Adjacent Brain Parenchyma Research Articles

Glioblastoma cells increase expression of notch signaling and synaptic genes within infiltrated brain tissue

Glioblastoma remains one of the deadliest brain malignancies. First-line therapy consists of maximal surgical tumor resection, accompanied by chemotherapy and radiotherapy. Malignant cells escape surgical resection by migrating into the surrounding healthy brain tissue, where they give rise to the recurrent tumor. Based on gene expression, tumor cores can be subtyped into mesenchymal, proneural, and classical tumors, each being associated with differences in genetic alterations and cellular composition. In contrast, the adjacent brain parenchyma where infiltrating malignant cells escape surgical resection is less characterized in patients. Using spatial transcriptomics (n = 11), we show that malignant cells within proneural or mesenchymal tumor cores display spatially organized differences in gene expression, although such differences decrease within the infiltrated brain tissue. Malignant cells residing in infiltrated brain tissue have increased expression of genes related to neurodevelopmental pathways and glial cell differentiation. Our findings provide an updated view of the spatial landscape of glioblastomas and further our understanding of the malignant cells that infiltrate the healthy brain, providing new avenues for the targeted therapy of these cells after surgical resection.

Intraoperative Comparison Between Strain Elastography and Preoperative Magnetic Resonance Imaging Features in High-Grade Gliomas Using Fusion Imaging: A Pilot Study

To compare the elastographic patterns of high-grade gliomas (HGGs) solid portions and those of adjacent healthy brain parenchyma, on intraoperative ultrasound, with magnetic resonance image (MRI) characteristics. Clinical records and images of HGGs patients, operated between June and December 2018, were retrospectively reviewed. Fusion images were used to compare preoperative gadolinium-enhanced T1-weighted MRI/fluid-attenuated inversion recovery images (Gd-T1 MRI/FLAIR) to intraoperative strain elastography (SE). FLAIR/Gd-T1 MRI images were used to define: enhancement patterns (absent/whole lesion/peripheral) and lesions' characteristics (primary and secondary pattern, further subdivided in solid/necrotic/cystic/infiltrating). HGGs SE patterns were categorized as homogeneous/inhomogeneous, while lesions' primary and secondary patterns as stiff/intermediate/elastic. The SE motive of neighboring healthy brain parenchyma was defined similarly. 18 patients (M:F, 11:7; mean age: 53 years) harboring 14 glioblastomas (77.8%, GBMs) and 4 anaplastic astrocytomas (22.2%, AAs) were compared. GBMs typically enhanced peripherally and had a primary necrotic pattern (78.6% and 64.3%, respectively), while AAs did not enhance and were solid (75% both) at T1-Gd MRI and FLAIR images. At SE AAs had a homogeneous stiff primary pattern, whereas the majority of GBMs primary patterns were heterogeneous (85.7%) and intermediate (78.6%). Three major SE patterns defined HGGs and adjacent healthy brain parenchyma. SE patterns varied accordingly to HGG histotypes and Gd-T1 MRI/FLAIR characteristics.

AB025. Efficacy of 5-ALA brightness analysis for malignant brain tumor surgery.

For fluorescence-guided neurosurgery, 5-aminolevulinic acid (5-ALA) is widely used for intraoperative tumor visualization. We quantified the brightness of 5-ALA by Image J and report the pathological results of glioma, and non-tumor lesions. From 2019 to 2023, we investigated 27 high-grade glioma patients who underwent surgery with 5-ALA. Twenty-three cases of glioblastoma (GBM) and four cases of anaplastic astrocytoma (AA) were examined. The pathological diagnosis was based on the classification of World Health Organization (WHO) 2016. The 5-ALA was administered before surgery, and the 5-ALA brightness was quantified. Other than high-grade glioma, four low-grade gliomas (LGGs), two radiation necrosis, and one inflammation patients were evaluated by Image J. In GBM, the mean brightness was 134.5±65.4, except for one negative case. AA showed the mean brightness with 180.5±51.6. All LGGs showed negative in the brightness. In two radiation necrosis cases, the mean brightness was 139.5±37.4. In one inflammatory case, the brightness was 239, but after the lesion removed, the adjacent brain parenchyma showed bright, and the border was not clear. In one GBM case, the ventricle was opened, and the brightness difference between the tumor and the ventricular wall was observed. 5-ALA brightness analysis by Image J would be helpful to distinguish between malignant glioma and LGG, and other non-tumor lesions to support rapid pathological diagnosis. Also, it would be useful to distinguish between the tumor and the ventricle wall. As for radiation necrosis and inflammation, border of the lesion is unclear.

