bluuebunny/crossref_metadata_2025 huggingface dataset:
OS03.6.A UNSUPERVISED CLUSTERING OF MORPHOLOGY PATTERNS ON WHOLE SLIDE IMAGES GUIDE PROGNOSTIC STRATIFICATION OF GLIOBLASTOMA PATIENTS
Authors: Baheti B , Innani S , Nasrallah M P , Bakas S
Published: September 2023

BACKGROUND

Glioblastoma is the most common malignant adult brain tumor with a poor prognosis and heterogeneous morphology. Stratifying glioblastoma patients according to overall survival (OS) from H&E-stained histopathology whole slide images (WSI) using advanced computational methods is a challenging task with direct clinical implications. We hypothesize that quantifying morphology patterns present in WSI can yield biomarkers of prognostic relevance contributing to optimizing clinical decision-making.

MATERIAL AND METHODS

This work is based on 188 glioblastoma (IDH-wt, grade 4) cases identified in the TCGA-GBM and TCGA-LGG, based on the 2021 WHO classification criteria. One Diagnostic WSI from each patient at 10X magnification was selected (ntraining/nhold-out-test =152 /36) and labeled as short (<9 months, n=94) or long (>13 months, n=94) survivors. The WSI is split into non-overlapping 256x256 patches, and extensive patch-level WSI curation is conducted to discard artifactual content, i.e., glass reflections, pen markings, black lines on the slide, and tissue tearing. Each patch is described by a feature vector of 512 dimensions using a pre-trained VGG16. Principal component analysis reduced the dimensionality of these vectors to 236 such that 85% variance is retained. Unsupervised k-means clustering revealed distinct groups of morphology patterns, where the number of clusters is automatically determined based on the rand index and silhouette coefficient. The proportions of these patterns describe the tumor’s spatial heterogeneity and are used to distinguish between short and long survivors using a random forest classifier.

RESULTS

We identified seven clusters of distinct morphology patterns, including 3 categories of tumor cellularity (low/intermediate/high), necrosis/macrophages, and other prognostically-relevant characteristics. The patient-level short vs long survivor prediction is driven by the proportion of these patterns present in WSI achieving classification accuracy, sensitivity and specificity of 83.83%, 94.44%, and 72.72% respectively on the hold-out test set. The high sensitivity signifies the algorithm’s ability to accurately predict the short survivors which is important in treatment planning and patient management.

CONCLUSION

The interpretability analysis of various morphologic patterns in distinct histologic sub-regions of glioblastoma may uncover correlations with short and long survivors, providing a deeper understanding of the complex relationship between histologic features and clinical outcomes and shedding light on the heterogeneity of glioblastoma. This association could offer additional prognostic information to clinical neuropathologists during microscopic assessment, leading to more refined prognostication and potentially impacting clinical decision-making for improved patient outcomes.
OS03.7.A AUTOFLUORESCENCE BASED RECOGNITION OF BRAIN TUMORS WITH A CONVOLUTIONAL NEURAL NETWORK
Authors: Richter S , Dremel J , Wang T , Eyüpoglu I , Czarske J , Kirsche K , Kuschmierz R , Polanski W , Uckermann O
Published: September 2023

BACKGROUND

The delineation of malignant brain tumors from surrounding tissue is crucial for maximal safe resection. Existing tools for intraoperative tumor visualization lack the possibility of real-time tissue classification. We therefore built a coherent fiber bundle (CFB) endoscope for autofluorescence imaging and trained a convolutional neural network (CNN) to distinguish tumor tissue (T) and non-tumor tissue (nT) in an ex vivo proof of concept study.

MATERIAL AND METHODS

The T-cohort included frozen tissue sections of 35 glioblastoma and 30 brain metastasis patients (10 breast cancer, 10 melanoma, 10 lung cancer). The nT-cohort comprised frozen tissue sections of hippocampi and temporal lobes from 23 patients undergoing surgery for epilepsy treatment. For image acquisition, a laser with excitation wavelength of 473 nm was coupled into a CFB and tissue autofluorescence between 500-550 nm was collected using a bandpass filter. The acquisition time of the camera was set to 700 ms. A CNN (VGG-19) was trained to differentiate the labels T from nT wherein the ground truth was defined by histopathological diagnosis. Training, validation and test sets were randomly generated across all patients in 66.6% / 16.6% / 16.6% proportion. Set generation was repeated 5 times and reported results for the independent test sets are mean values of all iterations.

RESULTS

In total, 3259 CFB images were acquired (T:2408, nT:851), with usually 40 CFB images per sample. Removal of CFB background was not improving classification accuracy and thus, was not performed. The classification accuracy of the CNN with a threshold probability of 0.5 for T-label assignment was 0.986 (sensitivity: 0.988, specificity: 0.982) for analysis of images and 0.98 (sensitivity: 0.971, specificity: 1) when calculating the result for each patient. To simulate clinical application where correct identification of healthy tissue is essential, we created a specificity-tuned CNN with adjusted threshold probability of 0.9 for T-label assignment. This led to a decreased accuracy of 0.945 but increased specificity on the image evaluation approach to 1 (sensitivity: 0.92).

CONCLUSION

Autofluorescence imaging through a CFB is capable of ex vivo recognition of brain tumor tissue with a CNN. The simplicity of the setup and minimal need for data pre-processing allows for intraoperative implementation and potentially enables real-time in vivo brain tumor delineation. To realize intraoperative transition, analysis of ex vivo bulk tissue will be upcoming to capture the signal complexity caused by tissue depth.
OS05.7.A MICROLENS: EXPLORING THE GAP BETWEEN PATIENT AND CAREGIVER NEEDS, AND TECHNICAL DEVELOPMENTS IN AI-ENABLED MEDICAL IMAGE INTERPRETATION
Authors: Pakzad-Shahabi L , Mauricaite R , Karamchandani U , Williams M
Published: September 2023

BACKGROUND

MicroLens aims to co-develop tools and functionality to enable patients & caregivers to view and understand their own brain tumour images, using an explicit design-led approach. Over 7 months we used meetings, written reports and online questionnaires to capture the views of 20 staff, patient and caregiver participants requirements for an AI-enhanced online medical image viewing tool. We have described our initial approach and results (1), but here we focus on how patient and caregiver needs differ from technological approaches described in the medical imaging literature.

