bluuebunny/crossref_metadata_2025 huggingface dataset:
METB-01. EFFECTS OF H3.3G34V MUTATION ON GENOMIC H3K36 AND H3K27 METHYLATION PATTERNS IN ISOGENIC PEDIATRIC GLIOMA CELLS
Authors: Huang Tina , Piunti Andrea , Qi Jin , Bartom Elizabeth , Saratsis Amanda
Published: June 2024

BACKGROUND

Histone H3.3 mutation (H3F3A) occurs in 50% of cortical pediatric high-grade gliomas (pHGGs). This mutation replaces glycine 34 with arginine or valine (G34R/V), impairing SETD2 activity (H3K36-specific trimethyltransferase). Consequently, reduced H3K36me3 is observed on H3.3G34V nucleosomes relative to wild-type, contributing to genomic instability and driving a distinct gene expression signature associated with tumorigenesis. However, it is not known if this differential H3K36me3 enrichment is due to H3.3G34V mutant protein alone. Therefore, we set to elucidate the effect of H3.3G34V mutant protein in pediatric glioma on H3K36me3, H3K27me3 and H3.3 enrichment in vitro.

METHODS

Experiments were conducted using an established H3.3G34V mutant patient-derived pediatric high-grade glioma cell line (KNS42), and Histone H3.3 wild-type human astrocytes (NHAs). Lentiviral delivery of a doxycycline-inducible RNAi vector targeted against H3F3A was transduced to KNS42 cells to knock down H3.3G34V protein expression. Cell lines were then compared via ChIP-Seq, Western Blot, proliferation and viability studies.

RESULTS

We found that the doxycycline-inducible shRNA knockdown of mutant H3F3A encoding the H3.3G34V protein resulted in loss of H3.3G34V enrichment and increased H3K36me3 enrichment throughout the genome. After knockdown, H3.3G34V enrichment was preserved at loci observed to have the greatest H3.3G34V and H3K36me3 enrichment prior to knockdown. Induced expression of mutant H3.3G34V protein in vitro was insufficient to induce genomic H3K36me3 enrichment patterns observed in H3.3G34V mutant glioma cells. We also observed strong co-enrichment of H3.3G34V and wild-type H3.3 protein, as well as greater H3K27me3 enrichment, in cells expressing H3.3G34V.

CONCLUSIONS

Our study demonstrates the effects of H3.3G34V mutant protein on genomic H3K36me3, H3K27me3 and H3.3 enrichment patterns in isogenic cell lines. Further studies examining the impact of theses findings are therefore underway.
METB-11. HOW METHYLATION PROFILING HELPS IN DIAGNOSING AND TREATING PEDIATRIC BRAIN TUMORS IN INDONESIA
Authors: Rahmartani Ludi Dhyani , Budiarso Michael Nathaniel , Gunawan Kevin , Susanto Eka , Sahm Felix , Ahmad Olfat , Pfister Stefan
Published: June 2024

BACKGROUNDS

Pediatric brain tumors (PBT) exhibit extensive heterogeneity, impacting treatment outcomes. While traditionally classified based on histopathological features, recent WHO classifications have integrated DNA methylation array profiling amongst other molecular characteristics, which improves diagnostic accuracy and thus treatment decisions. However, access to this technology is limited in low- and middle-income countries (LMICs) like Indonesia. As part of the MNP Outreach Consortium, we aimed to introduce methylation profiling in Indonesia to aid in diagnosing and stratifying PBT patients.

METHODS

In 2023, we conducted a case series involving seven challenging PBT cases from Cipto Mangunkusumo National General Hospital, re-assessing them with methylation profiling.

RESULTS

Through collaboration with the Institute of Neuropathology Heidelberg and the DKFZ, our centre adopted a discerning approach to re-evaluate histopathological samples from complex cases. This endeavour yielded notable results, reaffirming four initial diagnoses and altering three others Amongst the findings, one case initially diagnosed as anaplastic ependymoma, CNS WHO grade 3, was reclassified as a supratentorial ependymoma with YAP1 fusion gene, based on methylation class. Noteworthy within this latter group, one case initially categorized as low-grade pilocytic astrocytoma was reclassified as high-grade diffuse midline glioma, H3 K27 altered. Moreover identifying the copy number plot could indicate a KIAA1549::BRAF fusion to reclassify a case from diffuse pediatric glioma WHO grade 2 to pilocytic astrocytoma WHO grade 1. The recurrent pigmented neuroectodermal tumor of infancy (MNTI) was reclassified as Medulloblastoma, non-WNT/non-SHH, group 3 subtype II on methylation profiling, highlighting molecular similarities and potential treatment insights. These findings offer insights into genetic mechanisms and guide treatment strategies.

