bluuebunny/crossref_metadata_2025 huggingface dataset:
DIPG-51. DIFFUSE MIDLINE GLIOMAS HIJACK MYELOID CELL POPULATIONS TO INITIATE AN ANTI-INFLAMMATORY TUMOR IMMUNE MICROENVIRONMENT
Authors: Metselaar Dennis Serge , du Chatinier Aimée , Verbaan Annemieke , Gamas-Vis Susanne , Waranecki Piotr , Ruiz-Moreno Cristian , Kranendonk Mariette , Stunnenberg Hendrik , Phoenix Timothy , Hoving Eelco Wieger , Kool Marcel , Meel Michael Hananja , Hulleman Esther
Published: June 2024

BACKGROUND

Diffuse midline gliomas (DMG) are universally fatal pediatric brain tumors, for which no effective treatment exists. These tumors are known for their “cold” non-inflammatory tumor-immune microenvironment (TIME), which is thought to be a major hurdle for immunotherapy efficacy.

METHODS/RESULTS

To further investigate the mechanisms that drive this cold environment, we allografted immunocompetent mice with Histone 3.3 Lysine 27 (H3.3K27M) and 3.1 Lysine 27 (H3.1K27M) mutant murine DMG tumors, created through intra uterine electroporation, and performed single-cell analyses on the tumors that developed. Using Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITEseq) we mapped the single-cell RNA and protein expression profiles of the TIME of these tumors and healthy pontine regions, with a dominant focus on the myeloid cell populations. Through differential expression and pathway enrichment analyses, we found that DMG-microglia populations upregulate anti-inflammatory pathways and, over time, are pushed out by infiltrating anti-inflammatory macrophages. We confirmed these findings in single-cell sequencing data from DMG patients, taken at diagnosis and at late stage disease. Next, we established microglia cultures in vitro, by differentiating monocytes from healthy donors into microglia. We discovered that treatment of these microglia with tumor-conditioned medium, taken from primary DMG cultures, diminished their pro-inflammatory potential after stimulation with lipopolysaccharides (LPS), as observed by cytokine release arrays that showed a strong downregulation of IL-6 and TNF-alpha release, amongst others. Subsequently, using a Seahorse metabolic analyzer, we found that glycoATP potential was diminished in DMG-primed microglia after LPS stimulation, further suggesting that DMG-excreted factors are responsible for blocking the pro-inflammatory potential of microglia.

CONCLUSIONS

Taken together, these findings increase our understanding on how DMG cells reprogram tumor-associated myeloid cells to generate an immune-cold TIME, which will aid the scientific community to find therapeutic solutions to reverse this phenomenon and improve the efficacy of immunotherapy in these devastating malignancies.
DIPG-59. RADIATION-INDUCED DIPG IN A CHILD PREVIOUSLY IRRADIATED FOR CRANIOPHARYNGIOMA: CASE REPORT AND LITERATURE REVIEW
Authors: Ain Rahat Ul , Rehman Laeeq Ur , Qaiser Rabia Aqeel , Goraya Amber , Salman Zeena , Qaddoumi Ibrahim , Mushtaq Naureen , Bouffet Eric
Published: June 2024

BACKGROUND

Radiation-induced second malignancies occur in a subset of patients following cranial radiation therapy (RT). In Craniopharyngioma (CP), adjuvant RT is commonly recommended for residual tumor or recurrence, and radiation-induced malignant gliomas (RIMGs) are rarely reported.

METHODS

We report a case of radiation-induced diffuse intrinsic pontine glioma (DIPG) in pediatric Craniopharyngioma and conducted a review of previously reported cases.

RESULTS

A 14-year-old boy presented with complaints of headaches and vomiting for 1 month; difficulty in walking, and slurred speech for 1 week, with Lansky Performance Score (LPS) of 20. Eight years before this admission, he underwent surgical excision and 3D-conformal RT for Craniopharyngioma. His recent MRI brain was suggestive of DIPG and after a multidisciplinary discussion re-irradiation (30Gy in 10 fractions) was given. He has been alive for 5 months since diagnosis with improved symptoms and LPS (70). Including the index case, 19 cases of RIMGs in CP were identified. All except one were reported from high-income countries. Only 4 involved the pons/brainstem. The median age at CP diagnosis was 7.0 years (2.0-22.0 years), and with RIMG was 18 (6.8-41.0 years). Median latency period was 10.0 years (4.5-25.0 years). The female-to-male ratio was 1.8:1. The median previous RT dose was 54.8 Gy (49.3-60.1 Gy) with 37% cases treated with 3D conformal and 37% with conventional RT (not specified in 26%). Cerebral cortex (66.6%) was the most common site for the RIMG with temporal lobe predisposition. Chemotherapy was given in 56%, surgical excision in 50% and repeat RT in 31% cases with a median survival of 4 months (0-13 months).

CONCLUSION

We report the first case of radiation-induced DIPG in pediatric Craniopharyngioma in an LMIC. RIMG appears to be a rare occurrence in CP and doesn’t seem to be associated with the RT type. The overall prognosis is extremely poor.
DIPG-73. FOCUSED ULTRASOUND FOR TREATMENT OF CHILDREN DIAGNOSED WITH DIFFUSE MIDLINE GLIOMAS
Authors: Woldegerima Ayda , Wei Hong-Jian , Zhang Chunchao , Yadavillli Sridevi , Packer Roger , Wu Cheng-Chia , Nazarian Javad
Published: June 2024

BACKGROUND

Diffuse midline glioma (DMG) is a highly aggressive and fatal brain tumor that predominantly impacts children and young adults. The infiltrative pattern and rapid growth characteristics of DMG causes a significant challenge in finding an effective treatment. Additionally, the blood-brain barrier (BBB) poses a significant challenge by restricting the passage of therapeutic drugs to tumor bed. Currently the established standard of care is radiotherapy (RT), which is transitory. Thus there is a need for improved treatment options.

OBJECTIVE

Focused ultrasound (FUS) is an advancing non-invasive technology that has been used to open BBB and enhance drug delivery. We hypothesize that a combination therapy of FUS with pharmacological agents will be an effective and non-invasive treatment option for children diagnosed with DMG.