MATERIAL AND METHODS

As part of the MicroLens project, we used thematic analysis to extract key patient, caregiver and staff concerns and needs. We then compared this with technical themes of the medical imaging technical literature, drawn from conference proceedings (MICCAI).

RESULTS

The desired level of technical performance was relatively low: patients and caregivers would mostly be happy with labelling of common simple structures and sides, rather than detailed annotation. Other desirable functionality was around sharing imaging with family members and better understanding of imaging. In contrast, the technical literature had a focus on tumour segmentation, classification and prediction of outcomes - none of which appeared in patients' desiderata.

CONCLUSION

Patients, caregivers and staff want very different functionality than the work being conducted in the technical literature. The reasons for this are interesting, and multi-factorial, but reinforce the need for patient-led development. We are currently implementing a prototype and our software developers are designing and developing five of the key tools that emerged from MicroLens project, based on a combination of our findings and theoretical approaches such as the NASSS framework (2).

(1) https://blogs.imperial.ac.uk/componc/2022/10/04/introducing-microlens-using-a-design-approach-to-understand-what-brain-tumour-patients-want-from-their-images/

(2)Greenhalgh T, et al A New Framework for Theorizing and Evaluating Nonadoption, Abandonment, and Challenges to the Scale-Up, Spread, and Sustainability of Health and Care Technologies J Med Internet Res 2017;19(11):e367
OS07.5.A GLIOBLASTOMA VESSEL CO-OPTION AND TRANSITION TO A RESISTANT CELL STATE ARE INDUCED BY CHEMORADIATION
Authors: Pichol-Thievend C , Anezo O , Pettiwala A M , Bourmeau G , Montagne R , Lyne A , Guichet P , Deshors P , Ballestín A , Blanchard B , Reveilles J , Ravi V M , Joseph K , Heiland D H , Julien B , Leboucher S , Besse L , Legoix P , Dingli F , Liva S , Furumaya C , Kovandzic Marcos L , Masliantsev K , Daubon T , Schnell O , Beck J , Servant N , Karayan-Tapon L , Cavalli F M G , Seano G
Published: September 2023

BACKGROUND

Glioblastoma (GB) is one of the deadliest types of human cancer. Despite a very aggressive treatment regime, including resection of the tumor, radiation, and chemotherapy, the recurrence rate is more than 90%. Recurrence is mostly caused by the regrowth of highly invasive and resistant cells that have spread from the tumor bulk and are not removed by resection. To develop an effective therapeutic approach, we need to better understand the underlying molecular and cellular mechanisms of GB chemoradiation resistance and tumor spreading.

MATERIAL AND METHODS

To dynamically follow the changes occurring in GB post-therapy and investigate its relationship with vascular microenvironment, we employed multiple bulk and single-cell RNA-Seq analyses, phosphoproteome, in vitro and in vivo real-time imaging, organotypic cultures and functional assays, digital pathology, and spatial transcriptomics on patient material or preclinical models of GB.

RESULTS

We demonstrated that chemoradiation and the brain vasculature induce a transition to a functional cell state, which we named VC-Resist. This cell state is midway through the transcriptomic axis between proneural and mesenchymal GB cells and is closer to the AC/MES-like state. Better cell survival, G2M-arrest, activation of senescence/stemness pathways make this GB cell state more resistant to therapy. Notably, these persister GB cells are highly vessel co-opting, allowing homing to the perivascular niche, which, in turn, increases their transition to this cell state and resistance to therapy. Molecularly, the transition to the VC-Resist cell state is driven by FGF-FGFR1 signaling, which leads to the activation of DNA damage repair and YAP1 pathways.

CONCLUSION

These findings demonstrate that the perivascular niche and GB cell plasticity jointly generate a vicious loop that leads to resistance to therapy and brain infiltration during GB recurrence.

SUPPORT

This work was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 (Grant Agreement No. 805225), the INSERM-CNRS ATIP-Avenir grant, the NanoTheRad grant from Paris-Saclay University, Fondation ARC pour la recherche sur le cancer, Campus France and Canceropole Ile-de-France (2022-1-EMERG-06-ICR-1).
OS09.7.A THE ROLE OF MICROSURGERY IN THE FIRST LINE TREATMENT OF VESTIBULAR SCHWANNOMA: IT IS ALL ABOUT THE ODDS
Authors: Naros G , Wang S , Machetanz K , Weinbrenner E , Tatagiba M
Published: September 2023

BACKGROUND

Given the risk for a deterioration of facial function (FDR), first-line (1stline) microsurgery (MS) is discouraged in vestibular schwannoma (VS). In contrast, 1stline radiosurgery (SRS) preserves facial function but has a higher recurrence rate (RR). As salvage VS surgery is very challenging, it could be reasonable to accept a slightly increased FDR of 1stline MS in favor of the lower RR. The aim of the present study was to determine the FDR and RR values of salvage surgery and to calculate the break-even point of MS in the 1stline VS treatment.

