bluuebunny/crossref_metadata_2025_split huggingface dataset:
IMMU-46. ARTIFICIAL INTELLIGENCE-DIRECTED, GENE THERAPY-BASED TRANSDIFFERENTIATION OF GLIOBLASTOMA TO FUNCTIONAL DENDRITIC CELLS AS NOVEL CANCER IMMUNOTHERAPY
Authors: Jin Dan , Le Son , Sebastian Mathew , Chen Dongjiang , Jin Linchun , Tran David 
Published: November 2021

Abstract

BACKGROUND
Despite recent advances in tumor immunotherapy in solid tumors, success in GBM remains elusive, likely due to its poor immunogenicity and CNS barriers limiting immune cell trafficking. Here we describe a novel approach of stimulating glioma-specific immunity by transdifferentiating GBM cells in situ to induced dendritic cells (iDCs).

METHODS
We applied NETZEN, an integrated deep-learning and gene network-based ranking computational platform and identified cell fate determinants (CFDs) to convert GBM cells to DCs. CFDs were delivered using a viral vector. Transdifferentiation was assessed by immunophenotyping and iDCs functionally validated by their ability to prime naive T cells.

RESULTS
A four CFDs subnetwork anchored by PU.1 was sufficient to transdifferentiate mouse GBM cells to CD45+MHCII+ cells with high co-stimulatory CD80 expression and to induce nearly 98% of GBM cells to express 100-fold higher levels of MHCI. Consistent with a new identity of antigen-presenting cells (APC), the induced immune cells are growth arrested, exhibit 3-fold higher phagocytic activity and upregulate the canonical antigen processing and presenting machineries by 10-40 folds, resulting in 40-fold greater efficiency at processing ovalbumin and presenting SIINFEKL on MHCI compared to native GBM cells. Importantly, SIINFEKL-loaded iAPCs are capable of activating naive OTII-CD4+ and OTI-CD8+ T cells, indicating that they are DC-like. In addition, iDCs efficiently present tumor cell-intrinsic antigens and elicit &gt;20-fold higher activation and cytotoxicity in tumor-specific T cells compared to native GBM cells. Lastly, intratumoral GBM-DC transdifferentiation in a syngeneic orthotopic GBM model produces a robust memory T cell response in deep cervical draining lymph nodes compared to control animals.

CONCLUSIONS
Our results comfirm that GBM-derived iDCs acquire functions similar to native DCs, and thus, lay the foundation for a novel therapeutic approach in which poorly immunogenic tumors like GBM may be forced to generate their own immunity from within through cell fate transdifferentiation.
IMMU-50. GLIOBLASTOMA MANIPULATES HEMATOPOIETIC STEM CELL DIFFERENTIATION OUTCOMES AND DRIVES ALTERED IMMUNE RECONSTITUTION
Authors: Dean Bayli DiVita , Wildes Tyler , Dean Joseph , Shin David , Francis Connor , Font Laura Falceto , Moore Ginger , Flores Catherine 
Published: November 2021

Abstract

INTRODUCTION
Bone marrow-derived hematopoietic stem and progenitor cells (HSPCs) give rise to the cellular components of the immune system. Unfortunately, immune reconstitution from HSPCs are negatively impacted by solid cancers, including high-grade gliomas. For example, an expansion of myeloid progenitor cells has been previously described across several cancers that originate outside the CNS. A similar expansion of MDSCs coupled with diminished T cell function has also been described in the peripheral blood of patients with newly-diagnosed GBM. Alterations in both lymphoid and myeloid compartments due to CNS malignancy led us to determine how intracranial gliomas impact HSPCs in both their capacity to reconstitute the immune compartment and in their cell fate determination. This is important to better understand the impact of gliomas on immunity and how we can leverage these findings to better develop cellular immunotherapeutics.

METHODS
HSPCs were isolated from bone marrow of C57BL/6 mice with orthotopic KR158B glioma, or age-matched naïve mice. Experiments were conducted to compare relative changes in: gene expression (RNA-sequencing), precursor frequencies, cell fate determination, and cellular function of cells derived from HSPCs of glioma-bearing mice.

