Introduction The overall survival in patients with gliomas has not significantly increased in the modern era, despite advances such as immunotherapy. This is in part due to their notorious ability to suppress local and systemic immune responses, severely restricting treatment efficacy. Methods We have reviewed the preclinical and clinical evidence for immunosuppression seen throughout the disease process in gliomas. This review aims to discuss the various ways that brain tumors, and gliomas in particular, co-opt the body’s immune system to evade detection and ensure tumor survival and proliferation. Results A multitude of mechanisms are discussed by which neoplastic cells evade detection and destruction by the immune system. These include tumor-induced T-cell and NK cell dysfunction, regulatory T-cell and myeloid-derived suppressor cell expansion, M2 phenotypic transformation in glioma-associated macrophages/microglia, upregulation of immunosuppressive glioma cell surface factors and cytokines, tumor microenvironment hypoxia, and iatrogenic sequelae of immunosuppressive treatments. Conclusions Gliomas create a profoundly immunosuppressive environment, both locally within the tumor and systemically. Future research should aim to address these immunosuppressive mechanisms in the effort to generate treatment options with meaningful survival benefits for this patient population.

The CBTRUS Statistical Report: Pediatric Brain Tumor Foundation Childhood and Adolescent Primary Brain and Other Central Nervous System Tumors Diagnosed in the United States in 2014–2018 comprehensively describes the current population-based incidence of primary malignant and non-malignant brain and other CNS tumors in children and adolescents ages 0–19 years, collected and reported by central cancer registries covering approximately 100% of the United States population. Overall, brain and other CNS tumors are the most common solid tumor, the most common cancer, and the most common cause of cancer death in children and adolescents ages 0–19 years. This report aims to serve as a useful resource for researchers, clinicians, patients, and families.

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There is a broad differential diagnosis of infantile hepatosplenomegaly, with some etiologies being debilitating and treatable. A structured approach to history, examination, and laboratory and radiographic findings is important in diagnosis. Herein, we present a case of Wolman disease presenting as hepatosplenomegaly in an infant.

BACKGROUND The intent of this investigation is to validate a novel, high-affinity epidermal growth factor receptor (EGFR) chimeric antigen receptor (CAR) T-cell product for adoptive immunotherapy of EGFR-expressing malignancies of the central nervous system (CNS). Wild type EGFR is ubiquitously expressed on glial tumors in both children and adults, and the majority of solid tumors that metastasize to the CNS but is not expressed on healthy CNS tissues. EGFR and its isoform mutant, EGFRvIII, are hyperactivated or overexpressed receptor tyrosine kinases described in many human cancers. D2C7 is a recombinant monoclonal antibody short chain variable fragment (scFv) that binds to both wild type EGFR and EGFRvIII. We hypothesize that D2C7 adapted as a CAR on primary human T cells will generate potent, cytotoxic activity against EGFR-expressing tumors in vivo. METHODS In vitro interferon gamma release assays comparing the D2C7 CAR to the EGFRvIII CAR have proven that D2C7 CAR-T cells have high specificity and potent cytotoxicity against established murine glioblastoma (GBM) tumor cell lines, expressing both EGFR and EGFRvIII. Next steps include pre-clinical in vivo testing of the D2C7 CAR-T cells in murine models of CNS tumors expressing EGFR/EGFRvIII such as GBM, non-small cell lung carcinoma (NSCLC), breast carcinoma, and melanoma. CONCLUSIONS To improve and validate the effectiveness of CAR T-cell therapy for EGFR-expressing CNS tumors, our team has designed a high-affinity CAR-T cell that targets both EGFRvIII and wild-type EGFR, known as a D2C7 CAR-T cell. This investigation has established pre-clinical anti-tumor activity of D2C7-CAR T cells in vitro and we plan to present more mature data regarding efficacy in orthotopic murine models of GBM, NSCLC, breast carcinoma, and melanoma at the meeting this Fall.