MATERIAL AND METHODS

This retrospective study analyzed all patients with unilateral VS undergoing microsurgery between 03/2008 and 10/2021 (n=1470). We identified patient with 2ndline MS after previous MS (MS-MS) or radiosurgery (SRS-MS) as well as patients with 3rdline MS (MS-SRS-MS). After reviewing patients’ clinical and imaging data, we determined FDR and RR for each cohort. This data was compared to a 1stline MS cohort (CTRL) with a follow-up of at least 10 years (n=572). A mathematical prediction model (MPM) was applied to calculate the odds ratio (OR) of different treatment strategies (i.e., MS-MS, SRS-MS, MS-SRS-MS) depending on different FDR and RR values.

RESULTS

We identified 48 patients with 2ndline and 11 patients with 3rdline MS after failed MS/SRS. Time to recurrence in relation to the initial treatment was shortest in SRS-MS (35±34 mo) compared to MS-MS (128±179 mo) and MS-SRS-MS (38±17 mo). These patients had a significant worse preoperative facial function than CTRL patients. Extent-of-resection (EOR) was diminished in 2ndline (79% and 75%) compared to 1stline MS (97%). Both the FDR and RR were significantly increased in MS-MS (FDR:17%, RR:14%) and SRS-MS (FDR:45%, RR:5%) compared to CTRL (FDR:12%, RR:4%). Notably, MS-SRS-MS was associated with the highest FDR (60%) while having the lowest GTR rate (54%). MPM indicated that FDR<15% and RR<5% justify a 1stline MS. In the present cohort, these criteria were met for Koos 1-3 tumors (FDR:0-7%, RR:0-3%).

CONCLUSION

Recurrent VS surgeries fare much worse considering FDR, EOR and RR than first-line surgeries. Hence, reducing the RR of the first-line VS treatment is required. In smaller VS, the surgical oncofunctional outcome can reach the break-even point favoring microsurgery over radiosurgery as first-line treatment option. However, in situations with high FDR (e.g., large or cystic VS) a more conservative surgical approach might be beneficial.
P01.07.A HUB-RELATED GRAPH METRICS AS MARKER FOR COGNITIVE OUTCOMES IN ADULT GLIOMA SURVIVORS AFTER MULTIMODAL THERAPY
Authors: De Roeck L , Blommaert J , Sunaert S , Dupont P , Clement P , De Vleeschouwer S , Sleurs C , Lambrecht M
Published: September 2023

BACKGROUND

Although cognitive impairment is a serious and prevalent long-term side effect in adult glioma survivors after therapy, predictive imaging-based markers remain inconsistent to date. Structural brain network topology could be altered by both the tumor and its’ treatment through reorganization of hubs (i.e. highly interconnected nodes). Here, we explored the role of nodal hub-related graph metrics in higher cognitive functioning.

MATERIAL AND METHODS

48 WHO grade 2-3 adult glioma survivors (>1 year post-therapy) and 42 matched controls, underwent a cognitive assessment, covering five cognitive domains. Cognitive scores were transformed into w-scores, corrected for age and education. In addition, weighted nodal graph metrics were calculated based on diffusion weighted imaging, using multi-shell multi-tissue constrained spherical deconvolution and anatomically-constrained tractography. Hubs (hub score≥2) were calculated based on 4 nodal metrics, in which the 20% nodes with highest nodal strength and betweenness centrality, and lowest clustering coefficient and characteristic path length received 1 point (score 0-4). Significant differences in nodal graph metrics between patients and controls, and hubs versus non-hubs were tested in a repeated measures ANOVA, using Bonferroni correction for multiple testing. Significant group differences in nodal graph metrics were correlated to cognitive scores per domain.

RESULTS

In healthy controls 12/78 nodes were defined as hubs, i.e. the bilateral postcentral, precentral, superior frontal, parietofrontal, superior parietal gyri, thalamus and putamen. In glioma survivors, the left superior-parietal region and left putamen had a significantly lower likelihood of being a hub (p<.001). These specific areas showed assortativity to be positively correlated with attention, language and executive function (r(90)>.51, p<.001) and characteristic path length to be negatively correlated with all cognitive domains (r(90)>.51, p<.001). Nodal metrics of clustering coefficient, characteristic path length, local efficiency and assortativity were significantly different between groups in both hub and non-hub regions (both p<.001). Except for betweenness centrality, all nodal metrics strongly correlated with cognitive outcomes, occurring more often in hubs (33-50%) than intermediate hubs (10-33%) or non-hubs (4-12%).

CONCLUSION

Reorganization of hubs in the brain network is frequently observed in this cohort of glioma survivors compared to healthy controls. Hub connectivity seems to be important in cognitive functioning, more than for non-hub regions. Therefore, structural nodal hub-related graph metrics might be important to consider in predicting cognitive outcomes in glioma survivors.
P01.11.A MECHANISMS OF LANGUAGE PLASTICITY IN PATIENTS HARBORING LEFT HEMISPHERE GLIOMAS
Authors: Tate M , Ramsey M , Saxena M
Published: September 2023

BACKGROUND

Infiltrating gliomas are slow growing intrinsic brain lesions that have been shown to induce functional reorganization, although the mechanisms by which this occurs are not well understood. The present study examines glioma-induced neuroplasticity of language networks to investigate this phenomenon.

MATERIAL AND METHODS

117 patients’ fMRI scans were analyzed from patients harboring gliomas whom completed 1-5 fMRI language tasks. Data was analyzed via two methods: cluster-based and cortical/subcortical mask-based. Right hemisphere gliomas (RHG) (n=40) were first analyzed to establish a reliable control group by determining statistically significant voxels across all five language tasks (LT), yielding a core conserved network. The language network induced by left hemisphere gliomas (LHG) (n=77) was then directly compared to the RHG language network to examine language plasticity.