METHOD

Syngeneic DMG murine models were used to study the combination therapy of FUS with ONC201, FUS with anti-PD1 and FUS with RT. FUS mediated BBB opening was monitored with contrast-enhanced T1-weighted MRI. FUS-mediated drug delivery was validated with western blot, assessment of ROS, and optical label imaging. Kaplan Meier analysis was used to assess survival benefits. Single cell RNA-sequencing (scRNA-Seq) analysis is being done to assess the treatment effects of FUS and RT combination therapy.

RESULTS/CONCLUSION

We found that FUS and ONC201 combination therapy resulted in a decrease in NDUFA12 protein (a biomarker of ONC201 response) and an increase in ROS production compared to ONC201 monotherapy. For FUS and anti-PD1 combination therapy, an increased anti-PD1 delivery to the brainstem was detected. The overall survival of mice treated with FUS and anti-PD1 combination therapy increased when compared to anti-PD1 alone. Our preliminary scRNA-Seq analysis showed that combination therapy of FUS and RT induces innate immune response compared to the untreated group. Combination therapy with focused ultrasound shows a promising outcome by increasing the efficacy of therapeutic drugs and immunotherapy.
DIPG-80. IMAGING CHARACTERISTICS IN PEDIATRIC PATIENTS WITH DIFFUSE INTRINSIC PONTINE GLIOMA AND OUTCOME: THE MD ANDERSON CANCER CENTER EXPERIENCE
Authors: Stitzlein Lea M , Baig Muhammad , He Jiasen , Paulino Arnold , Yeboa Debra N , Calle Susana , Majd Nazanin , McGovern Susan , Zaky Wafik
Published: June 2024

BACKGROUND

Diffuse intrinsic pontine glioma (DIPG) occurs exclusively in children and, although rare, carries a poor prognosis with a median survival of approximately 10 months. Diagnosis is made on clinical and radiological appearance of the tumor. The treatment for DIPG is radiation therapy, but it is inadequate as most patients experience rapid progression and succumb to the disease. Our study sought to review radiological characteristics and survival outcomes in pediatric DIPG patients at MD Anderson Cancer Center to better understand imaging and improve current DIPG management.

METHODS

We performed a retrospective review of demographic and clinical data of patients with radiographic diagnosis of DIPG from 2006-2019, with IRB approval. The patients included in this study were treated at The University of Texas MD Anderson Cancer Center. Imaging findings upon diagnosis of DIPG, including the presence of hydrocephalus, intratumoral bleeding, contrast enhancement, and necrosis, were correlated with survival using Kaplan-Meier methods

RESULTS

This study included 25 patients diagnosed with DIPG via MRI imaging. The median OS was 13.7 months and median PFS was 10 months for this cohort. At diagnosis, if the patient had hydrocephalus or intratumoral bleeding, the median PFS were shorter compared with those who did not (8.5 and 5.4 months vs 12.2 and 10.8 months; Log-rank, P=0.019 and P=0.029, respectively). Other imaging findings, including contrast enhancement (CE) or presence of necrosis, are trending toward worse outcomes (CE vs no CE: PFS 7.9 vs 11.1 months, P=0.10; necrosis vs no necrosis: PFS 5.2 vs 10.5 months, P=0.78, respectively)

CONCLUSION

Imaging characteristics at diagnosis can be predictive of outcome. Hence, we propose to consider early interventions for these subgroups with worse outcomes to proceed with shunt placement and early enrollment for clinical trials as feasible. To further validate these findings, a large prospective study is required.
DIPG-91. CLINICAL, RADIOGRAPHIC, HISTOPATHOLOGIC, AND MOLECULAR CHARACTERISTICS OF LONG-TERM SURVIVORS OF DIFFUSE INTRINSIC PONTINE GLIOMA-AN UPDATE FROM THE INTERNATIONAL AND EUROPEAN SOCIETY FOR PEDIATRIC ONCOLOGY DIPG REGISTRIES (IDIPGR/SIOPE-DIPGR)
Authors: Pillay-Smiley Natasha , Nussbaumer Gunther , Damen-Corbijn Carin , Baugh Joshua , Webster Aaron , Lane Adam , Godschalk T C , Grill Jacques , Hawkins Cynthia , Leach James , Janssens Geert , Jones Blaise , Massimino Maura , Karremann Michael , van Vuurden Dannis G , Bailey Simon , Das Anirban , Thomale Ulrich-Wilhelm , Goldman Stewart , Perreault Sebastien , Biassoni Veronica , Minturn Jane , Hummel Trent , Kramm Christof , van Zanten Sophie Veldhuijzen , Hoffman Lindsey M
Published: June 2024

BACKGROUND

Diffuse intrinsic pontine glioma (DIPG) is a childhood tumor with median survival of < 1 year. Survival-associated factors for this rare disease are poorly understood.

METHODS

Clinical, radiological, and histo-molecular data were abstracted from databases of the IDIPGR and SIOPE-DIPGR and analyzed using descriptive statistics. Survival was estimated by the Kaplan Meier method. Short term survivors (STS) were defined as overall survival (OS) < 2 years, and long term survivors (LTS) had OS >2 years. We present data from the IDIPGR with additional analyses forthcoming.

RESULTS

Analysis included 1123 patients with DIPG, with 476 undergoing central radiographic review. Median OS for the entire cohort was 11 months (IQR 7-15 months), with 2 yr OS 6.9% (5.6% to 8.6%). Median age at diagnosis was 6.6 years (5-9.7 years) for 1045 STS (93.1%) and 6.8 years (3.7-13 years) for 78 LTS (6.9%). Factors significantly associated with LTS included longer symptom duration (STS 73.7% vs LTS 42%; p<0.001), age < 3 and > 10 years (STS 4.5 and 22.8% vs LTS 17.9 and 35.9%; p<0.0001), and receipt of chemotherapy at any time during therapy (STS 54.7% vs LTS 67.9%; p=0.025). A similar percentage of STS and LTS received EGFR, MTOR, PI3K, HDAC, local delivery and immunotherapy, although more LTS used VEGF inhibition (20.5 % vs 8.6%; p = 0.002). Of 104 patients with molecular data, 69 harbored the H3.3 histone mutations (7 LTS, 62 STS), and 15 had H3.1(3 LTS, 12 STS).

