bluuebunny/crossref_metadata_2025 huggingface dataset:
IMMU-19. IDENTIFICATION OF TARGET ANTIGENS FOR CHIMERIC ANTIGEN RECEPTOR T- CELL THERAPY AGAINST GLIOBLASTOMA USING A MONOCLONAL ANTIBODY LIBRARY RAISED AGAINST PATIENT-DERIVED TUMOR SPHERES
Authors: Kijima Noriyuki , Nakagawa Tomoyoshi , Hasegawa Kana , Ikeda Shunya , Yaga Moto , Wibowo Tansri , Kuroda Hideki , Hirayama Ryuichi , Okita Yoshiko , Tachi Tetsuro , Kagawa Naoki , Kanemura Yonehiro , Hosen Naoki , Kishima Haruhiko
Published: November 2022

New therapies for GBM are urgently needed due to its poor prognosis and chimeric antigen receptor T (CAR-T) cell therapy is thought to be a promising strategy. To develop CAR-T cell therapy, cell surface targets that is highly specific for GBM cells are needed.Although extensive transcriptome analyses of GBM cells were performed, few transcripts highly specific for GBM cells have been identified. However, GBM cell-specific antigen epitopes formed by post-translational modifications of proteins may have been missed, and could still be discovered by thoroughly searching for cancer-specific monoclonal antibodies and characterizing the antigens they recognize. In this study, we applied this strategy to search for GBM-specific cell surface targets using patient derived tumor spheres. We identified two monoclonal antibodies E61 and A13 as those reacting with GBM cells but not with normal brain parenchymal cells. CAR-T cells derived from both monoclonal antibodies produced IL-2 and IFNɤ and exerted cytotoxicity to GBM cells by chromium 51 release assay. In addition, we identified B7-H3, which is frequently used for a CAR-T cell target against GBM, as the antigen recognized by B7-H3 by the expression cloning method. These results indicate that the strategy shown in this study is useful for identifying antigens that are expressed on patient-derived GBM cells and potentially useful as targets for CAR T cells.
IMMU-22. REPROGRAMMING OF MICROGLIA/MACROPHAGES IN GLIOBLASTOMA IMPROVES ANTI-TUMOR T CELL RESPONSES
Authors: Fermi Valentina , Warta Rolf , Rapp Carmen , Trong Philip Dao , Jungwirth Gerhard , Andreas Unterberg , Herold-Mende Christel
Published: November 2022

Glioma-infiltrating myeloid cells such microglia and macrophages (GAM) are a major component of the immunosuppressive tumor microenvironment in glioblastoma (GBM). Especially their anti-inflammatory M2-like activation state might counteract efficacy of immunotherapeutic interventions by impairing effector T cell infiltration and function. Therefore, we studied the ability of the small molecule inhibitors (SMI) PLX3397, BLZ945, and GW2580 that target the M2-associated colony stimulating factor-1 receptor (CSF1R) to shape GAM phenotype towards a pro-inflammatory M1-like phenotype and how this affects the T cell compartment.Upon treatment of freshly isolated CD11b-sorted GBM patient-derived GAMs (n = 15) a decreased expression of CD163 (M2-like) and an increased expression of HLA-DR (M1-like) as well as an increased nitrite production as an indirect measure for iNOS activation (M1-like) was observed which was most pronounced for BLZ945, and GW2580. Transcriptome analysis of treated vs. untreated GAMs supported a reprogramming towards a pro-inflammatory phenotype. In addition, treatment of GAMs in a GBM patient-derived tumor organoid model confirmed a substantial decrease of CD163+ M2-polarized GAM together with a reduced number of proliferating tumor cells. Finally, treatment of patient-derived GAMs led to an increased T cell transmigration through a dense barrier of autologous tumor-derived endothelial cells and increased the ability of T cells to kill autologous tumor cells. Our results support CSF1R blockade is able to reduce the immunosuppressive and pro-tumorigenic functions of GAM substantially and thereby could enhance the effectiveness of T cell-based immunotherapy.
IMMU-24. TESTOSTERONE FUNCTIONS AS A TUMOR SUPPRESSOR IN GLIOBLASTOMA
Authors: Lee Juyeun , Silver Daniel , Chung Yoon-Mi , Sharifi Nima , Lathia Justin
Published: November 2022

A sex difference in the incidence and outcome of patients with glioblastoma (GBM), the most common primary malignant brain tumor, has been well established, as male patients experience a worse prognosis. However, the contribution of sex hormones to anti-tumor immunity has not been fully explored. To test this, we orthotopically implanted syngeneic mouse GBM cells into male mice after castration or sham surgery to assess survival differences. Castrated immune-competent mice succumbed to tumors significantly faster than the sham surgery group, and this was rescued by exogenous testosterone administration. This finding was further corroborated by that blockade of androgen signaling using enzalutamide reproduced the effect of castration with shortened survival. In contrast, castration on immunocompromised mice, NSG and RAG1KO, resulted in no survival difference compared to sham animals, suggesting a role for immune system. Flow cytometry analysis of tumor-infiltrating immune cells revealed decreased cytokine production in T and NK cells from castrated mice, while no difference was found in immune cell infiltration. Flank tumor experiments suggested brain-specific regulation of T cell recruitment, as tumor growth was delayed in castrated mice with increased infiltration of CD8+ T cell. It is noted that decreased cytokine production in T cells and NK cells was observed in tumor as well as lymph nodes from flank tumor model. Surprisingly, mass spectrometry of serum revealed upregulated levels of circulating corticosterone in castrated mice regardless of tumor presence, suggesting that castration may induce systemic immunosuppression and regulate T cell infiltration to brain via upregulation of glucocorticoids. Taken together, our data demonstrate that testosterone regulates T cell immunity, possibly via glucocorticoids, and ultimately affects GBM tumor growth. Given the decreased level of testosterone in aged males with higher risk of GBM, these findings further suggest the potential therapeutic intervention of testosterone in GBM.
IMMU-28. THE INTRA-TUMORAL SPATIAL HETEROGENEITY OF T CELL ANTIGENS IN GLIOBLASTOMA: AN INTEGRATED MULTI-OMICS APPROACH
Authors: Medici Gioele , Wacker Marcel , Dubbelaar Marissa , Schwitalla Carolin , Hanssen Friederike , Schulz Daniel , Vasella Flavio , Rushing Elisabeth , Bauer Jens , Bodenmiller Bernd , Rammensee Hans-Georg , Regli Luca , Walz Juliane , Weller Michael , Neidert Marian
Published: November 2022

