bluuebunny/crossref_metadata_2025 huggingface dataset:
RTID-06. TRENDS IN INTERNATIONAL INVESTMENT IN CHILDHOOD, ADOLESCENT AND YOUNG ADULT (CYA) BRAIN TUMOR RESEARCH 2006-2018, WITH A FOCUS ON DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG)
Authors: Davies Lynne , Weinstein Amy
Published: November 2021

Organizations funding brain tumor research want to identify gap areas for funding individually or in collaboration and want to better understand existing project focus to maximize new project investments. The International Cancer Research Partnership and the US Coalition Against Childhood Cancer used international research portfolio data to assess the landscape of CYA brain tumor research. From 2006-2018, investment for brain tumor research increased from $13m to $73m, and as a percentage of the CYA portfolio, brain tumor research received the highest percent investment (30%) in 2018. Research into treatment had risen (from $6m to $38m) as had research into biology (from $3m to $19m) - an essential foundation for more future personalized treatments. Given the lifelong impact on survivors it was encouraging that survivorship research investment had also started to increase. While 5-year survival for CYA cancers is now over 80%, survival for Diffuse Intrinsic Pontine Glioma (DIPG) remains very low. To assess capacity for future progress, several indicators were considered. The number of new DIPG projects per year increased from an average of 3 per year (2006-2012) to 11 (2013-2018) and funding increased from $0.5m (2006) to $10m (2018). Also, by 2018, 9 projects included a training component to build future research capacity. The number of laboratories researching DIPG increased from 2 in the US (2006) to 53 institutions in 6 countries (2018). Recent years had seen increased funding for pre-clinical models essential for identifying new targets. Collaborative initiatives such as DIPG-Open and DIPG-All had been funded to collect biological samples and accelerate translation of therapeutics to the clinic. Despite evidence that 5-year survival had improved from 1% to 2%, clearly major advances need to be made in new treatments, and monitoring the funding landscape carefully to make strategic investments will be essential.
SURG-01. CYSTIC BRAIN METASTASES MANAGED WITH RESERVOIR PLACEMENT AND STEREOTACTIC RADIOSURGERY
Authors: Park David , Unadkat Prashin , Goenka Anuj , Schulder Michael
Published: November 2021

BACKGROUND

Stereotactic radiosurgery (SRS) has become a mainstay of treatment for patients with metastatic brain tumors. However, metastatic tumors with a large cystic component often exceed the size limit for safe and effective SRS. In such cases, surgical resection may not be the preferred first method of treatment, due to tumor location, patient co-morbidities, and patient preference. In such cases volume reduction by cyst aspiration followed by SRS may be a preferred option.

OBJECTIVE

To present the treatment of patients with cystic metastases using reservoir placement followed by SRS.

METHODS

Seven patients were treated with this method. We performed reservoir insertion for the aspiration of cystic component in each patient and followed that with outpatient SRS.

RESULTS

Mean overall volume reduction from this treatment method was 80% (range 46.5-94.9). Mean volume reduction from the cyst aspiration alone was 60.7% (range 3.5-90.9), and after SRS a further 71.6% (range 34.6-94.4), accounting for some cyst reaccumulation between the time of surgery and SRS. The interval between those two procedures were 24 days on average (range 11-58 days). Repeat reservoir aspiration was done a total of 10 times in 5 patients.

CONCLUSION

Cyst aspiration with reservoir placement followed by SRS is a good option for patients with large cystic brain metastases. The reservoir allows for repeat aspiration if needed. Catheter placement at the center of the cyst, and SRS within 2-3 weeks of surgery, can maximize the likelihood of a successful outcome.
SURG-15. PITUITARY SPINDLE CELL ONCOCYTOMA: A CASE REPORT AND LITERATURE REVIEW
Authors: Taka Taha , Yang Chen Yi , Limbo Joshua , Chan Alvin , Davies Jordan , Kuan Edward , Turner Scott , Hsu Frank P K
Published: November 2021

BACKGROUND

Spindle cell oncocytoma (SCO) of the pituitary gland is an extremely rare non-functional WHO grade 1 tumor. SCO are often misdiagnosed as nonfunctional pituitary adenomas on pre-operative imaging. They are often hypervascular and locally adherent, which increases hemorrhage risk and limits surgical resection, leading to increased risk of recurrence. We report a case of SCO treated at our institution and provide a review of the current literature.

METHODS

A 75-year-old male with a history of hypertension, left thalamic stroke, Parkinson’s disease, and normal pressure hypertension presented to neurosurgery clinic with bitemporal hemianopsia, hyponatremia, and abnormal gait and mobility. Imaging showed an enhancing intra- and suprasellar, hyperdense tumor mass measuring 3.0 cm in diameter. We performed a systemic literature search in the PubMed database to identify previous reports of spindle cell oncocytoma. After exclusion of studies that did not meet criteria, 32 publications were selected for critical reading.

RESULTS

The patient underwent an endoscopic transsphenoidal resection of the tumor via a multi-disciplinary team. The tumor was fibrous and adherent to the intrasellar dura, with gross invasion of the diaphragm sella, necessitating partial resection of the diaphragm. The defect was repaired, and the patient made an uncomplicated recovery. Post-operatively, the patient experienced improved vision. Upon literature review, SCO present in older adults with an average age of 56.2 ± 14.7 with visual deficits (67.9%), headache (33.3%), hypopituitarism (24.7%), and nausea (11.1%). Full resection was achieved in 38.6% of cases leading to recurrence rate of 23.5% with an average time until recurrence of 32.5 months (range 1-120 months).

