bluuebunny/crossref_metadata_2025_split huggingface dataset:
IMMU-15. The immunologic context of pediatric central nervous system malignancies and identification of pan-histology immunomodulatory targets
Authors: Galvin Robert , Nikrad Julia , Jubenville Tyler , Maeser Danielle , Gruener Robert , Jena Sampreeti , Moertel Christopher , Largaspaeda David , Huang R Stephanie 
Published: June 2022

Abstract
Central nervous system tumors account for the most childhood cancer mortality. Immunotherapies have made major contributions to treat adult cancers, but application of immunotherapy for childhood brain tumors has been limited, in part due to the unique CNS microenvironment and mechanisms of immune escape in this context. To investigate the immunologic context, we query the transcriptomic profile of ~700 primary brain tumors released by the Children’s Brain Tumor Network. An immune subtype classification from The Cancer Genome Atlas project reveals that 81% of high-grade tumors across molecular subtypes are characterized by an immunosuppressive phenotype (C4) while an inflammatory phenotype (C3) is more common in low-grade lesions (p&lt;0.001). Adjusting for histologic grade and extent of resection, C4 associates with worse overall (OS) and progression-free survival (PFS) in this cohort (HR 3.1, p=0.008 and 1.6, p=0.03 respectively). Deconvolution of the transcriptome reveals that relative to C3, C4 tumors have decreased T-cell signature, OR 0.4 (0.2–0.8), and increased macrophage and tumor-proliferation signature (OR 2.0, 1.3–3.3, and 3.1, 2.3–4.2, respectively). In contrast to C3 tumors, T-cell signature in C4 tumors adversely impacts survival and correlates with multiple immunosuppressive genes and cytokines. Among them, the immune checkpoint CD276 has the highest associated impact on survival in C4 tumors (HR of log increase is 1.9, p&lt;0.001). Additionally, high-grade lesions have suppressed expression of antigen-presenting genes. EZH2 is implicated in downregulating antigen presentation and is found to be significantly upregulated in all high-grade lesions in this cohort. Treatment with the EZH1/2 inhibitor valemetostat resulted in upregulation of antigen-presenting genes and tissue differentiation pathways across three murine syngeneic models, one modeling diffuse midline glioma and two embryonal models. Future in-vivo studies with genetic and chemical modification of immunomodulatory genes of interest aim to identify immunotherapeutic targets with potential for broad applicability in pediatric neuro-oncology.
IMMU-23. Novel gene-edited CAR-T cell therapy against Diffuse Intrinsic Pontine Glioma
Authors: Balakrishnan Ilango , Leach Lillie , Lakshmanachetty Senthilnath , Pierce Angela , Madhavan Krishna , Chatwin Hannah , Fosmire Susan , Meadows Christina , Green Adam , Fry Terry , Vibhakar Rajeev , Kohler Eric M , Venkataraman Sujatha 
Published: June 2022

Abstract
BACKGROUND: We identified high expression of CD99 in DIPG tumors and developed a CAR using our newly identified single chain variable fragment (scFv) targeting CD99 incorporating a 4-1BB co-stimulatory domain. This CD99 CAR demonstrated the ability to dramatically shrink the established orthotopic DIPG tumor, however tumor recurrence remains an obstacle to cure, due to a loss of the CAR-T cells as they also express the target antigen, CD99 (fratricide). To overcome this obstacle, we modified these CAR-T by editing out CD99. METHODS: CD99 was knocked-out from the human T cells using CRISPR-cas9 gene-editing and subsequently transduced with our CD99 CAR-encoding virus, and isolated the pure population of CD99KO T-cells. These novel, gene-edited T-cells expressing CD99 CAR (“CD99KO CARs”) and the un-edited ones (“CD99 CAR”) were tested for tumor-lysis function when co-cultured with DIPG cells. DIPG tumor-bearing mice infused with a one-time dose of CD99KO CAR-T cells or CD99 CAR- or CD19 control CAR-T cells and were monitored for changes in the tumor burden. At the endpoint spleen and bone marrow were isolated to test for CAR+ cell persistence. RESULTS: The CD99KO CAR-T cells demonstrated effective tumor-lysis when co-cultured with DIPG cells. CD99KO CAR-T cells targeting CD99 showed complete clearance of DIPG tumor in orthotopic DIPG mouse models, and no tumor recurrence was seen well-beyond the time frame of expected tumor recurrence after treatment with un-edited CD99 CAR-T cells. There was an un-precedented increase in the xenograft survival, &gt; 200 days, in mice treated with CD99KO CARs and at which time point sustained persistence of CAR+ cells were evident in the animal spleen and bone marrow. CONCLUSIONS: We have generated a new and promising CAR-T cell therapy that is effective against DIPG with enhanced persistence in animal models which is critical for clinical translation.