Fluorescence-Guided Surgical Techniques in Adult Diffuse Low-Grade Gliomas: State-of-the-Art and Emerging Techniques: A Systematic Review.

Diffuse low-grade gliomas are infiltrative tumors whose margins are not distinguishable from the adjacent healthy brain parenchyma. The aim was to precisely examine the results provided by the intraoperative use of macroscopic fluorescence in diffuse low-grade gliomas and to describe the new fluorescence-based techniques capable of guiding the resection of low-grade gliomas. Only about 20% and 50% of low-grade gliomas are macroscopically fluorescent after 5-amino-levulinic acid (5-ALA) or fluorescein sodium intake, respectively. However, 5-ALA is helpful for detecting anaplastic foci, and thus choosing the best biopsy targets in diffuse gliomas. Spectroscopic detection of 5-ALA-induced fluorescence can detect very low and non-macroscopically visible concentrations of protoporphyrin IX, a 5-ALA metabolite, and, consequently, has excellent performances for the detection of low-grade gliomas. Moreover, these tumors have a specific spectroscopic signature with two fluorescence emission peaks, which is useful for distinguishing them not only from healthy brain but also from high-grade gliomas. Confocal laser endomicroscopy can generate intraoperative optic biopsies, but its sensitivity remains limited. In the future, the coupled measurement of autofluorescence and induced fluorescence, and the introduction of fluorescence detection technologies providing a wider field of view could result in the development of operator-friendly tools implementable in the operative routine.

NEAR-INFRARED SPECTROSCOPY IN VIVO DISTINGUISHES AMYLOID DEPOSITION IN SUBJECTS WITH ALZHEIMER’S DISEASE

Abstract Cerebral amyloid angiopathy (CAA), a condition characterized by amyloid beta peptide deposition in cerebral vasculature, is commonly found in patients with Alzheimer’s disease (AD). Previous studies have shown that it is possible to distinguish subjects with Alzheimer’s disease from age-matched controls in vivo using near-infrared (NIR) spectroscopy. However, correlating neuropathological findings with the spectral features that best distinguish disease from control remains a challenge. Tissue optics predict that pathology in the leptomeningeal vasculature should be distinguishable from that of the adjacent brain parenchyma. In this study, NIR spectra were acquired in vivo from subjects with autopsy confirmed AD (n= 26). Postmortem specimens were histologically classified according to the degree of CAA (0 to 3+) noted in the leptomeningeal vasculature for each patient. A feature selection approach was used to discover spectral features that distinguished patients with high versus minimal degrees of CAA found at autopsy (scored as 3+ vs. 0, respectively). Two distinct spectral regions around 768nm and 891nm were identified as discriminants which could properly classify patients according to their CAA score, suggesting that these regions are correlated with amyloid beta peptide deposition. These results suggest that NIR spectroscopy can be used to detect and possibly inform the burden of amyloid deposition. More research is needed to establish if this technique can be used to monitor disease progression and response to therapeutic interventions, especially in light of emerging new immunotherapies.

EXTH-25. IN VIVO TWO-PHOTON TUMOR IMAGING IN AN ORTHOTOPIC MEDULLOBLASTOMA MOUSE MODEL

Abstract BACKGROUND Medulloblastoma represents the most common primary brain malignancy in pediatric patients and is associated with neuro-cognitive impairment and frequent relapses after aggressive multimodal therapy. Adoptive immunotherapies such as CAR T-cell therapy are currently being investigated, showing promising results in preclinical models but lacking efficacy in first-in-human trials. Refined in vivo models to investigate reasons for treatment failures are therefore urgently needed. METHODS We developed a xenogeneic orthotopic medulloblastoma (MB) model in mice by combining a chronic cerebellar window with repetitive intravital two-photon laser scanning microscopy. Red tdTomato-fluorescent DAOY (SHH MB) tumor cells expressing B7-H3 were implanted intracranially into the cerebellum of immunodeficient mice (n = 7), and tumor cell formation was followed by in vivo-microscopy. Intravenous fluorescein isothiocyanate (FITC)-dextran was used for intravascular plasma staining. B7-H3-directed CAR T-cells were injected into the adjacent brain parenchyma. RESULTS Chronic cranial window implantation was well tolerated and allowed repetitive visualization of the mouse cerebellum. After intracranial tumor cell implantation, continuous tumor growth could be evaluated with epifluorescence as well as 2-photon laser scanning microscopy. Tumor formation was identified as early as day 5 in every mouse and could continuously be followed up to 35 days until mice succumbed due to tumor burden. Window quality and fluorescence intensity remained high until the end of the experiments. Studies on GFP-expressing CAR T-cell injection directed against B7-H3 are currently ongoing. CONCLUSIONS We herein establish a robust orthotopic medulloblastoma mouse model that allows repetitive in vivo tracking of fluorescence-expressing tumor cells, CAR T-cells and blood vessels over weeks. Such models may be used to study medulloblastoma tumor growth under the influence of different immunotherapies and reveal interactions between tumor cells and CAR T-cell therapies on a single-cell level.