CONCLUSION

Early analysis of factors associated with survival in patients with DIPG reveal similar findings as the prior IDIPGR/SIOPE-DIPGR study in 2018. These findings will be updated for the final presentation to include ~400 more cases and additional radiological and molecular data.
TRLS-11. PNOC005: ONCOLYTIC MEASLES VIRUS FOR THE TREATMENT OF CHILDREN AND YOUNG ADULTS WITH RECURRENT MEDULLOBLASTOMA OR ATYPICAL TERATOID RHABDOID TUMOR
Authors: Kline Cassie , Yu Bohyeon , Knowles Truman , Ranavaya Aeesha , Minturn Jane , Banerjee Anuradha , Leary Sarah , Abdelbaki Mohamed , Whipple Nicholas , Goldman Stewart , Margol Ashley , Dabobo Nour , Rauschecker Andreas , George Elizabeth , Nabavizadeh Ali , Hoare Owen , Jung Jangham , Phillips Joanna , Prados Michael , Molinaro Annette , Gupta Nalin , Raffel Corey , Cole Kristina , Diaz Aaron , Mueller Sabine
Published: June 2024

BACKGROUND

PNOC005 is a phase 1 clinical trial investigating the safety and tolerability of intratumoral or intrathecal administration of oncolytic measles virus (MV-NIS) in children and young adults with recurrent medulloblastoma (MB) or atypical teratoid/rhabdoid tumor (ATRT).

METHODS

Patients with recurrence of MB or ATRT were stratified into Stratum A (local recurrence) or B (disseminated recurrence). Stratum A patients received MV-NIS directly into the tumor bed at time of surgical resection. Stratum B patients received a single dose of MV-NIS via lumbar puncture. After safety was demonstrated in Stratum A and B, Stratum C was added with repeat dosing on Day 0 and 7 for patients with recurrent disseminated MB. Specimens for viral shedding were collected. Blood was collected on days 0, 4, 7, 14, and 28. RNA-sequencing deconvolution and time-series analysis were performed to estimate the composition and phenotypes of peripheral blood mononuclear cells (PBMCs).

RESULTS

Thirty-four patients (median age 8.5, range 2-31) enrolled between February 2017 and April 2021, with 23 evaluable patients with MB and 4 with ATRT. One patient experienced a dose-limiting toxicity (grade 3 alanine aminotransferase increase). There were four MV-NIS-related adverse events grade 3 or greater across all strata. Viral shedding was detected in 5 patients, all of which cleared by end-of-treatment. We found a similar gene-expression program in PMBCs that correlated across patients (n=18), which was upregulated at days 4-7 post treatment and consistent with an antiviral response. Concomitant changes in B, T, and natural-killer cell composition and activation were consistent with this interpretation.

CONCLUSION

This is the first trial investigating intratumoral as well as repeated intrathecal delivery of MV-NIS in children with MB and ATRT. We show that therapy is safe and well-tolerated with minimal adverse effects. Immune markers and biologic correlates preliminarily indicate anti-viral effects in tumors.
ETMR-01. BRAIN STEM TUMORS IN CHILDREN LESS THAN THREE MONTHS: CLINICAL AND RADIOLOGIC FINDINGS OF A RARE DISEASE
Authors: Papangelopoulou Danai , Bison Brigitte , Behrens Lars , Bailey Simon , Ansari Marc , Ehlert Karoline , Martinez Ofelia Cruz , Kramm Christof M , La Madrid Andres Morales , von Bueren Andre O
Published: June 2024

BACKGROUND

Brainstem gliomas account for 10-20% of all central nervous system pediatric neoplasms. Brain stem tumors in children less than three months old at diagnosis are extremely rare. Our aim is to study a retrospective cohort to improve the understanding of the disease course and guide patient management.

METHODS

This is a multicenter retrospective analysis across the European Society for Pediatric Oncology SIOP-E HGG/DIPG Working Group linked centers and included patients with a brainstem tumor diagnosed between 2009 and 2020 and aged less than 3 months at diagnosis. Clinical data was collected, and imaging characteristics were analyzed blindly and independently by two experienced neuroradiologists.

RESULTS

Five cases (female; n=4) were identified of which no patient received any therapy. The epicenter of 2 tumors was in the medulla oblongata alone and in the medulla oblongata and the pons in 3 cases. For patients with tumor in equal parts in the medulla oblongata and the pons (n=3) the extension at diagnosis involved the spinal cord; for the 2 patients with the tumor epicenter in the medulla oblongata alone (n=2) the extension at diagnosis included the pons (n=2) and the spinal cord (n=1). Biopsy was performed in one patient identifying a pilocytic astrocytoma. Two patients died rapidly. In one patient autopsy revealed a high-grade glioma (case 3). Three survivors showed either spontaneous tumor regression (n=2) or stable disease (n=1). The surviving patients were followed-up for 10, 7, and 0.6 years, respectively. One case had the typical imaging characteristics of a dorsal exophytic low-grade glioma.

CONCLUSIONS

No patient fulfilled the radiologic criteria defining a high-grade glioma. Central neuroradiological review and biopsy (if feasible) may provide useful information with regards to the patient’s management.
ETMR-08. DECODING TUMOR-NEURONAL COMMUNICATION IN PEDIATRIC BRAIN TUMORS: INSIGHTS FROM ETMR 3D MODEL REVEALING MECHANO-SIGNALING DYNAMICS AND THERAPEUTIC OPPORTUNITIES
Authors: Sterbies Nicolas , de Faria Flavia Watusi , Riedel Nicole , Münter Daniel , Altendorf Lea , Göbel Carolin , Inserte Clara , Roy Rajanya , Thomas Christian , Schüller Ulrich , Bruder Jan M , Kerl Kornelius
Published: June 2024

INTRODUCTION

Exploring tumor-neuronal interactions is essential for comprehending brain tumor proliferation, chemotherapy resistance, and patient survival. While glioma research has made significant strides, our understanding of tumor-neuronal interactions in pediatric brain tumors, notably Embryonal Tumors with Multilayered Rosettes (ETMRs), remains limited.

