Status epilepticus in patients with brain tumors and metastases: A multicenter cohort study of 208 patients and literature review.

OBJECTIVE: Brain tumors and metastases account for approximately 10% of all status epilepticus (SE) cases. This study described the clinical characteristics, treatment, and short- and long-term outcomes of this population. METHODS: This retrospective, multi-center cohort study analyzed all brain tumor patients treated for SE at the university hospitals of Frankfurt and Marburg between 2011 and 2017. RESULTS: The 208 patients (mean 61.5 ± 14.7 years of age; 51% male) presented with adult-type diffuse gliomas (55.8%), metastatic entities (25.5%), intracranial extradural tumors (14.4%), or other tumors (4.3%). The radiological criteria for tumor progression were evidenced in 128 (61.5%) patients, while 57 (27.4%) were newly diagnosed with tumor at admission and 113 (54.3%) had refractory SE. The mean hospital length of stay (LOS) was 14.8 days (median 12.0, range 1-57), 171 (82.2%) patients required intensive care (mean LOS 8.9 days, median 5, range 1-46), and 44 (21.2%) were administered mechanical ventilation. All patients exhibited significant functional status decline (modified Rankin Scale) post-SE at discharge (p < 0.001). Mortality at discharge was 17.3% (n = 36), with the greatest occurring in patients with metastatic disease (26.4%, p = 0.031) and those that met the radiological criteria for tumor progression (25%, p < 0.001). Long-term mortality at one year (65.9%) was highest in those diagnosed with adult-type diffuse gliomas (68.1%) and metastatic disease (79.2%). Refractory status epilepticus cases showed lower survival rates than non-refractory SE patients (log-rank p = 0.02) and those with signs of tumor progression (log-rank p = 0.001). CONCLUSIONS: SE occurrence contributed to a decline in functional status in all cases, regardless of tumor type, tumor progression status, and SE refractoriness, while long-term mortality was increased in those with malignant tumor entities, tumor progressions, and refractory SE. SE prevention may preserve functional status and improve survival in individuals with brain tumors.

Intrathecal IgM synthesis as a diagnostic marker in patients with suspected CNS lymphoma.

For CNS lymphomas (CNSL), there is a high need for minimally invasive and easily obtainable diagnostic markers. Intrathecal IgM synthesis can easily be determined in routine CSF diagnostics. The aim of this study was to systematically investigate the diagnostic potential of intrathecal IgM synthesis in primary and secondary CNSL (PCNSL and SCNSL). In this retrospective study, patients with a biopsy-proven diagnosis of PCNSL or SCNSL were compared with patients with other neurological diseases in whom CNSL was initially the primary radiological differential diagnosis based on MRI. Sensitivity and specificity of intrathecal IgM synthesis were calculated using receiver operating characteristic curves. Seventy patients with CNSL were included (49 PCNSL and 21 SCNSL) and compared to 70 control patients. The sensitivity and specificity for the diagnosis of CNSL were 49% and 87%, respectively, for the entire patient population and 66% and 91% after selection for cases with tumor access to the CSF system and isolated intrathecal IgM synthesis. In cases with MRI-based radiological suspicion of CNSL, intrathecal IgM synthesis has good specificity but limited sensitivity. Because of its low-threshold availability, analysis of intrathecal IgM synthesis has the potential to lead to higher diagnostic accuracy, especially in resource-limited settings, and deserves further study.

Concurrent gliomas in patients with multiple sclerosis.