P02.03.A INTEGRATIVE (EPI)GENETIC ANALYSIS OF INVASION-PROMOTING GENES IN HIGH-GRADE GLIOMA CELLS

Abstract BACKGROUND DNA methylation-based analyses of brain tumors including glioma is currently the gold standard for diagnostic classification. Aberrant epigenetic alterations can lead to inappropriate gene expression and thereby promote tumorigenesis. Glioblastoma (GBM), CNS WHO grade 4, is characterized by a very diffuse infiltrative growth into the adjacent brain parenchyma. Due to these highly invasive but also genetically heterogeneous and plastic cellular phenotypes, standard treatment, including maximum resection, radio- and chemotherapy, has limited efficacy. It can be assumed that intertumoral or molecular heterogeneity of gliomas on transcriptional level is caused by altered epigenetic changes within the individual tumor cells. Considering this, we hypothesize that tumor cell invasion being one of the critical hallmarks of highly malignant gliomas goes along with altered DNA methylation status and following from this changes in invasion-promoting transcript expression. MATERIAL AND METHODS We performed several in vitro screening approaches to describe the genetic, epigenetic and transcriptional status of invasion glioma cells. Within our first approach, we isolated fractions of glioma cells with increased invasive properties and performed Illumina® array-based methylation profiling as well as RNA sequencing analysis to identify methylation-driven, invasion-associated gene sets. During a second approach, the inducible CRISPR/Cas9 Synergistic Activation Mediator (SAM) system and a genome-wide sgRNA library were introduced in a serum-free glioma cell line. During CRISPR/Cas9 SAM mediated single-gene activation cells were subjected to a transwell invasion assay and sgRNA representation within the invasive glioma cell fraction was determined by next-generation-sequencing (NGS). RESULTS In this study, we integrated Illumina HumanMethylation850K methylation data, RNA-sequencing data and invasion-promoting sgRNA representation data. By systemic screening we identified an invasion-promoting gene signature and the correlating promotor DNA-methylation status. Future studies will be directed to further investigate the impact of identified genes in invasion of high-grade glioma cells. CONCLUSION This integrative experimental approach complements existing genome-wide inhibitory screens as well as incorporates for the first time DNA-methylation profiles and transcriptome analysis with gene-sets identified by CRISPR/Cas9 activation screen and thereby holds the potential to identify novel invasion-essential candidate genes.

OS09.1.AIN VIVOTWO-PHOTON TUMOR IMAGING IN AN ORTHOTOPIC MEDULLOBLASTOMA MOUSE MODEL

Abstract BACKGROUND Medulloblastoma represents the most common primary brain malignancy in pediatric patients and is associated with neuro-cognitive impairment and frequent relapses after aggressive multimodal therapy. Adoptive immunotherapies such as CAR T-cell therapy are currently being investigated, showing promising results in preclinical models but lacking efficacy in first-in-human trials. Refined in vivo models to investigate reasons for treatment failures are therefore urgently needed. METHODS We developed a xenogeneic orthotopic medulloblastoma (MB) model in mice by combining a chronic cerebellar window with repetitive intravital two-photon laser scanning microscopy. Red tdTomato-fluorescent DAOY (SHH MB) tumor cells expressing EphA2 were implanted intracranially into the cerebellum of immunodeficient mice (n = 7), and tumor cell formation was followed by in vivo-microscopy. Intravenous fluorescein isothiocyanate (FITC)-dextran was used for intravascular plasma staining. EphA-directed CAR T-cells were injected into the adjacent brain parenchyma. RESULTS Chronic cranial window implantation was well tolerated and allowed repetitive visualization of the mouse cerebellum. After intracranial tumor cell implantation, continuous tumor growth could be evaluated with epifluorescence as well as 2-photon laser scanning microscopy. Tumor formation was identified as early as day 5 in every mouse and could continuously be followed up to 35 days until mice succumbed due to tumor burden. Window quality and fluorescence intensity remained high until the end of the experiments. Studies on GFP-expressing CAR T-cell injection directed against EphA2 are currently ongoing. CONCLUSIONS We herein establish a robust orthotopic medulloblastoma mouse model that allows repetitive in vivo tracking of fluorescence-expressing tumor cells, CAR T-cells and blood vessels over weeks. Such models may be used to study medulloblastoma tumor growth under the influence of different immunotherapies and reveal interactions between tumor cells and CAR T-cell therapies on a single-cell level.