LGG-05. A Nine-month-old Boy with Regression of Milestones and Severe Constipation: An Unusual Case of a Spinal Pilocytic Astrocytoma
Authors: Offenbacher Rachel , Kobets Andrew , Dalvi Nagma , Hsu Kevin , Chin Steven , Snuderl Matija , Levy Adam , Martin Allison 
Published: June 2022

Abstract
Pilocytic astrocytoma (PA), a World Health Organization Grade 1 tumor, is the most common brain tumor in children between 5 and 14 years of age and the second most common in children younger than 5 and older than 14. Although classical to the cerebellum and hypothalamic regions, it can also arise in the spinal cord. A nine-month-old boy with a history of torticollis and plagiocephaly presented with a four-month history of regression of milestones, irritability and severe constipation. He was noted to have flaccid paralysis of the lower extremities and decreased reflexes. Ophthalmologic exam was significant for papilledema and magnetic resonance imaging of the spine were notable for a large infiltrative heterogeneously enhancing lesion extending from T4 to the conus containing several loculated intratumoral cysts with abnormal enhancing margins from T4 to T8. He underwent embolization and complete tumor resection. Post-op MRI was notable for an oval shape non-enhancing soft tissue measuring 8 mm along the medial wall of the left lateral ventricle. Comprehensive tumor molecular profiling on the resected spinal tumor tissue (Caris MI), revealed an NTRK1 fusion, MEF2D-NTRK1, Exon 12. Larotrectinib was initiated at 100mg/m2 per dose oral twice daily to target this specific mutation. Follow up imaging 3 months later showed decrease in the size of intracranial lesions. To date, there is only one other case report demonstrating intracranial metastasis from a spinal PA. Due to the size of his spinal lesion, we believe this was his primary site; however, as described in the literature, there is no definitive way to determine the initiating lesion. The use of comprehensive molecular profiling facilitated the discovery of a targetable oncogenic mutation that changed initial management. To the best of our knowledge there has been only one other case report describing this specific fusion in a pediatric spinal CNS tumor.
LGG-08. MR Imaging of pediatric low-grade gliomas: Pretherapeutic differentiation ofBRAF V600E mutation,BRAF-Fused and Wild-Type tumors in patients without Neurofibromatosis-1
Authors: Trasolini Andrew , Erker Craig , Cheng Sylvia , Crowell Cameron , McFadden Kathryn , Moineddin Rahim , Sargent Michael , Mata-Mbemba Daddy 
Published: June 2022

Abstract
OBJECTIVE: The prognosis and treatment of pediatric low-grade gliomas (pLGGs) is influenced by their molecular subtype. MRI remains the mainstay for initial work-up and surgical planning. We aimed to determine the relationship between imaging patterns and molecular subtypes of pLGGs. METHODS: This is a bi-institutional retrospective study for patients diagnosed from 2004 to 2021 with pathologically confirmed pLGG, molecularly defined as BRAF fusion (KIAA1549-BRAF), BRAF V600E mutation, or wild-type (negative for both BRAF V600E mutation and BRAF fusion). Two neuroradiologists, blinded, independently reviewed imaging parameters on the initial MRI and discrepancies were solved by consensus. Bivariate analysis was used followed by pairwise comparison of Dwass, Steel, and Critchlow-Fligner methods to compare the 3 molecular subtypes. Agreement between reviewers was assessed using Kappa (k). RESULTS: 70 patients were included: 30 with BRAF fusion, 19 with BRAF V600E mutation, and 21 wild-type. There was substantial agreement between the two readers for overall imaging variables (k=0.75). BRAF