METHODS

To elucidate tumor-neuronal interactions in ETMRs, we developed a 3D model by co-aggregating the human ETMR cell line BT-183 with human induced pluripotent stem cells (iPSCs) and allowing them to mature into forebrain organoids for 30 days, forming ETMR-forebrain organoids (ETMR-FBO). We further employed single-cell RNA sequencing to compare the gene expression profile of healthy forebrain organoids (FBO) with the ETMR-FBOs. Additionally, we conducted immunohistochemistry of 3D model sections for comparative evaluation and spatial transcriptomics of murine and human primary ETMR samples.

RESULTS

Our integrated dataset of 48,764 cells of healthy FBOs (n = 4) and ETMR-FBOs (n = 6) revealed that ETMR tumor cells impeded the neuronal differentiation of the FBO cells. The ETMR-FBOs exhibited a significant enrichment of neuro-stem cells (67% vs 49%), accompanied by a reduction of more differentiated neuronal cells. Comparative trajectory analysis confirmed a blockage of neuronal maturation/differentiation in ETMR-FBOs compared to controls without ETMR cells. Immunohistochemistry further confirmed an enrichment of SOX2-positive/synaptophysin-negative neuronal progenitors in the organoid areas closest to the tumor border. Additionally, we identified upregulated extracellular matrix-related pathways, particularly integrin and YAP/TEAD signaling, in the neuro-stem cell compartment of ETMR-FBOs. This implies a tumor-specific mechano-signaling mechanism influencing the neuronal differentiation state of the tumor microenvironment.

CONCLUSION

Our findings suggest that mechano-signaling-related tumor-neuronal interactions in ETMR contribute to the formation of an immature neuronal niche. Targeting mechano-signaling may hold promise for innovative therapies by disrupting tumor architecture and enhancing susceptibility to chemotherapy.
ETMR-11. RECURRENT GENETIC ALTERATIONS IN EPIGENETICALLY DEFINED PINEOBLASTOMA SUBTYPES
Authors: Goschzik Tobias , Yuan Mathias , Pfaff Elke , Mynarek Martin , Doerner Evelyn , Jones David T W , Pfister Stefan M , Rutkowski Stefan , Pietsch Torsten
Published: June 2024

INTRODUCTION

Genome-wide methylation analyses recently revealed distinct epigenetic pineoblastoma (PBL) subtypes. The aim of the study was to shed further light onto the genetic characteristics underlying the pathogenesis of pineoblastoma subtypes.

METHODS

Cytogenetic alterations of tumor samples of 76 patients with a diagnosis of PBL confirmed by reference neuropathology and methylation-based subtyping were analyzed by high-resolution genome-wide molecular inversion probe analysis. Seventy-two cases were screened for mutations by next-generation DNA panel sequencing. Survival data of 49 patients were available. Patients ≥4y received postoperative RT followed by maintenance chemotherapy (n=42); infants (<4y) were primarily treated on RT-sparing regimens with intensified chemotherapy.

RESULTS

According to epigenetic consensus PBL subtypes (Liu et al., 2021), our cohort consisted of 48 PBL-miRNA1 (1A=40; 1B=8), 17 PBL-miRNA2, 4 PBL-MYC/FOXR2, and 7 PBL-RB1 samples. PBL-miRNA subtype tumors had characteristic alterations in microRNA-processing genes; DICER1 mutations (n=18) and homozygous deletions of the DROSHA locus (n=17) were most abundant, followed by DROSHA mutations (n=12). Most frequent cytogenetic aberrations in PBL-miRNA were whole chromosome (chr.) 7 gain (n=30) and chr. 14 loss (n=21). DICER1 mutations were significantly associated with chr. 14 loss (p<0.001). Twenty-one cases showed gains of chr. 14, 8 additional cases gains of the OTX2 oncogene (chr. 14q). In the miRNA subtypes we identified cases with polyploid cytogenetics (n=15). Of note, only one of the 8 patients with polyploid tumors and survival data died, while the remaining patients of the miRNA subtypes had a 5-year PFS/OS of 61.46±9.27/63.24±9.23% (14 of 35 died) after a median follow-up time of 5.52 years. However, this comparison did not reach statistical significance (p=0.25).

CONCLUSION

The epigenetically defined PBL-miRNA subtypes are characterized by distinct cytogenetic and mutational events. A possible prognostic role for a superior (e.g. polyploidy) or inferior outcome requires investigation in prospective clinical trials.
ETMR-21. PRIMARY DIFFUSE LEPTOMENINGEAL MELANOMATOSIS (PDLM) ASSOCIATED WITH INTRACRANIAL BLEEDING AND RAPID PROGRESSION IN A CHILD
Authors: Sim Megan , Hendson Glenda , Yip Stephen , Singhal Ash , Haji Faizal , Pauranik Anvita , Hukin Juliette , Michaiel George
Published: June 2024

BACKGROUND

PDLM is a rare and aggressive disease with limited cases reported worldwide and few cases in the pediatric population. Herein we report on clinical, histologic, and molecular/genetic findings of a young child with PDLM and rapid clinical progression.

CASE STUDY

A 12-year-old right-handed male presented with two months of intermittent fevers, progressive frontal headaches, lethargy, vomiting, and weight loss, and one month of focal seizures with altered awareness, speech arrest, eye deviation, and tonic posturing. Examination revealed bilateral papilledema and signs of increased intracranial pressure. A brain CT demonstrated increased density of the anterosuperior right frontal lobe and punctate focus of increased density along the left frontal lobe suggestive of hemorrhage. MRI revealed diffuse leptomeningeal thickening and enhancement throughout the brain and spinal cord. At biopsy, the frontal lesion was noted to be grossly abnormal and discolored, and on pathology demonstrated a melanocytic neoplasm infiltrating the subarachnoid space and extending into Virchow-Robin spaces. Tumor cells stained strongly for HMB45, vimentin, Melan-A, and PRAME and were BRAFV600E negative. RNA sequencing was negative for structural variants, Whole exome sequencing revealed a Tier I missense variant in NRAS (c.181C>A) among other copy number variations and loss of heterozygosity. Comprehensive ophthalmologic and dermatologic examinations as well as whole body PET/CT did not reveal any other sites of disease. He was due to commence immunotherapy with combination PD-1/CTLA-4 inhibitors but developed status epilepticus and raised intracranial pressure, warranting ventriculoperitoneal shunt insertion. Three days later, he had further deterioration with altered level of consciousness, hypertension, eye deviation, and vomiting. CT brain revealed large bifrontal hematomas with mass effect and care was redirected to palliation.