Ultrasound findings of subpial hemorrhage in neonates

Subpial hemorrhage (SPH) is a subtype of intracranial hemorrhage characterized by damage to the adjacent brain parenchyma. The aim of this study was to describe the sonographic features of SPH in neonates. The cranial ultrasound (US) findings of neonates with SPH confirmed by brain magnetic resonance imaging (MRI) were analyzed retrospectively. Initial and follow-up US and MRI scans were reviewed by two pediatric radiologists who were blinded to both clinical history and outcomes. The US features were compared with the MRI findings. Sixteen patients were included (median gestational age, 38 weeks; range, 26 to 40 weeks; 69% term). SPH was detected most often in the temporal lobe (63%), and multiple SPHs were found in seven of 16 neonates, based on MRI. Acute SPH with an underlying venous infarct (UVI) was detected on US in 15 of 16 patients: small or large fan-shaped hyperechoic lesions (n=7 and 4, respectively) and gyriform hyperechoic lesions (n=4). The sonographic yin-yang sign was observed in three of the four large fan-shaped SPH cases. The accompanying findings on US were intraventricular hemorrhage (four out of six MRI-confirmed cases), and concurrent periventricular venous infarcts (five out of nine MRI-confirmed cases). In five patients, subpial cysts were observed on follow-up US or MRI (n=4 and n=4, respectively). Acute SPH with UVI can appear as a peripheral fan-shaped or gyriform hyperechoic lesion on cranial US. SPH can be detected and suspected based on the US features of SPH with the accompanying findings.

In vivo dynamics and anti-tumor effects of EpCAM-directed CAR T-cells against brain metastases from lung cancer

ABSTRACT Lung cancer patients are at risk for brain metastases and often succumb to their intracranial disease. Chimeric Antigen Receptor (CAR) T-cells emerged as a powerful cell-based immunotherapy for hematological malignancies; however, it remains unclear whether CAR T-cells represent a viable therapy for brain metastases. Here, we established a syngeneic orthotopic cerebral metastasis model in mice by combining a chronic cranial window with repetitive intracerebral two-photon laser scanning-microscopy. This approach enabled in vivo-characterization of fluorescent CAR T-cells and tumor cells on a single-cell level over weeks. Intraparenchymal injection of Lewis lung carcinoma cells (expressing the tumor cell-antigen EpCAM) was performed, and EpCAM-directed CAR T-cells were injected either intravenously or into the adjacent brain parenchyma. In mice receiving EpCAM-directed CAR T-cells intravenously, we neither observed substantial CAR T-cell accumulation within the tumor nor relevant anti-tumor effects. Local CAR T-cell injection, however, resulted in intratumoral CAR T-cell accumulation compared to controls treated with T-cells lacking a CAR. This finding was accompanied by reduced tumorous growth as determined per in vivo-microscopy and immunofluorescence of excised brains and also translated into prolonged survival. However, the intratumoral number of EpCAM-directed CAR T-cells decreased during the observation period, pointing toward insufficient persistence. No CNS-specific or systemic toxicities of EpCAM-directed CAR T-cells were observed in our fully immunocompetent model. Collectively, our findings indicate that locally (but not intravenously) injected CAR T-cells may safely induce relevant anti-tumor effects in brain metastases from lung cancer. Strategies improving the intratumoral CAR T-cell persistence may further boost the therapeutic success.