CONCLUSION

Careful surgical technique is needed due to SCO hypervascularity and strong adherence to minimize risk of injury to surrounding neurovascular structures. Long-term follow up is recommended due risk of recurrence.
TAMI-19. IMMUNOHISTOLOGICAL ANALYSIS OF ANGIOGENIC FACTORS OTHER THAN VEGF IN GLIOBLASTOMAS IN RELATION TO THE USE OF BEVACIZUMAB
Authors: Ezaki Taketo , Tamura Ryota , Tanaka Toshihide , Kuranari Yuki , Miyake Keisuke , Yamamoto Yohei , Takei Jun , Akasaki Yasuharu , Murayama Yuichi , Tamiya Takashi , Sasaki Hikaru
Published: November 2021

Although bevacizumab was shown to improve progression-free survival and performance status of the patients with high-grade gliomas, clinical trials consistently showed lack of benefit in terms of patients’ overall survival. The recurrent tumors are inevitably more aggressive and invasive as compared with the original tumors, and the in-situ observation in actual human specimens is essential to elucidate the mechanism of resistance. In Japan, bevacizumab was approved not only for recurrent but also for newly diagnosed cases. The safety as well as efficacy of resection following neoadjuvant bevacizumab has been reported, and a phase II study is currently ongoing (UMIN-000025579). In the present study, the expression of angiogenic factors other than VEGF (basic fibroblast growth factor (bFGF), placenral growth factor (PlGF), angiopoietin1/2 and ephrinA2) was investigated by immunohistochemistry to be compared among tumors with no previous bevacizumab treatment, those resected following bevacizumab, and those refractory to bevacizumab. Fifty-nine samples from 42 patients were included; 24 of newly diagnosed glioblastomas with no previous bevacizumab (naïve group), 16 resected following neoadjuvant bevacizumab (effective group), and 6 resected after recurrence or autopsied (refractory/autopsied group). 12 were paired samples (8 naïve and refractory, 4 effective and refractory). The expression of PlGF significantly increased in the effective group as compared with the naïve group (p=0.003). In the paired specimens, there was a trend towards increased expression of PlGF in the second specimens (refractory/autopsied group) as compared with the specimens of initial surgery (p=0.083). Angiopoietin1, angiopoietin2 and ephrinA2 were characteristically expressed in the microvessels less than 15μm. The increased expression of PlGF might be associated with the recurrence after bevacizumab.
TAMI-23. ANTIBODY COCKTAIL IMMUNOTHERAPY FOR GLIOBLASTOMA BY DUAL TARGETING OF IL-6 AND CD40
Authors: Yang Fan , Brem Steven , Fan Yi
Published: November 2021

Glioblastoma (GBM) is refractory to current T cell-based immunotherapies such as checkpoint blockade. GBM is characterized by extensive infiltration of immunosuppressive macrophages that contribute to the treatment resistance. Here we develop a dual-targeting strategy to synergistically activate tumor-associated macrophages (Mφs), which efficiently overcomes GBM resistance to therapeutic blockade of the PD1 and CTLA4 checkpoints. Consistent with a pro-tumor role of IL-6 in alternative Mφ polarization, we here show that targeting IL-6 by genetic ablation or pharmacological inhibition moderately improves T-cell infiltration into GBM and enhances mouse survival; however, IL-6 inhibition does not synergize PD-1 and CTLA-4 checkpoint blockade. Interestingly, anti-IL-6 therapy reduces CD40 expression in GBM-associated Mφs. We identify a Stat3/HIF-1α-mediated axis, through which IL-6 executes an anti-tumor role to induce CD40 expression in Mφs. Combination of IL-6 inhibition with CD40 stimulation reverses Mφ-mediated tumor immunosuppression, sensitizes tumors to checkpoint blockade, and extends animal survival in two syngeneic GBM models. Notably, this antibody cocktail-based combination immunotherapy with checkpoint blockade almost doubles animal survival in the genetically engineered mouse GBM model and induces complete tumor regression in the GL261 model. Thus, antibody cocktail-based immunotherapy that combines checkpoint blockade with dual-targeting of IL-6 and CD40 may offer exciting therapeutic opportunities for GBM.
TAMI-35. DETECTING SINGLE-CELL INTERACTIONS IN ORGANOTYPIC CULTURES OF GLIOBLASTOMA USING BARCODED RABIES VIRUS
Authors: Andersen Brian , Wheeler Michael , Li Zhaorong , Chiocca E Antonio , Reardon David , Quintana Francisco
Published: November 2021

Cell-cell interactions are thought to drive tumor-promoting signals in the microenvironment of glioblastoma, but standard approaches for single cell analysis do not directly identify cell interactions and the mechanisms that mediate them. We recently developed a novel method to analyze cell-cell interactions—rabies barcode interaction detection followed by sequencing (RABID-seq), which combines barcoded viral tracing and single-cell RNA sequencing (scRNAseq). RABID-seq was first implemented in transgenic mice to investigate the interactions of astrocytes with other cells in the CNS enabling the study of astrocyte connectome perturbations and candidate therapeutic targets in multiple sclerosis and its pre-clinical model, experimental autoimmune encephalomyelitis (EAE). Here, we report the first use of RABID-seq in human tissues in organotypic cultures established from three IDH-wildtype glioblastoma (GBM) patients. In organotypic GBM cultures, initial infection by pseudotyped barcoded rabies virus deficient for viral glycoprotein was achieved after previous culture transduction with a lentivirus containing the avian TVA receptor and rabies glycoprotein under the human EF1a promoter. We employed this system to initially infect approximately 1,000 malignant or non malignant cells in the tumor microenvironment. After five days, infected cells were isolated from cultures and processed for single cell analysis using SMART seq. We were able to capture at least 6,000 interacting cells per tumor specimen, from which barcodes were recovered and cDNA was sent for sequencing. Here we present connectomic data from our initial cohort of three glioblastoma patients as an introduction to RABID-seq, with a focus on astrocyte-tumor interactions. Candidate mechanisms of cellular interactions will undergo functional validation in murine models of glioblastoma.
TAMI-45. MICROGLIAL CYTOKINES INDUCE INVASIVENESS AND PROLIFERATION THROUGH PYK2 AND FAK ACTIVATION IN HUMAN GLIOBLASTOMA CELL
Authors: Nunez Rebeca , Valle Miguel Mayol-Del , Almodovar Luis , Kucheryavykh Lilia
Published: November 2021