RESULTS

LHG induced global reorganization of the canonical language network, including preserved homologous and novel left hemisphere (LH) and right hemisphere (RH) activation clusters. In each of the five LT, the LHG group showed activation of fewer total suprathreshold voxels in both the cluster (3 fewer clusters and 38,892 fewer active voxels/task) and mask-based (8 fewer active masks/task and 91,965 fewer active voxels/task) analyses while having a higher peak intensity (5.4 total increase in zmax) within the activated clusters. In addition, a generalized pattern of increased RH recruitment was seen in LHG patients, with 87% (137/157) of non-zero masks shifting their laterality index (LI) to the right hemisphere. These data suggest that the reorganized LHG-induced language network functions through less nodes along with a rightward shift of language lateralization. In addition, a subgroup analysis of frontal (n=16) and temporal (n=32) LHG revealed that frontal tumors promote increased RH activation relative to temporal tumors, with 94% (32/34) of non-zero masks shifting their LI to the RH compared to 68% (23/34), respectively. Frontal tumors also preferentially recruit the contralateral (RH) frontal lobe and ipsilateral (LH) temporal lobe, while temporal gliomas preferentially recruit the ipsilateral frontal lobe.

CONCLUSION

Infiltrating tumors within the left hemisphere promote language plasticity via consolidation of the classical LH language network along with recruitment of previously silent, novel language areas in the right and left hemispheres. This improved understanding of patterns of language plasticity may aid in more accurate pre-surgical risk stratification and counseling, therapeutic targeting for post-surgical recovery, and intelligent “pre-habilitation” strategies to maximize neuroplasticity prior to tumor resection.
P02.14.B SPATIAL TRANSCRIPTOMIC ARCHITECTURE OF TUMOURS OF THE PERIPHERAL NERVOUS SYSTEM
Authors: Heiland P , Menstell J A , Schnell O , Beck J , Bremer J , Heiland D
Published: September 2023

BACKGROUND

Studies into the genetics of peripheral nerve tumors have been focused on their association with known gene mutations and syndromes as well as on the tumor microenvironment of malignant peripheral nerve sheath tumors. Still, not many advances have been made into clarifying the structure and diverse pathophysiology of these tumors. Here we present spatially resolved transcriptomic profiling of benign and malignant entities and describe the topographical architecture of the neoplastic and microenvironmental diversity.

MATERIAL AND METHODS

We employed spatially resolved transcriptomics using the 10X Visium technology from paraffine embedded specimens. We included hybrid peripheral nerve sheath tumors (HPNSTs) plexiform neurofibromas and malignant peripheral nerve sheath tumors (MPNST). Computational analysis was employed by the SPATA2 toolbox. Transcriptomic niches were identified by graph-based spatial clustering. Correlation of histomorphological features and transcriptomic programs was performed by a co-expression network-based analysis.

RESULTS

We identified hub genes associated with neurofibroma and schwannoma histopathology across primary pathologies and discovered that neurofibroma regions of HPNSTs exhibited unique transcriptional programs marked by a significant higher local accumulation of bone-derived macrophages and lymphoid cells compared to primary neurofibromas. A novel marker, Apolipoprotein D (APOD), was found to accurately identify neurofibroma subregions in HPNSTs, which was confirmed by immunostaining in a control cohort. In MPNSTs, we observed a high grade of inter- and intrapatient heterogeneity driven by unique transcriptional niches and genetic variability. Subsequent pathway analysis revealed distinct oncogenic signaling driver across regional niches along with variance in immune infiltration. Our findings highlight the disbalance between histological annotation and actual tumor cell abundance in MPNSTs indicated by inferred copy number alterations.

CONCLUSION

Our integrated analysis pipeline revealed distinct transcriptional signatures and cellular interactions within benign PNSTs, including neurofibromas and hybrid peripheral nerve sheath tumors (HPNSTs) and sought to expose the tumor heterogeneity of MPNST and identify various cancer niches. Our study underscores the potential of spatially resolved transcriptomics as a powerful tool for advancing our understanding of PNST biology, and ultimately improving diagnosis, prognosis, and treatment strategies.
P02.17.A FEATURES OF METABOLIC PSEUDO-PROGRESSION VISUALIZATION OF GRADE 3-4 GLIOMAS AFTER COMBINATION THERAPY. CORRELATION WITH MRI
Authors: Smirnova A , Gromova E , Plakhotina N , Anishkin M , Smirnova A
Published: September 2023

BACKGROUND

Follow-ap assessment of post-therapeutic changes in gliomas of 3-4 raids revealed the phenomen of metabolic pseudoprogression. This feature was manifested in a transistor increase in the capture of the radiopharmaceutical. This "anomaly" requires study for a correct differential diagnosis between progression and pseudoprogression

MATERIAL AND METHODS

For the period from 2019 to 2023, 27 patients aged 24-72 years (average age 55 years) with the phenomena of metabolic pseudoprogression of 3-4 grades gliomas after combination therapy participated in the study. The studies were carried out using PET-CT and 1.5T, 3.0T MR scanners using T2, T2 flair, T13D before and after contrast, T2* perfusion. Postprocessing was carried out using a workstation SINGO.VIA using technological processes: neuro3d, MM oncology, MR neurology.