This study investigates the intratumoral heterogeneity of T cell antigen presentation in 15 newly diagnosed glioblastoma patients. Our multi-omics approach includes mass spectrometry-based immunopeptidome analysis, next-generation sequencing (whole-exome and RNA sequencing), and imaging mass cytometry performed on biopsies deriving from the necrotic core (NEC), the gadolinium contrast-enhancing region (T1), and the peritumoral infiltrating zone (INF, 5-ALA positive). A total of 24493 unique HLA class I and 17394 unique HLA class II peptides were identified. Comparative profiling of peptides from our study and a benign tissue database (in-house; n = 429 donors combined with HLA ligand atlas (https://hla-ligand-atlas.org)) revealed that 20% of HLA class I ligands are glioblastoma exclusive. Of these ligands, 21%, 21%, and 15% were exclusively presented in the INF, T1, or NEC zone, respectively. Here, we focused on the INF-specific antigens as this zone is likely to remain after tumor resection and gives rise to glioblastoma recurrence. Interestingly, two INF-specific HLA ligands showed a frequency presentation of 45% in our patient cohort. One ligand originated from BAALC (Brain and acute leukemia cytoplasmic protein) and one from NCAN (Neurocan core protein), which are both known to be glioblastoma-associated proteins. Immunogenicity of pre-selected candidate antigens was assessed with autologous expanded T cells and revealed a set of novel promising targets for immunotherapy. Integrated RNA/DNA sequencing also enabled the identification of neoepitopes deriving from tumor- and region-specific mutations. Furthermore, imaging mass cytometry contributed to investigating the immune compartment of the tumor microenvironment in high dimensionality and spatial resolution. In conclusion, our approach characterized the intra-tumoral regional heterogeneity of both infiltrating immune cells and tumor antigens. This multi-omics spatial atlas of the immune landscape can be used for the informed design of immunotherapy strategies against glioblastoma.
IMMU-31. PROTEASOME REARRANGED PEPTIDES ARE A NOVEL SOURCE OF ANTIGENS FOR THE PEPTIDE VACCINE IMMUNOTHERAPY OF GLIOBLASTOMAS
Authors: Fidanza Mario , Gupta Puja , Shanker Varun , Wong Nicollette , Skirboll Stephen , Lim Michael , Wong Albert
Published: November 2022

pepVIII, an anticancer vaccine targeting EGFRvIII, has been tested in several trials for glioblastoma including ACT IV. a randomized Phase III trial for newly diagnosed patients. While results from ACT IV were equivocal, available data suggests the elimination of EGFRvIII was not robust. Despite its essential role in antigen presentation, enhancing proteasomal processing is an unexploited strategy for improving vaccines. We examined 20 peptides in silico and experimentally, which showed that a tyrosine substitution (Y6-pepVIII) maximizes proteasome cleavage and survival in a subcutaneous tumor model. In an intracranial glioma model, Y6-pepVIII showed a 62 and 31% improvement in median survival compared to control animals and pepVIII-vaccinated mice. Y6-pepVIII vaccination altered tumor-infiltrating lymphocyte subsets and expression of PD-1 on intratumoral T cells. Combination with anti–PD-1 therapy cured 45% of the Y6-pepVIII–vaccinated mice but was ineffective for pepVIII-treated mice. LC-MS/MS analysis of proteasome-digested pepVIII and Y6-pepVIII revealed that most fragments were similar but more abundant inY6-pepVIII digests and 77% resulted from proteasome-catalyzed peptide splicing (PCPS). We identified 10 peptides that bound human and murine MHC class I. Nine were PCPS products and only one peptide was colinear with EGFRvIII, indicating that PCPS fragments may be a component of MHC class I recognition. Despite not being colinear with EGFRvIII, two of three PCPS products tested were capable of increasing survival when administered independently as vaccines. We hypothesize that the immune response to a vaccine represents the collective contribution from multiple PCPS and linear products. Our work suggests a strategy to increase proteasomal processing of a vaccine that results in an augmented immune response and enhanced survival in mice.
IMMU-35. TREM2 RESTRAINS ANTI-TUMOR CELL ACTIVITY OF MYELOID CELLS IN GLIOBLASTOMA
Authors: Sun Rui , Khan Saad , Luo Jingqin , McCornack Colin , Chen Yun , Jiang Haowu , Mao Diane D , Yang Alicia , Liu Qin , Petti Allegra , Holtzman David , Kim Albert
Published: November 2022