fusion tumors compared to V600E and wild-type had larger size (p=0.0022), greater mass effect (p=0.0053), and increased rate of hydrocephalus (p=0.0002). BRAF fusion tumors had increased frequency of diffuse enhancement compared with BRAF V600E and wild-type (p &lt;0.0001). BRAF V600E mutant tumors were more often located in a cerebral hemisphere (p &lt;0.0001). Diffusion restriction (qualitatively) was uncommon but only seen in BRAF V600E (p=0.0042) with lower ADC ratio (quantitatively) (p=0.003). Additionally, BRAF V600E mutant tumors appeared more infiltrative than BRAF fusion and wild-type (p=0.0002). CONCLUSION:BRAF fusion and BRAF V600E mutant pLGG have unique imaging features that can be used to differentiate from each other and wild-type pLGG using standard radiology review with high inter-reader agreement. In the era of targeted therapy, these features can be useful for therapeutic planning prior to surgery.
LGG-18. Inhibition of Bcl-xL targets the senescent compartment of pilocytic astrocytoma
Authors: Selt Florian , Sigaud Romain , Valinciute Gintvile , Sievers Philipp , Zaman Julia , Alcon Clara , Peterziel Heike , Tsai Jessica W , Guiho Romain , Martínez-Barbera Juan Pedro , Pusch Stefan , Schuhmann Martin U , El Damaty Ahmed , Bandopadhayay Pratiti , von Deimling Andreas , Pfister Stefan M , Montero Joan , Capper David , Herold-Mende Christel , Oehme Ina , Sahm Felix , Jones David T W , Witt Olaf , Milde Till 
Published: June 2022

Abstract
INTRODUCTION: Pilocytic astrocytoma (PA) is a mitogen-activated protein kinase (MAPK)-driven disease. Treatment of sub-totally resected PA remains challenging and relapses occur even after MAPK-targeted therapies such as MEK inhibition. Oncogenic activation of the MAPK-pathway drives the majority of cells into oncogene-induced senescence (OIS). OIS might represent a complementary vulnerability exploitable by senolytic agents. Here we investigated the senolytic properties of BH3-mimetics in PA. METHODS: Four patient-derived PA cell lines, DKFZ-BT66, -BT308, -BT317 (KIAA1549:BRAF-fusion) and DKFZ-BT314 (BRAF V600E-mutation) were treated with different BH3-mimetics, chemotherapeutics and MEK-inhibitors in proliferation (expression of SV40 large T (TAg)) and OIS (repression of TAg) states. Inhibition of metabolic activity (CellTiterGlo® 2.0) and reduction of viability (trypan blue) was assessed after 72 hours. Target expression was determined using gene expression data and Western blot. On-target activity was verified by immunoprecipitation. Dependence on Bcl-xL was investigated by shRNA-mediated knockdown and BH3-profiling. Gene expression data of primary PA and 751 cancer cell lines (GDSC dataset) was analyzed. RESULTS: BH3-mimetics inhibiting Bcl-xL (Bcl-xLi; Navitoclax, A-1131852, A-1155463, AZD4320) showed activity in 3/4 models (DKFZ-BT66, -BT314 and -BT317) in the OIS state (IC50s &lt;300nM). Other BH3-mimetics, chemotherapeutics and MEK-inhibitors had no effect on all models in OIS. Bcl-xL mRNA expression levels were similar, on-target activity and dependence on Bcl-xL protein was comparable in all models. Bcl-xLi-resistance of DKFZ-BT308 was linked to upregulation of genes of the HALLMARK_XENOBIOTICS_METABOLISM gene set involved in drug metabolism. Correlation of these genes with IC50s of navitoclax was validated in an independent dataset (GDSC). CONCLUSION: Treatment with Bcl-xLi is a promising strategy targeting the senescent part of PA. IC50s of the clinically available drug navitoclax were &gt;20-fold below achievable plasma concentration indicating translatability. Genes from the gene set HALLMARK_XENOBIOTICS_METABOLISM could represent a predictive biomarker.