BACKGROUND: Concurrent malignant brain tumors in patients with multiple sclerosis (MS) constitute a rare but paradigmatic phenomenon for studying neuroimmunological mechanisms from both molecular and clinical perspectives. METHODS: A multicenter cohort of 26 patients diagnosed with both primary brain tumors and multiple sclerosis was studied for disease localization, tumor treatment-related MS activity, and molecular characteristics specific for diffuse glioma in MS patients. RESULTS: MS neither predisposes nor protects from the development of gliomas. Patients with glioblastoma WHO grade 4 without isocitratdehydrogenase (IDH) mutations have a longstanding history of MS, whereas patients diagnosed with IDH-mutant astrocytoma WHO grade 2 receive multiple sclerosis diagnosis mostly at the same time or later. Concurrent MS is associated with a lesser extent of tumor resection and a worse prognosis in IDH-mutant glioma patients (PFS 32 vs. 64 months, p = 0.0206). When assessing tumor-intrinsic differences no distinct subgroup-defining methylation pattern is identified in gliomas of MS patients compared to other glioma samples. However, differential methylation of immune-related genetic loci including human leukocyte antigen locus on 6p21 and interleukin locus on 5q31 is found in MS patients vs. matched non-MS patients. In line, inflammatory disease activity increases in 42% of multiple sclerosis patients after brain tumor radiotherapy suggesting a susceptibility of multiple sclerosis brain tissue to pro-inflammatory stimuli such as ionizing radiation. CONCLUSIONS: Concurrent low-grade gliomas should be considered in multiple sclerosis patients with slowly progressive, expansive T2/FLAIR lesions. Our findings of typically reduced extent of resection in MS patients and increased MS activity after radiation may inform future treatment decisions.

Brain tumors such as gliomas can evade attacks by the immune system. In contrast, some diseases of the central nervous system such as multiple sclerosis (MS) are caused by an overactive immune system. Our study looks at a cohort of rare patients with both malignant glioma and concurrent MS and examines how each disease and their treatments affect each other. Our data suggest that even in patients with known MS, if medical imaging findings are unusual, a concurrent brain tumor should be excluded at an early stage. Radiotherapy, as is the standard of care for malignant brain tumors, may worsen the inflammatory disease activity in MS patients, which may be associated with certain genetic risk factors. Our findings may help to inform treatment of patients with brain tumors and MS.

Machine-Learning-Aided Prediction of Brain Metastases Development in Non-Small-Cell Lung Cancers.

PURPOSE: Non-small-cell lung cancer (NSCLC) shows a high incidence of brain metastases (BM). Early detection is crucial to improve clinical prospects. We trained and validated classifier models to identify patients with a high risk of developing BM, as they could potentially benefit from surveillance brain MRI. METHODS: Consecutive patients with an initial diagnosis of NSCLC from January 2011 to April 2019 and an in-house chest-CT scan (staging) were retrospectively recruited at a German lung cancer center. Brain imaging was performed at initial diagnosis and in case of neurological symptoms (follow-up). Subjects lost to follow-up or still alive without BM at the data cut-off point (12/2020) were excluded. Covariates included clinical and/or 3D-radiomics-features of the primary tumor from staging chest-CT. Four machine learning models for prediction (80/20 training) were compared. Gini Importance and SHAP were used as measures of importance; sensitivity, specificity, area under the precision-recall curve, and Matthew's Correlation Coefficient as evaluation metrics. RESULTS: Three hundred and ninety-five patients compromised the clinical cohort. Predictive models based on clinical features offered the best performance (tuned to maximize recall: sensitivity∼70%, specificity∼60%). Radiomics features failed to provide sufficient information, likely due to the heterogeneity of imaging data. Adenocarcinoma histology, lymph node invasion, and histological tumor grade were positively correlated with the prediction of BM, age, and squamous cell carcinoma histology were negatively correlated. A subgroup discovery analysis identified 2 candidate patient subpopulations appearing to present a higher risk of BM (female patients + adenocarcinoma histology, adenocarcinoma patients + no other distant metastases). CONCLUSION: Analysis of the importance of input features suggests that the models are learning the relevant relationships between clinical features/development of BM. A higher number of samples is to be prioritized to improve performance. Employed prospectively at initial diagnosis, such models can help select high-risk subgroups for surveillance brain MRI.