CONCLUSION

PDLM can be challenging to diagnose with a rapidly progressive course. Advanced molecular diagnostics may provide new targets for precision therapy, though overall outcomes remain dismal.
EPEN-06. IDENTIFICATION OF CSF MIRNA BIOMARKERS FOR THE EARLY DETECTION OF MEASURABLE RESIDUAL DISEASE IN PAEDIATRIC EPENDYMOMA: A BIOMECA STUDY
Authors: Chapman Rebecca J , Scurlock Zachary G L , Scarpini Cinzia G , Lourdusamy Anbarasu A , Ritzmann Timothy A , Murray Matthew J , Grundy Richard G
Published: June 2024

BACKGROUND

Ependymoma (EPN) is the second most common malignant paediatric brain tumour. 50% of children relapse. Detection of Measurable Residual Disease (MRD) via MRI is difficult and lacks sensitivity for very early recurrence, necessitating an urgent need for identifying new, robust biomarkers for the early diagnosis, prognosis, and clinical management of disease progression in EPN. We hypothesise that microRNA (miRNA) quantification in the cerebrospinal fluid (CSF) will have clinical utility in the early detection of MRD in these patients.

PATIENTS/METHODS

A discovery cohort of EPN CSF samples (n=12) from patients enrolled on the SIOP Ependymoma II clinical trial (trials.gov identifier: NCT02265770) and control leukaemia CSF samples (n=8) underwent RNA-sequencing (QIAGEN) after total RNA extraction using QIAGEN miRNeasy Serum/Plasma kit. The EPN cohort consisted of infratentorial (IT; n=9), supratentorial (ST; n=1) and spinal (SP; n=2) cases taken prior to, or at, resection (primary/relapse).

RESULTS

Raw sequencing data entered a quality-control pipeline (Tally/Cutadapt), followed by alignment to miRBase-v22 (https://mirbase.org/) using Chimira (PMID:26093149). Two outlying (infratentorial) EPN samples were removed, leaving a 10 (IT+ST+SP) versus 8 comparison. Extracted raw counts were normalised across samples using DESeq2 (PMID:25516281) and 87 differentially-expressed miRNAs identified (adj-p<0.05). EPN samples completely segregated from controls on clustering/heatmap analysis. From these 87 miRNAs, a core set of 53 were overlapping in comparisons removing spinal (IT+ST remaining) and supratentorial (IT alone) samples. These miRNAs underwent combined ranking by adjusted-p and abundance (normalised count) values, and top-ranking candidates taken forward for confirmation using highly-sensitive Taqman PCR, prior to validation in additional samples.

CONCLUSION

Circulating miRNA quantification offers promise for EPN diagnosis and MRD detection. Further CSF study in larger patient cohorts, and serum/plasma analysis, are now warranted.
EPEN-12. EZHIP IMPACTS CELLULAR DIFFERENTIATION IN POSTERIOR FOSSA GROUP A EPENDYMOMA
Authors: Jaunecker Carola , Jenseit Anne , Zehetbauer Theresa , Stepien Natalia , Wang Shanzheng , Bruckner Katharina , Hübner Jens-Martin , Gabler Lisa , Lang Alexandra , Madlener Sibylle , Mager Leah , Haberler Christine , Berger Walter , Dorfer Christian , Filbin Mariella , Kool Marcel , Gojo Johannes , Lötsch-Gojo Daniela
Published: June 2024

BACKGROUND

High-risk ependymomas are central nervous system tumors comprising ten molecular groups with posterior fossa group A (PFA) and supratentorial ependymoma with zinc finger translocation associated (ST-ZFTA) fusions being among the most aggressive subgroups in children. Loss of H3K27 trimethylation maintained by Enhancer of Zeste homologs Inhibitory Protein (EZHIP) overexpression in PFA or ZFTA-RELA oncofusions in ST-ZFTA ependymoma are known as important driver events. Additionally, we uncovered that high-risk ependymomas arise from undifferentiated cell populations, while more differentiated ependymal-like signatures (e.g. ciliogenic programs) are enriched in prognostically favourable subtypes.

METHODS

We investigated presence of “ependymal-like” signatures by analysing mRNA expression of selected genes (RSPH1, DNAAF1, SLC47A2, CAPS, CAPS-L) in ependymoma bulk samples (n=90). Gene expression was correlated to clinicopathological characteristics (EZHIP expression, 1q-gain/6q-loss, DNA methylation subtype). Impact on mRNA levels of ependymal-like markers was investigated upon an inducible EZHIP knockdown using lentiviral vectors in EPD210FH PFA cells.

RESULTS

Ependymal-like markers were significantly lower expressed in ST-ZFTA as compared to spinal and PFB ependymoma. In PFA ependymoma two distinct groups showing either low or high expression of these ependymal-like genes were present. In detail, “ependymal-like-high” PFA were assigned to the PFA-2 subtype which was also confirmed in an independent cohort. EZHIP was strongly negative prognostic in our cohort and the expression was distinctly induced during PFA progression accompanied by increased ependymal-like signature genes. This suggests an impact of EZHIP on cell differentiation processes particularly during PFA progression. Knock-down of EZHIP in EPD210FH PFA cells increased expression of ependymal signature genes associated with ciliogenesis. Next, we will spatially dissect the correlation between EZHIP and ependymal-like genes in primary and recurrent PFA and investigate DNA methylation, histone marks and EZHIP binding at these gene loci.