RESULTS
RNA-sequencing revealed 700+ genes whose expression was significantly up- or downregulated in HSPCs from glioma-bearing mice, particularly those involved with stemness and metabolic activity. Importantly, HSPCs from glioma-bearing mice expressed upregulation of genes involved in myelopoiesis relative to naïve mice. This was coupled with an expansion of granulocyte macrophage precursors (GMPs), the progenitors to gMDSCs. Next, differentiation assays revealed that HSPCs from glioma-bearing mice had higher propensity of differentiating into MDSC under homeostatic conditions relative to controls both in vitro and in vivo. Furthermore, mice bearing intracranial gliomas possess an expansion of MDSCs which are more suppressive on T cell proliferation and hinders T cell-mediated tumor cell killing relative to MDSCs derived from naïve control mice.
INNV-22. FACTORS GUIDING THE INITIATION OF TUMOR TREATING FIELDS (TTFIELDS; 200 KHZ) THERAPY FOR GLIOBLASTOMA: SELF-REPORTED PATIENT AND ONCOLOGIST PERSPECTIVES
Authors: Frongillo Peggy , Gwyn P Gage , Wagenknecht Connie , Adams Nichelle Renae 
Published: November 2021

Abstract

BACKGROUND
The standard-of-care for newly-diagnosed glioblastoma (ndGBM) has been the standard Stupp protocol. In ndGBM, approved TTFields (200 KHz) concomitant with maintenance temozolomide significantly improved progression-free survival and overall survival. TTFields-therapy selectively disrupts cancer cell division, requiring array-application to the shaved-scalp to non-invasively deliver TTFields to tumor location and confer clinical benefit. This survey-study assessed factors impacting decision of oncologist/patient/caregiver to initiate TTFields-therapy.

METHODS
A clinical-market research group administered double-blinded, online-questionnaires (30-min) to oncologists/ndGBM-patients/caregivers. Survey questions, an amalgamate of closed-/open-ended questions, were designed to track awareness, perceptions, and acceptance of ndGBM treatments in a representative United States (US) oncologist and adult patient/caregiver population (semi-annually; 2018-2020). The present survey-analysis focuses on results related to initiation of TTFields-therapy for ndGBM.

RESULTS
Four separate patient/caregiver surveys (Q1/2018-Q3/2020; (n=50-51/wave) and 4 separate oncologist surveys (Q2/2019-Q4/2020; n=130/wave) were conducted. Results suggest majority of patients with ndGBM research treatment options, including TTFields-therapy, immediately after surgery and before radiation/initial temozolomide; and initiate TTFields-therapy after radiation/initial temozolomide (ie, before maintenance temozolomide). Patients-reported initially learning about TTFields post-surgery via oncologists, nurses, support groups, social-media, and TTFields web-based resources. Among 97% of current/previous TTFields-users, the key patient-driver for selecting TTFields, mirroring oncologist-driver to recommend, was efficacy/survival benefit. Other highly-rated selection-drivers were anti-mitotic mechanism (93%), improved long-term 5-year survival (87%), sustained quality-of-life (87%), and no travel requirement to start (87%). In latest study wave, reported patient usage-barrier was the inability to subsequently enroll in clinical trials (64%), while the top-reported oncologist prescribing-barrier was concern with patient treatment usage (60%). Also, survey suggests oncologists discuss TTFields with most patients with ndGBM, citing efficacy and National Comprehensive Cancer Network® inclusion as key treatment-initiation drivers.

CONCLUSIONS
Overall, survey data suggests awareness (100%, aided; 61%-68%, unaided) by US oncologists/patients/caregivers of TTFields (200 kHz) as a viable treatment option for adults with ndGBM.
PATH-16. EVALUATION OF SEX-BASED DIFFERENCES IN CLINICAL OUTCOMES AND TUMOR GENOMICS IN PATIENTS WITH NEWLY DIAGNOSED IDH-WILDTYPE GLIOBLASTOMA RECEIVING CHEMORADIATION
Authors: Shi Diana , Lim-Fat Mary Jane , Nassar Amin , Woods Jared , Youssef Gilbert , Pisano William , Whorral Sydney , Allen Marie , Cagney Daniel , Tanguturi Shyam , Haas-Kogan Daphne , Aizer Ayal , McFaline-Figueroa J Ricardo , Chukwueke Ugonma , Lee Eudocia Quant , Reardon David , Nayak Lakshmi , Bi Wenya Linda , Beroukhim Rameen , Ligon Keith , Alexander Brian , Wen Patrick , Rahman Rifaquat 
Published: November 2021