BACKGROUND Medulloblastoma is the most common malignant brain tumor in children 0-19 years of age and current treatment requires surgical resection, followed by high dose chemotherapy and radiotherapy. Therapy carries high morbidity, with late effects including neurocognitive decline, endocrine dysfunction, and subsequent malignancies. Chimeric antigen receptor (CAR) T cell therapy presents the potential for less toxic and more effective treatment for medulloblastoma. Epidermal growth factor (EGFR) is expressed in medulloblastoma derived cell lines and appears to serve an important role in the metastatic potential of this tumor type. D2C7 is a recombinant monoclonal antibody short chain variable fragment (scFv) with dual specificity, binding to wild type EGFR (EGFRwt) and its mutant EGFR variant III (EGFRvIII). We previously developed a novel, third-generation chimeric antigen receptor T-cell construct utilizing the D2C7 scFv and performed analysis on both glioblastoma and medulloblastoma tumor models. METHODS U87 and U87vIII glioblastoma and DAOY medulloblastoma cell lines were characterized by flow cytometry to evaluate for EGFRwt and EGFRvIII expression. Cytotoxicity assays were performed utilizing flow cytometry on serially diluted effector: target ratios of U87, U87vII, and DAOY mixed with D2C7 CAR. DAOY was orthotopically implanted into the frontal lobe of NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice. After tumor implantation, D2C7 CAR was introduced within the tumor bed. RESULTS EGFR was detected in U87, U87vIII, and DAOY on flow analysis. EGFRvIII was expressed only on U87vIII. D2C7 CAR demonstrated effective in vitro cytotoxicity against all three cell lines with >90% cytotoxicity achieved at an effector: target ratio of 2.5:1. In vivo, D2C7 CAR treatment significantly prolonged survival compared to treatment with mock CAR. CONCLUSION D2C7 CAR demonstrates efficacy in vitro and in mouse models of medulloblastoma and glioblastoma. Future steps in our work will set out to assess the D2C7 CAR in NSG mice with DAOY in the posterior fossa.

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Glioblastoma (GBM) is the most aggressive primary brain cancer with a median survival of less than 16 months. This dire prognosis signifies the urgent need for improved treatment options, such as immunotherapy. Chimeric antigen receptor (CAR) T cells have helped revolutionize immunotherapy, achieving considerable success in eliminating hematological cancers but generally failing to control solid tumors. One major hindrance to CAR T cell success in solid tumors is tumor heterogeneity. Tumor-associated or tumor-specific antigens (TAA or TSA, respectively) are rarely expressed by all malignant cells within a tumor. As a specific example in GBM, the most prevalent TSA, EGFRvIII, is present in just 30% of tumors, and then on only 30-50% of cells. Our pre-clinical and clinical experiences with CAR T cells reveal that tumors possessing as few as 5-10% EGFRvIII-negative cells will easily escape EGFRvIII-targeted CARs. Tumor cells that lack EGFRvIII expression often overexpress the wildtype isoform of EGFR (EGFRwt). Notably, EGFR is absent on normal brain. Therefore, a superior approach would be to simultaneously target EGFRvIII and EGFRwt, an approach that would bypass EGFR heterogeneity in EGFRwt/EGFRvIII-expressing tumors. Here, we generated a third generation CAR using the D2C7 single-chain variable fragment (scFv) targeting moiety that recognizes an epitope present in EGFRwt and EGFRvIII. Initial in vitro characterization of D2C7 CAR validated the specificity and function of D2C7 CAR, as it potently killed murine cell lines engineered to express either EGFRwt or EGFRvIII, but not a cell line expressing neither. Concomitant IFN-γ release supported these conclusions. Additionally, D2C7 CAR killed the human-derived GBM cell line U87 and vIII-transfected U87, U87vIII. Importantly, intracranially-administered D2C7 CAR significantly prolonged survival of mice bearing orthotopic U87vIII or U87/U87vIII heterogeneous tumors compared to mock-treated controls. Altogether, these data provide evidence that D2C7 CAR T cells represent a viable therapeutic option for EGFRwt/EGFRvIII heterogeneous tumors.