Tumor-associated myeloid cell populations occupy a major part of the glioblastoma (GBM) tumor microenvironment (TME). The prevailing view is that myeloid cells in the TME are immunosuppressive and promote GBM tumor progression. However, myeloid cells have the functional plasticity to either restrict or support tumor cell growth. TREM2 has been shown to alter the myeloid cell landscape in cancers arising in the body and plays important roles in brain microglial function in neurodegenerative diseases. But the role of TREM2 in the GBM TME and specifically in myeloid cell function has not been examined. Here we found that TREM2 is highly expressed in myeloid subsets, including macrophages and microglia in human and mouse GBM tumors, and that high TREM2 expression is associated with poor prognosis in GBM patients. TREM2 loss of function in human macrophages and mouse myeloid cells increased tumoricidal capacity in vitro using patient-derived glioblastoma stem cells and mouse glioblastoma cells. Accordingly, we found TREM2 in myeloid cells restricts proinflammatory polarization in both LPS-induced innate and IFNγ-induced adaptive immunity in vitro, mainly through the inhibition of NFκB and MAPK p38 signaling pathways. Orthotopic injection of mouse glioblastoma cells into TREM2 knockout mice increased animal survival compared to littermate wildtype mice. In addition, co-implantation of TREM2 knockdown macrophages or microglia with mouse glioblastoma cells in brains of immunocompetent mice increased animal survival compared to co-implantation of control myeloid cells or injection of tumor cells alone, suggesting an important role for TREM2 in myeloid cells in GBM growth in vivo. Together, these data indicate that TREM2 operates by restricting the anti-tumor and proinflammatory function of myeloid cells in GBM and that inhibition of the TREM2 pathway may represent a potential therapeutic strategy for these patients.
IMMU-36. EVALUATION OF TUMOR DERIVED SERPINA3N IN EXPERIMENTAL GLIOBLASTOMA
Authors: Wolf Delaney , Ayasoufi Katayoun , Zheng Jiaying , Tritz Zachariah , Jin Fang , Hansen Michael , Johnson Aaron
Published: November 2022

Glioblastoma (GBM) is an incurable brain cancer which is associated with severe peripheral immune suppression. Using experimental GBM, we recently determined that peripheral immunosuppression involves thymic atrophy, stunted T cell proliferation, and release of circulating factors that inhibit immune responses. RNA sequencing and proteomic studies have determined that transcripts and protein levels of Serpina3n are upregulated in the brain and serum of GBM patients and correlates with poor prognosis. We determined Serpina3n is a highly upregulated gene in the brain and the thymus of glioma-bearing mice using RNA sequencing technologies. Proteomic analysis of serum from glioma-bearing mice identified an upregulation of pathways associated with the extracellular expression of Serpina3n. We therefore sought to determine the role of Serpina3n in peripheral immunosuppression in GL261 glioma harboring wild type and Serpina3n knockout mice. Glioma implantation in Serpina3n knockout mice resulted in similar survival and peripheral immunosuppression compared to controls. Western blotting experiments confirmed that Serpina3n is expressed and secreted by GL261 gliomas isolated from WT and Serpina3n knockout mouse brains. Together this data suggests that tumor-derived, but not host derived, Serpina3n needs to be evaluated as a putative factor associated with peripheral immunosuppression.
INNV-02. MULTIFOCAL, DURABLE AND PATHOLOGICALLY-CONFIRMED BRAIN METASTASIS COMPLETE RESPONSE TO TRASTUZUMAB DERUXTECAN
Authors: Tosi Umberto , Moss Nelson , Santomasso Bianca , Beal Kathryn , Modi Shanu
Published: November 2022

Antibody-based conjugates (ADCs) have transformed the treatment of Her2+ breast and other cancers. Unfortunately, the CNS remains a sanctuary site for many such patients in part due to differential activity of macromolecules across the blood-brain and blood-brain tumor barriers. Trastuzumab deruxtecan (T-DXd), a high-payload ADC, was recently found to improve the progression-free survival of Her2+ breast cancer patients compared with prior-generation trastuzumab emtansine, prompting us to evaluate this agent in a woman with CNS-only metastatic disease. T-DXd achieved complete response despite heavy pretreatment. Three persistent (and previously-irradiated) lesions were subsequently biopsy-proven to represent treatment effect. Response was durable through 7 months of treatment, with subsequent recurrence in the setting of treatment holiday; partial response was observed with drug rechallenge. Drug discontinuation was ultimately required due to concern for pulmonary toxicity. Our case suggests T-DXd is active in Her2+ breast cancer brain metastases and supports further prospective evaluation in randomized clinical trials.
INNV-05. CO-OCCURRENCES OF A HIGH-GRADE GLIOMA WITH CAVERNOUS MALFORMATIONS AND PATHOGENIC VARIANTS IN PDCD10 AND SMARCA4
Authors: Damodharan Sudarshawn , Glanz Hannah , Smith-Simmer Kelcy , Helgager Jeffrey , Puccetti Diane
Published: November 2022

INTRODUCTION

The co-occurrence of multiple disease processes can make for more challenging diagnoses. Here we report an unusual case of a patient found to have an IDH1-mutant high-grade glioma along with multiple cerebral cavernous malformations and pathogenic germline variants in PDCD10 and SMARCA4. Case Description: A 17-year-old female presented with left arm paresthesia and weakness along with persistent headaches within the frontal and occipital regions that progressed in intensity to include nausea and emesis. A fast sequence magnetic resonance imaging (MRI) of her head was obtained that revealed the presence of multiple bilateral cystic lesions suspicious for cavernomas with the most notable lesion in the right parietal lobe. Ophthalmology consultation revealed grade III papilledema bilaterally. A full brain MRI with and without contrast was obtained and demonstrated a right anterior parietal lobe lesion with associated mass effect, as well as multiple bilateral supratentorial and left cerebellar cavernous malformations. The patient underwent tumor debulking of her dominant lesion. Pathology revealed an IDH1 mutant diffuse astrocytoma, WHO grade 3. Germline genetic testing was pursued which revealed a PDCD10 pathogenic variant consistent with familial cerebral cavernous malformation syndrome and a likely pathogenic variant in SMARCA4. Treatment of her high-grade-glioma included radiation therapy followed by maintenance oral temozolomide.

