unchanged by either knockdown. Conclusions. Cell function and metabolic state are coupled independently of hypoxia, and glucose metabolic pathways are causatively involved in regulating "go or grow" cellular programs.

Interstitial photodynamic therapy (iPDT) using 5-aminolevulinic acid (5-ALA) induced protoporphyrin IX (PPIX) as a cytotoxic photosensitizer has been shown to be a feasible treatment option for malignant gliomas. We present outcome measures and a risk profile analysis of salvage iPDT in a large monocentric cohort with local tumor recurrence following standard therapy. This study included consecutive adult patients undergoing salvage iPDT for small, circumscribed, biopsy-proven malignant glioma recurrences not deemed eligible for safe complete resection of contrast enhancing tumor. A modified 3-D treatment-planning software was used to calculate the treatment-volume and the position of the stereotactic light diffusers within the lesion. Outcome measurements included estimated time-to-treatment-failure (TTF), post-recurrence survival (PRS) and the risk profile of iPDT. Prognostic factors were obtained from logistic regression models. The institutional review board approved the study. A total of 44 patients (median age: 49.4 years, range 33.4–87.0 years, 17 female) were included. Recurrent tumors included 37/44 glioblastomas WHO grade IV and 7/44 anaplastic astrocytomas WHO grade III. Thirty (68.2%) tumors were MGMT methylated. Median treatment volume was 3.3 ccm (range, 0.5–22.8 ccm). A median number of 4 (range: 3–8) laser fibers were used. Median illumination time was 60min (range: 60–167 min). Symptomatic edema (8/44) or intratumoral hemorrhagic imbibition (7/44) did not result in any permanent morbidity. Median TTF was 7.1 months and median PRS was 13.0 months. The 2- and 5-years PRS rates were 25.0% and 4.5%. Treatment response was heterogeneous and not significantly associated with patient characteristics, treatment-related factors or molecular markers. In conclusion, iPDT was associated with promising outcome measurements in local malignant glioma recurrences in highly selected patients. Transient neurologic deterioration did not lead to any permanent morbidity. The procedure deserves further prospective evaluation particularly to identify mechanisms of favorable treatment response and prognostic factors associated with long-term survival.

2520 Background: Bevacizumab failed to demonstrate overall survival benefit despite markedly prolonged progression-free survival in glioblastoma patients. Reasons for this divergence may include suboptimal patient selection and delayed diagnosis of progression on MRI scans under bevacizumab. Imaging analyses of retrospective and uncontrolled clinical trial cohorts suggest MRI diffusion mapping as a predictor of benefit from bevacizumab. Moreover, amino acid PET has been proposed by the RANO working group for the differentiation of tumor versus edema or gliosis based on proof-of-principle studies demonstrating earlier detection of progression with PET compared to MRI. Methods: ARTE (NCT01443676) was a 2:1 randomized, multi-center, open-label trial of hypofractionated radiotherapy in combination with intravenous bevacizumab every 2 weeks (BEV/RT) versus RT alone in patients with newly diagnosed glioblastoma aged 65 years or older. Patients with histologically and molecularly confirmed IDH wildtype glioblastoma aged 65 years or older were analyzed. MRI was available from 67 and serial 18FET PET from 30 patients in this post hoc analysis. 18FET PET intensity ratios and herein reported MRI parameters including tumor volumetric analyses and ADC were analyzed blinded for outcome and study arm. Results: Demographic, clinical and molecular parameters were balanced between treatment arms. Overall survival benefit from bevacizumab was observed for larger contrast-enhancing tumor volumes (hazard ratio [HR] per cm3 0.94, 95% CI 0.89-0.99, p = 0.032) and higher ADC (HR 0.18, 95% CI 0.05-0.66, p = 0.025) on pre-treatment MRI. Response in the BEV/RT arm by the standard MRI-based RANO criteria was associated with overall survival by trend (HR 0.56, 95% CI 0.30-1.10, time-dependent p = 0.094). In a multivariate model controlling for established risk factors, 18FET tumor-to-brain uptake ratios (TBR) of non-contrast-enhancing tumor portions predicted inferior overall survival specifically in the BEV/RT arm (HR [per 0.1 18FET TBR] 1.50, 95% CI 1.05-2.13, time-dependent p = 0.025). Controlling for 18FET TBR at first follow-up identified benefit from BEV/RT by trend (HR 0.41, 95% CI 0.16-1.07, p = 0.069). Conclusions: Large contrast-enhancing tumor mass and high ADC identify patients with overall survival benefit from bevacizumab. Under bevacizumab, non-contrast enhancing tumor portions can be adequately monitored by amino acid PET.