CONCLUSION

Accurate diagnosis, facilitated by advanced molecular profiling, enhances prognostication and enables personalized treatment plans, even in LMICs. This underscores the importance of expanding access to advanced diagnostic technologies in resource-limited settings.
GCT-01. CENTRAL NERVOUS SYSTEM GERM CELL TUMORS – GENERATING A CONSENSUS IN THEIR DIAGNOSIS AND MANAGEMENT
Authors: Abdelbaki Mohamed S
Published: June 2024

BACKGROUND

Despite the excellent outcomes of central nervous system (CNS) germ cell tumors (GCTs), there still exists significant differences in how GCTs are diagnosed and managed in different parts of the world. Additionally, the long-term toxicities and morbidities of the current therapies, and their substantial negative impact on the social wellbeing of our patients should clearly indicate that the current achievements are not enough. Further, important molecular data have emerged over the past decade that we have not witnessed their translation into any of the ongoing clinical trials.

METHODS

A comprehensive review of all major CNS GCT clinical trials will be discussed, in addition to a detailed review of the several issues of debate. Moreover, the latest developments in molecular landscape of GCTs will be provided in order to identify the hurdles that affect their incorporation in GCT clinical trials.

RESULTS

Tumor marker cut-offs that differentiate between germinoma and non-germinomatous germ cell tumors are clearly different between the various groups around the world. Additionally, differences exist in the chemotherapy backbones, radiation therapy field and dose, and the appropriate regimens to treat some of the rarer GCTs. Furthermore, there is no clear guideline on how to treat patients who do not achieve complete response after chemotherapy.

CONCLUSIONS

Discussing the clear differences that exist in the diagnosis and management of CNS GCTs is a critical first step in generating a clear consensus between the North American, European, Asian, and Latin American groups, which will certainly guide future clinical trials, improve the outcomes as well as the long-term treatment effects for this group of patients.
GCT-15. CLINICAL AND MOLECULAR CHARACTERIZATION OF INFANTILE CENTRAL NERVOUS SYSTEM GERM CELL TUMORS
Authors: Fukuoka Kohei , Takami Hirokazu , Satomi Kaishi , Nakano Yoshiko , Inoue Yohei , Miyahara Akira , Matsushita Yuko , Hibiya Yuko , Kato Miho , Takimoto Tetsuya , Nakazawa Atsuko , Yoshioka Takako , Hirato Junko , Nakazato Yoichi , Shibahara Junji , Oka Hidehiro , Kurihara Jun , Koh Katsuyoshi , Matsutani Masao , Nishikawa Ryo , Nagane Motoo , Ichimura Koichi
Published: June 2024

BACKGROUND

The management of infantile central nervous system germ cell tumors (CNS-GCTs) presents unique challenges, including variable clinical presentations such as tumor size and propensity for hemorrhage. Moreover, data on the clinical and molecular features remain limited.

METHODS

We conducted a clinical and molecular analysis of CNS-GCTs in children aged 6 years or younger, registered with the Japan Children’s Cancer Group and the iGCT consortium. DNA methylation analysis was performed using the Illumina Methylation EPIC array to identify potential molecular prognostic indicators.

RESULTS

The cohort comprised 43 patients, with a median age at onset of 6.5 months (0–68 months). Notably, 23 patients (54%) were diagnosed before 1 year of age. The male-female ratio was 27:15. Most common tumor location was cerebellum (13 cases). The median AFP level was 538 ng/ml (0–206460). Pathologically, the tumors were predominantly diagnosed as teratomas and yolk sac tumors. Teratomas were more common in patients diagnosed before 1 year of age, while mixed GCTs were more frequent in those diagnosed after 3 years. Molecular analysis identified four cases as embryonal tumors, including three AT/RTs and one DICER1-mutant intracranial sarcoma. The 3-year overall survival rates varied significantly by diagnosis: mixed GCTs at 100%, teratomas at 90.6%, yolk sac tumors at 30.0%, and embryonal tumors at 0%. Notably, two patients with teratomas developed metachronous tumors more than 10 years post-diagnosis, with both secondary tumors exhibiting mutations in the MAPK pathway absent in the primary tumors.

CONCLUSION

Infantile CNS-GCTs exhibit distinct clinical and molecular profiles compared to those in older children and adults. Not all tumors classified as GCTs based on molecular characterization were GCTs; some were embryonal tumors, potentially impacting treatment strategy. The genetic analysis suggests that some metachronous GCTs may represent second primary tumors rather than recurrences.
GCT-16. LONG-TERM OUTCOMES AND COMPLICATION MANAGEMENT IN CNS GERM CELL TUMORS: INSIGHTS FROM A PHASE II HISTOPATHOLOGY-STRATIFIED TREATMENT TRIAL
Authors: Takami Hirokazu , Nishikawa Ryo , Suzuki Tomonari , Takabatake Kazuhiko , Fujimaki Takamitsu , Okamoto Michinari , Yamaguchi Shigeru , Kanamori Masayuki , Matsuda Kenichiro , Sonoda Yukihiko , Natsumeda Manabu , Ichinose Toshiya , Nakada Mitsutoshi , Muroi Ai , Ishikawa Eiichi , Takahashi Masamichi , Narita Yoshitaka , Higuchi Fumi , Shin Masahiro , Mineharu Yohei , Arakawa Yoshiki , Kagawa Naoki , Kawabata Shinji , Wanibuchi Masahiko , Takayasu Takeshi , Yamasaki Fumiyuki , Fujii Kentaro , Ishida Joji , Date Isao , Miyake Keisuke , Fujioka Yutaka , Kuga Daisuke , Yamashita Shinji , Takeshima Hideo , Shinojima Naoki , Mukasa Akitake , Tanaka Shota , Asai Akio , Matsutani Masao
Published: June 2024