Abstract

BACKGROUND
We evaluated sex-based differences in clinical outcomes and tumor genomics in patients with newly-diagnosed GBM.

METHODS
We reviewed 665 IDH-wild type GBM patients with Karnofsky Performance Status (KPS) ≥60 treated at our institution from 2010-2019 including; 585 patients with targeted exome sequencing of 447 cancer associated genes (OncoPanel). Deleterious mutations were defined as homozygous deletions or loss of function mutations of known tumor suppressors (as reported in TCGA, ≥ 3 times in the COSMIC database, or predicted as “damaging” in SIFT and/or “probably damaging” in Polyphen 2) or known oncogenic mutations in proto-oncogenes (reported in TCGA or ≥ 3 times in COSMIC).

RESULTS
There were 384 (57.7%) males and 281 (42.3%) females. Median OS was 22.5 months for females and 19.3 months for males (hazard ratio [HR] 0.81, 95% CI 1.03-1.48, p = 0.02). On multivariable analysis adjusted for age, KPS ≥90, extent of resection, and MGMT methylation status, female sex (adjusted hazard ratio 0.78, 95% CI [0.64-0.95], p = 0.015) was associated with improved OS. Superior OS in females was observed in MGMT-unmethylated patients (HR 0.69, 95% CI [0.54-0.90], p = 0.005) but not MGMT-methylated patients. Thirteen genes were deleteriously altered in ≥5% of our cohort: CDK4 (12.1% male vs. 7.8% female), CDKN2A (46.5% vs. 45.7%), CDKN2B (41.8% vs. 43.3%), EGFR (34.7% vs. 40.0%, MTAP (18.2% vs. 18.8%), NF1 (11.5% vs. 9.4%), PTEN (28.2% vs. 29.8%), TP53 (28.2% vs. 30.2%), RB1 (5.6% vs. 6.5%), MDM4 (6.2% vs. 5.7%), ATM (5.9% vs. 3.7%), MDM2 (7.4% vs. 4.1%), PIK3R1 (6.2% vs. 4.1%). There were no differences in frequency of mutations in these individual genes between males and females (χ 2 [1, N=585] = 0.05-2.86, p = 0.09-0.86).

CONCLUSIONS
Female sex is associated with improved survival. We did not identify sex-based differences in deleterious genomic alterations amongst commonly altered genes in GBM.
PATH-23. OLIGOSARCOMA, IDH-MUTANT IS A DISTINCT AGGRESSIVE TYPE
Authors: Suwala Abigail K , Felix Marius , Friedel Dennis , Stichel Damian , Schrimpf Daniel , Hewer Ekkehard , Schweizer Leonille , Dohmen Hildegard , Pohl Ute , Erny Daniel , Koelsche Christian , Turner Clinton , Özduman Koray , Prinz Marco , Acker Till , Herold-Mende Christel , Wick Wolfgang , Capper David , Wesseling Pieter , Sahm Felix , von Deimling Andreas , Hartmann Christian , Reuss David 
Published: November 2021