CONCLUSION

Overall, our data indicate that ependymal-like cell differentiation is deregulated by EZHIP particularly in progressive PF-A ependymoma.
METB-07. FREQUENCY AND OUTCOMES OF CDKN2A/B LOSS IN PEDIATRIC GLIOMA
Authors: Power Phoebe C , Jones Jacquelyn , Chi Susan N , Baird Lissa , Fehnel Katie P , Ullrich Nicole J , Ligon Keith L , Alexandrescu* Sanda , Bandopadhayay* Pratiti , Kiat Yeo* Kee
Published: June 2024

BACKGROUND

Chromosome 9p21 deletions involving the tumor-suppressor genes cyclin-dependent kinase 2A and 2B (CDKN2A/B) have been identified as a poor prognostic factor in various cancer types, including adult low-grade gliomas. The frequency and influence of CDKN2A/B hemi- and homozygous deletions in pediatric glioma are less well defined. Herein, we report a single-institution evaluation of the frequency and clinical outcomes of CDKN2A/B loss in pediatric gliomas.

METHOD

We performed a retrospective, IRB-approved single institutional study, utilizing an existing institutional data registry to identify pediatric patients (age < 21) diagnosed with a glioma who had undergone targeted DNA next generation panel sequencing (Oncopanel) between 2013-2023. IDH1/2-mutant gliomas were excluded. Clinical features, treatment details and outcome data were collected and analyzed.

RESULTS

Oncopanel was performed on 510 pediatric gliomas. Of these, 372 (72.9%) had low-grade and 138 (27%) had high-grade gliomas. Sixty-six (12.9%) gliomas harbored CDKN2A/B hemi-/homozygous loss; this included 26/372 (7%) low-grade and 40/138 (29%) high-grade gliomas. Homozygous loss was seen in 13/372 (3.5%) low-grade and 26/138 (18.8%) high-grade gliomas. The most common co-alteration with CDKN2A/B loss was BRAFV600E (28/66, 42%), followed by TP53 (8/66, 12%). Median follow-up time of the entire cohort was 3.2 years (range:0.1-36). The 10-year overall survival for pLGGs with CDKN2A/B wildtype and CDKN2A/B homozygous deletion were 95% and 85%, respectively (p=0.03). There was no significant difference in survival of pLGGs with CDKN2A/B wildtype and CDKN2A/B hemizygous deletion. For pHGGs, there was no difference in survival outcomes based on CDKN2A/B status. Further univariate and multivariable analyses are underway. Central pathology review and methylation subtyping to confirm rates of malignant transformation are also ongoing.

CONCLUSION

CDKN2A/B loss is identified in a subset of both pediatric low- and high-grade gliomas. Our data suggest that homozygous CDKN2A/B loss in pLGG is associated with poorer long-term survival.
GCT-06. THE OUTCOMES OF PATIENTS WITH DISSEMINATED GERMINOMA TREATED ON ACNS0232: A REPORT FROM THE CHILDREN’S ONCOLOGY REPORT
Authors: Shatara Margaret , Selukar Subodh , Lin Tong , Gajjar Amar , Donahue Bernadine , Leary Sarah , Fouladi Maryam , Allen Jeffrey C , Abdelbaki Mohamed S
Published: June 2024

BACKGROUND

Central nervous system (CNS) germinomas are curable with craniospinal irradiation (CSI). However, concerns about long-term sequelae led to investigations into neoadjuvant chemotherapy. The ACNS0232 study, a phase III trial, evaluated the efficacy of neoadjuvant chemotherapy followed by response-based radiotherapy (RT) in patients with germinomas.

METHODS

Patients aged 3-21 years with newly-diagnosed histologically-confirmed germinoma were randomized to standard RT alone (Regimen A: 24 Gy CSI with a boost of 21 Gy) or neoadjuvant chemotherapy followed by response-based RT (Regimen B: 2 cycles of carboplatin/ etoposide, and if not in complete response (CR), two additional cycles of of cisplatin/ cyclophosphamide were administered followed by 21 Gy CSI with boost of 9 Gy). The study objectives included comparing event-free (EFS), overall survival (OS) and evaluating response to pre-RT chemotherapy.

RESULTS

Twenty-two patients (10 in Regimen A, 12 in Regimen B) were randomized between January 2007 and May 2009, including 13 with disseminated disease (5 in Regimen A, 8 in Regimen B). The study closed early due to low accrual. The median study follow-up time was 5.8 years. The 5-year EFS estimates were 0.89 (95% CI 0.47, 0.98) for Regimen A and 0.92 (95% CI 0.47, 0.99) for Regimen B. Regimen B was well-tolerated and demonstrated a 72.7% CR rate.

CONCLUSION

Despite the premature closure of the study, ACNS0232 provides valuable insights into the role of neoadjuvant chemotherapy with response-based RT in the treatment of disseminated germinoma. However, it is crucial to acknowledge the limitations of drawing conclusions with such a small sample size. The COG oncology community was not supportive of the proposed phase 3 design, but there is value in expanding the limited experience using Regimen B in a single arm phase 2 study to validate the safety and efficacy of neoadjuvant chemotherapy strategies in patient’s with disseminated CNS germinoma.
GCT-07. CONTRIBUTORS TO DELAYED TREATMENT OF NON-GERMINOMATOUS GERM CELL TUMORS IN CHINA: A TERTIARY-CENTER REVIEW
Authors: Zhang Anan , Liu Anthony P Y , Zhang Rong , Yang Bo , Han Yali , Chen Haiyan , Qaddoumi Ibrahim , Salman Zeena , Chan Godfrey C F , Gao Yijin
Published: June 2024

BACKGROUND

Non-Germinomatous Germ Cell Tumors (NGGCT) are rare malignancies with potential for treatment delays. This study aims to identify risk factors and systemic challenges contributing to delayed management of NGGCT in China.