LGG-22. SJ901: Phase I/II evaluation of single agent mirdametinib (PD-0325901), a brain-penetrant MEK1/2 inhibitor, for the treatment of children, adolescents, and young adults with low-grade glioma (LGG)
Authors: Vinitsky Anna , Chiang Jason , Bag Asim K , Campagne Olivia , Stewart Clinton F , Dunphy Paige , Shulkin Barry , Li Qian , Lin Tong , Hoehn Mary Ellen , Johnson Jason N , Towbin Jeffrey A , Khan Raja , Tatevossian Ruth G , Armstrong Gregory T , Potter Brian , Conklin Heather , Shearer Todd , Scott Susan , Robinson Giles W 
Published: June 2022

Abstract
BACKGROUND: MEK inhibitor trials in pediatric low-grade glioma (pLGG) have yielded promising results, but there remains room for improvement since objective responses are rarely complete and disease recurrence after completion of therapy is common. Mirdametinib (PD-0325901) is a highly selective MEK1/MEK2 inhibitor that, in preclinical studies, has been reported to have superior blood-brain-barrier penetration compared to other MEK inhibitors. As such, we recently launched the SJ901 clinical trial (NCT04923126) to determine the safety, recommended phase 2 dose, pharmacokinetics, and preliminary efficacy of mirdametinib in patients with pLGG when administered continuously. Here, we present preliminary phase 1 data. METHODS: SJ901 is a multi-arm phase I/II trial of mirdametinib in patients &gt;2 and &lt;25 years with LGG. Phase I requires participants to have no prior exposure to MEK inhibitors and recurrent/progressive disease with biopsy-proven evidence of MAPK pathway activation. Three escalating dose levels (2 mg/m2/dose BID, 2.5mg/m2/dose BID and 3mg/m2/dose BID) are planned using a rolling 6 design. RESULTS: Accrual began in June 2021. As of Jan 13, 2022, eleven patients enrolled: 5 on dose level 1 (DL1) and 6 on dose level 2 (DL2). Median age is 10 (3-21) years. Ten patients have somatic gene rearrangements (7 BRAF, 1 MYB, 1 RAF1, 1 FGFR1) and one has an NF1 germline mutation. Four have metastatic disease. No dose-limiting toxicities occurred for DL1 (whereas data are pending for DL2) and only grade 1/2 treatment-related adverse events have been observed. No MEK-related retinopathy or cardiopathy has been observed. Four of the six patients with at least one follow-up disease evaluation have a minor response (&gt;25%-&lt;50% decrease). Median time on therapy is 6.6 (2.2-7) months. No disease progressions have occurred. CONCLUSION: Thus far, mirdametinib is well-tolerated and clinically promising when dosed continuously in patients with recurrent/progressive pLGG. More information will be forthcoming.
LGG-23. Cardiac function in children and young adults treated with MEK inhibitors: a single institution retrospecive cohort study
Authors: Robison Nathan , Su Jennifer , Fang Melody , Malvar Jemily , Menteer Jondavid 
Published: June 2022

Abstract
INTRODUCTION: MEK inhibitors (MEKi) have shown efficacy in pediatric low-grade glioma, among other tumors, but have been associated with acute cardiac dysfunction in adults. Cardiac consequences in children are unknown. MATERIAL AND METHODS: We performed a single center retrospective cohort study evaluating cardiac function by echocardiography (echo) in children and young adults &lt;21 years old receiving MEKi at Children’s Hospital Los Angeles between October 2013 and May 2018. Blinded assessment of left ventricular function by fractional shortening (FS) and ejection fraction (EF) was performed on all available echocardiograms obtained before, during, and following therapy, as well as after re-initiation of therapy. RESULTS: Twenty-six patients underwent MEKi therapy with echo follow-up during the study period. Twenty-four of these had complete echo data. Median follow-up was 12 months. Borderline EF (EF 53-57.9%) occurred in 12 (50%) patients; and 3 (12.5%) progressed to abnormal EF (EF &lt;53%). Cardiac dysfunction, when it occurred, was mild (lowest documented EF was 45%, and lowest FS was 24.4%). EF abnormalities typically fluctuated during therapy, resolved off therapy, and recurred with MEKi re-initiation. No clinical or demographic differences were detected between those who maintained normal cardiac function and those who developed borderline or overt cardiac dysfunction. Symptomatic heart failure did not occur. CONCLUSION: In this cohort of children and young adults, MEKi use was associated with a relatively high incidence of borderline decrease in left ventricular function, often of uncertain clinical significance. There was no evidence of permanent cardiac dysfunction. Further evaluation in larger prospective trials is needed.