DISCUSSION

This case illustrates the unusual co-occurrences of a high-grade glioma with familial cavernous malformation syndrome and germline pathogenic variants in PDCD10 and SMARCA4. Our patient continues to do well clinically, but because of her now significant risk of developing ovarian cancer she has elected to undergo a prophylactic bilateral salpingo-oophorectomy. Recognition of abnormal genetic results is critical in the setting of multiple disease processes and can play a crucial role in the on-going care for a patient.
INNV-09. IMPACT OF MOLECULAR MARKERS ON TREATMENT OUTCOME OF GLIOBLASTOMA PATIENTS TREATED WITH CONCURRENT TUMOR-TREATING FIELDS (TTF) AND CHEMORADIATION: SECONDARY ANALYSIS OF SPARE TRIAL
Authors: Cappelli Louis , Kayne Allison , Poiset Spencer , Niazi Muneeb , Ali Ayesha , Alnahhas Iyad , Shi Wenyin
Published: November 2022

OBJECTIVES

SPARE trial (Scalp-sparing radiation with concurrent temozolomide and tumor treating fields; NCT03477110) is a single-arm pilot study that evaluated the safety and feasibility of concurrent TTF with chemoradiation for adult patients with newly diagnosed GBM. The current study is a secondary analysis evaluating the impact of molecular markers (PTEN, TP53, EGFR, and TERT) on overall survival (OS) and progression-free survival (PFS) of the patients in the trial.

METHODS

Molecular markers of histologically-confirmed, IDH-wildtype GBM patients age ≥ 18 years old with a KPS ≥ 60 who received concurrent chemoradiation and TTF followed by maintenance TMZ + TTF were evaluated. Molecular profile was evaluated with next-generation sequencing. Impact of mutations in PTEN, TP53, EGFR, and TERT on OS and PFS was evaluated using a multivariable backward model.

RESULTS

A total of 30 patients were enrolled in the SPARE trial, and 1 patient with IDH-mutant was excluded from the current analysis. All patients underwent concurrent TTF and chemoradiation. The median age is 58 and KPS was 90. 9 patients had methylated MGMT promotor. 14 patients were found to have PTEN mutation, 9 patients with EGFR, 7 with TP53 mutation, and 23 patients with TERT mutated. MGMT methylation remained statistically significant for an increased OS (p=0.032; HR 7.18). TERT mutation had a statistically significant improvement in PFS (P=0.003) and OS (p=0.012). However, neither EGFR, TP53, nor PTEN showed any association of PFS or OS for patients who received concurrent TTF and CRT.

CONCLUSIONS

In this secondary analysis, patients with MGMT methylation showed better PFS and OS as expected. Neither EGRF, TP53, or PTEN mutation showed any association with PFS or OS. Patients with TERT mutant showed improved OS of patients treated with concurrent TTF with chemoradiation. A TERT mutation may be a new molecular biomarker in the described treatment approach.
INNV-12. REPRODUCIBLE REDUCTIONS OF CONTRAST-ENHANCED TUMOR VOLUMES IN TWO END-STAGE RECURRENT GLIOBLASTOMA PATIENTS WITH IN-HOME ONCOMAGNETIC MONOTHERAPY
Authors: Helekar Santosh , Baskin David
Published: November 2022

A spinning oscillating magnetic field-generating device called the Oncomagnetic device selectively kills glioblastoma (GBM) cells. It produced > 30% shrinkage of a recurrent GBM tumor in an end-stage patient after < 5 weeks of Oncomagnetic treatment (OMT). We have now reproduced this treatment response with additional insights into device effectiveness in two more such patients undergoing compassionate use OMT. We provided OMT to a 55-year-old man with massive recurrent tumor regrowth and a 79-year-old woman with multifocal recurrent GBM showing rapid progression, with leptomeningeal spread in both cases. Both had failed standard of care chemoradiotherapy and in the former case had not tolerated Optune treatment. They received one 2-hour, two 2-hour and three 2-hour OMTs per day in the clinic on the first three days under the supervision of the treating physician. 3 2-hour daily treatments were continued subsequently at home. The first patient received a steroid drug along with OMT to control cerebral edema from the start. In the second patient it was added after 14 days while also reducing OMT to 2 hours a day because of significant evidence of edema. MRI scans were done periodically to assess the treatment response. Both patients tolerated OMT well with no serious adverse effects – for 7 months in the first patient, including four 2-hour treatments for the last 5 months, and for 2 months in the second patient. Their last MRI scans at Day 146 and Day 42 showed > 35% and > 91% reduction, respectively, in contrast-enhanced tumor volume compared to pre-OMT scans. A modified treatment response assessment mapping analysis showed substantial reductions in both necrotic and active tumor volumes. These findings strongly support the observations in our published single patient case report and provide firm grounds for proposing in-home OMT monotherapy as a safe and effective noninvasive treatment for GBM.
INNV-14. PROSPECTIVE SURGICAL STUDY ON THE FEASIBILITY OF SEMI-AUTOMATED TISSUE COLLECTION, STABILIZATION, PRESERVATION, AND SITE TRANSFER IN GLIOBLASTOMA - IMPROVING UNDERSTANDING OF IMMUNE LANDSCAPE OF TUMOR
Authors: Mohammadi Alireza , Grabowski Matthew , Watson Dionysios , Lauko Adam , Lathia Justin , Ahluwalia Manmeet
Published: November 2022

INTRODUCTION

Despite advances in targeted therapy and immunotherapy of many cancers, glioblastoma outcome is still suboptimal in part due to heterogeneity of tumor. Standard surgical approach for glioblastoma is to remove the enhancing tumor and adjuvant treatment used to treat residual infiltrative tumor in non-enhancing surgical wall. We evaluated samples from both areas using advanced techniques of intraoperative resecting, collecting and biologically preserving viable fresh tissue for evaluation of immune landscape and special genomics of tumor.