Tumor-derived GDF-15 blocks LFA-1 dependent T cell recruitment and suppresses responses to anti-PD-1 treatment.

Immune checkpoint blockade therapy is beneficial and even curative for some cancer patients. However, the majority don't respond to immune therapy. Across different tumor types, pre-existing T cell infiltrates predict response to checkpoint-based immunotherapy. Based on in vitro pharmacological studies, mouse models and analyses of human melanoma patients, we show that the cytokine GDF-15 impairs LFA-1/ß2-integrin-mediated adhesion of T cells to activated endothelial cells, which is a pre-requisite of T cell extravasation. In melanoma patients, GDF-15 serum levels strongly correlate with failure of PD-1-based immune checkpoint blockade therapy. Neutralization of GDF-15 improves both T cell trafficking and therapy efficiency in murine tumor models. Thus GDF-15, beside its known role in cancer-related anorexia and cachexia, emerges as a regulator of T cell extravasation into the tumor microenvironment, which provides an even stronger rationale for therapeutic anti-GDF-15 antibody development.

Intracranial injection of natural killer cells engineered with a HER2-targeted chimeric antigen receptor in patients with recurrent glioblastoma.

BACKGROUND: Glioblastoma (GB) is incurable at present without established treatment options for recurrent disease. In this phase I first-in-human clinical trial we investigated safety and feasibility of adoptive transfer of clonal chimeric antigen receptor (CAR)-NK cells (NK-92/5.28.z) targeting HER2, which is expressed at elevated levels by a subset of glioblastomas. METHODS: Nine patients with recurrent HER2-positive GB were treated with single doses of 1 × 107, 3 × 107, or 1 × 108 irradiated CAR-NK cells injected into the margins of the surgical cavity during relapse surgery. Imaging at baseline and follow-up, peripheral blood lymphocyte phenotyping and analyses of the immune architecture by multiplex immunohistochemistry and spatial digital profiling were performed. RESULTS: There were no dose-limiting toxicities, and none of the patients developed a cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome. Five patients showed stable disease after relapse surgery and CAR-NK injection that lasted 7 to 37 weeks. Four patients had progressive disease. Pseudoprogression was found at injection sites in 2 patients, suggestive of a treatment-induced immune response. For all patients, median progression-free survival was 7 weeks, and median overall survival was 31 weeks. Furthermore, the level of CD8+ T-cell infiltration in recurrent tumor tissue prior to CAR-NK cell injection positively correlated with time to progression. CONCLUSIONS: Intracranial injection of HER2-targeted CAR-NK cells is feasible and safe in patients with recurrent GB. 1 × 108 NK-92/5.28.z cells was determined as the maximum feasible dose for a subsequent expansion cohort with repetitive local injections of CAR-NK cells.

Diagnostic yield, indications, and outcomes of cranial imaging in AML patients admitted for intensive induction or consolidation chemotherapy: a single-center experience.

Cranial imaging (CI) is a widely used diagnostic procedure, especially in acute myeloid leukemia (AML) patients with suspected bleeding or infection. However, common clinical decision rules to guide CI do not apply to AML patients and the diagnostic yield and outcomes of CI for AML patients are largely unknown. We retrospectively evaluated all CI from newly diagnosed non-promyelocytic AML patients receiving intensive induction or consolidation chemotherapy between 2007 and 2019 for imaging indications, diagnostic yield, and consequences. A total of 110 of 462 patients (24%) received CI for 152 imagings in distinct clinical situations. Forty-four patients (40%) had at least one new and acute pathological finding. Main indication was focal neurologic deficit, craniocerebral trauma, and suspected cerebral hypertension. The most common new finding was intracranial hemorrhage (13% of all imagings), followed by sinusitis (9%). CI led to therapy change in 21 patients. There were no clear associations between indications, laboratory values, and a positive imaging. Positive imaging was associated with adverse overall survival. Our study suggests that the overall rate of ordered CI was appropriate and that CI should generally be performed at a low threshold. A systematized approach to CI may further increase diagnostic yield but is complicated by variable clinical presentation.