METHODS

We reviewed the clinical features and referral pattern of 56 consecutively diagnosed NGGCT patients at Shanghai Children’s Medical Center (SCMC) from 9/2018-2/2023. Patients were diagnosed by pathology (n=42), or by elevated markers alone (n=14, AFP>10ng/ml, and/or β-HCG>50mIU/ml). Patients were treated per COG ACNS0122. Delay of treatment was defined as chemotherapy initiated more than 6 months after symptom onset.

RESULTS

Forty-three males and 13 females were included. Median age at diagnosis was 9.17year (4month-16year). Primary tumor locations included the pineal region (n=31), sellar region (n=19), basal ganglia (n=5), and posterior fossa (n=1). Presenting symptoms included features of increased intracranial pressure (ICP, n=29), endocrine symptoms (n=21), blurred vision or squint (n=7), and hemiplegia (n=4). Delayed treatment occurred in 16 cases (29%), and was more likely in patients with non-pineal region primary (Chi-square p=0.003), and absence of symptoms pertaining to increased ICP (Chi-square p<0.001). Reasons for delay included lack of parental recognition on symptoms (n=7), misdiagnosis (n=3), and inappropriate/incomplete workup (n=6). As a national referral center, patients commuted a median of 483 km (range: 12-2943km) to SCMC (median 2 hospitals (1,5) before SCMC), including 10 patients with obvious hydrocephalus travelling before any CSF diversion procedure. Three-year Event-Free Survival (EFS) was 76.9% and Overall Survival was 86.0%. There was a trend to inferior outcome in patients with delay in treatment (3y EFS 69.6%) compared with those without (3year EFS 80.6%, p=0.112).

CONCLUSIONS

Delay in treatment is common for children with NGGCT managed at a tertiary referral center in China. Improving public awareness, training for primary-care clinicians, and establishing a national referral network are potential strategies to enhancing the outcome.
HGG-04. MALIGNANT GLIOMA IN L-2-HYDROXY GLUTARIC ACIDURIA; THOROUGH MOLECULAR CHARACTERIZATION OF A CASE AND LITERATURE REVIEW
Authors: Cordier Fleur , Wesseling Pieter , Tops Bastiaan B J , Kester Lennart , French Pim J , van den Bent Martin , Hinz Felix , Aronica Eleonora , Slot K Mariam , Abbink Floor , van der Knaap Marjo , kranendonk Mariëtte E G
Published: June 2024

L-2-hydroxyglutaric aciduria (L-2-HGA) is a rare neurometabolic disorder characterized by accumulation of L2-hydroxyglutarate (L-2-HG) due to mutations in the L2HGDH gene. L-2-HGA patients have a significantly increased lifetime risk of central nervous system (CNS) tumors. Here, we present a 16-year-old girl with L-2-HGA who developed a tumor in the right cerebral hemisphere, which was discovered after left-sided neurological deficits of the patient. Histologically, the tumor had a high-grade diffuse glioma phenotype. DNA sequencing revealed the germline L2HGDH mutation as well as inactivating mutations in TP53, BCOR and NF1. Genome-wide DNA-methylation analysis was unable to classify the tumor with high confidence. More detailed analysis revealed that this tumor clustered amongst IDH-wildtype gliomas by methylation profiling and did not show the glioma CpG island methylator phenotype (G-CIMP) (in contrast to IDH-mutant diffuse gliomas with accumulated levels of D-2-HG). These findings were against all our expectations given the inhibitory potential of 2-HG on DNA-demethylation enzymes. Our final integrated histomolecular diagnosis was diffuse pediatric-type high-grade glioma, H3-wildtype and IDH-wildtype. Due to rapid tumor progression the patient died nine months after initial diagnosis. In this manuscript we provide extensive molecular characterization of the tumor as well as a literature review focusing on oncogenetic considerations of L-2-HGA-associated CNS tumors.
HGG-09. CONTRASTING CLINICAL COURSES OF THREE PEDIATRIC PATIENTS WITH PDGFRA AMPLIFIED RADIATION-INDUCED HIGH-GRADE GLIOMA
Authors: Greenwell Alyssa M , Bhambhani Kanta , Toll Stephanie , Kupsky William , Altinok Deniz , Gorsi Hamza S
Published: June 2024

BACKGROUND

Radiation-induced gliomas (RIG) can occur in 3% of patients receiving cranial radiation. Often, these gliomas are high-grade, treatment refractory, and share common molecular profiles like PDGFRA amplification, regardless of their previous malignant origin. Despite similar genetic alterations, the clinical course of these tumors is varied and not well-studied. Herein, we describe three patients with a PDGRFA-amplified RIG with a particular focus on their contrasting disease course. CASE DESCRIPTION: Our first patient is a now-deceased male diagnosed with medulloblastoma at 5 years of age, treated with surgical resection and craniospinal radiation followed by chemotherapy per COG ACNS0332. Ten years later, he was diagnosed with diffuse pediatric type high-grade-glioma (HGG) in the pons with PDGFA, KIT, MTAP amplification, and CDKN2A/B loss. His condition deteriorated quickly, and he succumbed to his disease in 8 weeks after family decided against further therapies. Our second patient is a now 20-year-old female, initially diagnosed with a craniopharyngioma at 6 years of age and treated with surgical resection and adjuvant radiation therapy. Eleven years later, she developed a diffuse pediatric type HGG in the pons with PDGFRA, MDM2, and MYCN amplification. She was treated with radiation therapy and has had stable disease on serial imaging for 3 years. Our third patient is a now-deceased male diagnosed with a right temporal melanotic neuroectodermal tumor at 5 years of age, treated with surgical resection and craniospinal radiation followed by chemotherapy per POG99701. Fifteen years later, he developed a diffuse pediatric-type HGG in the cerebellum/pons with PDGRFA amplification. He was treated with proton radiation and concurrent oral Temozolomide per COG ACNS0423. His disease progressed on treatment, and he died prior to initiation of a PDGFRA kinase inhibitor (avapritinib).