RESULTS

It was found that in all cases of transient increase in radiopharmaceuticals capture after radiotherapy in terms from 9 months to 36 months, the values of radiopharmaceuticals accumulation were determined in the range of 1.8-3.5 and were they were divided into two groups according to MRI data: group A (n=17) with structural changes, group B (n=10) with a stable MR pattern. According to MRI data in group A, there was an increase in the pathological zone, these changes involved white matter with more pronounced changes in the periventricular regions. In group B, the changes concerned gray matter. In addition, changes in group B were accompanied by manifestations of vasculopathy of the SMART type (Stroke-Like Migraine Attacks After Radiation Therapy). In subsequent observations, these changes in both groups were reduced, both according to PET and MRI

CONCLUSION

A temporary increase in the values of the capture of radiopharmaceuticals after combination therapy for high grade gliomas can be determined both in the white and gray matter of the brain. This may correspond to the manifestations of a post-radiation reaction. Compared with the MRI data, there is a difference in morphological manifestations at the level of gray and white matter, which is probably due to their different radioresistance. These newly discovered factors may be of key importance for further treatment of patients
P02.18.B INTEGRATIVE OMICS ANALYSIS OF IDH1 MUTANT GLIOMA PATIENTS REVEALS ALTERATIONS IN BUTYRATE METABOLISM
Authors: Fritah S , Cano-Galiano A , Toth R , Hau A , Martinez-Garcia E , Allega M , Sumpton D , Fack F , Dieterle M , Adiamah M , Gobin M , Nicot N , Muller A , Kaoma T , Lesur A , Mittelbronn M , van Dyck E , Prasad Bekal M , Esquenazi Y , Hiller K , Sakariassen P , Miletic H , Dittmar G , Nazarov P , Tardito S , Lund-Johansen M , Bjerkvig R , Golebiewska A , Niclou S
Published: September 2023

BACKGROUND

Mutations in isocitrate dehydrogenase (IDH) 1 or 2 define glioma classification and determine the biology of these tumors. Although IDH is an essential enzyme in the cellular metabolism, powerful genome-wide analyses focus mostly at the genetic and epigenetic levels, while differences between distinct glioma entities at the proteomics, metabolomics, and functional levels are still poorly understood. Here, we provide an integrative multi-omics analysis of glioma patients to reveal metabolomic vulnerabilities of gliomas stratified by IDH mutation.

MATERIAL AND METHODS

We performed a multi-omics analysis of two cohorts of glioma patients (n=28) stratified based on IDH mutation status. Molecular assessment included LC-MS analysis, EPIC DNA methylation arrays, RNA-seq/HTA array-based transcriptomics and label-free quantitative proteomics. In 13 patients 13C-glucose was injected prior to surgery and tumor and adjacent brain tissue was collected. Gut microbial profiling using 16S ribosomal RNA (rRNA) sequencing was performed in a separate cohort of 128 glioma patients and 24 healthy individuals. Additional validation was performed in isogenic glioma stem-like cultures with CRISPR knock-in of IDH mutation.

RESULTS

We show that several molecular layers collectively contribute to biological differences between IDH mutant and wild-type gliomas, with strongest differences observed at the DNA methylation level. IDH mutant gliomas present specific molecular features linked to tumor metabolism. We confirm previous findings on 2-HG, cysteine and de novo glutathione synthesis pathways, which are specifically altered in IDH mutant gliomas. We further identify butyrate metabolism as a novel pathway highly active in IDH mutant gliomas. Butyrate is a bacterial metabolite with multiple systemic effects that is normally synthesized in the gut. This is supported by our gut microbiota metagenomics analysis of glioma patients. Yet the detection of enzymes associated with butyrate metabolism in tumor tissue and cell lines suggests a differential/enhanced metabolic rewiring of the butyrate signaling in IDH mutant gliomas

CONCLUSION

Our data shows the importance of multiple molecular layers in shaping specific features of IDH mutant gliomas. We unravel an activated butyrate metabolism in IDH mutant gliomas that may underly a novel gut-brain axis in glioma patients.
P02.26.B METABOLIC PLASTICITY IN GLIOBLASTOMA TUMOR-INITIATING CELL AND RESISTANCE TO LSD1-DIRECTED THERAPY
Authors: Marotta G , Costanza B , Osti D , Faletti S , Zaccheroni E , Richichi C , Del Bene M , Pelicci G
Published: September 2023

BACKGROUND

Glioblastoma (GBM), the most common primary brain tumor in adults, remains incurable despite multimodal therapy. There is a pressing unmet medical need for new therapeutic strategies, especially because patients experience only short-term benefit after primary treatment and the vast majority inevitably relapse. Adaptation to harsh microenvironmental conditions, including nutrient deprivation, proteostasis perturbation, hypoxia and drug treatment, induce molecular and metabolic changes in glioblastoma that lead to the acquisition of a tolerance to stress and resistance to drug. In this context, we demonstrated that Lysine-specific histone demethylase 1 (LSD1) is a regulator of tumor-initiating cell (TICs) survival, adaptation and recovery from stress. LSD1 pharmacological inhibition with a specific and brain penetrant inhibitor (LSD1i) induces a maladaptive integrated stress response (ISR) which leads to the death of TICs exposed to ER stress or nutrient deficiency.

MATERIAL AND METHODS

Given the high GBM heterogeneity, we analyzed different patient-derived TICs grown in vitro as sphere and characterized for their genetic landscape and in vitro/in vivo stem cell-like features. We applied mechanistically different strategies, including biological, metabolic and pharmacological approaches, as well as transcriptomic and proteomic profiling. Zebrafish and GBM xenografts have been exploited as in vivo models.

RESULTS

LSD1i treatment induces physical and functional rearrangements of mitochondria, culminating into their enhanced bioenergetic activity and ATP production that predispose to cell death. Interestingly, only a subset of patient-derived TICs benefits from LSD1i therapy. These samples are largely dependent on glycolysis and, upon LSD1i administration, they are unable to further enhance it when mitochondrial energy production is inhibited. The samples resistant to LSD1i maintain their cellular behavior unaltered even upon prolonged treatment. They display reduced susceptibility to the stressful cues represented by either LSD1i and the known ER stressors Thapsigargin and Tunicamycin, by efficiently restoring energy homeostasis and properly activating the Activating Transcription Factor 4 (ATF4)-dependent ISR. Remarkably, LSD1i resistant samples display metabolic flexibility and switch between glycolytic and oxidative metabolism to ensure their survival.