MR imaging profile and histopathological characteristics of tumour vasculature, cell density and proliferation rate define two distinct growth patterns of human brain metastases from lung cancer.

PURPOSE: Non-invasive prediction of the tumour of origin giving rise to brain metastases (BMs) using MRI measurements obtained in radiological routine and elucidating the biological basis by matched histopathological analysis. METHODS: Preoperative MRI and histological parameters of 95 BM patients (female, 50; mean age 59.6 ± 11.5 years) suffering from different primary tumours were retrospectively analysed. MR features were assessed by region of interest (ROI) measurements of signal intensities on unenhanced T1-, T2-, diffusion-weighted imaging and apparent diffusion coefficient (ADC) normalised to an internal reference ROI. Furthermore, we assessed BM size and oedema as well as cell density, proliferation rate, microvessel density and vessel area as histopathological parameters. RESULTS: Applying recursive partitioning conditional inference trees, only histopathological parameters could stratify the primary tumour entities. We identified two distinct BM growth patterns depending on their proliferative status: Ki67high BMs were larger (p = 0.02), showed less peritumoural oedema (p = 0.02) and showed a trend towards higher cell density (p = 0.05). Furthermore, Ki67high BMs were associated with higher DWI signals (p = 0.03) and reduced ADC values (p = 0.004). Vessel density was strongly reduced in Ki67high BM (p < 0.001). These features differentiated between lung cancer BM entities (p ≤ 0.03 for all features) with SCLCs representing predominantly the Ki67high group, while NSCLCs rather matching with Ki67low features. CONCLUSION: Interpretable and easy to obtain MRI features may not be sufficient to predict directly the primary tumour entity of BM but seem to have the potential to aid differentiating high- and low-proliferative BMs, such as SCLC and NSCLC.

Sex-Dependent Analysis of Temozolomide-Induced Myelosuppression and Effects on Survival in a Large Real-life Cohort of Patients With Glioma.

BACKGROUND AND OBJECTIVE: To investigate the association of radiochemotherapy-induced cytopenia with sex and its potential effect on survival in patients with glioma. METHODS: We retrospectively analyzed cytopenia during temozolomide-based concomitant radiochemotherapy in 492 patients with glioma. Histologic grading, molecular pathology, surgical procedures, adjuvant chemotherapy subsequent to the radiochemotherapy phase, and overall survival (OS) were recorded. The extent of cytopenia was correlated with sex and outcome. RESULTS: Treatment-induced severe cytopenia (leukocytopenia, lymphocytopenia, neutropenia, and thrombocytopenia) was more frequent in women than men (44 vs 18%; p = 0.0002). In women with IDH-wt high-grade astrocytomas, there was a negative correlation of severe cytopenia in general and thrombocytopenia in particular during temozolomide radiochemotherapy with OS independent from other predictors (92 [77-111] vs 73 [21-127] weeks; p < 0.05). In men, there was also a trend for this unfavorable effect. In addition, severe cytopenia in all blood cell lineages correlated with reduced temozolomide dose exposure during radiochemotherapy (all p < 0.05 in the total cohort) and reduced dose exposure was independently associated with worse OS (hazard ratios for OS in complete vs reduced temozolomide dose in the total and female cohort 0.66 [0.47-0.92] and 0.4 [0.24-0.69], p < 0.05). DISCUSSION: Our analysis of treatment-induced cytopenia in a large cohort of patients with glioma confirms that women are at higher risk and demonstrates an association of cytopenia with shortened survival in women. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that women with glioma treated with temozolomide-based concomitant radiochemotherapy have more frequent treatment-induced severe cytopenia than men and that severe myelosuppression correlates with worse OS in women.