Glioblastoma (GBM) is the most aggressive and highly invasive primary brain tumor in adults. Evidence suggests that microglia create a microenvironment favoring glioma invasion and proliferation. Indeed, previous reports indicate the involvement of focal adhesion kinase (FAK) signaling cascades in glioma cell proliferation. Besides, studies from our laboratory support a critical role of Pyk2, a relative of FAK, in glioma invasion by tumor-infiltrating microglia. However, the microglial-released factors modulating Pyk2 and FAK signaling pathways are unknown. In this study, 20 human GBM specimens were evaluated to identify the cytokine expression patterns in purified microglia and FAK and Pyk2 phosphorylation in glioma cell fraction by RT-PCR and western blot. A Pierson correlation test demonstrated a high correlation (0.8-1.0) of gene expression for PDGFα, PDGFβ, SDF-1α, IL-6, IL-8, and EGF in percoll-purified microglia, and pPyk2(Y579/580) and pFAK(Y925) levels in glioma cell fraction. The role of cytokines in cell invasion and proliferation by Pyk2/FAK activation was further investigated in primary cell lines from three patients. Thirty percent up-regulation of pPyk2 and pFAK was detected in glioma cells treated (2 hrs.) with microglia conditioned media (MCM) compared to control cells. siPyk2 or siFAK knockdown identified IL-6 (100 μM) and EGF (1 μM) as key factors of Pyk2- and FAK-dependent activation in all glioma cell lines. Similar results with siPyk2 or siFAK were observed for matrix degradation, invadopodia formation, cell viability, and mitosis. Indeed, Tocilizumab (IL-6R blocker, 100 ng/mL) and Gefitinib (EGFR blocker, 1 μM) reversed the effect of MCM on glioma cell proliferation and invasion in all cell lines evaluated. These findings support a pivotal role of Pyk2 and FAK in enhancing proliferation and invasion of glioma tumors through IL-6 and EGF-dependent pathways. The latter could be of clinical relevance for new therapeutic developments in GBM patients.
TAMI-54. SEXUAL DIMORPHISM IN IRON ACQUISITION IN GLIOBLASTOMA
Authors: Pandya Bhavyata , Webb Becky Slagle , Zacharia Brad , Lathia Justin , Rubin Joshua , Berens Michael , Barnholtz-Sloan Jill
Published: November 2021

Sexual dimorphism in incidence and the clinical outcomes of Glioblastoma (GBM) has been reported, however, our knowledge of contributing biological mechanisms is limited. Iron acquisition is key to robust tumor growth. Upregulation of Transferrin (TF, iron transport protein)/Transferrin receptor (TFR) is critical for found in multiple different cancers, specifically, we have identified H-ferritin (FTH1) as a contributor to iron transport and protection in cancer stem cells. To interrogate brain tumor iron uptake mechanisms,we performed binding studies on homogenized samples of human male and female GBM tissue samples using 125I labeled TF and FTH1. Tumors from males had a ̴ 3.8-fold increased binding of both proteins compared to tumors from females. We interrogated iron uptake in a syngeneic orthotopic mouse model (GL261 cells) using male and female mice. After the tumors were established, radioactive 125I labeled TF and FTH1 proteins were injected retro-orbitally in the mice. After 24 hours, tumors wereremoved, and analyzed for TF and FTH1 uptake. Male tumors showed an increased uptake, of ̴ 3.2-fold, as compared to female tumors. There was no significant difference in TF uptake between male and female tumors nor between tumor and matched non-tumor brain tissue. We next queried role of FTH1 in the context of sexual dimorphism in GBM in a FTH1+/- mouse strain developed in our laboratory. Survival was monitored in the mice which were injected with GL261 cells at 3 months. Male mice that had reduced expression of FTH1 had poorer survival as compared to the male wild type controls whereas wild type and FTH+/- females had no major differences in survival outcomes. In summary, this study demonstrates sexual dimorphism in iron acquisition in GBM and animal models further suggesting a pathophysiological role of iron metabolism in GBM development and its possible role in prognosis.
TAMI-59. RECIPROCAL IMPACT OF CANCER IMMUNITY AND TUMOR HYPOXIA DURING GLIOBLASTOMA PROGRESSION
Authors: Sattiraju Anirudh , Kang Sangjo , Marallano Valerie , Brusco Concetta , Chen Zhihong , Ramakrishnan Aarthi , Shen Li , Hambardzumyan Dolores , Friedel Roland , Zou Hongyan
Published: November 2021