EXTH-02. ANTI-TUMOR EFFECTS AND IN VIVO DYNAMICS OF EPCAM-DIRECTED CAR T-CELLS FOR BRAIN METASTASES FROM LUNG CANCER

Abstract BACKGROUND Lung cancer patients are at a high risk for brain metastases, and affected patients frequently succumb to their intracranial disease. Chimeric Antigen Receptor (CAR) T-cells emerged as a powerful cell-based immunotherapy for hematological malignancies; however, it remains unclear whether CAR T-cells represent a viable therapeutic avenue for brain metastases. METHODS A fully immunocompetent, orthotopic cerebral metastasis model was established in mice by combining a chronic cranial window with repetitive intracerebral two-photon laser scanning microscopy. This approach enabled the in vivo-characterization of fluorescent CAR T-cells and tumor cells on a single-cell level over weeks. Intraparenchymal injection of EpCAM-expressing Lewis lung carcinoma cells was performed, and EpCAM-directed CAR T-cells (EpCAMCAR T-cells) were injected into the adjacent brain parenchyma after brain tumor formation. RESULTS All mice had visible tumor take with rapidly growing lesions following intracranial tumor cell injection. In mice treated with EpCAMCAR T-cells, we observed substantial CAR T-cell accumulation within the tumor compared to controls treated with undirected T-cells. This was paralleled by lower velocities of EpCAMCAR T-cells, characterizing antitumor cytotoxicity due to ‘immune cell’-‘tumor cell’ contacts. Consequently, treatment with EpCAMCAR T-cells resulted in reduced tumorous growth as determined per in vivo-microscopy (median tumor area on day 10: 1.8 versus 10.8 mm2; p=0.001) and immunohistochemistry of excised brains. However, the number of intratumoral EpCAMCAR T-cells within the tumor markedly decreased during the observation period, pointing towards insufficient persistence. Accordingly, survival was prolonged in mice receiving EpCAMCAR T-cells but long-lasting remission was rare (median survival: 15 versus 13 days; p=0.012). No CNS-specific or systemic toxicities of EpCAMCAR T-cells were encountered. CONCLUSION Our findings indicate that EpCAMCAR T-cells injected into the cerebral parenchyma may safely induce relevant anti-tumor effects in brain metastases from lung cancer. Strategies improving the CAR T-cell persistence within brain metastases are warranted to further boost the therapeutic success.

ANGI-02. EPIGENETIC REGULATION OF GLIOMA INVASION BY CHITINASE-3-LIKE PROTEIN 1 (CHI3L1) CPG PROMOTER METHYLATION

Abstract Epigenetically controlled processes play an important role in development but also in the formation and progression of many common diseases. Molecular signatures are increasingly incorporated into cancer classifications and DNA methylation-based analyses of brain tumors including glioma is currently the gold standard. Glioblastoma (GBM), CNS WHO grade 4, is characterized by a very diffuse infiltrative growth into the adjacent brain parenchyma. Due to these highly invasive but also genetically heterogeneous and plastic cellular phenotypes, standard treatment, including maximum resection, radio- and chemotherapy, has limited efficacy. It can be assumed that intertumoral or molecular heterogeneity of gliomas at the transcriptome level is caused by altered epigenetic changes within the individual tumor cells. Considering this, we hypothesize that tumor cell invasion being one of the major hallmarks of highly malignant gliomas can be associated with altered DNA methylation and therefore transcript expression. To analyze this, we isolated fractions of glioma cells with increased invasive properties and performed Illumina® array-based methylation profiling as well as RNA sequencing analysis to identify methylation-driven, invasion-promoting genes. Among other, we focused on Chitinase-3-like protein 1 (CHI3L1) as a candidate gene with significantly decreased promoter methylation in invasive cell fractions and overall strong transcript expression in high-grade gliomas. Differential expression and methylation correlation of TCGA data combined with our own dataset revealed that CHI3L1 expression is dependent on the methylation status of at least three CpG sites within the gene promoter region. We validated these findings using several in vitro experimental settings and propose an upstream regulatory mechanism in which single CpG DNA demethylation within the CHI3L1 promoter facilitates transcription factor binding resulting in gene expression.

Assessing the Malignancy Risk of a Meningioma by Its Location.