BACKGROUND

This detailed examination merges outcomes from a Phase II clinical trial targeting central nervous system (CNS) germ cell tumors (GCTs) conducted between 1995 and 2003. It evaluates the impact of histopathologically driven treatment modalities on survival, recurrence, and post-treatment life and social outcomes, aiming to delineate the long-term effects of such stratified treatment approaches.

METHODS

The cohort comprised 228 patients, stratified into three groups based on histology: germinoma (n=161), intermediate prognosis (n=38), and poor prognosis (n=28), each receiving customized chemotherapy and radiation treatments. With a median follow-up duration of 222 months, this longitudinal study scrutinized survival rates, recurrence patterns, and a spectrum of socio-economic and health-related outcomes.

RESULTS

For the germinoma group, the 10- and 20-year event-free survival (EFS) rates stood impressively at 82% and 73%, respectively, with overall survival (OS) rates reaching 97% and 92%. The intermediate prognosis group witnessed 10- and 20-year EFS rates of 76% and 66%, and OS rates of 87% and 70%. The poor prognosis group recorded EFS rates of 49% at both intervals, with OS diminishing to 61% and 53%. Notably, germinomas localized in the basal ganglia exhibited high relapse rates absent initial whole-brain radiation, yet were effectively managed upon subsequent interventions. The comprehensive follow-up illuminated striking disparities in socio-economic achievements: higher educational attainments, more stable employment, and improved health outcomes were predominantly observed among patients without recurrence. Non-recurrent germinoma patients, in particular, showcased enhanced educational and employment status, vividly illustrating the profound impact of disease progression and treatment on life quality.

CONCLUSIONS

The findings highlight the critical importance of customized initial treatments for improving survival and life quality in CNS GCT patients, stressing the need for detailed long-term follow-up to address relapses and complications effectively. The study advocates for personalized care that balances treatment intensity to optimize long-term outcomes, enhancing post-treatment care.
HGG-01. DURABLE RESPONSE TO IMMUNOTHERAPY IN AN ADOLESCENT PATEINT WITH CONSTITUTIONAL MISMATCH REPAIR DEFICIENCY CMMRD AND SYNCHRONOUS THREE PRIMARY MALIGNANCIES
Authors: Mobarak NAHLA Aly , Alotabi Fahad , Balbaid Ali Abdullah O , Shakweer Wafa Al , Alrasheed Rana , AlMalki Salman Turbush A , Alharbi Musa , AlFakeeh Ali H
Published: June 2024

BACKGROUND

Familial Cancer Syndrome FCS is of particular concern in Saudi Arabia due to the high rates of consanguinity. Constitutional mismatch repair deficiency Syndrome (CMMRD) is an autosomal recessive FCS with a wide spectrum of malignancies Caused by Biallelic germline mutations in one of 4 mismatch repair genes (MLH1, PMS2, MSH2, and MSH6).

METHODS

we report 13 yr. Saudi boy, previously healthy with multiple café-au-lait (CAL) macules, and Consanguineous parents with a positive family history of Malignancy. presented with progressive headache, vomiting, abdominal pain, weight loss, and microcytic anemia. MRI Brain showed a Large left hemispheric necrotic mass, MRI abdomen: Circumferential gastric body wall thickening Distal transverse colon intraluminal polypoid mass, and liver hypodense lesion. He had a Resection of the brain tumor and Upper GI endoscopy + colonoscopy with polypectomy: which showed an Ugly gastric ulcer, and multiple colonic polyps.

RESULTS

Brain tumor molecular pathology: Gliosarcoma WHO grade 4 with negative IHC expression in PMS2 protein, hypermutant tumor with somatic PMS2 ATRX, TP53, NFI, and PIK3R1 genes mutation. stomach biopsy confirmed invasive gastric adenocarcinoma and Colonic polyp biopsy: Tubulovillous adenoma. Genetic testing Detect pathogenic Biallelic germline PMS2 mutation. He received adjuvant focal Brain radiation therapy 59.4Gy/33 F concurrent with immunotherapy (PD-1) inhibitor Nivolumab. Follow-up Abdominal imaging showed excellent response to immunotherapy with no significant residual lesion. MRI of the brain showed surgical bed multi-cystic lesions with thick nodular enhancement suggestive either of radiation necrosis vs. progressions/pseudoprogression. repeated MRI confirmed further progression of the enhancing surgical cavity lesion which was unresectable. CTLA-4 Inhibitor ipilimumab was added to Nivolumab to optimize therapy. UpToDate our patient is clinically stable on Maintenance Nivolumab with no side effects.