Tumor hypoxia is linked to poor outcome for glioblastoma (GBM), a highly malignant brain cancer, but the underlying mechanisms and the environmental factors that initiate tumor hypoxia are poorly understood. We tracked tumor hypoxia in GBM in immunocompetent mice with a hypoxia sensitive fluorescent reporter combined with single cell transcriptomics. We found that hypoxic GBM cells are quiescent, immunosuppressive and display a mesenchymal transition, all of which are linked to malignant potency. We also captured in vivo hypoxia gene signature, which is more represented in recurrent GBM and predicts worse outcome. Interestingly, hypoxic GBM cells is a diverse population, consisted of four subclusters, and enriched for immune pathways. Concordantly, our reporter highlighted a distinct geographic pattern of immune cells in hypoxic regions, with phagocytic tumor-associated macrophages (TAMs) and CD8+ cytotoxic T cells (CTLs) congregated in hypoxic cores confined by hypoxic GBM cells in pseudo-palisading patterns. Mechanistically, this is a dynamic temporospatial process, requiring cytokine CCL8. Remarkably, the sequestered TAMs also experience hypoxia, and they are reprogrammed to express immunotolerant markers by factors released from hypoxic GBM cells. Contrary to the conventional viewpoint that hypoxia arises from rapid tumor expansion outstripping vascular supply, we discovered anticancer immunity as an important driving force of tumor hypoxia; attenuating immune responses by implanting GBM in host mice with immunodeficiency or IL1β deletion greatly decreased GBM hypoxia. Analyses of human patient GBM samples highlighted a connection of mesenchymal subtype, immune response, and tumor hypoxia, all contributing to poor survival. Altogether, our study revealed a reciprocal influence of anti-tumor immunity and tumor hypoxia, which has significant ramifications for prognosis and immunotherapy for GBM.
TAMI-75. LIPID METABOLISM AS A THERAPEUTIC VULNERABILITY IN BET INHIBITOR-RESISTANT MEDULLOBLASTOMA
Authors: Lupien Leslie , Boynton Adam , Kumbhani Rushil , Gionet Gabrielle , Goodale Amy , Root David , Bandopadhayay Pratiti
Published: November 2021

MYC-driven medulloblastomas are a particularly devastating group of pediatric brain tumors that exhibit resistance and continued progression despite standard of care treatments. Our preclinical work identified BET-bromodomain inhibitors as a potentially promising new class of drugs for children with medulloblastoma and other MYC-driven cancers, providing rationale to evaluate these agents in clinical trials. However, treatment with BET inhibitor (BETi) alone is unlikely to be sufficient for a cure, with most tumors evolving to acquire resistance to single-agent targeted therapies. We applied an integrative genomics approach to identify genes and pathways mediating BETi response in medulloblastoma. These studies revealed that MYC-driven medulloblastoma cells with acquired resistance to BETi reinstate transcription of essential genes suppressed by drug, and exhibit changes in cell state and new vulnerabilities not present in drug-sensitive cells. We now have a growing body of evidence showing that BET inhibition downregulates the expression of key lipid metabolism genes and metabolism-related signaling pathways, and that medulloblastoma cells with adaptive resistance to drug differentially express and exhibit preferential dependency on specific lipid metabolic genes and transcriptional regulators. Our studies explore the possibility of exploiting these novel metabolic vulnerabilities in order to overcome BETi resistance and provide a more efficacious upfront therapy.
TMOD-06. CREATION OF PATIENT-DERIVED LOWER GRADE GLIOMA ORGANOID MODELS FOR PERSONALIZED TREATMENT RESPONSE ASSESSMENT
Authors: Abdullah Kalil , Buehler Joseph , Bird Cylaina , Savani MIlan , Sternisha Alex , Levitt Michael , Hatanpaa Kimmo , Richardson Timothy , McBrayer Samuel
Published: November 2021

Creating in vitro models of lower grade glioma represents a major challenge in neuro-oncology research. There are few such models that are tractable and widely used, which has hindered understanding of the biology of these tumors. Recently, substantial progress has been made in generating patient-derived in vitro organoid models of high grade glioma, but modeling lower grade disease remains difficult. Based on our experience creating neurosphere cultures of lower grade astrocytomas from genetically engineered mice, we hypothesized that modifying patient-derived organoid generation protocols to incorporate physiological oxygen levels would allow establishment and propagation of lower grade glioma organoids. In this study, we show that this approach supports efficient organoid model generation from primary glioma specimens across all histological subtypes and tumor grades (WHO Grade I-IV, n = 20). These organoid models retain key characteristics of their respective parental tumors, including IDH mutations and other genetic alterations, metabolite profiles, intratumoral heterogeneity, cellular composition, and cytoarchitectural features. Importantly, lower grade glioma organoids can be cultured for months and reanimated after biobanking. Our high success rate ( >90%) in establishing organoid models from primary lower grade glioma tissue samples further highlighted opportunities for treatment response assessments. To perform longitudinal measurements of therapy-induced changes in glioma organoid viability, we designed a novel, non-invasive imaging assay (termed rapid apex imaging) to determine real-time treatment response in low and high grade gliomas. We evaluated longitudinal responses of glioblastoma and IDH1 R132H-positive Grade II astrocytoma organoids to temozolomide and olaparib with and without radiation treatment. We quantified topological changes in organoid structure by building a bioinformatics tool to translate imaging data into a cellularity metric as a biomarker of organoid response. Our work unveils an effective new method to create in vitro, personalized models of lower grade glioma that supports elucidation of treatment sensitivity profiles.
TMOD-12. COMPARING TUMOR CELL INVASION AND MYELOID CELL COMPOSITION IN GENETICALLY IDENTICAL PRIMARY AND RELAPSING GLIOBLASTOMA
Authors: Kälin Roland , Zhao Dongxu , Zhang Huabin , Uyar Ramazan , Tonn Jörg-Christian , Glass Rainer
Published: November 2021