Abstract
Oligodendrogliomas are defined by IDH-mutations and the co-deletion of chromosomal arms 1p and 19q. In the past, case reports and small series described gliomas with sarcomatous features arising from oligodendrogliomas, so called oligosarcomas. Here, we report a group of 23 IDH-mutant oligosarcomas that form a distinct methylation group. The tumors were recurrences from prior oligodendrogliomas or developed de novo. Precursor tumors of 11 oligosarcomas were histologically and molecularly indistinguishable from conventional oligodendrogliomas. Tumor cells were embedded in a reticulin fibers network in all oligosarcomas, frequently showing p53 accumulation, positivity for SMA, and regain of H3K27me3 as compared to primary lesions. In 5 oligosarcomas no 1p/19q co-deletion was detectable, even though it was present in the primary lesions. Oligosarcomas harbored an increased chromosomal copy number variation load with frequent CDKN2A/B deletions. Proteomic profiling demonstrated oligosarcomas to be highly distinct from conventional grade 3 oligodendrogliomas with consistent evidence for smooth muscle differentiation. Expression of several tumor suppressors including NF1 and STAG2 was lost whereas oncogenic YAP1 was aberrantly overexpressed in oligosarcomas. Panel sequencing revealed mutations in TP53 and NF1 along with IDH1/2 and TERT promoter mutations. Survival of patients was significantly poorer for oligosarcomas as for grade 3 oligodendrogliomas but comparable to grade 4 IDH-mutant astrocytomas. These results establish oligosarcoma as a distinct type of IDH-mutant glioma differing from conventional oligodendrogliomas on the histologic, epigenetic, proteomic, molecular and clinical level. Diagnosis can be based on the characteristic DNA methylation profile or the combined evidence of sarcomatous histology, IDH-mutation and TERT promoter mutation with or without 1p/19q co-deletion.
PATH-26. EVALUATING THE DISTRIBUTION AND PROGNOSIS OF IMMUNE CELL SIGNATURES OF THE TUMOR MICRO-ENVIRONMENT IN DIFFUSE GLIOMAS
Authors: Mehani Bharati , Asanigari Saleembhasha , Chung Hye-Jung , Aldape Kenneth 
Published: November 2021

Abstract
The tumor micro-environment (TME) plays an important role in the biology of cancer, including gliomas. Single cell studies have highlighted the role of specific TME components in gliomas, and the methods to deconvolve bulk profiling data may serve to complement these studies on clinically annotated tumors. In this study, we estimated cell type proportions in 3 large glioma datasets (TCGA, CGGA-325, CGGA-693) using CIBERSORTx. Using a signature matrix comprising 22 immune cell types, we identified IDH mutation status-specific immune cell distributions and found that the proportions of 10 cell types were significantly different between IDHmut and IDHwt tumors across the 3 datasets. Looking further within IDHmut tumors, we found that monocytes were enriched in 1p/19q non-co-deleted tumors across the 3 glioma datasets, consistent with prior single cell studies. We then examined estimated gene expression among immune cell types relative to IDH mutation status and found clear separation of gene expression in 15 of 22 cell types in all 3 datasets. When we applied these 22 gene expression signatures in each tumor sample onto cluster-of-cluster analyses to identify tumor groups with distinct immune signature patterns, we found that samples were distributed largely according to the IDH status in all 3 datasets, confirming that immune cell expression is distinct based on IDH status. Among IDH-specific groups, cluster-of-cluster analyses showed that immune cell-based cluster groups had distinct survival outcomes, and that IDHwt samples were distributed significantly based on tumor grades as well as based on EGFR overexpression. Among IDHmut tumors, the distributions of tumor grade and 1p/19q co-deletion status were significantly different in the immune-based clusters in 2 of the 3 datasets examined. Overall, these results highlight the biological and clinical significance of the immune cell environment in gliomas, including distinctions based on IDH mutation status as well as prognosis within IDH-specific groups.
PATH-28. RE-DEFINING CLONALITY OF THE TERT PROMOTER MUTATION WITH DEEP SEQUENCING AND MAXIMAL SAMPLING OF NEWLY DIAGNOSED AND RECURRENT GBM AND OLIGODENDROGLIOMA
Authors: Appin Christina , Suwala Abigail K , Hilz Stephanie , Mathur Radhika , Smirnov Ivan , Hong Chibo , Stevers Nicholas , Shai Anny , Berger Mitchel , Chang Susan , Phillips Joanna , Costello Joseph 
Published: November 2021