Immune profile and radiological characteristics of progressive multifocal leukoencephalopathy.

BACKGROUND AND PURPOSE: Progressive multifocal leukoencephalopathy (PML) constitutes a severe disease with increasing incidence, mostly in the context of immunosuppressive therapies. A detailed understanding of immune response in PML appears critical for the treatment strategy. The aim was a comprehensive immunoprofiling and radiological characterization of magnetic resonance imaging (MRI) defined PML variants. METHODS: All biopsy-confirmed PML patients (n = 15) treated in our department between January 2004 and July 2019 were retrospectively analysed. Data from MRI, histology as well as detailed clinical and outcome data were collected. The MRI-defined variants of classical (cPML) and inflammatory (iPML) PML were discriminated based on the intensity of gadolinium enhancement. In these PML variants, intensity and localization (perivascular vs. parenchymal) of inflammation in MRI and histology as well as the cellular composition by immunohistochemistry were assessed. The size of the demyelinating lesions was correlated with immune cell infiltration. RESULTS: Patients with MRI-defined iPML showed a stronger intensity of inflammation with an increased lymphocyte infiltration on histological level. Also, iPML was characterized by a predominantly perivascular inflammation. However, cPML patients also demonstrated certain inflammatory tissue alterations. Infiltration of CD163-positive microglia and macrophage (M/M) subtypes correlated with PML lesion size. CONCLUSIONS: The non-invasive MRI-based discrimination of PML variants allows for an estimation of inflammatory tissue alterations, although exhibiting limitations in MRI-defined cPML. The association of a distinct phagocytic M/M subtype with the extent of demyelination might reflect disease progression.

The PI3K/Akt/mTOR pathway as a preventive target in melanoma brain metastasis.

BACKGROUND: Brain metastases (BM) are a frequent complication of malignant melanoma (MM), with limited treatment options and poor survival. Prevention of BM could be more effective and better tolerated than treating established BM in various conditions. METHODS: To investigate the temporospatial dynamics of PI3K/Akt/mTOR (PAM) pathway activation during BM formation and the preventive potential of its inhibition, in vivo molecular imaging with an Akt biosensor was performed, and long-term intravital multiphoton microscopy through a chronic cranial window in mice. RESULTS: In vivo molecular imaging revealed invariable PAM pathway activation during the earliest steps of brain colonization. In order to perform a long-term intravascular arrest and to extravasate, circulating MM cells needed to activate their PAM pathway during this process. However, the PAM pathway was quite heterogeneously activated in established human brain metastases, and its inhibition with the brain-penetrant PAM inhibitor GNE-317 resulted in only modest therapeutic effects in mice. In contrast, giving GNE-317 in preventive schedules that included very low doses effectively reduced the growth rate and number of BM in two MM mouse models over time, and led to an overall survival benefit. Longitudinal intravital multiphoton microscopy found that the first, rate-limiting steps of BM formation-permanent intravascular arrest, extravasation, and initial perivascular growth-are most vulnerable to dual PI3K/mTOR inhibition. CONCLUSION: These findings establish a key role of PAM pathway activation for critical steps of early metastatic brain colonization and reveal its pharmacological inhibition as a potent avenue to prevent the formation of clinically relevant BM.

DNA methylation-based prediction of response to immune checkpoint inhibition in metastatic melanoma.

BACKGROUND: Therapies based on targeting immune checkpoints have revolutionized the treatment of metastatic melanoma in recent years. Still, biomarkers predicting long-term therapy responses are lacking. METHODS: A novel approach of reference-free deconvolution of large-scale DNA methylation data enabled us to develop a machine learning classifier based on CpG sites, specific for latent methylation components (LMC), that allowed for patient allocation to prognostic clusters. DNA methylation data were processed using reference-free analyses (MeDeCom) and reference-based computational tumor deconvolution (MethylCIBERSORT, LUMP). RESULTS: We provide evidence that DNA methylation signatures of tumor tissue from cutaneous metastases are predictive for therapy response to immune checkpoint inhibition in patients with stage IV metastatic melanoma. CONCLUSIONS: These results demonstrate that LMC-based segregation of large-scale DNA methylation data is a promising tool for classifier development and treatment response estimation in cancer patients under targeted immunotherapy.