Meningiomas represent 30% of primary intracranial tumors. The current incidence is up to 4.5 cases per 100,000 habitants worldwide. Although there is no prognostic difference among benign histopathological subtypes, atypical meningiomas and malignant meningiomas (WHO grade II and III respectively) may extend to the adjacent brain parenchyma, dura mater, and osseous tissue with a recurrence score (21-49%). This manuscript analyzes the malignancy risk according to neoplastic localization through a logistic retrospective analysis from a total sample of 452 patients with grade I, II, and III (WHO) meningiomas. Detailed data collection through a three-year retrospective analysis (January 2008 to December 2011) was applied at Mexico's National Neurology and Neurosurgery Institute including patients with intracranial or spinal-cord meningioma, preoperative imaging study availability and post-surgical histopathological diagnosis. Formal written consent was not required with a waiver by the appropriate national research ethics committee in accordance with the provisions of the regulations of the general health law of Mexico. Convexity lesions displayed an increased risk of malignancy turning for non-benign meningiomas with an odds ratio of 3.1 (95% CI 1.6 to 5.7, p=0.0002) meanwhile skull-base meningiomas present an inverse risk with an odds ratio of 0.4 (95% CI 0.2 to 0.9, p=0.02), as well as spinal-cord meningiomas with an odds ratio of 0.3 (95% CI 0.1 to 0.9). Skull base and spinal cord meningiomas usually have benign behavior, meanwhile grade II or III meningiomas within this location are rare. The present work provides an additional criterion for decision making, according to the meningioma's location.

Semi-automated mapping of occluded arterial segments in acute large vessel stroke from computed tomography angiography

Catheterisation of occluded artery is the most crucial step in the mechanical thrombectomy of large vessel occlusions. Being a blind procedure, potential major untoward events could be anticipated at this stage. In this study, we evaluated the feasibility of reconstruction of the occluded vascular segment from CT angiography, exploiting the attenuation difference between the clot and adjacent brain parenchyma. Twenty-five patients with large vessel occlusion who achieved TICI2B/3 recanalization were identified. The semi-automated reconstruction was done using an open-source 3D segmentation software by two observers. The generated arterial anatomy was categorized as congruent, if all the major arterial segments namely, internal carotid artery, M1 middle cerebral artery, bifurcation, and major divisions matched with post thrombectomy angiograms. The discrepancy of one or more than one arterial segment was classified as mild or total mismatch respectively. Congruent arterial mapping was possible in 88% and 92 % patients for observer 1 and observer 2 respectively, while mild mismatch was noted in two patients for both the observers. Mismatch mostly occurred in superior division for both observers(100% vs 66.6%). The interrater agreement was good (0.77) and the accuracy was not influenced by the length of the clot. The median time for reconstruction was 4 minutes for both the observers (p - 0.21). Delineation of the anatomy of the occluded major intracranial artery is possible and corresponds with the actual anatomy. It could be used as a guide during thrombectomy procedures.

OS03.4.A In vivo dynamics and anti-tumor effects of EpCAM-directed CAR T-cells against brain metastases from lung cancer

Abstract Background Lung cancer patients are at a particularly high risk for brain metastases, and a considerable number of affected patients succumb due to their intracranial disease. Chimeric Antigen Receptor (CAR) T-cells emerged as a powerful class of cell-based immunotherapy for hematological malignancies. However, it remains unclear whether CAR T-cells also represent a safe and effective therapeutic option for brain metastases. Material and Methods A fully syngeneic orthotopic cerebral metastasis model in mice was established by combining a chronic cranial window with repetitive intracerebral two-photon laser scanning microscopy. This approach enabled the in vivo characterization of red fluorescent CAR T-cells and tumor cells on a single-cell level over weeks. Intraparenchymal injection of Lewis lung carcinoma cells (expressing the tumor cell-antigen EpCAM) was performed, and CAR T-cells directed against EpCAM (EpCAMCAR T-cells) were injected into the adjacent brain parenchyma after solid brain tumors have formed. Results All mice had visible tumor take four days after the intracranial tumor cell injection, and rapid growth of solitary lesions was seen in the following days. No toxicities mediated by intracranially injected EpCAMCAR T-cells were encountered. In mice treated with EpCAMCAR T-cells, we initially observed substantial CAR T-cell accumulation within the tumor compared to controls (median number: 1700 versus 939 cells/mm2; p = 0.007). This was paralleled by lower velocities of EpCAMCAR T-cells, characterizing T-cell receptor (TCR)-mediated antitumor cytotoxicity due to long-lasting contacts between effector immune cells and tumor cells. Consequently, treatment with EpCAMCAR T-cells resulted in reduced tumorous growth as determined per in vivo microscopy (median tumor area on day 10: 1.8 versus 10.8 mm2; p = 0.001) and immunohistochemistry of excised brains (median tumor volume on day 10: 3.6 versus 33.2 mm3; p = 0.001). However, the number of EpCAM-directed CAR T-cells within the tumor markedly decreased during the observation period, pointing towards insufficient persistence of EpCAM-directed CAR T-cells. In line with these findings, survival was prolonged in mice receiving EpCAMCAR T-cells but long-lasting remission was rare (median survival: 15 versus 13 days; p = 0.012). Conclusion Our findings indicate that CAR T-cells injected into the cerebral parenchyma may induce relevant anti-tumor effects in brain metastases from lung cancer. Due to the translational nature of our study, prospective clinical cohorts appear warranted. Strategies improving the intratumoral persistence of CAR T-cells in brain metastases may be utilized to further boost the success of such promising therapy.