Abstract
TERT promoter mutation (TPM), found in over 80% of IDH-wildtype glioblastomas (GBMs) and oligodendrogliomas, leads to reactivation of telomerase and consequently tumor cell immortalization, which is potentially reversible. TERT could therefore serve as an effective target in treating tumors with TPM, if TPM is present throughout the tumor. Previous studies using a single sample or minimal sampling per tumor have shown potentially conflicting results, suggesting TPM is clonal in some cases and subclonal in others. Here we use spatially mapped tumor samples representing maximal tumor sampling to address this critical issue. Sanger sequencing was performed on 311 newly diagnosed and recurrent tumor samples from 19 IDH-wildtype GBMs and 10 oligodendrogliomas. To validate Sanger sequencing and resolve potentially ambiguous samples, deep amplicon sequencing was performed on 164 samples. To determine tumor purity and TERT expression levels, whole exome sequencing (164 samples) and RNA-Seq (129 samples) data sets were analyzed computationally. Sanger and amplicon sequencing showed that TPM was present in 305 of 311 samples (98.1%). TPM was not detected in 6 samples which had tumor purity estimates too low to be accurately determined by FACETS and lacked evidence of any driver mutation. Variant allele frequencies (VAFs) of TPM showed high positive correlation with those of clonal alterations in GBMs (r(90) = .93, p &lt; .0001) and oligodendrogliomas (r(48) = .96, p &lt; .0001). TPM VAFs also showed high positive correlation with tumor purity in both GBMs (r(112) = .92, p &lt; .0001) and oligodendrogliomas (r(48) = .89, p &lt; .0001). TPM VAF showed a moderate positive correlation with TERT expression in GBMs (r(78) = .40, p &lt; .001) and oligodendrogliomas (r(47) = .49, p &lt; .001). Therefore, TPM is a tumor-wide, clonal mutation in both newly diagnosed and recurrent GBMs and oligodendrogliomas. TPM VAF is moderately correlated with TERT expression.
PATH-29. GLIOBLASTOMA TUMOR CLASSIFICATION BASED ON SPATIAL ANALYSIS OF ONCOGENIC AMPLIFICATIONS AND PROTEIN EXPRESSION
Authors: Walentynowicz Kacper , Engelhardt Dalit , Yadav Shreya , Onubogu Ugoma , Salatino Roberto , Vincentelli Cristina , McDonald Thomas , Michor Franziska , Janiszewska Michalina 
Published: November 2021

Abstract
Heterogeneity of glioblastoma (GBM) has been extensively studied in recent years with identification of oncogenic drivers of GBM cellular subtypes. However, little is known about how these cells interact with each other or with the surrounding tumor microenvironment (TME). We employed spatial protein profiling targeting immune and neuronal markers (79 proteins) coupled with single-cell spatial maps of fluorescence in situ hybridization (FISH) for EGFR, CDK4, and PDGFRA on human GBM tissue sections. Several cores from 20 GBM samples were collected to create a tissue microarray, and 96 regions of interests were profiled with 37,844 nuclei for oncogenic amplification screen. Spatial protein profiling identified strong correlation of certain immune markers, TAU-associated proteins, and oligodendrocyte-enriched protein groups and overall high intratumor heterogeneity of TME. Our single-cell quantification of FISH signals showed differences among tumors based on the prevalence of dual amplification of EGFR and CDK4 within a cell relative to single oncogene amplified cells. High relative frequency of dual amplification was associated with increased expression of immune-related markers and decreased expression of EGFR protein. Moreover, this protein expression signature was associated with survival in another GBM dataset. Here, we present spatial genetic analysis at the single cell level coupled with protein expression profiles associated with tumor microenvironment. Our results suggest that assessment of genetic heterogeneity in GBM could potentially drive improved patient stratification and treatment.
NIMG-03. TUMOR HABITAT ANALYSIS BY MAGNETIC RESONANCE IMAGING DISTINGUISHES TUMOR PROGRESSION FROM RADIATION NECROSIS IN BRAIN METASTASES AFTER STEREOTACTIC RADIOSURGERY
Authors: Lee Da Hyun , Park Ji Eun , Kim Ho Sung 
Published: November 2021

Abstract

OBJECTIVES
Identification of viable tumor after stereotactic radiosurgery (SRS) is important for future targeted therapy. This study aimed to determine whether tumor habitat on structural and physiologic MRI can distinguish viable tumor from radiation necrosis of brain metastases after SRS.