CONCLUSION

The identification of specific metabolic vulnerabilities could offer unique opportunities for therapeutic intervention: the selective LSD1i vulnerability relies on the preferential dependence on glycolysis, while the great metabolic plasticity of LSD1i resistant TICs coordinates changes that favor their adaptation to stressful microenvironments and therapeutic insults.
P04.01.B MEK INHIBITORS IN PEDIATRIC RECURRENT SYMPTOMATIC UNRESECTABLE LOW-GRADE GLIOMAS HARBORING MAPK ALTERATION: A SINGLE CENTER EXPERIENCE
Authors: Fonte C , Castelli B , Tellini M , Guidi M , Giunti L , Di Nicola M , Buccoliero A , Caporalini C , Giordano F , Mussa F , Genitori L , Sardi I
Published: September 2023

BACKGROUND

Treatment of inoperable, recurrent, progressive pediatric low-grade gliomas (pLGGs) remains controversial. Recent studies focused on aberrant activation of the mitogen-activated protein kinase (MAPK) pathway, due to gain of function mutations in RAS or BRAF genes or loss or inactivation of NF1. Selumetinib and trametinib, orally bioavailable and selective MEK1/MEK2 inhibitors (MEKi), act on MAPK pathway. In April 2020 the US Food and Drug Administration and in June 2021 the European Medicines Agency approved selumetinib for inoperable plexiform neurofibromas in Neurofibromatosis type 1 (NF1). We evaluated MEKi efficacy and safety in pLLGs harboring MAPK alteration.

MATERIAL AND METHODS

From July 2021 to February 2023 eight patients (5 females, 3 males, median age 8 years, range 4-18) were admitted to our hospital for symptomatic, recurrent, inoperable pLGGs (location: 3 hypothalamic-optic chiasm region, 2 posterior fossa, 1 temporo-mesial, 1 quadrigeminal plate, 1 diffuse leptomeningeal; MAPK alteration: 3 NF1 inactivation, 4 KIAA1549/BRAF gene fusion, 1 RNF130/BRAF fusion). MEKi were administered (6 selumetinib, 2 trametinib) after disease progression for failure of previous treatments (6 partial resection, 7 multiple chemotherapies, 2 radiotherapy). MRI assessment was performed every 4 months and radiological response was defined in accordance with RAPNO criteria.

RESULTS

At first evaluation, 3/8 patients (37,5%) showed a partial radiological response (-64,96% mean volume reduction, range 52,61%-77,19%) and 4/8 (50%) stable disease (0-41.67% volume decrease). Disease progression was observed in a patient heavily pretreated for acute leukemia. One patient with leptomeningeal spreading showed progressive disease at second evaluation. Median time to progression has not yet been reached. Six of 8 patients experienced at least one toxicity. The most frequent toxicities reported were mucocutaneus disorders (rash, mucositis, eczema). Three patients presented creatine phosphokinase (CPK) increase (one grade 2 with rapid normalization after therapy discontinuation). All patients on trametinib had to reduce treatment dose (for skin toxicity or increasing blood pressure).

CONCLUSION

MEKi, selumetinib and trametinib, represent promising strategies in children with recurrent/progressive LGGs harboring MAPK alterations. In our small series, the treatment was effective and well tolerable in patients with localized disease and without other risk factors. The most common toxicities were CPK elevation and rash. Further studies are needed to identify patients who may benefit most from MEKi treatment and to establish whether such treatments are superior to chemotherapy in front line setting for MAPK altered pLGGs.
P06.10.A CAR-ENGINEERED PRIMARY NK CELLS SHOW PROMISING EFFECTS AS TARGETED THERAPY AGAINST EGFR-POSITIVE GLIOBLASTOMA
Authors: Roller B , Reindl L M , Strassheimer F , Ludmirski G , Elleringmann P , Kiefer A , Röder J , Steinbach J P , Wels W S , Ullrich E , Burger M C
Published: September 2023

BACKGROUND

Glioblastoma (GB) is the most frequent primary brain tumor and despite intensive treatment regimens including surgery, radiotherapy, and chemotherapy, it is still characterized by a dismal prognosis. Immunotherapies such as T cells or natural killer cells (NK) that carry tumor-specific chimeric antigen receptors (CAR) hold promise for the development of more effective treatment strategies. CAR-engineered derivatives of the human NK cell line NK-92 targeting EGFR or EGFRvIII showed potent antitumor activity against glioblastoma cell lines in vitro and in vivo. Nevertheless, NK-92 has some limitations compared to primary NK cells, such as the required irradiation prior to application in humans.

MATERIAL AND METHODS

To overcome this limitation, we evaluated the suitability of peripheral blood derived human primary NK cells (pNK) as carriers for a CAR targeting the common GB antigen epidermal growth factor receptor (EGFR) and the tumor-specific EGFR variant EGFRvIII. pNK cells from healthy donors were transduced with a lentiviral vector encoding the cetuximab-derived 225.28.z CAR (CAR-pNK) which recognizes an epitope common to both receptors. Specific tumor cell lysis by the CAR-pNK cells was then investigated in FACS-based cytotoxicity assays with GB cells expressing EGFR, EGFRvIII, or both target antigens. In addition, we tested in vivo feasibility of the CAR-pNK cells by single time intravenous injection in a subcutanous LNT-229/EGFRvIII glioblastoma xenograft model.

RESULTS

In comparison to non-transduced pNK cells, CAR-pNK cells displayed enhanced lysis of LNT-229 GB cells expressing EGFR and EGFRvIII. Likewise, markedly increased cytotoxicity of CAR-pNK was observed against GB cell lines such as SKMG-3 and BS153 with intrinsic EGFR gene amplification or expression of EGFRvIII, respectively. Furthermore, in a subcutaneous LNT-229/EGFRvIII glioblastoma xenograft model we observed delayed tumor growth after a single intravenous injection of CAR-pNK cells.