Background Aerobic glycolysis confers several advantages to tumor cells, including shunting of metabolites into anabolic pathways. In glioblastoma cells, hypoxia induces a flux shift from the pentose phosphate pathway toward glycolysis and a switch from proliferation to migration. The mechanistic link between glycolysis and migration is poorly understood. Since glucose-6-phosphate isomerase (GPI) is identical to the secreted cytokine autocrine motility factor (AMF), we investigated whether GPI/AMF regulates glioblastoma cell invasion. Methods The expression and hypoxic regulation of GPI/AMF and its receptor AMFR were analyzed in glioblastoma tissue and cell lines. Functional effects were studied in vitro and in xenograft models. Results High GPI/AMF expression in glioblastomas was found to be associated with a worse patient prognosis, and levels were highest in hypoxic pseudopalisades. Hypoxia upregulated both GPI/AMF and AMFR expression as well as GPI/AMF secretion in vitro. GPI/AMF stimulated cell migration in an autocrine fashion, and GPI/AMF expression was upregulated in migratory cells but reduced in rapidly proliferating cells. Knockdown or inhibition of GPI/AMF reduced glioblastoma cell migration but in part stimulated proliferation. In a highly invasive orthotopic glioblastoma model, GPI/AMF knockdown reduced tumor cell invasion but did not prolong survival. In a highly proliferative model, knockdown tumors were even larger and more proliferative than controls; however, perivascular invasion, provoked by simultaneous bevacizumab treatment, was reduced. Conclusions GPI/AMF is a potent motogen for glioblastoma cells, explaining in part the association between glycolysis and migration. Targeting GPI/AMF is, however, problematic, since beneficial anti-invasive effects may be outweighed by unintended mitogenic effects. Key points 1.Increased glycolysis is linked with increased cell migration and invasion in glioblastoma cells. 2.The glycolysis enzyme GPI/AMF may serve as a target for antimetabolic and anti-invasive therapy. 3.Despite reducing tumor invasion, GPI/AMF targeting may have unwanted growth stimulatory effects.

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.

BACKGROUND: Precise tissue sampling during resection of suspected low-grade gliomas (LGG) is the basis for an accurate histopathological diagnosis to enable adequate patient management. In the course of malignant transformation of initial LGG, small intratumoral areas of glioblastoma tissue can potentially arise that might be unrecognized during surgery and thus result in treatment failure. Recently, 5-aminolevulinic acid (5-ALA) induced fluorescence was identified as intraoperative marker for visualization of focal intratumoral WHO grade III areas. The aim of this study is thus to clarify if 5-ALA is also capable to identify areas of unexpected glioblastoma tissue during surgery of radiologically suspected LGG. METHODS: Our database at the Medical University of Vienna and University of California, San Francisco was screened for adult patients with 5-ALA fluorescence-guided resection of a suspected glioma with non-significant MRI contrast-enhancement (CE; no, patchy/faint or focal CE). In this study, only patients with newly diagnosed lesions were included. In contrast, recurrent gliomas and biopsy only cases were excluded. In all patients, histopathological diagnosis was established according to the WHO classification. RESULTS: Altogether, 7 patients (median age: 53 years, range: 30–66 years) with histological diagnosis of a glioblastoma were identified despite initial radiological suspicion of LGG. Of these, no CE was found on preoperative MRI in two cases (29%), patchy/faint CE in two cases (29%) and focal CE in three cases (42%). During surgery, intratumoral areas with focal 5-ALA induced fluorescence were observed in all 7 patients. In contrast, no visible fluorescence was found in the remaining intratumoral regions. CONCLUSIONS: Our study indicates that 5-ALA induced fluorescence is able to identify intratumoral areas containing even focal glioblastoma tissue in radiologically suspected LGG. Thus, the 5-ALA technique will in future markedly improve tissue sampling during resection of suspected LGG to allow a precise histopathological diagnosis and optimized postoperative patient management.