CONCLUSION

Our case confirms immunotherapy’s efficacy for treating CMMRD-related cancers, which can improve survival while reducing toxicity from less effective conventional therapies.
HGG-11. TRANS-SPECIES STUDY OF IDH-MUTANT REPLICATION-REPAIR DEFICIENT HIGH-GRADE GLIOMAS (RRD-HGG) AND RESPONSE TO COMBINED TARGETED AND IMMUNOTHERAPY: AN IRRDC STUDY
Authors: Das Anirban , Fernandez Nicholas R , Bielamowicz Kevin J , Abebe-Campino Gadi , Caspi Shani , Per Nyman , Graham Richard T , Kim John Y , Wilhelmsson Mari , Jorgensen Mette , Michaeli Orli , Fernández Maria Baro , Li Amanda , Levine Adrian , Aamir Zoya , Stengs Lucie , Negm Logine , Bianchi Vanessa , Edwards Melissa , Bennett Julie , Ertl-Wagner Birgit , Dirks Peter , Bouffet Eric , Hawkins Cynthia , Tabori Uri
Published: June 2024

BACKGROUND

IDH-mutant gliomas comprise <10% of HGG in children. RRD-HGG comprise 5-10% of childhood HGG, demonstrate high mutation burden (TMB) and respond to immune-checkpoint inhibition (ICI). The impact of RRD with childhood IDH-mutant gliomas, and effective therapeutic options for these patients are not well-established.

METHODS

Clinical and multi-omic analyses were performed on IDHmut-RRD-HGG registered to the IRRDC and the glioma taskforce. Tumor development and genomic data were studied from a novel IDHmut-RRD-HGG immunocompetent mouse model. Outcome following ICI and targeted therapy were evaluated.

RESULTS

IDH mut-RRD-HGG accounted for >60% of childhood IDH-mutant-HGG. Conversely, IDH1-mutations were detected in 20% of RRD-HGG. All patients (n=48) harboured germline mutations in MMR genes (CMMRD: 62%, Lynch syndrome: 38%). Contrary to sporadic IDH-mutant-gliomas, the majority (>90%) were high-grade. Diffuse/multifocal involvement, predominantly involving the frontal lobe, was frequent. TMB was lower than IDH-wildtype RRD-HGG (median: 28 mutations/Mb, p<0.05). Secondary POLE/POLD1 mutations were absent. TP53 and ATRX were frequent somatic hits. Copy number changes, particularly loss of CDKN2A/2B, were common. CD8-T-cell infiltration (immunohistochemistry) and tumor inflammation score (transcriptome) were lower than IDH-wildtype RRD-HGG (p<0.05). A novel mouse model (Olig2Cre+/Msh2LoxP/LSL-Idh1R132H) revealed similar lower TMB, diffuse cerebral involvement, slower growth, and low immune infiltrates as compared with IDH-wildtype RRD-HGG models. IDHmut-RRD-HGG demonstrated worse survival as compared to sporadic IDH-mutant-HGG (p<0.001). Within RRD-HGG, ICI monotherapy resulted in inferior survival in IDHmut-RRD-HGG vs IDH-wildtype RRD-HGG (p<0.05). Five patients developed metachronous IDHmut-RRD-HGG while on anti-PD1 treatment for IDH-wildtype RRD-HGG, suggesting intrinsic resistance. Interestingly, an IDH-inhibitor demonstrated objective response in 4/8 IDHmut-RRD-HGG. Furthermore, for IDHmut-RRD-HGG on ICI treatment, the addition of an IDH-inhibitor prolonged survival at 12-months in comparison to those without (p=0.01).

CONCLUSION

Hypermutant RRD-HGG with IDH1;p.R132H harbour unique immuno-biology and do not respond to anti-PD1 monotherapy. The addition of IDH-inhibition demonstrated favourable responses, supporting need for evaluation of the combination in clinical trials.
HGG-17. DECIPHERING GENETICS AND EPIGENETICS OF HIGH-GRADE GLIOMAS WITH BRAF ACTIVATING ALTERATION IS SUPPORTING THE DISCOVERY OF A NEW INTRACRANIAL SARCOMA-LIKE BRAF POSITIVE ENTITY
Authors: Lhermitte Benoit , Wolf Thibaut , Reita Damien , Salmanli Chinar , Chammas Agathe , Deschuyter Marlène , Gauchotte Guillaume , Entz-Werlé Natacha
Published: June 2024

BACKGROUND

The current WHO classification of Central Nervous System tumors recognizes several glioma types driven by the BRAFV600E mutation. These tumors mostly encompass pediatric low-grade gliomas. Nevertheless, a subset of them behaves as anaplastic gliomas and, currently, the unique predictive criterion linked to anaplasia is an elevated mitotic index (more than 2.5 mitoses/mm2). Histologically, the high-grade gliomas harboring BRAFV600E alteration mostly correspond to WHO grade 3 pleomorphic xanthoastrocytoma, IDH wild-type glioblastoma, entering the WHO grade 4 subset like the epithelioid subtype, and the rarer high-grade gliomas with piloïd features. These tumor types share their histomolecular features making differential diagnoses difficult. In this setting, DNA methylation profiling may be very useful to precise the integrative diagnosis. However, some of those high-grade forms failed in our experience to be classified in any methylation class with v11b4 version of the Heidelberg classifier.