METHOD
Multiparametric contrast-enhanced T1-and T2-weighted imaging, apparent diffusion coefficient (ADC), and cerebral blood volume (CBV) were obtained from 52 patients with 69 metastases, showing enlarging enhancing masses after SRS. Voxel-wise clustering identified three structural MRI habitats (enhancing, solid low-enhancing, and nonviable) and three physiologic MRI habitats (hypervascular cellular, hypovascular cellular, and nonviable). Habitat-based predictors for viable tumor or radiation necrosis were identified by logistic regression. Performance was validated using the area under the curve (AUC) of the receiver-operating-characteristics curve in an independent dataset with 24 patients.

RESULTS
None of the physiologic MRI habitats were indicative of viable tumor. Viable tumor was predicted by a high-volume fraction of solid low-enhancing habitat (low T2-weighted and low CE-T1-weighted values; odds ratio [OR] 1.74, P&lt; .001) and a low-volume fraction of nonviable tissue habitat (high T2-weighted and low CE-T1-weighted values; OR, 0.55, P&lt; .001). Combined structural MRI habitats yielded good discriminatory ability in both development (AUC 0.85, 95% confidence interval [CI]: 0.77–0.94) and validation sets (AUC 0.86, 95% CI:0.70–0.99), outperforming single ADC (AUC 0.64) and CBV (AUC 0.58) values. The site of progression matched with the solid low-enhancing habitat (72%, 8/11).

CONCLUSION
Solid low-enhancing and nonviable tissue habitats on structural MRI can help to localize viable tumor in patients with brain metastases after SRS.
NIMG-15. 2-HYDROXYGLUTARATE MAGNETIC RESONANCE SPECTROSCOPY IN ADULT BRAINSTEM GLIOMA PATIENTS
Authors: Nagashima Hiroaki , Tanaka Kazuhiro , Fujita Yuichi , Hashiguchi Mitsuru , Maeyama Mashahiro , Somiya Yuichiro , Hirose Takanori , Itoh Tomoo , Sasayama Takashi 
Published: November 2021

Abstract

OBJECTIVE
The onco-metabolite, 2-Hydroxyglutarate (2HG), is non-invasive biomarker for detecting isocitrate dehydrogenase (IDH) mutant glioma by MR-Spectroscopy. Especially 2HG-MRS may be useful in patients with brainstem lesions, where surgical biopsy presents high risk of neurological injury. Here, we examined the utility of 2HG-MRS for diagnosis of IDH mutant adult brainstem glioma.

METHODS
We conducted 3 tesla -MRS (3T-MRS) in 8 radiographically identified brainstem tumor (7 male and 1 female, median age 39). Single-voxel was localized from the T2-FLAIR using a 2HG-tailored MRS protocol (Philips, Achieva, PRESS, TE 35 ms). All patients underwent tumor biopsy using an intraoperative navigation system (Brain LABTM) or stereotactic biopsy system (Komai’s CT-stereotactic frame) before initial treatment. IDH and H3K27M status were diagnosed by IHC and DNA sequence.

RESULTS
3 cases were H3K27M and 4 cases were IDH mutant (R132H 1 case, R132S 2 cases, and R132G 1 case). 1 case were neither H3K27M nor IDH mutant. H3-K27 and IDH1 mutations were mutually exclusive. All tumor located at pons. There were no significant radiological difference between H3K27M and IDH mutant in conventional MRI sequence. Pearson's chi-square test demonstrated that 2HG concentrations &gt;1.5 mM were 100% sensitive and 75% specific for IDH mutant glioma (p = 0.0285). The median overall survival survival were 127 month in IDH mutant glioma (n=4) and 22.5 months in IDH wild-type glioma (n=4), respectively.

CONCLUSIONS
2HG in adult brainstem glioma was detected by conventional 3T-MRS successfully. A noninvasive 2HG-MRS may be useful diagnostic modality for evaluating molecular status and prognosis in brainstem glioma noninvasively.