Dural Venöz Sinüsler ya da Kalvarum İçerisine Beyin Herniasyonlarının Tespitinde Yüksek Rezolüsyonlu 3T MRG Yararı

Objective: Brain parenchyma herniation into the dural venous sinus or calvarium is considered a rare anatomical variation. The aim of this study is to evaluate the frequency, localization, and clinical and radiological findings of brain herniation into dural venous sinus and/or calvarium with high resolution 3 Tesla magnetic resonance imaging in a large group of patients.Material and Methods: A total of 6825 cranial magnetic resonance images containing pre-contrast and post-contrast 3D T1-weighted sequences as well as conventional sequences were retrospectively evaluated. The presence of brain herniation into dural sinuses or calvarium, location and size of herniation, signal intensity of the adjacent brain parenchyma, presence of arachnoid granulation adjacent to the herniation were noted.Results: Brain herniation into DVS/ calvarium was determined in 50 patients (0.73%). The detected brain herniations were most frequently associated with the temporal lobe parenchyma (n=37, 68.5%), and 91% (n=49) extended into the transverse sinuses. All brain herniations were detected both by 3D T1-weighted and 3D T2-weighted sequences; however, 29 (53.7%) of the 54 herniations were not detected by conventional sequences.Conclusion: High resolution MRI sequences are superior to conventional sequences in detecting brain herniation into DVS/ calvarium. Patients with brain herniation into DVS/ calvarium may present with heterogeneous symptomatology, and the relationship between brain herniation and symptoms is controversial.

CNS tumor with BCOR internal tandem duplication: Clinicopathologic, molecular characteristics and prognosis factors

The central nervous system tumor with BCOR internal tandem duplication (CNS tumor with BCOR ITD) is a recently identified rare tumor entity, the complete morphologic characteristic, genetic alteration, classification, clinical outcomes and optimal treatment for this tumor entity have not been fully clarified. Here, two new cases of CNS tumor with BCOR ITD were reported and the clinicopathologic, molecular characteristics, and prognosis were analyzed through reviewing of the reported literature. The histological features included a clear border with adjacent brain parenchyma, an extensively microcystic background, and the cells with round to oval nuclei containing delicate chromatin, ependymoma-like perivascular pseudorosettes, and palisading necrosis. Immunohistochemical features showed strong and diffuse positive expression for BCOR, scattered positive expression for OLIG2, and negative expression for GFAP, Syn, and EMA. PCR and direct DNA sequencing analysis identified exon 15 ITD of the BCOR gene in both cases. Interestingly, both cases revealed two duplication segments, which had not been reported in the literature. A review of the literature shows that CNS tumor with BCOR ITD has a poor prognosis with a median survival of 1.7 years; surgical gross total resection is a good prognostic factor. A combination of radiation treatment and chemotherapy, while trending towards significance, does not reach statistical significance. On the contrary, the OS is not associated with age, gender, and tumor location. In conclusion, CNS tumor with BCOR ITD is a rare tumor entity with characteristic morphologic and molecular features and a poor prognosis. The optimal treatment strategies need further studies.

Frameless neuronavigation with computer vision and real-time tracking for bedside external ventricular drain placement: a cadaveric study.