METHODS

To understand the reasons explaining this standard classification failure, we investigated with multi-omics approaches (epigenetics, next-generation sequencing, RNAseq, proteomics and metabolomics) a well clinical characterized cohort of 17 high-grade pediatric intracranial tumors harboring this mutation.

RESULTS

Interestingly, almost all tumors show similar morphological features and associated passenger molecular alterations mostly CDKN2A homozygous deletion. When using the new v12.5 brain tumor classifier, the methylation profiling of the 2/17 unclassified tumors was clustering with a new MPNST (Malignant Peripheral Nerve Sheath Tumor) methylation entity. The RNAseq and proteomics analyses were showing a different molecular pattern from standard BRAF-mutated high-grade gliomas, even the clinical, radiological and histomolecular characteristics were comparable.

CONCLUSION

So, methylation profiling should be part of the mandatory molecular assessments to perform when a BRAF-mutated tumor is seen by neuropathologists. Furthermore, the multiomics analyses helped us to define a specific molecular pattern of this new BRAF-driven entity, where frequency and prognosis need to be determined on another larger series.
HGG-32. PNOC008: A PILOT TRIAL TESTING THE CLINICAL BENEFIT OF USING MOLECULAR PROFILING TO DETERMINE AN INDIVIDUALIZED TREATMENT PLAN IN CHILDREN AND YOUNG ADULTS WITH NEWLY DIAGNOSED HIGH-GRADE GLIOMA (EXCLUDING DIFFUSE INTRINSIC PONTINE GLIOMA)
Authors: Franson Andrea T , Kilburn Lindsay B , Cooney Tab M , Stoller Schuyler , Reddy Alyssa T , Banerjee Anu , Packer Roger J , Bendel Anne E , Skrypek Mary M , Minturn Jane E , Abdelbaki Mohamed S , Whipple Nicholas S , Chan Priya , Crawford John R , Crotty Erin E , Waanders Angela J , Elster Jennifer D , Raabe Eric H , George Elizabeth , Pinto Soniya N , Vossough Arastoo , Kraya Adam A , Prados Michael , Kline Cassie , Nazarian Javad , Solomon David A , Long-Boyle Janel R , Molinaro Annette M , Waszak Sebastian M , Mueller Sabine
Published: June 2024

BACKGROUND

Children and young adults diagnosed with high-grade glioma (HGG) face extremely poor prognoses. Despite multiple clinical trials testing new treatments in this population, a survival advantage has yet to be achieved. Herein we assessed, in a single-arm, multi-center pilot trial, the feasibility of molecular profiling of primary HGG tumor tissue to create an individualized treatment plan with up to four FDA approved medications.

METHODS

Patients aged <21 years with newly diagnosed, localized, hemispheric HGG (Stratum A) or midline HGG (non-DIPG; Stratum B) were eligible. Tumor tissue underwent comprehensive molecular profiling (targeted gene panel, whole exome, and whole transcriptome sequencing). Based on detailed review of the molecular data by a dedicated tumor board, an individualized treatment plan that combined up to four FDA approved drugs was recommended. Circulating tumor DNA (ctDNA), imaging, and quality of life (QOL) measures were collected at multiple timepoints.

RESULTS

Fifty-five patients enrolled between 2018 and 2023 (median age 11 years [range 2-20], n=31 female, n=29 Stratum A). The most common integrated diagnoses included H3K27-altered diffuse midline glioma (n=17), H3/IDH-wildtype diffuse pediatric-type HGG (n=16), and H3G34-mutant diffuse hemispheric glioma (n=12). Median overall survival (OS) from the time of study enrollment was 26.5 months in Stratum A (lower 95% CI: 18.7) and 21.7 months in Stratum B (lower 95% CI: 16.8), with a median follow-up of 35.4 months for all patients (lower 95% CI: 32.5). The most common grade 3 or 4 treatment-related adverse events were decreased neutrophils (n=28), decreased platelets (n=22), and decreased white blood cells (n=16). As of December 2023, seven patients remain on therapy. Central imaging, ctDNA, and QOL analyses are underway.