METHODS

20 patients with glioblastoma enrolled in the study. Before removal of tumor, 3 different samples from central core, enhancing rim and non-enhancing portion of tumor were obtained using navigation assisted NICO Myriad. Fresh tissue was collected separately by an intraopertive Automated Tissue Preservation System (ATPS) and promptly prepare in iced-cold container for laboratory evaluation of tumor tissue viability, bio-banking and flow-cytometric analysis.

RESULTS

Average age was 65 years-old and 11 patients were female (55%). No adverse event was observed and on average, sampling added 10 minutes to surgical time. Flow-cytometry showed that non-enhancing portion of glioblastoma compared to enhancing tumor has less immune cells and different abundance of multiple subsets including lower CD8:CD4 ratio and more abundant of CD4 memory T-cells. However there remain activated/exhausted T-cells and suppressive myeloid cells in the non-enhancing tumor. Tissue is sent for micro-RNA analysis and next-generation sequencing as well.

CONCLUSION

Taken together, navigation assisted sampling and semi-automated tissue collection, stabilization, and preservation using ATPS is a safe and feasible technique to obtain viable cells for evaluation of heterogeneity of glioblastoma, especially for non-enhancing portion of tumor. This information can be used developing next-generation therapy. Initial results of flow-cytometry showed overall decreased leukocyte infiltration, with underrepresentation of selected immune cell subsets in non-enhancing tumor compared to enhancing portion. Further studies regarding micro-RNA analysis and next-generation sequencing are underway.
INNV-15. MANAGEMENT AND LONG-TERM OUTCOMES OF ADULTS WITH MEDULLOBLASTOMA
Authors: Neth Bryan , Raghunathan Aditya , Kizilbash Sani , Uhm Joon , Breen William , Johnson Derek , Daniels David , Sener Ugur , Carabenciov Ivan , Campian Jian , Mahajan Anita , Ruff Michael
Published: November 2022

INTRODUCTION

Medulloblastomas (MB) are embryonal tumors arising in the cerebellum, predominantly affecting pediatric patients. Recognition of molecularly defined subgroups has advanced management. Factors influencing the prognosis and management of adult MB patients remain poorly understood.

METHODS

We retrospectively reviewed our experience with adult (> 18 years at initial diagnosis) MB patients, diagnosed between 1992-2020. Molecular subtyping corresponding to the 2021 WHO Classification was performed. Kaplan-Meier estimates (Log-rank test assessing for group differences) were performed for univariate survival analysis with cox regression used for multivariate (subgroup, age, gender, disseminated disease, extent of resection) analyses.

RESULTS

Our cohort included 76 adult MB patients (62% male), with a median age of 31.7 years (range: 18-66) at diagnosis, and median follow-up of 7.7 years (range: 0.6-26.9). 58 patients had sufficient tissue for molecular characterization by immunohistochemistry and corresponded to the SHH-activated (n=37; 64%), non-WNT/non-SHH (n=12; 21%), WNT-activated (n=9; 15%) subgroups. At initial diagnosis, all patients underwent radiotherapy, with 97% (n=66) receiving craniospinal irradiation with a boost either to the posterior fossa (75%) or tumor bed (22%); and underwent gross total resection (n=51; 67%) and chemotherapy (n=56; 75%). Median overall survival (OS) for the whole cohort was 14.8 years (93% 2-year OS; 86% 5-year OS; 64% 10-year OS) and was longer for younger patients (< 30: > 15.4 years, > 30: 9.9 years; Log-rank p< 0.001). No significant OS difference was identified by MB molecular subgroup (SHH, TP53-wt: 14 years, WNT: 11.4 years, non-WNT/non-SHH: > 14.8 years; Log-rank p=0.1167) or extent of resection. Only age at diagnosis remained significant in multivariate survival analyses.

DISCUSSION

We report one of the largest retrospective cohorts in adult MB patients with molecular subtyping. Survival and molecular subgroup frequencies were similar to previous reports. Survival was longer for younger patients and was not significantly different by MB molecular subgroup or extent of resection.
INNV-23. MANAGING CENTRAL NERVOUS SYSTEM MANIFESTATIONS OF CHRONIC GRAFT VERSUS HOST DISEASE FOLLOWING HEMATOPOIETIC STEM CELL TRANSPLANTATION: A CASE REPORT
Authors: Kundalia Ronak , Hanini Anas , Gatewood Tyra , Mishra Asmita , Pina Yolanda , Mokhtari Sepideh
Published: November 2022

Central nervous system (CNS) manifestation of chronic graft versus host disease (cGVHD) is a rare, difficult to diagnose phenomenon that can follow allogeneic hematopoietic stem cell transplantation (HSCT). CNS-cGVHD typically onsets 2-31 months post-transplant, involves diffuse infiltration of inflammatory cells, demyelination, and cerebral vasculitis, and is associated with an extremely poor prognosis. We present a case of a 37-year-old man who developed seizures, myopathy, bilateral upper and lower extremity weakness, confusion, and irritability almost 2 years after HSCT for acute myeloid leukemia (AML). CNS-cGVHD diagnosis was confidently determined via magnetic resonance imaging (MRI) demonstrating enhanced focal white matter lesions, cerebrospinal fluid (CSF) studies demonstrating elevated globulin (12.7 mg/dL; normal range: 0-6 mg/dL) and elevated immunoglobulin G (IgG) synthesis rate (13.9 mg/d; normal range: ≤ 8 mg/d), and a right brain biopsy demonstrating encephalitis, perivascular inflammation, microglial activation, and gliosis with predominately intramural and perivascular CD3+ T-cells, CD4+ and CD8+ cells. Complete resolution of neurological symptoms, including seizures, was achieved with a combination of steroids, ibrutinib, intravenous immunoglobulin (IVIG), and anti-seizure medications. Improvements to CNS-cGVHD was further indicated by normalized MRI studies without abnormal enhancements and improved CSF studies with reduction in globulin levels (11.3 mg/dL) and complete normalization of IgG synthesis rate (≤ 0 mg/d). It is imperative that CNS-cGVHD be considered in patients that present with neurological signs post-transplant. An early, confident diagnosis generates prompt intervention and as demonstrated, can lead to complete resolution of neurological symptoms.
INNV-33. FUNCTIONAL EX VIVO TESTING PROSPECTIVELY IDENTIFIES NEWLY DIAGNOSED GLIOBLASTOMA PATIENTS SENSITIVE TO TEMOZOLOMIDE TREATMENT IRRESPECTIVE OF MGMT METHYLATION STATUS
Authors: DesRochers Tessa , Lipinski Lindsay , Abad Ajay , Fenstermaker Robert , Fabiano Andrew , Edenfield Jeffery , Kanos Charles , Redjal Navid , Rodriguez Analiz , Mansouri Alireza , Zacharia Brad , Butowski Nicholas , Jia-Xin Liu Jesse , Han Seunggu , Ziu Mateo , Cohen Adam , Smith Ashley , Vibat Cecile Rose , Ledford Aubrey
Published: November 2022