e14062Background: The vascular endothelial growth factor antibody, bevacizumab (Avastin), received approval for the treatment of recurrent glioblastoma in Switzerland in 2009. Here we explored the ...

Reactive oxygen species mediate cellular signaling and neuropathologies. Hence, there is tremendous interest in monitoring (sub)cellular redox conditions. We evaluated the genetically engineered redox sensor HyPer in mouse hippocampal cell cultures. Two days after lipofection, neurons and glia showed sufficient expression levels, and H2O2 reversibly and dose-dependently increased the fluorescence ratio of cytosolic HyPer. Yet, repeated H2O2 treatment caused progressively declining responses, and with millimolar doses an apparent recovery started while H2O2 was still present. Although HyPer should be H2O2 specific, it seemingly responded also to other oxidants and altered cell-endogenous superoxide production. Control experiments with the SypHer pH sensor confirmed that the HyPer ratio responds to pH changes, decreasing with acidosis and increasing during alkalosis. Anoxia/reoxygenation evoked biphasic HyPer responses reporting apparent reduction/oxidation; replacing Cl(-) exerted only negligible effects. Mitochondria-targeted HyPer readily responded to H2O2-albeit less intensely than cytosolic HyPer. With ratiometric two-photon excitation, H2O2 increased the cytosolic HyPer ratio. Time-correlated fluorescence-lifetime imaging microscopy (FLIM) revealed a monoexponential decay of HyPer fluorescence, and H2O2 decreased fluorescence lifetimes. Dithiothreitol failed to further reduce HyPer or to induce reasonable FLIM and two-photon responses. By enabling dynamic recordings, HyPer is superior to synthetic redox-sensitive dyes. Its feasibility for two-photon excitation also enables studies in more complex preparations. Based on FLIM, quantitative analyses might be possible independent of switching excitation wavelengths. Yet, because of its pronounced pH sensitivity, adaptation to repeated oxidation, and insensitivity to reducing stimuli, HyPer responses have to be interpreted carefully. For reliable data, side-by-side pH monitoring with SypHer is essential.

2-6 July 2007 This paper reports results from experiments carried out in a laboratory flume to investigate the process of seabed scour around cylinders of finite length under the action of currents close to the threshold of motion for the bed sediment. The conditions relate to the design of large caisson foundations for offshore oil and gas installations and wind turbines. Results show that depth and extent of scour are much reduced for cylinders that stand less than one diameter above the seabed compared to tests with a surface-piercing cylinder. When truncated cylinders stand on shallow foundations, scour patterns are not sensitive to skirt depth, even when the cylinder has been undermined. For the present tests, maximum scour depth around truncated cylinders in a tidally reversing current was found to be less than 50% of equilibrium scour depth for an equivalent unidirectional flow.

