bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract

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

Abstract

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 (&lt;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&lt;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

Abstract

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&gt;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

Abstract

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&lt;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

Abstract

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

Abstract

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 &lt; 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

Abstract

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

Abstract

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&gt;10ng/ml, and/or β-HCG&gt;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&lt;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

Abstract
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

Abstract

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.