LGG-24. Neurocognitive impairment and functional independence in adult survivors of childhood glioma: A report from the Childhood Cancer Survivor Study (CCSS)
Authors: Papini Chiara , Xing Mengqi , Salehabadi Sedigheh Mirzaei , Olsson Ingrid Tonning , Lange Katharine , de Blank Peter , Salloum Ralph , Srivastava Deo Kumar , Leisenring Wendy M , Howell Rebecca M , Oeffinger Kevin , Robison Leslie L , Armstrong Gregory T , Krull Kevin R , Brinkman Tara M 
Published: June 2022

Abstract
PURPOSE: Survivors of pediatric glioma are at risk of developing physical and neurocognitive sequelae secondary to their tumor and its treatment. The contribution of these conditions to attainment of functional independence has not previously been examined. METHODS: 1,284 adult survivors of pediatric glioma (48% male, median [range] 30 [18-51] years at assessment, 22 [15-34] years since diagnosis) completed the CCSS Neurocognitive Questionnaire with impairment defined as scores &gt; 90th %ile of sibling norms. Treatment exposures were categorized as surgery only, chemotherapy (± surgery), or cranial radiation (± chemotherapy/surgery). Self-reported chronic health conditions (CHCs) were graded by organ system using NCI’s CTCAE v4.3. Latent class analysis utilized six factors (employment, marital status, independent living, driver’s license, assistance with routine needs, assistance with personal care needs) to identify classes of functional independence. Multivariable modified Poisson regression evaluated relative risk (RR) of neurocognitive impairment between the classes, adjusting for sex, race, age at assessment, and age at diagnosis. Path analysis explored the impact of treatment exposures on functional independence, mediated by Grade 2-4 CHCs and neurocognitive impairment. RESULTS: Three latent classes of functional independence were identified: independent (58%), moderately independent (20%), and non-independent (22%). Compared to the independent class, non-independent survivors were at elevated risk for impaired task efficiency (RR=3.86, 95% CI, 2.97-5.01), memory (RR=2.39, 95% CI, 1.91-2.98), organization (RR=2.04, 95% CI, 1.64-2.54), and emotional regulation (RR=1.67, 95% CI, 1.30-2.15). Path analysis revealed significant direct paths from cranial radiation (β=0.14), impaired task efficiency (β=0.42), and sensorimotor (β=0.22) and endocrine conditions (β=0.24) to non-independence. Cranial radiation also was indirectly associated with non-independence through impaired task efficiency (β=0.06), and sensorimotor (β=0.06) and endocrine conditions (β=0.10). CONCLUSIONS: Neurocognitive impairment and chronic health conditions partially mediate the association between treatment exposures and attainment of independence in adulthood, identifying potential intervention targets to promote independence in long-term survivors.