The Warburg effect describes the metabolic redirection in tumor cells away from oxidative phosphorylation to aerobic glycolysis, a status even enhanced by hypoxia. We recently discovered an oxygen concentration-dependent reciprocal metabolic switch between glycolysis and the pentose phosphate pathway, which is associated with a pro-migratory as opposed to a pro-proliferative phenotype, respectively (Kathagen et al., Acta Neuropathol 2013). However, the mechanistic link between glycolysis and cell migration is poorly understood. Since the hypoxia-induced glycolytic enzyme glucose 6-phosphate isomerase (GPI) is identical to autocrine motility factor (AMF), a secreted cytokine that binds to the cell surface receptor AMFR, we studied the functional effects of GPI/AMF on glioblastoma cells. Recombinant GPI/AMF strongly stimulated the migration of glioblastoma stem-like (GS) cells in modified Boyden chamber assays and was even more powerful than Hepatocyte Growth Factor/Scatter Factor, a known highly potent glioma cell motogen. In contrast, GPI/AMF moderately reduced the proliferation of GS cells. Erythrose 4-phosphate, an inhibitor of GPI/AMF activity, abrogated the pro-migratory effect of GPI/AMF while having no effect on GS cell proliferation. Gene expression profiling, qPCR and Western Blot analyses revealed a strong upregulation of GPI/AMF as well as of AMFR expression in response to hypoxia. Furthermore, the amount of secreted GPI/AMF in supernatants of GS cells was strikingly increased under hypoxia. GS cell-conditioned medium had a pro-migratory effect on cells, which was abrogated by immunodepletion of GPI/AMF from the culture medium. Knockdown of GPI/AMF expression by shRNA reduced GS cell migration but had no effect on proliferation. Immunostaining of human glioblastoma sections revealed increased expression of both GPI/AMF and AMFR in hypoxic pseudopalisading regions. To conclude, GPI/AMF is an extraordinarily potent motogen for GS cells, which explains in part the association between increased glycolytic activity. GPI/AMF may be thus be a valuable target for inhibiting glioblastoma cell invasion.

Background The EANO ESMO guidelines have proposed a classification of leptomeningeal metastases (LM) based on clinical (typical/atypical), cytological (positive/negative/equivocal) and MRI (A linear, B nodular, C linear + nodular, D normal or hydrocephalus only) presentation. Type I LM is defined by the presence of tumor cells in the cerebrospinal fluid (CSF) (confirmed LM) whereas type II LM is defined by typical clinical and MRI signs (probable or possible LM). Here we explored the correlation between EANO ESMO subtypes of LM and outcome to assess their clinical utility. Methods We collected data from 254 patients with newly diagnosed LM from different primary solid tumors. Survival curves were estimated using the Kaplan-Meier method and compared by Log-rank test. Results Median age at LM diagnosis was 56.5 years (range 20-82 years). The main primary tumors were breast cancer (n = 98, 45%), lung cancer (n = 65, 25.5%) and melanoma (n = 51, 13.5%). Typical clinical LM symptoms or signs were noted in 225 patients (88.5%); only 13 patients (5%) were clinically asymptomatic. The most common MRI subtype was A seen in 117 patients (46%). Types B (n = 33, 13%), C (n = 54, 21%) and D (n = 50, 19.5%) were less common. Tumor cells were observed in the CSF in 186 patients (73%) whereas the CSF was equivocal in 24 (9.5%) and negative in 44 (17.5%) patients. Assignment to EANO ESMO classes was as follows: type IA 86 (34%), IB 19 (7.5%), IC 39 (15.5%), ID 45 (17.5%), IIA 28 (11%), IIB 13 (5%), IIC 16 (6.5%), IID 8 (3%). LM was confirmed in 189 (74.5%), probable in 51 (20%) and possible in 14 (5.5%) patients. The median overall survival (OS) was 2.75 months (range 0.09-220 months). OS was inferior in type I compared with type II LM patients (p = 0.0024). EANO ESMO subtype IIA patients had the longest survival (p = 0.0103). Patients with MRI patterns A and D pooled had poorer survival than B and C patients pooled in the presence of tumor cells in the CSF (type I) (p = 0.0402), but longer survival in the absence of tumor cells in the CSF (type II) (p = 0.0273). Conclusions The presence of tumor cells in the CSF appears to have a greater prognostic role than the neuroimaging presentation. EANO ESMO LM subtypes are prognostic and should be considered in the design of clinical trials. Legal entity responsible for the study University Hospital of Zurich. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.