CONCLUSIONS

A personalized treatment recommendation for children and young adults with HGG based on comprehensive transcriptomic and genomic analysis is feasible. Current survival data are encouraging, and molecular subgroup analyses are ongoing.
HGG-33. HIGH GRADE TRANSFORMATION OF CNS TUMOR WITH BCOR:CREBBP FUSION: A CASE REPORT
Authors: Rocco Abbey , Beck Mary , McHugh Michele , Lampe Ashley , Meyer Ashley , Ogle Andrea , Shatara Margaret , Cluster Andrew , Abdelbaki Mohamed S , Brossier Nicole M
Published: June 2024

BACKGROUND

The discovery of unique EP300:BCOR and CREBBP:BCORL1 fusions has extended the spectrum of BCOR altered CNS tumors previously associated with BCOR internal tandem duplication (ITD). Due to the rarity of CNS tumors with BCOR alterations, there is limited information on the clinical outcomes and the effective treatment strategies.

METHODS

Literature review and retrospective chart analysis

RESULTS

An 18-year-old male who presented with seizures was found to have a left temporal mass. Histologic diagnosis was low grade glioneural tumor harboring a pathogenic CREBBP:BCOR1 fusion, matching to CNS tumor with EP300:BCOR/BCORL1 fusion by methylation. A re-resection aimed at gross total resection was then performed. Histologic examination revealed residual glioma with focal high-grade transformation, Ki67 up to 35% and CDKN2A loss via FISH analysis. The patient was treated with focal radiation to 54Gy. He remains disease- and seizure-free 1 month post radiation therapy. This case displayed some similarities to previously reported cases, including oligodendroglial- or ependymoma-like features, positivity for Olig2 and/or GFAP, presence of calcifications, and branching capillary networks. However, this case had less frequent mitoses than previously reported cases. In a series of 21 patients with BCOR altered tumors, BCOR-fusion tumor patients had a more favorable PFS compared to BCOR-ITD tumors. In a reported case series of high grade BCOR altered CNS tumors, 5 out of 8 patients remained alive, all of whom received radiation therapy as a primary treatment or at relapse. There is one prior report of an EP300:BCOR tumor undergoing high-grade transformation; increased mitoses, cellularity, and necrosis were observed. This case was lacked necrosis.

CONCLUSIONS

The optimal treatment for BCOR altered tumors of the CNS is largely unknown given the limited reported cases. Radiation therapy in addition to gross total resection may be an effective treatment leading to more favorable PFS and OS.
HGG-38. COMBINING TARGETED THERAPY AND RADIATION OUTPERFORMS SINGLE TREATMENTS IN PEDIATRIC HIGH-GRADE GLIOMA
Authors: Chan Kenneth Chun-Ho , Hofmann Nina , Roscher Mareike , Euler-Lange Rosemarie , Steimel Kevin , Fransisca Mathea , Cais Alessia , Dokic Ivana , Jones David T W , Burhenne Jürgen , Kurth Ina , Pfister Stefan M , Zuckermann Marc
Published: June 2024

BACKGROUND

Pediatric-type diffuse high-grade gliomas (pHGGs) are a diverse group of central nervous system tumors in children and adolescents with typically fatal outcomes. Addressing this disease requires new treatment approaches to enhance both survival and quality of life for affected patients. Recently, targeting oncogenic receptor tyrosine kinases (RTKs) has provided promising initial responses in different pHGG subtypes. However, even in these cases, the disease invariably relapses.

METHODS

We utilized murine tumor cell cultures carrying oncogenic alterations in different RTKs, such as an NTRK fusion, an ALK fusion and activating FGFR1 mutations to evaluate the synergy of radiotherapy and a variety of specific small molecule inhibitors using viability and apoptosis assays. By conducting pharmacokinetic analyses in murine models, we quantified the availability of selected compounds in the mouse brain in vivo, informing downstream preclinical experiments.

RESULTS

We found that concomitant radiation potentiated the antitumor effect of all tested targeted compounds, mostly outperforming calculated additivity of single treatments. Of note, the level of potentiation was comparable between different inhibitors targeting the same RTK, but was highly dependent on the underlying tumor genotype. Using erdafitinib or futibatinib and a dose of 2 Gy in a FGFR1-driven pHGG model, the combined treatment resulted in a remarkably high late apoptosis rate of 90%, warranting ongoing in vivo studies. Through pharmacokinetic analyses, we identified that among all tested small-molecule-inhibitors, only lorlatinib and futibatinib reach clinically relevant concentrations in the murine brain.

CONCLUSIONS

Our preliminary data showed that the combination of targeted therapy and radiation elicits encouraging anti-tumor effects in different pHGG cultures. We are currently performing preclinical in vivo studies using immunocompetent orthotopic mouse models to evaluate benefits of combined treatment. Our data will inform future clinical trials and hopefully improve the prognosis and quality of life for a fraction of pediatric patients diagnosed with pHGG.
HGG-45. HIGH GRADE GLIOMA PRESENTING AS A SYNCHRONOUS CANCER IN A PATIENT WITH DIFFUSE LARGE B CELL LYMPHOMA: A UNIQUE TREATMENT DILEMMA
Authors: Kendel Nicole , Wilson Yelena , Wright Erin N
Published: June 2024

BACKGROUND

Patients with synchronous tumors pose significant treatment dilemmas. We present a pediatric patient found to have concomitant Diffuse Large B-cell Lymphoma (DLBCL) and a High Grade Glioma (HGG). His unique presentation and family history uncovered a familial diagnosis of Lynch Syndrome.