CONCLUSION

In summary, these results demonstrate promising efficacy of primary CAR-NK cells targeting EGFR and EGFRvIII both in vitro and in vivo. In ongoing work we are evaluating CAR-pNK cells in an orthotopic LNT-229 glioblastoma xenograft mouse model, which may provide the basis to translate this approach to early clinical testing.
P06.13.B GRAPHENE NANOSHEET ENABLED REPROGRAMMING OF GLIOBLASTOMA MYELOID CELLS TO UNLOCK THE EFFICACY OF IMMUNOTHERAPY
Authors: Kisby T , Stylianou M , Despotopoulou D , Parker H , Thawley A , Lozano N , MacDonald A , Kostarelos K
Published: September 2023

Immunotherapy has substantiated its promise and achieved striking clinical efficacy in at least a subset of patients in several cancer types. However, in patients with glioblastoma multiforme (GBM), immunotherapies have lacked efficacy as a consequence of the highly immunosuppressive “cold” tumour microenvironment. Small, thin graphene oxide (GO) nanosheets possess notable pharmacokinetic properties in GBM including deep translocation throughout the whole tumour volume and selective internalization by tumour associated macrophages and microglia (TAMMs) following local administration. The current study aimed to investigate whether this selective nanomaterial-TAMM interaction could be exploited to reprogram the immune-microenvironment of GBM. GO nanosheets were non-covalently complexed with a TLR7/8 agonist to form a stable immunomodulatory nanosystem (imodGO) which was tested in primary macrophages in vitro, and an orthotopic syngeneic GBM model in vivo. imodGO enhanced the polarization of macrophages toward a pro-inflammatory M1-like phenotype in vitro without disrupting their phagocytic or cytokine producing capacity. A single intratumoral administration of the same nanocomplex in an intracranial GL261 model was also effective in increasing M1-like TAMMs (CD86+, MHCII+, TNFα+) while decreasing immunosuppressive M2-like TAMMs (Ym1+, Arg1+) which resulted in a wider reprogramming of the brain tumour immune-microenvironment. Repeat imodGO administration was able to significantly inhibit tumour progression highlighting the therapeutic potential of this nanomaterial enabled immunomodulatory strategy. Based on these

RESULTS

, imodGO has emerged as a novel strategy to ameliorate the immunosuppressive character of GBM. Further work is warranted to assess whether imodGO could enhance the efficacy of systemic immunotherapies used in combination.
P07.05.B DNA-METHYLATION PROFILING IS AN EFFECTIVE ASSET FOR IDENTIFICATION OF TUMORS IN SUSPECTED, YET IMMUNOHISTOCHEMICALLY UNSPECIFIABLE, NEURO-ONCOLOGICAL CASES
Authors: Onken J S
Published: September 2023

BACKGROUND

Patients with a suspected neurooncological disease on radiographic images and no histopathological evidence of a tumor on the surgically retrieved tissue, pose a great challenge for clinicians and neuropathologists. DNA methylation-based classifications and copy number variation (CNV) analysis allow robust brain tumor classification. Here, we aim to evaluate their diagnostic properties in histopathologically unspecifiable or negative cases.

MATERIAL AND METHODS

We screened all neurosurgical cases, which underwent surgery at our institution between 2009 and 2021, with suspected neurooncological, but negative or unspecific histopathological diagnosis. We differentiated two groups: cases with cell-enriched, reactive tissue (+/- single tumor cells), insufficient to fully classify the lesion according to criteria of WHO for CNS tumors (group 1) and cases without histological evidence of tumor cells (group 2). In both groups, DNA methylation profiling was applied. Endpoints were diagnostic results of DNA methylation profiling (classifier Score ≥0.9) and evidence/no evidence of tumorigenic CNV alterations and eventually feasibility to make a diagnosis according to WHO 2021 criteria for brain tumors.

RESULTS

23 cases with unspecifiable histopathological diagnosis were identified, out of whom 5 (21.7%) were confirmed as healthy brain tissue via DNA-methylation profiling, whereas the eventual diagnosis of tumorigenic tissue was provided in 18 (78.3%) cases. 14 of these were assigned to group 1, 4 cases to group 2. In 6 cases of group 1 (42.9%) DNA-methylation profiling resulted in a successful tumor classification (score ≥0.9) compared to 1 case (25%) in group 2. CNV indicated tumorigenic alterations in 9 (64.3%) patients in group 1 and 2 (50%) patients in group 2. Specific tumor alterations in the CNV were found in 8 (57.1%) patients in group 1 and in 1 (25%) patient in group 2. Combining CNV and DNA-methylation profiling, a final tumor diagnosis according to WHO 2021 criteria was feasible in 9 (64.3%) cases in group 1 and 3 (75%) cases in group 2. Median time from surgery to histopathological diagnosis was 6 and 7 days and 32.5 and 31 days for integrated diagnosis (group 1 vs. group 2).

CONCLUSION

Molecular diagnostics with DNA-methylation profiling and CNV analysis substantially increases the likelihood of a definitive diagnosis according to 2021 WHO criteria for these challenging cases.
P08.02.B NEEDS OF SUPPORT IN GLIOBLASTOMA - FROM THE PATIENTS’ PERSPECTIVE
Authors: Ståhl P , Henoch I , Smits A , Rydenhag B , Ozanne A
Published: September 2023

BACKGROUND

Patients with IDH-wt glioblastoma carry a poor prognosis with a rapidly progressive illness trajectory. It is clear that the disabling symptoms experienced throughout the course of the disease require different kind of support depending on the nature of the problems. Previous research has drawn attention to support needs for brain tumour in general, but there is a lack of data focusing on patients with glioblastoma. This study aimed to explore the need of support during the illness trajectory for patients with glioblastoma considered from their own perspective.