A 25-year retrospective, single center analysis of 343 WHO grade II/III glioma patients: implications for grading and temozolomide therapy.

PURPOSE: Classification and treatment of WHO grade II/III gliomas have dramatically changed. Implementing molecular markers into the WHO classification raised discussions about the significance of grading and clinical trials showed overall survival (OS) benefits for combined radiochemotherapy. As molecularly stratified treatment data outside clinical trials are scarce, we conducted this retrospective study. METHODS: We identified 343 patients (1995-2015) with newly diagnosed WHO grade II/III gliomas and analyzed molecular markers, patient characteristics, symptoms, histology, treatment, time to treatment failure (TTF) and OS. RESULTS: IDH-status was available for all patients (259 mutant, 84 IDH1-R132H-non-mutant). Molecular subclassification was possible in 173 tumors, resulting in diagnosis of 80 astrocytomas and 93 oligodendrogliomas. WHO grading remained significant for OS in astrocytomas/IDH1-R132H-non-mutant gliomas (p < 0.01) but not for oligodendroglioma (p = 0.27). Chemotherapy (and temozolomide in particular) showed inferior OS compared to radiotherapy in astrocytomas (median 6.1/12.1 years; p = 0.03) and oligodendrogliomas (median 13.2/not reached (n.r.) years; p = 0.03). While radiochemotherapy improved TTF in oligodendroglioma (median radiochemotherapy n.r./chemotherapy 3.8/radiotherapy 7.3 years; p < 0.001/ = 0.06; OS data immature) the effect, mainly in combination with temozolomide, was weaker in astrocytomas (median radiochemotherapy 6.7/chemotherapy 2.3/radiotherapy 2.0 years; p < 0.001/ = 0.11) and did not translate to improved OS (median 8.4 years). CONCLUSION: This is one of the largest retrospective, real-life datasets reporting treatment and outcome in low-grade gliomas incorporating molecular markers. Current histologic grading features remain prognostic in astrocytomas while being insignificant in oligodendroglioma with interfering treatment effects. Chemotherapy (temozolomide) was less effective than radiotherapy in both astrocytomas and oligodendrogliomas while radiochemotherapy showed the highest TTF in oligodendrogliomas.

Compensatory CSF2-driven macrophage activation promotes adaptive resistance to CSF1R inhibition in breast-to-brain metastasis.

Tumor microenvironment-targeted therapies are emerging as promising treatment options for different cancer types. Tumor-associated macrophages and microglia (TAMs) represent an abundant nonmalignant cell type in brain metastases and have been proposed to modulate metastatic colonization and outgrowth. Here we demonstrate that targeting TAMs at distinct stages of the metastatic cascade using an inhibitor of colony-stimulating factor 1 receptor (CSF1R), BLZ945, in murine breast-to-brain metastasis models leads to antitumor responses in prevention and intervention preclinical trials. However, in established brain metastases, compensatory CSF2Rb-STAT5-mediated pro-inflammatory TAM activation blunted the ultimate efficacy of CSF1R inhibition by inducing neuroinflammation gene signatures in association with wound repair responses that fostered tumor recurrence. Consequently, blockade of CSF1R combined with inhibition of STAT5 signaling via AC4-130 led to sustained tumor control, a normalization of microglial activation states and amelioration of neuronal damage.

Linking epigenetic signature and metabolic phenotype in IDH mutant and IDH wildtype diffuse glioma.