CASE

A 7-year-old male presented with acute appendiceal rupture. Surgical resection identified an appendiceal mass consistent with localized DLBCL. While undergoing staging evaluations, the patient complained of new onset blurry vision with normal neurologic and ophthalmologic exams. Subsequent imaging was concerning for a high-grade lesion. Biopsy confirmed HGG and he underwent gross total resection. Family history included a brother with relapsed leukemia status post bone marrow transplant and multiple first cousins with lymphoma and gastrointestinal cancers.

RESULTS

While awaiting genetics and mutational analysis, we initiated treatment. The HGG was treated with focal radiation to the tumor bed starting 2 weeks after resection. Lymphoma therapy was initiated concurrently per the REBOOT regimen with the goal of decreasing doxorubicin dosing during radiation. Lumbar punctures and intrathecal chemotherapy were deferred until completion of radiation. Biopsy of residual abdominal masses following consolidation 1 showed <5% viable cells and therapy was intensified to ANHL1331, Group C1. Evaluation of both lesions identified hypermutation (mutational burden > 150mutations/Mb). Two unique germline mutations of PMS2 were also identified, consistent with Lynch syndrome. After completion of above therapy, the patient received maintenance therapy with nivolumab checkpoint inhibition. The patient developed severe neutropenia leading to cessation of nivolumab and quick progression of his HGG.

CONCLUSION

Synchronous tumors pose significant treatment dilemmas given the need to treat multiple lesions while balancing side effects. While checkpoint inhibitors may provide a way to address multiple lesions, our patient had unacceptable side effects limiting the utility of this therapy.
IMG-10. IMAGING SUBTYPES OF PEDIATRIC LOW-GRADE GLIOMA ARE ASSOCIATED WITH DISTINCT MOLECULAR CHARACTERISTICS
Authors: Kazerooni Anahita Fathi , Kraya Adam , Rathi Komal S , Kim Meen Chul , Kesherwani Varun , Vossough Arastoo , Familiar Ariana , Khalili Nastaran , Storm Phillip B , Ware Jeffrey B , Song Yuanquan , Foster Jessica , Mueller Sabine , Fisher Michael J , Resnick Adam C , Nabavizadeh Ali
Published: June 2024

BACKGROUND

Pediatric low-grade gliomas (pLGGs) have diverse molecular subtypes with distinct prognoses, necessitating personalized treatments. We aimed to determine whether radiomic features of pLGGs co-segregate with molecular subtypes, establishing a proof-of-concept that distinct molecular aberrations could manifest in differentiable imaging features.

METHODS

Leveraging radiomic, genomic, and transcriptomic data from 201 pLGG patients from the Children’s Brain Tumor Network (CBTN), we identified imaging-based pLGG subtypes through their radiophenotypes. This involved investigating the association of imaging subtypes with 2021 WHO pLGG classifications and profiling transcriptional characteristics distinguishing pLGG clusters. We used principal component analysis and K-Means clustering on 881 radiomic features and incorporated clinical variables (age, sex, tumor location), and derived three imaging subtypes.

RESULTS

BRAF V600E mutations were mainly found in subtype 3, while BRAF::KIAA1549 fusion in subtype 1. To ascertain transcriptome pathways most closely associated with imaging-based subtypes, we applied a supervised machine learning model with elastic net logistic regression using a one-versus-rest strategy for each imaging cluster, considering the top 100 most variable pathways, identified through gene set enrichment and gene co-expression network analyses, molecular subtype, tumor location, age, sex, and race. The predictive accuracy (area under the receiver operating characteristic curve) of the model was 0.86 | 0.72 for imaging subtype 1, 0.93 | 0.71 for subtype 2, and 0.91 | 0.64 for subtype 3 in the training | testing sets. Notably, each imaging subtype exhibited distinct molecular mechanisms; subtype 1 showed up-regulation of oxidative phosphorylation, PDGFRB, and interleukin 4, 10, and 13 signaling, while subtype 3 was linked to histone acetylation and DNA methylation pathways, relating to BRAF V600E pLGGs.