Standard of care (SOC) therapy for newly diagnosed (ND) glioblastoma (GBM) patients consist of temozolomide (TMZ) concurrent with radiation therapy. It is well known that patients with an unmethylated MGMT promoter are less likely to respond to TMZ, however, this trend is not universal. We have previously shown that 3D Predict™ glioma can identify patient response to TMZ, often differentially than the methylation status would predict. Here we present expanded clinical data relating to functional ex vivo testing capable of identifying patients responsive to alkylating therapies such as TMZ, regardless of methylation status.

METHODS

Fresh tissue specimens taken from ND GBM patients enrolled into the 3D PREDICT clinical study were examined by 3D Predict glioma to evaluate ex vivo therapeutic response to TMZ. Overall Survival (OS) and Progression Free Survival (PFS) in patients having â‰¥ 6 months follow-up post-surgery or < 6 months follow up but experiencing progression/death as of September 1, 2022 will be presented. Prospective correlation of clinical response and test-predicted response will be demonstrated in this expanded cohort of ND GBM patients.

IMPACT

This data has the potential to change treatment for ND GBM patients by stratifying according to functional therapeutic response rather than epigenetic factors that are not completely predictive of clinical response. It is feasible that 3D Predict glioma could dramatically impact patient care by determining which unmethylated patients should be treated with TMZ, and methylated patients who would potentially derive greater benefit from clinical trials or other treatment regimens.
PATH-03. IMPACT OF GAP-43 AND ACTIN EXPRESSION ON THE OUTCOME AND OVERALL SURVIVAL IN DIFFUSE AND ANAPLASTIC GLIOMAS
Authors: Krigers Aleksandrs , Demetz Matthias , Moser Patrizia , Kerschbaumer Johannes , Brawanski Konstantin , Fritsch Helga , Thomé Claudius , Freyschlag Christian
Published: November 2022

Background. Distant intercellular communication in gliomas is based on the expansion of tumor microtubuli (TMs), where actin forms cytoskeleton and GAP-43 mediates the axonal conus growth. We aimed to investigate the impact of GAP-43 and actin expression on overall survival (OS) as well as crucial epidemiologic, radiological and neuropathological prognostic factors. Methods. FFPE tissue of adult patients with diffuse and anaplastic gliomas, who underwent first surgery in our center between 2010 and 2019, were selected. GAP-43 and actin expression was analyzed using immunohistochemistry and semi-quantitatively ranked. Clinical, neuropathological as well as follow-up-data were gained from the institutional neuro-oncological database. Results. 118 patients with a median age of 46 years (IqR: 35 – 57) were evaluated. 48 (41%) presented with a diffuse glioma and 70 (59%) revealed anaplasia. 96 (82%) cases presented with intermediate or strong GAP-43 expression and 78 (67%) with no or light actin expression. Tumors with higher expression of GAP-43 (p=0.024, HR=1.71/rank) and actin (p< 0.001, HR=2.28/rank) showed significantly reduced OS. IDH1 wildtype glioma demonstrated significantly more expression of both proteins: GAP-43 (p=0.009) and actin (p< 0.001). The same was confirmed for anaplasia (GAP-43 p=0.028, actin p=0.029), higher proliferation rate (GAP-43 p=0.016, actin p=0.038), contrast-enhancement in MRI (GAP-43 p=0.023, actin p=0.037) and age (GAP-43 p=0.004, actin p<0.001). Conclusions. The intercellular distant communication network in diffuse and anaplastic gliomas formed by actin and GAP-43 is associated with a negative impact on overall survival and with oncologically unfavorable prognostic features.
PATH-04. CURRENT STATUS AND PROSPECTS OF MALIGNANT BRAIN TUMOR TREATMENT IN CANCER GENOMIC MEDICINE
Authors: Koizumi Shinichiro , Yamasaki Tomohiro , Oishi Tomoya , Kurozumi Kazuhiko
Published: November 2022

INTRODUCTION

The cancer gene panel test was covered by insurance in June 2019 in Japan. Our institution started the test in May 2020 and has experienced 16 cases. We will report on the current status and future prospects.