AIMS: Changes in metabolism are known to contribute to tumour phenotypes. If and how metabolic alterations in brain tumours contribute to patient outcome is still poorly understood. Epigenetics impact metabolism and mitochondrial function. The aim of this study is a characterisation of metabolic features in molecular subgroups of isocitrate dehydrogenase mutant (IDHmut) and isocitrate dehydrogenase wildtype (IDHwt) gliomas. METHODS: We employed DNA methylation pattern analyses with a special focus on metabolic genes, large-scale metabolism panel immunohistochemistry (IHC), qPCR-based determination of mitochondrial DNA copy number and immune cell content using IHC and deconvolution of DNA methylation data. We analysed molecularly characterised gliomas (n = 57) for in depth DNA methylation, a cohort of primary and recurrent gliomas (n = 22) for mitochondrial copy number and validated these results in a large glioma cohort (n = 293). Finally, we investigated the potential of metabolic markers in Bevacizumab (Bev)-treated gliomas (n = 29). RESULTS: DNA methylation patterns of metabolic genes successfully distinguished the molecular subtypes of IDHmut and IDHwt gliomas. Promoter methylation of lactate dehydrogenase A negatively correlated with protein expression and was associated with IDHmut gliomas. Mitochondrial DNA copy number was increased in IDHmut tumours and did not change in recurrent tumours. Hierarchical clustering based on metabolism panel IHC revealed distinct subclasses of IDHmut and IDHwt gliomas with an impact on patient outcome. Further quantification of these markers allowed for the prediction of survival under anti-angiogenic therapy. CONCLUSION: A mitochondrial signature was associated with increased survival in all analyses, which could indicate tumour subgroups with specific metabolic vulnerabilities.

Activation of Epidermal Growth Factor Receptor Sensitizes Glioblastoma Cells to Hypoxia-Induced Cell Death.

BACKGROUND: The epidermal growth factor receptor (EGFR) signaling pathway is genetically activated in approximately 50% of glioblastomas (GBs). Its inhibition has been explored clinically but produced disappointing results, potentially due to metabolic effects that protect GB cells against nutrient deprivation and hypoxia. Here, we hypothesized that EGFR activation could disable metabolic adaptation and define a GB cell population sensitive to starvation. METHODS: Using genetically engineered GB cells to model different types of EGFR activation, we analyzed changes in metabolism and cell survival under conditions of the tumor microenvironment. RESULTS: We found that expression of mutant EGFRvIII as well as EGF stimulation of EGFR-overexpressing cells impaired physiological adaptation to starvation and rendered cells sensitive to hypoxia-induced cell death. This was preceded by adenosine triphosphate (ATP) depletion and an increase in glycolysis. Furthermore, EGFRvIII mutant cells had higher levels of mitochondrial superoxides potentially due to decreased metabolic flux into the serine synthesis pathway which was associated with a decrease in the NADPH/NADP+ ratio. CONCLUSIONS: The finding that EGFR activation renders GB cells susceptible to starvation could help to identify a subgroup of patients more likely to benefit from starvation-inducing therapies.

Regorafenib CSF Penetration, Efficacy, and MRI Patterns in Recurrent Malignant Glioma Patients.

(1) Background: The phase 2 Regorafenib in Relapsed Glioblastoma (REGOMA) trial indicated a survival benefit for patients with first recurrence of a glioblastoma when treated with the multikinase inhibitor regorafenib (REG) instead of lomustine. The aim of this retrospective study was to investigate REG penetration to cerebrospinal fluid (CSF), treatment efficacy, and effects on magnetic resonance imaging (MRI) in patients with recurrent high-grade gliomas. (2) Methods: Patients were characterized by histology, adverse events, steroid treatment, overall survival (OS), and MRI growth pattern. REG and its two active metabolites were quantified by liquid chromatography/tandem mass spectrometry in patients' serum and CSF. (3) Results: 21 patients mainly with IDH-wildtype glioblastomas who had been treated with REG were retrospectively identified. Thirteen CFS samples collected from 3 patients of the cohort were available for pharmacokinetic testing. CSF levels of REG and its metabolites were significantly lower than in serum. Follow-up MRI was available in 19 patients and showed progressive disease (PD) in all but 2 patients. Two distinct MRI patterns were identified: 7 patients showed classic PD with progression of contrast enhancing lesions, whereas 11 patients showed a T2-dominant MRI pattern characterized by a marked reduction of contrast enhancement. Median OS was significantly better in patients with a T2-dominant growth pattern (10 vs. 27 weeks respectively, p = 0.003). Diffusion restrictions were observed in 13 patients. (4) Conclusion: REG and its metabolites were detectable in CSF. A distinct MRI pattern that might be associated with an improved OS was observed in half of the patient cohort. Treatment response in the total cohort was poor.