LGG-32. Integrated biologic, radiologic and clinical analysis of pediatric low-grade gliomas during and after targeted therapy treatment
Authors: Tsai Jessica W , Choi Jungwhan John , Ouaalam Hakim , Murrillo Efrain Aguilar , Yeo Kee Kiat , Vogelzang Jayne , Sousa Cecilia , Woods Jared K , Ligon Keith L , Warfield Simon K , Bandopadhayay Pratiti , Cooney Tabitha M 
Published: June 2022

Abstract
BACKGROUND: Pediatric low grade gliomas (pLGGs) are the most common central nervous system tumor in children, characterized by driver alterations in the RAS and MAPK pathways. Genomic advances have facilitated use of molecular targeted therapies, however their long-term impact on tumor behavior remains critically unanswered. METHODS: We performed an IRB-approved, retrospective chart and imaging review of pLGGs treated with off-label targeted therapy at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center from 2010 to 2020. Volumetric analysis was performed for BRAFV600E and BRAF fusion/duplication driven pLGG subsets. RESULTS: Fifty-five patients were identified (dabrafenib n = 15, everolimus n = 26, trametinib n = 11, and vemurafenib n = 3). Targeted agent was used as first or second-line therapy for 58% (32/55). Median duration of targeted therapy was 0.79 years (0.01 – 4.87), and overall median follow-up was 2.50 years (0.01 – 7.39). The 1-year, 3-year, and 5-year EFS from targeted therapy initiation were 62.1%, 38.2%, and 31.8%, respectively. Mean volumetric change for BRAFV600E mutated pLGG on BRAF inhibitors was -54.11%, and median time to best volumetric response was 8.28 months (n = 12). Median time to largest volume post-treatment was 2.86 months. Mean volumetric change for BRAF fusion/duplication pLGG on MEK inhibitors was +7.34% with median time to best volumetric response of 6.71 months (n = 7). Median time to largest volume post-treatment was 2.38 months. CONCLUSIONS: Our integrated clinical and volumetric data suggest the majority of patients receiving BRAF inhibitors or trametinib achieve reduction in tumor volume while on therapy and that tumor stability can be achieved following targeted therapy cessation. Moreover, volumetric analysis shows promise as a tool to assess targeted therapeutic response in pLGGs.
LGG-38. Dose-dependent seizure control for an NF1 patient treated via MEK-inhibition for optic pathway glioma
Authors: Cantor Evan , Meyer Ashley , Ogle Andrea , Shatara Margaret , Cluster Andrew , Abdelbaki Mohamed S , Morris Stephanie , Weisenberg Judith , Brossier Nicole M 
Published: June 2022

Abstract
BACKGROUND: Low-grade gliomas (LGG) are the most common solid tumor of childhood and can result in neurologic complications, including seizures, focal neurologic deficits, and learning difficulties. Molecularly targeted agents are increasingly being utilized to treat LGG, but the effect of these agents on accompanying neurologic complications are poorly understood. CASE: An 8-years old male with Neurofibromatosis Type 1 (NF1), medically refractory epilepsy and deep extensive glioma (extending from the optic pathway and involving the basal ganglia and corpus collosum) began selumetinib therapy due to radiographic and symptomatic tumor progression. Radiographic response (resolution of enhancement) was observed at 12 weeks of therapy, accompanied by improvement in seizure frequency, hemiparesis, and academic performance. Due to cardiotoxicity observed at that time (asymptomatic decreased ejection fraction and shortening fraction on echocardiogram), selumetinib was reduced to 50% dosing. On this reduced dose of selumetinib, seizures increased in frequency with subsequent worsening hemiparesis and recurrence of learning difficulties. One month later, dosing was escalated back to 100% due to interval resolution of cardiotoxicity, resulting in resolution of seizures and improvement in focal neurologic deficits and cognition. DISCUSSION: Dose-dependent response to MEK inhibition was observed without concurrent changes in anti-epileptic medications. The tumor was stable in size despite improved enhancement with treatment, suggesting that objective response by RANO criteria is not necessary for improved seizure control in LGG. Recent work has implicated the RAS/MEK/ERK pathway in neuronal precursor cells as a cause for epilepsy, suggesting that MEK inhibition of NF1-heterozygous neurons could be contributing to treatment response in this patient. Improvements in weakness and academic performance may have been due to improved seizure control or a direct effect of MEK inhibition on NF1-heterozygous neurons. CONCLUSION: MEK inhibition may have a clinically relevant anti-seizure effect for patients with pediatric LGG or NF1.