METHODS

The subjects were 16 patients (Average age 48.4) who underwent the cancer gene panel test with FoundationOne CDx. [Results] The cases included 9 glioblastomas, 3 anaplastic astrocytomas, 2 anaplastic oligodendrogliomas, an ependymoma, and a pituitary carcinoma. On average, 11.0 genetic changes were detected totally, oncogene mutations were 4.4, and gene mutations of unknown relevance to cancer were 5.6. Major oncogene mutations were IDH1 mutation in 5 cases, ATRX mutation in 2 cases, TP53 mutation in 9 cases, CDKN2A/2B mutation in 5 cases, and BRAF V600E mutation in 1 case. Based on our results, a 25-year-old man with BRAF V600E mutation and a 47-year-old male with IDH1 mutation could be given molecular-targeted drugs. Furthermore, a 59-year-old male with pituitary carcinoma had more than 10 mut/Mb in tumor mutational burden (TMB), indicating that anti-PD-1 antibody drugs can be administered. The chance of finding an appropriate drug by cancer gene panel test is approximately 10-20%. In cases that are resistant to standard treatment, the benefits can be expected if the drugs associated with the cancer gene panel test can be used.

CONCLUSIONS

Comprehensive cancer gene panel test has the potential to provide personalized medicine. And we suggest that the active use of cancer gene panel test may contribute to the development of new drugs with high response rates and the improvement of prognosis.
PATH-08. A COMPREHENSIVE GENOMIC STUDY OF 390 H3F3A-MUTANT PEDIATRIC-TYPE DIFFUSE HIGH-GRADE GLIOMAS WHO CNS GRADE 4
Authors: Williams Erik , Brastianos Priscilla , Wakimoto Hiroaki , Santagata Sandro , Cahill Daniel , Juratli Tareq
Published: November 2022

OBJECTIVES

Histone gene mutant malignant gliomas - H3K27-altered diffuse midline glioma (DMG) and diffuse hemispheric glioma (DHG) H3G34-mutant - occur in all age groups and can have significant variation in clinical outcomes. Here, we report comprehensive genomic profiling from one of the largest collections of H3F3A-mutant gliomas analyzed to date, identifying subsets defined by recurrently co-mutated genes.

METHODS

We identified 390 H3F3A-mutant diffuse gliomas WHO grade 4 (201 females and 189 males) that were profiled in the comprehensive genomic profiling program at Foundation Medicine between 2013-2020. Information from pathology reports, histopathology reviews, and clinical data was assessed.

RESULTS

Our cohort comprised 304 (77.9%) H3K27M-mutant DMG WHO grade 4 (156 females and 148 males) and 86 H3G34-mutant DHG (45 females and 41 males) with a median age of 20 years (1-74 years). H3K27M-mutant DMG distributed equally between pediatric and adult patients, with 52% of the patients older than 20 years, 30% older than 30 years, and 18% older than 40 years at the time of first diagnosis. Clonal FGFR1 hotspot mutations were exclusively detected in K27M-mutant DMG (n = 64/304, 21%; p=0.0001), with a significant association with a higher age at first diagnosis (median 32.5 years), and with a wide tumor distribution across the diencephalon. Additional genes which were significantly more frequently altered in K27M-mutant compared to G34-mutant diffuse gliomas included NF1 (31% vs. 8.1%; p=0.0001) and PIK3CA/PIK3R1 (27.9% vs. 15.1%; p=0.016). Conversely, targetable alterations of the cell-cycle pathway (CDK4/6 amplifications and CDKN2A/B deletions) were enriched in H3G34-mutant DHG (26%) compared to H3K27M-mutant DMG (7%). Potentially targetable PDGFR alterations were present in 32.5% of H3G34-mutant DHG and in 18% of H3K27M-mutant DMG.

CONCLUSIONS

These data expand our understanding of the tumor-specific molecular features of pediatric-type high-grade gliomas, identifying cohort sub-structure by recurrent co-mutations, which can inform diagnosis and clinical trial design.
PATH-17. DISTINCT MOLECULAR SUBCLASSES OF H3F3A-WILDTYPE, EGFR-ALTERED PEDIATRIC-TYPE DIFFUSE MIDLINE GLIOMAS WHO CNS GRADE 4
Authors: Williams Erik , Brastianos Priscilla , Wakimoto Hiroaki , Cahill Daniel , Santagata Sandro , Juratli Tareq
Published: November 2022

OBJECTIVES

Histone gene H3K27-altered diffuse midline glioma (DMG) are malignant tumors that occur in all age groups. In this study, we report comprehensive genomic profiling from H3F3A-wildtype, EGFR-altered DMG, as a distinct and newly recognized subset of pediatric-type DMG.

METHODS

Tumors were profiled in the comprehensive genomic profiling (CGP) program at Foundation Medicine between 2013-2020. Information from pathology reports, histopathology review, and patient clinical data was assessed.

RESULTS

We collected demographic and genomic data from 39 pediatric patients with H3F3A-wildtype, EGFR-altered HGG (17 females, 22 males; median age: 8.5 years, range 1-18 years). Female patients were younger at first diagnosis compared to male (median age 7 years vs. 10 years). All cases were microsatellite stable (MSS). The EGFR alterations consisted of 30 mutations and 9 amplifications. The mutations were distributed across the entire gene with no clear hotspot location. Our genomic data converged to identify three distinct molecular patterns. The first and most common group contained TP53 mutations (n = 17, 43.5%), showed no association with patient sex (8 females, 9 males), contained ATRX mutations (n = 3) and CDKN2A deletions (n = 5); these tumors did not harbor pathogenic mutations in TERTp, PIK3CA/PIK3R1, BCOR/BCORL1, STAG2, or SETD2. The second group featured TERTp-mutant tumors (n = 10), were more common in males (70%), and often demonstrated additional mutations in PIK3CA/PIK3R1 (n = 4), BCOR/BCORL1 (n = 4), CDKN2A/B (n = 4), and SETD2 (n = 2). The third group (n = 12) lacked TERTp and TP53 mutations and had a heterogeneous spectrum of non-recurrent mutations, including one CDKN2A/B deletion.