Glioblastoma (GBM) recurrence after treatment is almost inevitable, but addressing this issue with adequate preclinical models has remained challenging. Here, we introduce a GBM mouse model allowing non-invasive and scalable de-bulking of a tumor mass located deeply in the brain, which can be combined with conventional therapeutic approaches. Towards this aim we genetically engineered mouse GBM cells to stably express the herpes simplex virus thymidine kinase. Strong reduction of the GBM volume is achieved after pharmacologically inducing a tumor-specific cell death mechanism by the prodrug ganciclovir. This is followed by GBM re-growth over a predictable timeframe. Pharmacological de-bulking followed by tumor relapse was accomplished with an orthotopic mouse glioma model. Relapsing experimental tumors recapitulated pathological features often observed in recurrent human GBM, like increased invasiveness or altered immune cell composition. Orthotopic implantation of GBM cells originating from biopsies of one patient at initial or follow-up treatment reproduced these findings. Interestingly, relapsing GBM of both models contained a much higher ratio of monocyte-derived macrophages (MDMs) versus microglia than primary GBM. This was not altered when combining pharmacological de-bulking with invasive surgery. We interpret that factors released from viable primary GBM cells preferentially attract microglia whereas relapsing tumors preponderantly release chemoattractants for MDMs. All in all, this relapse model has the capacity to provide novel insights into clinically highly relevant aspects of GBM treatment.
TMOD-18. DIRECT IN VIVO CRISPR SCREEN IDENTIFIES COOPERATING TUMOR SUPPRESSORS THAT DRIVE PROGRESSION OF IDH1-MUTANT LOW-GRADE GLIOMA TO AGGRESSIVE GLIOBLASTOMA
Authors: Yanchus Connor , Drucker Kristen , Kollmeyer Thomas , Tsai Ricky , Jiang Lingyan , Ali Asma , Carson Brittany , Pawling Judy , Malik Ahmad , Al-Zahrani Khalid , Loganathan Sampath Kumar , Fortin Jerome , Zhou Lily , Elia Andrew , Dennis James W , Mak Tak , Taylor Michael , Zadeh Gelareh , Dirks Peter , Jenkins Robert , Schramek Daniel
Published: November 2021

Low-grade glioma (LGG) are generally slowly growing brain cancers, that frequently undergo malignant progression to aggressive, secondary glioblastoma with a dismal prognosis. By combining genetically engineered Idh1-mutant mice with in vivo CRISPR gene editing we generated a mouse model faithfully recapitulating the founder mutations of LGG. Clonal activation of the neomorphic Idh1 R132H mutation cooperates with Trp53 and Atrx mutations to trigger development of brain tumors but only with ~30% penetrance and very long latency. To elucidate the molecular mechanisms underlying the malignant progression of IDH1-mutant LGG, we devised and deployed a direct in vivo CRISPR screen targeting genes commonly mutated in human IDH-mutant secondary glioblastoma. Stereotaxic delivery of a lentiviral sgRNA library targeting the mouse orthologs of these genes into the brain of Idh1 R132H ;Trp53;Atrx;Cas9 and control Idh1 wt ;Trp53;Atrx;Cas9 compound mutant mice resulted in rapid formation of tumors that recapitulate human Idh1-mutant glioblastoma. Deconvoluting the screen showed that PI3K pathway members Pten and Pik3ca as well as Notch1, Smarca4 and Fat1 are preferentially enriched in Idh1 R132H-tumors, while Rb1 and NF2 were enriched in Idh1 wt tumors. Co-mutation analysis further identified additional co-occurring driver combinations such as Bcor-Met, Olig2-Met, Olig2-Med12 or Bcor-Olig2. We validated the tumor suppressive function of Notch1 and Pten using conventional floxed knock-out alleles and found that Notch1 functions in a haploinsufficient manner. Interestingly, Idh1 R132H did not alter tumor latency or pathology in a high grade p53;Pten;Rb1 mutant background, indicating that the neomorphic IDH-mutations can drive low but not high grade glioma development. Our study provides a functional landscape of gliomagenesis suppressors in vivo.
TMOD-21. A NOVEL IN-VITRO METHOD TO MODEL MACROPHAGES IN GLIOBLASTOMA
Authors: Alrefai Hasan , Beierle Andee , Nassour Lauren , Eustace Nicholas , Patel Zeel , Anderson Joshua , Hicks Patricia , King Peter , Willey Christopher
Published: November 2021

BACKGROUND

The GBM tumor microenvironment (TME) is comprised of a plethora of cancerous and non-cancerous cells that contribute to GBM growth, invasion, and chemoresistance. In-vitro models of GBM typically fail to incorporate multiple cell types. Others have addressed this problem by employing 3D bioprinting to incorporate astrocytes and macrophages in an extracellular matrix; however, they used serum-containing media and classically polarized anti-inflammatory macrophages. Serum has been shown to cause GBM brain-tumor initiating cells to lose their stem-like properties, highlighting the importance of excluding it from these models. Additionally, tumor-associated macrophages (TAMs) do not adhere to the traditional M2 phenotype.

METHODS

THP-1 monocytes and normal human astrocytes (NHAs) were transitioned into serum-free HL-1 and neurobasal-based media, respectively. Monocytes were stimulated towards a macrophage-like state with PMA and polarized by co-culturing them with GBM patient-derived xenograft(PDX) lines, using a transwell insert. CD206 expression was used to validate polarization and a cytokine array was used to characterize the cells.

RESULTS

There was no difference in proliferation rates at 72 hours for THP-1 monocytes grown in serum-free HL-1 media compared to serum-containing RPMI 1640 (p > 0.95). Macrophages polarized via transwell inserts expressed the lymphocyte chemoattractant protein, CCL2, whereas resting(M0), pro-inflammatory(M1), and anti-inflammatory(M2) macrophages did not. Additionally, these macrophages expressed more CXCL1 and IL-1ß relative to M1 macrophages. We have also demonstrated a method to maintain a tri-culture model of GBM PDX cells, NHAs, and TAMs in a serum-free media that supports the growth/maintenance of all cell types.