A major obstacle to improving bedside neurosurgical procedure safety and accuracy with image guidance technologies is the lack of a rapidly deployable, real-time registration and tracking system for a moving patient. This deficiency explains the persistence of freehand placement of external ventricular drains, which has an inherent risk of inaccurate positioning, multiple passes, tract hemorrhage, and injury to adjacent brain parenchyma. Here, the authors introduce and validate a novel image registration and real-time tracking system for frameless stereotactic neuronavigation and catheter placement in the nonimmobilized patient. Computer vision technology was used to develop an algorithm that performed near-continuous, automatic, and marker-less image registration. The program fuses a subject's preprocedure CT scans to live 3D camera images (Snap-Surface), and patient movement is incorporated by artificial intelligence-driven recalibration (Real-Track). The surface registration error (SRE) and target registration error (TRE) were calculated for 5 cadaveric heads that underwent serial movements (fast and slow velocity roll, pitch, and yaw motions) and several test conditions, such as surgical draping with limited anatomical exposure and differential subject lighting. Six catheters were placed in each cadaveric head (30 total placements) with a simulated sterile technique. Postprocedure CT scans allowed comparison of planned and actual catheter positions for user error calculation. Registration was successful for all 5 cadaveric specimens, with an overall mean (± standard deviation) SRE of 0.429 ± 0.108 mm for the catheter placements. Accuracy of TRE was maintained under 1.2 mm throughout specimen movements of low and high velocities of roll, pitch, and yaw, with the slowest recalibration time of 0.23 seconds. There were no statistically significant differences in SRE when the specimens were draped or fully undraped (p = 0.336). Performing registration in a bright versus a dimly lit environment had no statistically significant effect on SRE (p = 0.742 and 0.859, respectively). For the catheter placements, mean TRE was 0.862 ± 0.322 mm and mean user error (difference between target and actual catheter tip) was 1.674 ± 1.195 mm. This computer vision-based registration system provided real-time tracking of cadaveric heads with a recalibration time of less than one-quarter of a second with submillimetric accuracy and enabled catheter placements with millimetric accuracy. Using this approach to guide bedside ventriculostomy could reduce complications, improve safety, and be extrapolated to other frameless stereotactic applications in awake, nonimmobilized patients.

Mechanisms of Cell Cycle Arrest and Apoptosis in Glioblastoma

Cells of glioblastoma, the most frequent primary malignant brain tumor, are characterized by their rapid growth and infiltration of adjacent healthy brain parenchyma, which reflects their aggressive biological behavior. In order to maintain their excessive proliferation and invasion, glioblastomas exploit the innate biological capacities of the patients suffering from this tumor. The pathways involved in cell cycle regulation and apoptosis are the mechanisms most commonly affected. The following work reviews the regulatory pathways of cell growth in general as well as the dysregulated cell cycle and apoptosis relevant mechanisms observed in glioblastomas. We then describe the molecular targeting of the current established adjuvant therapy and present ongoing trials or completed studies on specific promising therapeutic agents that induce cell cycle arrest and apoptosis of glioblastoma cells.

Improved visualization of the subthalamic nucleus on synthetic MRI with optimized parameters: initial study.

Synthetic magnetic resonance imaging (SyMRI) enables to reformat various images by adjusting the MR parameters. To investigate whether customization of the repetition time (TR), echo time (TE), and inversion time (TI) in SyMRI could improve the visualization of subthalamic nucleus (STN). We examined five healthy volunteers using both coronal SyMRI and quantitative susceptibility mapping (QSM), seven patients with Parkinson's disease (PD) using coronal SyMRI, and 15 patients with PD using coronal QSM. Two neuroradiologists reformatted SyMRI (optimized SyMRI) by adjusting TR, TE, and TI to achieve maximum tissue contrast between the STN and the adjacent brain parenchyma. The optimized MR parameters in the PD patients varied according to the individual. For regular SyMRI (T2-weighted imaging [T2WI] and STIR), optimized SyMRI, and QSM, qualitative visualization scores of the STN (STN score) were recorded. The contrast-to-noise ratio (CNR) of the STN was also measured. For the STN scores in both groups, the optimized SyMRI were significantly higher than the regular SyMRI (P < 0.05), and there were no significant differences between optimized SyMRI and QSM. For the CNR of differentiation of the STN from the substantia nigra, the optimized SyMRI was higher than the regular SyMRI (volunteer: T2WI P = 0.10 and STIR P = 0.26; PD patient: T2WI P = 0.43 and STIR P = 0.25), but the optimized SyMRI was lower than the QSM (volunteer: P = 0.26; PD patient: P = 0.03). On SyMRI, optimization of MR parameters (TR, TE, and TI) on an individual basis may be useful to increase the conspicuity of the STN.