CONCLUSIONS

We have identified three distinct molecular subclasses that defined specific genomic tumor subgroups in pediatric-type EGFR altered DMG. Overall, these data increase our understanding of the pathobiology of this DMG subset and can guide the design of clinical trials.
PATH-20. CILIA-ASSOCIATED GENE EXPRESSION PREDICTS SURVIVAL IN LOW-GRADE GLIOMAS
Authors: Kaculini Christian , Singh Komudi , Springer Megan , Jung Mi-Yeon , Johnson Kory , Brown Desmond
Published: November 2022

Low-grade gliomas (WHO II and III) encompass a histopathologically and clinically heterogeneous constellation of neoplasms. Molecular biomarkers play an increasingly important role in glioma classification, therapy, and prognostication. Primary cilia are microtubule-based organelles that regulate several canonical signal transduction cascades and they have been implicated in the pathogenesis of many malignancies. We hypothesized that LGGs differentially express ciliary genes resulting in unique molecular and prognostic clusters. Four-hundred-sixty-seven LGG patients within The Cancer Genome Atlas (TCGA) were stratified based on differential expression of cilia-associated genes. Four statistically distinct clusters (P < 0.0001) were identified including a high- (median overall survival [OS] 95.5 months; CI [52.1-NA]), mid- (median OS 63.5 months; CI [43.9-NA]) and a low-surviving (median OS 23.7 months; CI [19-134]) cluster. OS was independent of IDH status, 1p/19q codeletion or MGMT promoter methylation status on multivariate analysis. Orthogonal validation was performed using 442 LGGs from the Chinese Glioma Genome Atlas (CGGA). Again, four discrete clusters were found including a high- (median OS 78.4 months, CI [45.8-NA]) and a low-surviving (median OS 16.5 months, CI [12.2-25.5]) cluster. While LGGs with 1p/19q codeletions were present in all clusters, they were overrepresented in the high-surviving groups. The most robustly differentially expressed genes were compared across clusters to find cluster-defining genes most associated with OS. LGGs in the high-surviving group are defined by the expression profiles of 13 genes while low-surviving LGGs are identified by the differential expression of 15 non-overlapping genes. LGGs can be classified into four distinct clusters that are independently associated with OS based on cilia-associated gene expression alone. Within these clusters, there is a high- and a low-surviving group, each with their own unique genetic profiles. These new molecular markers may inform novel therapeutic targets and predictors of clinical outcomes.
PATH-21. INVESTIGATING CHANGES IN IDH MUTATION STATUS AT GLIOMA RECURRENCE
Authors: Voisin Mathew , Gui Chloe , Zadeh Gelareh
Published: November 2022

PURPOSE

Isocitrate dehydrogenase (IDH) mutation status is a key diagnostic and prognostic feature of gliomas. It is thought to occur early in glioma tumorigenesis and remains stable over time. We investigated our tumour bank to identify patients where IDH mutation status changed after glioma recurrence.

METHODS

We identified four patients with immunohistochemistry-recorded IDH mutation statuses that conflicted between multiple tumour samples taken over time. Tissue samples from the tumour bank were analyzed using methylation profiling and Sanger sequencing of IDH1 and IDH2 to verify IDH status.

RESULTS

In all four instances, we found that IDH mutation status in fact remained stable, and there were reasonable explanations as to why mutation status was misinterpreted. One tumour had a non-canonical IDH2 R172K mutation that is not routinely tested for. Two patients had perilesional samples, revealed by methylation profiling to contain a mixture of tumour and normal brain. One patient had a IDH wildtype sample with a methylation profile consistent with reactive brain tissue rather than tumour.

CONCLUSIONS

All four cases of IDH mutation change at glioma recurrence were due to either misinterpreting perilesional or reactive tissue as tumour or overlooking a non-canonical mutation. This finding supports the concept that IDH mutation is a fixed characteristic of gliomas and highlights the importance of accurate surgical biopsy and molecular testing at initial diagnosis.
PATH-24. ACCURATE IDENTIFICATION OF GLIAL MALIGNANCIES FROM PERIPHERAL BLOOD
Authors: Anichini Giulio , Fulmali Pooja , O'Neill Kevin , Datta Vineet , Crook Timothy , Syed Nelofer
Published: November 2022

Symptomatic presentation of patients with intra-cranial malignancy is frequently non-specific and differentiating such patients from those with benign conditions is challenging. Accordingly, GBM presents as a medical emergency more frequently than any other common cancer, implying that effective strategies for rapid and simple diagnostic stratification of such patients are urgently required. Here we describe the detection of glial malignancies based on the enrichment and identification of Circulating Glial Cells (CGCs) in peripheral blood. The first case controlled study included blood from 189 participants split into discrete training and test sets (145 GBM, 44 benign CNS conditions). The second case controlled study included 40 cases of glial malignancies, 22 benign CNS conditions, 24 solid tumors with brain metastases, and 500 healthy individuals with no prior diagnosis of cancer and no current suspicion of cancer. A third prospective study was also carried out in 68 individuals with radiologically evident intracranial space-occupying lesion suspected of glial malignancies. Blood specimens were blindly evaluated for detection of CGCs through TruBlood assay to determine clinical sensitivity and specificity. 98% sensitivity and specificity was observed in detecting glial malignancies and differentiating them from benign CNS conditions in both case controlled studies. We detected and differentiated glial malignancies from benign CNS, healthy samples, and brain metastases. In the prospective study, 56 were positive for CGS, and 12 were negative for CGCs. All CGC positive specimens were confirmed glial malignancies and all CGC negative specimens benign CNS conditions. We present a non-invasive approach to the diagnostic stratification of patients presenting with suspicious but non-specific neurocognitive symptoms and hence early detection of glial malignancies. Moreover, immunocytochemistry facilitates the differentiation of GBM from metastatic intra-cranial epithelial cancers.