CONCLUSIONS

We have demonstrated a novel method by which we can polarize macrophages towards a tumor-supportive phenotype that differs in cytokine expression from traditionally polarized macrophages. This higher-fidelity method of modeling TAMs in GBM can aid in the development of targeted therapeutics that may one day enter the clinic in hopes of improving outcomes in GBM.
TMOD-27. IDENTIFYING ONCOGENIC C-MYC AND MYCN COMPLEXES IN HIGH-RISK PEDIATRIC CANCERS
Authors: Qiu Bo , Qiu Bo , Qiu Bo
Published: November 2021

The MYC family of proto-oncogenes is activated in a variety of cancers, including multiple high-risk pediatric malignancies. c-MYC (MYC) is ubiquitously expressed in human tissues, while MYCN (MYCN) has tissue and developmentally restricted expression patterns. In both neuroblastoma and medulloblastoma, enhanced activity of either MYCN or c-MYC drives high-risk disease. As transcription factors, MYC proteins exert oncogenic functions through protein-protein interaction networks that alter gene expression, but also mediate a growing list of target-gene independent nuclear functions (transcriptional elongation, chromatin changes throughout the cell cycle, etc…). While c-MYC and MYCN share many functions, they also regulate distinct cellular processes, and within medulloblastoma, they are activated in distinct molecular sub-groups (i.e. MYCN amplification is found in aggressive sonic hedge hog (SHH) subgroup tumors, while MYC amplification is found in aggressive group 3 and group 4 tumors). Here, we present an approach to identify oncogenic functions of c-MYC and MYCN in medulloblastoma and neuroblastoma using human induced pluripotent stem cell (iPSCO based orthotopic model systems. We hypothesize that the protein interaction networks and oncogenic functions of c-MYC and MYCN are impacted by cellular context, which are recapitulated in our orthotopic models (cell transcriptional and epigenetic landscape, tumor microenvironment). This premise is supported by recent single cell sequencing efforts in medulloblastoma and neuroblastoma, where primary human tumor cells are found to recapitulate specific transcriptional cell states found in normal hindbrain and sympathetic nervous system development, respectively. Through proximity labeling and quantitative mass spectrometry, we aim to identify tumor and oncogene specific protein interaction networks. This information will guide functional screening approaches to identify tumor-specific vulnerabilities. * Note MYC(N) refers to c-MYC and MYCN.
BRMP-05. Intraoperative neural tract positioning method for the maximal safe resection of tumors
Authors: Yamaguchi Fumio
Published: November 2021

Brain mapping is a gold standard for the surgery of tumors in eloquent area. Especially subcortical mapping is an essential method for the preservation of important neural fibers conveying motor, sensory and even higher brain functions such as language control. The efforts to estimate the fiber localizations in brain white matter sometimes result in the unprecise identification that is caused by several factors including electrical heterogeneity of brain tissues. To solve this long-standing problem, NY Tract Finder (Yamaguchi Tract Finder) was invented and has been used for intraoperative brain mappings. Now this electrode and method is used in more than 30 major hospitals in Japan, China, Taiwan and Russia. The novel and unique neural fiber positioning technique and our efforts for the maximal preservation of patients’ QOL will be introduced.
FLGS-05. Maximal safe glioma resection using high resolution exoscope with 5-ALA-induced fluorescence
Authors: Saito Kuniaki , Sasaki Nobuyoshi , Kobayashi Keiichi , Nakatomi Hirofumi , Shiokawa Yoshiaki , Nagane Motoo
Published: November 2021

INTRODUCTION

5-aminolevulinic acid (5-ALA) guided surgery has been reported to prolong progression-free survival of patients with high grade glioma. Although blue-light capable microscope enables us to detect fluorescence intraoperatively, visualization of anatomy is difficult under blue-light microscope. On the other hand, exoscope permits to visualize both fluorescence and anatomy under blue-light conditions. We introduce our glioma surgery using an exoscope equipped with a 5-ALA fluorescence visual system.

METHODS

We attempted maximal safe resection for the patients with high grade glioma using 3D/4K exoscope with 5-ALA-induced fluorescence, neuronavigation, and electrophysiological monitoring or awake mapping. Visualization of fluorescence and anatomy under blue light, extent of resection, morbidity, and postoperative infarction were retrospectively reviewed.

RESULTS

Twenty patients (age 26–79, male 10/female 10, glioblastoma 11/lower grade glioma 9) underwent exoscopic tumor removal. Intraoperative fluorescence was observed in 100% of the tumor with gadolinium enhancement. Surrounding structures such as white matter, vessels and nerves were clearly visualized under blue light. Even perforators were visible and could be preserved. Supra-total resection and gross total resection of gadolinium-enhancing tumor was achieved in 6 (30%) and 10 (50%) patients, respectively. Surgical morbidity included hemianopsia in 1 patient and transient hemiparesis in 1 patient. Postoperative infarction was observed in 2 (10%) patients, which tended to be lower compared to 23 of 77 (29.9%) patients with glioblastoma who underwent tumor resection with fluorescence-equipped microscope(p=0.05).