CONCLUSIONS

Further investigation into the underlying factors that drive the differing disease course in patients with RIG is needed.
HGG-10. YAP1-MAML2 FUSION IN YOUNG CHILDREN WITH PEDIATRIC HIGH-GRADE GLIOMA: A CASE REPORT
Authors: Jewels Emily , Bergeron-Gravel Samuel , Lagacé Simon , Hazrati Lili-Naz , Saikali Stephen , Dunham Christopher , Cheng Sylvia
Published: June 2024

BACKGROUND

High-grade gliomas (HGG) in children are a heterogeneous group of central nervous system (CNS) tumors that are very aggressive and highly malignant. Few patients achieve long-term survival despite decades of clinical trials. International collaborations have sought to better describe and understand the genetic underpinnings of pediatric HGG in hopes to uncover more effective treatment options. We report two HGG cases of young children with a YAP1-MAML2 fusion.

METHODS

Clinical data was collected retrospectively, and pathology was reviewed to confirm the diagnosis. RNA sequencing was performed using the Illumina TruSight RNA Pan-cancer Next Generation Sequencing Panel. Methylation profiling was completed using the HumanMethylation450 BeadChip platform (Illumina, San Diego, CA).

RESULTS

Two children ages less than 5 years with HGG were identified to have the YAP1-MAML2 fusion. One child was diagnosed at age 4 years and had an additional somatic BRAF V600D mutation. The child was treated initially with surgical debulking and cisplatin-based chemotherapy but had rapid clinical and radiologic progression. Due to the BRAF V600D mutation, the child started Dabrafenib and Trametinib but continued to have rapid craniospinal dissemination and died within 8 weeks of presentation. The second child was diagnosed at age 2 years and had an additional oncogenic PTENpF341V mutation. DNA methylation profiling on this tumor did not show evidence of clustering with any known CNS tumor entity. This child was treated with surgical debulking, chemotherapy (Baby POG), focal radiation 5400cGy, and maintenance chemotherapy (lomustine and temozolomide as per COG ACNS 0423). This child continues to have stable residual disease 29 months from presentation.

CONCLUSION

We present two cases of HGG in young children with a unique YAP1-MAML2 fusion. Future studies are needed to further characterize the significance of how this new molecular alteration impacts treatment and long-term outcomes in pediatric HGG.
HGG-19. H3- AND IDH-WILDTYPE DIFFUSE PAEDIATRIC-TYPE HIGH-GRADE GLIOMA WITHMYCN-AMPLIFICATION: AN INDICATION CRITERION FOR LI-FRAUMENI SYNDROME TESTING
Authors: Foo Jen Chun , Mun Kein Seong , Tae Sok Kun , Chang Kenneth Tou En
Published: June 2024

BACKGROUND: In the current World Health Organization (WHO) Classification of Tumors of the Central Nervous System (CNS) (5th edition), the introduction of a molecular layer to the integrated diagnosis not only helps to characterize and prognosticate paediatric CNS tumors but the molecular alteration may predict a potential therapeutic option with a targeted agent. Furthermore, certain gene alterations may be a presage of germline alterations or cancer predisposition syndromes, portending significant implications to the index patients and their families. We report a 5-year-old boy diagnosed with non-metastatic left hemispheric H3-wildtype and IDH-wildtype diffuse paediatric-type high-grade glioma with MYCN-amplification, who was subsequently found to have Li-Fraumeni syndrome. He presented with a 3-day history of facial asymmetry, unsteady gait and right sided weakness. There was no family history of malignancy. Initial MRI revealed a restricting and enhancing solid cystic lesion (5.9 x 4.3 x 5.8cm) in the left frontal-temporal-parietal region. Tumor debulking was performed. Histopathological examination by the local pathologist revealed features of high-grade glioma. Second pathology review with next generation sequencing confirmed H3-wildtype and IDH-wildtype diffuse paediatric-type high-grade glioma with MYCN-amplification and TP53 p.Y103* mutation. He was started on focal radiotherapy and oral temozolomide but succumbed to local and metastatic progressive disease. After genetic counselling, his DNA extracted from blood was sent for targeted exome sequencing and germline mutation of TP53 was demonstrated. Cascade screening of the family members were negative of TP53 mutation. Guerrini-Rousseau et al reported that 57% (n=7) of H3-wildtype and IDH-wildtype diffuse paediatric-type high-grade glioma with MYCN-amplification harboured germline TP53 pathogenic variants. This case further highlights the importance of screening of Li-Fraumeni syndrome in patient with H3-wildtype and IDH-wildtype diffuse paediatric-type high-grade glioma with MYCN-amplification even in the absence of a family history.
HGG-25. IDENTIFYING YB1 AND NPM1 AS PART OF THE MUTANT HISTONE 3 PROTEIN INTERACTOME IN H3 MUTATED PHGG
Authors: Dhillon Mehar , Read Eleanor , Layfeild Rob , Haque Farhana
Published: June 2024

Paediatric high-grade gliomas (pHGG) are the leading cause of childhood cancer deaths, accounting for over 40% of deaths in the UK. pHGG tumours harbour histone H3 mutations, defining 50% of pHGG cases. Studies show prominent mutations as being H3.3K27M and H3.3G34R/V. Our previous proteomic research on H3 intercatomes, identified unique and common interacting binding partners of H3-G34R and H3-G34V mutant proteins relative to wild type H3. Among these proteins we have focused on YB-1 and Nucleophosmin 1 (NPM1). YB-1, is multifunctional transcription factor and a well-characterised oncogenic protein. NPM1 is a molecular chaperone and frequently overexpressed in cancers. Our aim is to analyse the role of YB-1 and NPM1 in H3 mutated pHGG, in order to identify targeted therapeutic options for these difficult to treat tumours. H3 mutated glioma cell lines, H3 wild type pHGG cells and control cells were cultured and then subjected to comparative immunofluorescence microscopy, and western blot analyses to investigate YB-1 and NPM1 expression. Results showed statistically significant altered protein expression and localisation of YB-1 and NPM1 in H3 mutated pHGG in comparison to wild type and control cells. YB-1 expression was increased in H3 mutated cells and NPM1 showed increased cytoplasmic localization in H3 mutated cells in comparison to H3 WT glioma and control cells. Results of the study support that YB-1 and NPM1 are important interacting proteins in H3G34-mutated pHGGs and can be explored as potential therapeutic targets in H3 mutated pHGG.