MATERIAL AND METHODS

Twelve individual interviews with patients with glioblastoma were conducted during 2022 in Sweden. The inclusion criteria were histologically confirmed diagnosis of IDH-wt glioblastoma since at least 2 months and age ≥ 18 years at the time of diagnosis. The focus of the interviews was on experiences and specific needs of support. The interviews took place on one occasion, at a location based on the participant's preferences. Three interviews were conducted face-to-face, eight via telephone and one was a video interview. Interviews were audio recorded and transcribed verbatim. The analysis process based on qualitative content analysis is still in progress, but preliminary data will be discussed.

RESULTS

The preliminary results indicate that persons with glioblastoma need support in how to handle troublesome symptoms as well as practical support with e.g., transport and work abilities. More specifically, they wanted help in finding coping strategies and how to overcome deteriorated executive abilities. They found it positive to have been attributed a specific contact to discuss such questions or problems. Knowing whom to turn to in troublesome situations contributed to a sense of security even if the contact was not used. Furthermore, they wanted healthcare to be easily accessible, and to use an empathetic approach for the individual.

CONCLUSION

The preliminary results indicate that patients with glioblastoma need person-centred support throughout the course of the disease. Support is needed at different organizational healthcare levels; partly on a more comprehensive level, where accessibility is emphasised as an important factor, but also on an individual level where the attitude by the health care staff is seen as an important part of the support from the healthcare system.
P09.01.A IMPACT OF TIMING OF ANTISEIZURE MEDICATION WITHDRAWAL ON SEIZURE RECURRENCE IN GLIOMA PATIENTS: A RETROSPECTIVE OBSERVATIONAL STUDY
Authors: van der Meer P B , Dirven L , Fiocco M , Vos M J , Kerkhof M , Kouwenhoven M C , van den Bent M J , Taphoorn M J B , Koekkoek J A F
Published: September 2023

BACKGROUND

Withdrawal of antiseizure medication treatment (ASM) can be considered after completion of antitumour treatment in glioma patients who no longer suffer from seizures. We compared the risk of recurrent seizures after ASM withdrawal between patients with short-term, medium-term versus long-term seizure freedom after antitumour treatment.

MATERIAL AND METHODS

In this retrospective observational study, the primary outcome was time to recurrent seizure, from the starting date of no ASM treatment up to 36 months follow-up. Cox proportional hazards models were used to study the effect of risk factors on time to recurrent seizure. Stratification was done with information known at baseline. Short-term seizure freedom was defined as ≥3 months, but <12 months; medium-term as 12-24 months; and long-term as ≥24 months seizure freedom from the date of last antitumour treatment.

RESULTS

This study comprised of 109 patients; 31% (34/109) were in the short-term, 29% (32/109) in the medium-term, and 39% (43/109) in the long-term group. A recurrent seizure was experienced by 44% (15/34) of the patients in the short-term, 31% (10/32) in the medium-term, and 44% (19/43) in the long-term group. Seizure recurrence risk was similar between patients in the short-term group as compared to the medium-term (cause-specific adjusted hazard ratio [aHR]=0.65 [95%CI=0.29-1.46]) and long-term group (cause-specific aHR=1.04 [95%CI=0.52-2.09]).

CONCLUSION

Seizure recurrence risk is relatively similar between patients with short-term, medium-term, and long-term seizure freedom after completion of antitumour treatment.
P10.05.A INDUCED SENESCENCE AND CALCIFICATION TO ANAPLASTIC MENINGIOMA
Authors: YOKOGAMI K , Watanabe T , Mizuguchi A , Yamashita S , Matsumoto F , Takeshima H
Published: September 2023

BACKGROUND

Although the majority of meningiomas are slow-growing and benign, atypical and anaplastic meningiomas behave aggressively with a penchant for recurrence. The 5-year risk of progression for incompletely resected meningiomas is over 80 percents. Specifically, the 5-year survival rates are 78-91% and 41-65% for atypical and anaplastic meningiomas, respectively. On the other hand, it has been reported that benign meningiomas with psammoma bodies or those with bone hyperplasia at the attachment site and subtype of high calcification have a low growth rate. Here we show that BMP signals essential for bone formation, especially GREM2 upstream inhibitor of BMP signals, are involved in meningioma growth, senescence and calcification.

MATERIAL AND METHODS

1) A long-term primary cultured meningioma and commercially available anaplastic meningioma (IOMM-lee and HKB-MM) are used. For immunohistochemistry and expression analysis, 87 surgical samples operated in our hospital were used.2) We observed changes in phenotype, proliferation rate and cell cycle by inhibiting BMP signal. Overexpression of GREM2, an upstream inhibitor of BMP signals, was performed in anaplastic meningiomas and analyzed comprehensively. Downloaded RNA-seq data from GREIN, a public database, and performed a comprehensive analysis of the extent of GREM2 expression and gene expression related to cellular senescence.

RESULTS

1) Inhibition of BMP signaling reduced proliferation. Moreover, long term inhibition of BMP signals induced calcification. 2) Expression of GREM2 related to proliferation in surgical samples. GREM2 mainly localized surrounding of psammoma bodies. 3)Overexpression of GREM2 increased sub-G1 population and inhibits cell proliferation. 4)Expression of GREM2 shifts tryptophan catabolism from Kynurenine/NAD/NADH to serotonin production. 5) Comprehensive analysis using RNA-seq data from GREIN showed that high expression of GREM2 decreases oxidative phosphorylation. 6)Senescence assay showed that inhibition of BMP signaling induced senescence.

CONCLUSION

Inhibition of BMP signaling reduced proliferation and induced calcification. The underlying mechanism is shifting tryptophan catabolism from Kynurenine/NADH/NAD to serotonin production.