CONCLUSION

Clear visualization of 5-ALA-indced tumor fluorescence and anatomical structures with use of high resolution exoscope help maximal safe tumor resection. Longer progression-free survival is expected as a result of greater extent of tumor resection.
IOTG-03. Rapid intraoperative flow cytometry of brain tumor useful for surgical decision-making
Authors: Muragaki Yoshihiro , Koriyama Shunichi , Saito Taiichi , Nitta Masayuki , Komori Takashi , Kawamata Takakazu
Published: November 2021

Flow cytometry is a measuring device frequently used in basic research, we have developed a fully automatic flow cytometer device that performs cell isolation, staining of cell nuclei, and measurement for intraoperative diagnosis. Placing a small specimen in a reagent containing PI calculates, the total number of cells, the DNA histogram, and the Malignancy Index (MI), which means in the proliferation phase, the ratio of the number of cells (S, G2, M) / total number of cells. The major feature of this device is that calculating takes only 10 minutes by thoroughly reviewing the process. We here introduce our study of this device, rapid diagnosis, WHO grading, prognosis in glioma, and differentiation from malignant lymphoma (PCNSL), then how to use it in decision making in the operation. In the analysis of 323 gliomas, the threshold between the peripheral brain and the tumor was 7%, and the MI value was correlated with WHO grade (II 13%, III 35%, IV 47%) (J Neurosurg 2013). A correlation was also found between the MI value and the number of residual tumors (Brain Tumor Path 2018). Furthermore, it was also useful for differentiating from PCNSL with many S-phase cells (World Neurosurg 2018). In addition, the relationship between the presence of DNA aneuploidy and poor prognosis in 102 grade II patients (Clin Neuro Neurosurg 2018), and the high MI in 102 grade IV patients showed a good prognosis and an inverse correlation with expectations (Neurosurg 2018). Intraoperative flow cytometry has enabled various intraoperative decision-making support by converting intraoperative histology, which was an analog-like transmission, into digitized histological information. In the future, the development of this research makes expectations for more accurate diagnosis and prediction by artificial intelligence and the development of other departments.
ITVT-05. Intraoperative Ultrasound Guidance Improves Resection In Gliomas – Results From A Single Centre Propensity Matched Comparative Cohort Analysis Of 2D Vs Navigated 3D Ultrasound In 500 Gliomas
Authors: Moiyadi Aliasgar , Shetty Prakash , Singh Vikas
Published: November 2021

INTRODUCTION

Intraoperative ultrasound (iUS) is a promising tool for glioma surgery. Navigated 3-D (n3D) iUS has many benefits over standard 2-D iUS.

METHODS

This was a retrospective comparative cohort study using propensity score matching (PSM). 500 consecutive histologically confirmed gliomas were divided into 2 cohorts – 2DiUS - Cohort A; and n3DiUS -Cohort B. PSM was used to account for known confounders (250 in each group; 1:1 matching). Gross total resection rates (based on iUS findings as well as postoperative MR) and perioperative morbidity were analyzed across the groups as were factors influencing these outcomes (using univariate as well as multivariate regression models).

RESULTS

Overall, the majority of the patients were adults (94%), males (71%) with hemispheric tumors (96%). 35% had tumors close to eloquent regions and 23% had received some prior treatment. The majority were high-grade gliomas (85%). 2D iUS was employed mainly for localization (80%) whereas n3D was used predominantly for resection control (84%) [p < 0.001]. GTR rate was higher in the n3D cohort (55.2% vs 38.4% in 2D; p = 0.001). The odds of having a complete resection in the n3D cohort was twice that of the 2D. Prior treatment, hemispheric location, and use of fluorescence were also significantly associated with higher GTR rates on univariate analysis. On multivariate analysis, all of these remained significant. There was no difference in the morbidity rates in the two cohorts. N3D iUS had a higher specificity and positive likelihood ratio in detecting tumor residue.

CONCLUSION

For hemispheric gliomas undergoing resective surgery, the use of navigated 3D ultrasound improves GTR rates, with no added morbidity. It is more likely to be used for resection control mode than is 2DUS and this is probably because n3DUS is more specific and likely to pick up tumor residues contributing to its better accuracy.
ITVT-07. Robotic alignment module Cirq for navigated brainstem tumor biopsies
Authors: van Baarsen Kirsten , Woerdeman Peter , Slot Mariam , Hoving Eelco
Published: November 2021

BACKGROUND

With the incorporation of the robotic alignment module Cirq (Brainlab, Germany) into our neurosurgical armamentarium, we aimed to know our baseline accuracy in stererotactic biopsies. We therefore retrospectively reviewed our data on biopsy accuracy for brain(stem) tumors using the non-robotic alignment instrument Varioguide (Brainlab, Germany). Because of unexpectedly large deviations from the intended target, we sought to improve our registration accuracy when we introduced Cirq. Intraoperative 3D CT with bone fiducials was added to the pre-operative 3D T1 MRI with skin fiducials. This made it possible to compare surgical devices as well as registration methods.

AIMS

To share our experience with the new robotic alignment module Cirq for navigated brain(stem) tumor biopsies and to evaluate its target accuracy with bone fiducial registration, as compared to the previously used Varioguide with skin fiducial registration.

METHODS

All patients (0–18 years old) that underwent a brain(stem) biopsy in our institution were included. Over 2018–2020, data were collected retrospectively (cohort Varioguide with 3D T1 MRI registration with skin fiducials). From 2021, data were collected prospectively (cohort Cirq with both 3D T1 MRI registration with skin fiducials and intraoperative CT registration with bone fiducials). For both cohorts, Euclidian distances were calculated between the intended target and the obtained target. For the prospective cohort, registration errors were calculated for bone versus skin fiducials.

PRELIMINARY REUSLTS

The deviation from the intended target was much smaller in the Cirq cohort versus the Varioguide cohort. Within the Cirq cohort, registration errors were submillimetric for bone fiducial registration as compared to several millimeters for skin fiducial registration. CONCLUSION: The Cirq robotic arm is convenient, safe and highly accurate, especially when combined with intraoperative 3D CT bone fiducial registration. Skin fiducial registration does not offer the level of precision that is mandatory in brainstem tumor biopsies.
TWMP-02. Supplementary motor area syndrome in glioma surgery - towards a classification system based on clinical and imaging data
Authors: Tuncer Mehmet Salih , Fekonja Lucius , Ott Stefanie , Pfnür Andreas , Karbe Anna-Gila , Engelhardt Melina , Faust Katharina , Picht Thomas , Coburger Jan , Dührsen Lasse , Vajkoczy Peter , Onken Julia
Published: November 2021

OBJECTIVES

Surgical resection of gliomas involving the supplementary motor area (SMA) frequently results in a symptom complex commonly described as „SMA syndrome“, which is characterized by transient contralateral akinesia and mutism. As factors potentially influencing the severity and duration of symptoms still remain elusive, we aim to further investigate potential predictors in a multicentric cohort of glioma patients.