Distribution and prognostic impact of microglia/macrophage subpopulations in gliomas.

While the central nervous system is considered an immunoprivileged site and brain tumors display immunosuppressive features, both innate and adaptive immune responses affect glioblastoma (GBM) growth and treatment resistance. However, the impact of the major immune cell population in gliomas, represented by glioma-associated microglia/macrophages (GAMs), on patients' clinical course is still unclear. Thus, we aimed at assessing the immunohistochemical expression of selected microglia and macrophage markers in 344 gliomas (including gliomas from WHO grade I-IV). Furthermore, we analyzed a cohort of 241 IDH1R132H-non-mutant GBM patients for association of GAM subtypes and patient overall survival. Phenotypical properties of GAMs, isolated from high-grade astrocytomas by CD11b-based magnetic cell sorting, were analyzed by immunocytochemistry, mRNA microarray, qRT-PCR and bioinformatic analyses. A higher amount of CD68-, CD163- and CD206-positive GAMs in the vital tumor core was associated with beneficial patient survival. The mRNA expression profile of GAMs displayed an upregulation of factors that are considered as pro-inflammatory M1 (eg, CCL2, CCL3L3, CCL4, PTGS2) and anti-inflammatory M2 polarization markers (eg, MRC1, LGMN, CD163, IL10, MSR1), the latter rather being associated with phagocytic functions in the GBM microenvironment. In summary, we present evidence that human GBMs contain mixed M1/M2-like polarized GAMs and that the levels of different GAM subpopulations in the tumor core are positively associated with overall survival of patients with IDH1R132H-non-mutant GBMs.

Area postrema syndrome as frequent feature of Bickerstaff brainstem encephalitis.

OBJECTIVE: Area postrema (AP) syndrome (defined as: nausea and/or emesis and/or singultus at onset of brainstem dysfunction) comprises complex pathophysiologic mechanisms triggered by different entities. The first objective was to assess the frequency of AP syndrome as a clinical feature in brainstem encephalitis (BE). Finding an especially high prevalence of AP syndrome in Bickerstaff brainstem encephalitis (BBE), we also analyzed the frequency of AP syndrome in other autoimmune diseases with anti-ganglioside antibodies (Guillain-Barré syndrome (GBS) and its variants). METHODS: We systematically evaluated the prevalence of AP syndrome in BE in all patients treated at our university hospital during a 15-year period. In a second step, BBE patients were compared to GBS and Miller Fisher syndrome (MFS) patients as clinical subtypes of a disease continuum without brainstem dysfunction. RESULTS: We found AP syndrome in 8 of 21 BE patients, including 3 of 7 BBE and in 4 of 112 GBS/MFS patients. AP syndrome was as a frequent but under-recognized feature of BE with a significant impact on patients' well being. INTERPRETATION: Manifestation of AP syndrome in BBE but also in GBS and its subtypes point toward a role of autoimmune antibodies that should be investigated in future studies. Considerable misdiagnosis or nonrecognition complicates diagnostic and therapeutic management. Therefore, AP syndrome should be considered in any episode of otherwise unexplained nausea, emesis, or singultus.