METHODS

Fifty patients with gliomas located in the superior frontal gyrus from 3 centers were included in this retrospective study. Patients with injury of M1 and/or the corticospinal tract were excluded. Early postoperative motor outcome, the occurrence of mutism and duration of acute symptoms in days were assessed. The long-term outcome was assessed in follow-up examinations 3 months after surgery. Atlas-based lesion-symptom mapping was performed using postoperative MR imaging estimating surgical grey matter damage as well as white matter disconnection severity. Associations between functional outcome and imaging findings were analyzed using group tests and correlation analyses.

RESULTS

Median duration of symptoms in the cohort was 3 days (range: 1 – 42 days). Persistent deficits concerning fine motor movements and speech after initial recovery were found in 27 patients (54%). Disconnection of the central segment of the corpus callosum was associated with longer symptom duration (FDR corr. p < 0.05), while disconnection of the mid-posterior segment of the corpus callosum was associated with persistent deficits at follow-up (FDR corr. p < 0.05).

CONCLUSIONS

The present study shows a high variability regarding the recovery time of postoperative SMA syndrome and a high prevalence of persistent deficits in fine motor movements and speech after initial recovery of acute symptoms. The pivotal role of interhemispheric connectivity in the recovery process is reinforced. These findings will help neurosurgeons in patient consultation and provide a foundation for future studies aiming to establish prediction models of the SMA syndrome.
A functional artificial neural network for noninvasive pretreatment evaluation of glioblastoma patients
Authors: Zander Eric , Ardeleanu Andrew , Singleton Ryan , Bede Barnabas , Wu Yilin , Zheng Shuhua
Published: November 2021

Background

Pretreatment assessments for glioblastoma (GBM) patients, especially elderly or frail patients, are critical for treatment planning. However, genetic profiling with intracranial biopsy carries a significant risk of permanent morbidity. We previously demonstrated that the CUL2 gene, encoding the scaffold cullin2 protein in the cullin2-RING E3 ligase (CRL2), can predict GBM radiosensitivity and prognosis. CUL2 expression levels are closely regulated with its copy number variations (CNVs). This study aims to develop artificial neural networks (ANNs) for pretreatment evaluation of GBM patients with inputs obtainable without intracranial surgical biopsies.

Methods

Public datasets including Ivy-GAP, The Cancer Genome Atlas Glioblastoma (TCGA-GBM), and the Chinese Glioma Genome Atlas (CGGA) were used for training and testing of the ANNs. T1 images from corresponding cases were studied using automated segmentation for features of heterogeneity and tumor edge contouring. A ratio comparing the surface area of tumor borders versus the total volume (SvV) was derived from the DICOM-SEG conversions of segmented tumors. The edges of these borders were detected using the canny edge detector. Packages including Keras, Pytorch, and TensorFlow were tested to build the ANNs. A 4-layered ANN (8-8-8-2) with a binary output was built with optimal performance after extensive testing.

Results

The 4-layered deep learning ANN can identify a GBM patient’s overall survival (OS) cohort with 80%–85% accuracy. The ANN requires 4 inputs, including CUL2 copy number, patients’ age at GBM diagnosis, Karnofsky Performance Scale (KPS), and SvV ratio.

Conclusion

Quantifiable image features can significantly improve the ability of ANNs to identify a GBM patients’ survival cohort. Features such as clinical measures, genetic data, and image data, can be integrated into a single ANN for GBM pretreatment evaluation.
Prediction Tool to Identify Children at Highest Risk of Tuberculosis Disease Progression Among Those Exposed at Home
Authors: Brooks Meredith B , Lecca Leonid , Contreras Carmen , Calderon Roger , Yataco Rosa , Galea Jerome , Huang Chuan-Chin , Murray Megan B , Becerra Mercedes C
Published: November 2021

Background

There is a dearth of research to understand which children, among those who are exposed at home to tuberculosis (TB), are at the highest risk of TB disease, to tailor care. We sought to identify predictors of TB progression in children.

Methods

We conducted a prospective cohort study of children living with adults with pulmonary TB in Lima, Peru (2009–2012). We applied classification and regression tree analysis to examine potential predictors of incident TB disease during 12 months in 3 age groups (0–4, 5–9, and 10–14 years). We calculated the relative risk (RR) for top predictors in each age group.

Results

Among 4545 children 0–14 years old, 156 (3.4%) were diagnosed with TB within 1 year of household exposure to TB (3.4%, 2.3%, and 4.7% in children 0–4, 5–9, and 10–14 years old, respectively). The most important predictor of TB was having a positive tuberculin skin test (TST) result, with RRs of 6.6 (95% CI, 4.0–10.7), 6.6 (95% CI, 3.2–13.6), and 5.2 (95% CI, 3.0–9.0) in the age groups 0–4, 5–9, and 10–14 years, respectively. In young children with a positive TST, not using isoniazid preventive treatment further increased risk of disease (RR, 12.2 [95% CI, 3.8–39.2]).

Conclusions

We present a tool that identifies child household contacts at high risk of TB disease progression based on data collected during contact tracing. In addition to the use of TB preventive therapy for all children exposed at home to TB, those children at highest risk of progressing to TB disease may benefit from more frequent follow-up.