CONCLUSIONS

Our radiogenomics study suggests that intrinsic molecular characteristics of tumors drive distinct imaging subgroups of pLGG, providing a basis for future multi-modal investigations that may better define progression and targetability of the disease.
IMG-16. DECIPHERING THE NEUROIMAGING SPECTRUM OF AT/RT: A PICTORIAL REVIEW OF ATYPICAL TERATOID/RHABDOID TUMORS
Authors: Gonçalves Fabrício G , Goldman-Yassen Adam E , Desai Sandeep , Chauhan Richa S , Rusyn Anastasiia , Carvajal Mario Enrique M , Cardenas Agustin , Cerron-Vela Carmen , Yildiz Harun , Dias Tassiana Cristhina S , Li Rong , Dhall Girish , Johnston James M
Published: June 2024

BACKGROUND

This study presents a detailed pictorial review of Atypical teratoid/rhabdoid tumor (AT/RT), a high-grade central nervous system (CNS) malignancy, emphasizing the relationship between neuroimaging characteristics and clinical, molecular, and histopathological aspects. AT/RT is mainly characterized by the biallelic inactivation of SMARCB1 and occasionally SMARCA4 genes.

METHODS

The review methodically analyzes neuroimaging findings from various imaging techniques, notably MRI. It documents AT/RT appearances in different brain regions, including the cerebellum, cerebellopontine angle cistern, intraventricular, suprasellar, supratentorial, pineal, spinal canal, and cranial nerves. The study integrates these findings with clinical presentation, molecular subtypes (AT/RT-SHH, AT/RT-TYR, and AT/RT-MYC), and pathogenesis, highlighting the connection between imaging features and molecular subtypes.

RESULTS

The results indicate distinctive neuroimaging characteristics of CNS AT/RT, varying with tumor location and molecular subtypes. Common imaging features include contrast enhancement and signal intensity variations on MRI, including subtype-specific variations. Advanced neuroimaging plays a key role in distinguishing AT/RT from other pediatric CNS tumors, aiding in biopsy and treatment planning. Notably, imaging findings are linked with genetic changes, particularly the involvement of SMARCB1 and SMARCA4, affecting tumor appearance and behavior.

CONCLUSIONS

This review underscores the significance of neuroimaging in diagnosing and treating CNS AT/RT. The comprehensive analysis of imaging, combined with molecular and histopathological data, offers valuable insights into AT/RT’s heterogeneous nature. This integrative approach is crucial for a better understanding of AT/RT and for the development of more effective, targeted therapies.
IMG-19. CLINICAL UTILITY OF NON-FDG PET-MRI IN CHILDREN WITH CNS NEOPLASMS: A TERRITORY-WIDE STUDY FROM HONG KONG
Authors: Liu Anthony P Y , Yan Carol L S , Cheng P W , Lo S S M , Chow Terry T W , Fu Eric C H , Yau Jeffrey P W , Lee Vincent , Chan Godfrey C F , Ku Dennis T L , Shing Matthew M K , Siu Deyond Y W
Published: June 2024

INTRODUCTION

Magnetic resonance imaging (MRI) is the gold-standard for neuroimaging, yet details from anatomical scans might be inconclusive in certain scenarios. This study aimed to investigate the utility of amino-acid tracer positron emission tomography-magnetic resonance imaging (PET-MRI) based on a territory-wide Pediatric Neuro-Oncology cohort from Hong Kong.

METHODS

We reviewed the PET-MRI scans of pediatric patients with suspected/confirmed CNS neoplasms co-managed by Hong Kong Children’s Hospital and St. Teresa’s Hospital, Hong Kong from 5/2022-1/2024. Tracers used included C11-MET (n=10, before 5/2023) and F18-FET (n=15, in/after 5/2023). Lesion-to-normal SUVmax ratios (LNRmax) were measured with reference to adjacent or contralateral normal brain structures.

RESULTS

Twenty-five patients were included (M:F=13:12) with a median age of 10 years (range: 1-17). Anatomical sites of interest were the pituitary (n=13), basal ganglia (n=3), cerebellum (n=3), brainstem (n=2), frontal lobe (n=2), cerebellopontine angle (n=1), and spine (n=1). PET-MRI was performed as part of initial diagnostics in 21, to assess post-operative residual in 2, and for possible relapse in 2. Among those evaluated upfront (n=21), median SUVmax and LNRmax were 1.53 (range: 0.87-2.6) and 0.87 (range: 0.45-1.92) respectively in patients with presumed/confirmed low-grade glioneuronal (n=5) or non-oncologic lesions (n=8), versus 4.75 (range: 2.58-9.6) and 3.26 (range: 1.78-4.9) in patients with histologically/biochemically confirmed high-grade lesions (germinoma=6, high-grade glioma=2). Availability of functional PET imaging was deemed useful for scan interpretation in all 25 patients. Specifically, the use of PET-MRI facilitated decision for radiographic surveillance without biopsy/resection in 12 patients, refined tumor grading in 2 patients with discrepant clinical-histologic features, and allowed response-adapted therapy after serial scans in 5 patients.

CONCLUSIONS

Our study demonstrates the potential benefits of PET-MRI in the management of children with CNS pathologies. PET-MRI contributes to the diagnosis, monitoring, and treatment guidance of these patients, providing crucial information for clinical decision-making.
IMG-27. ASSESSMENT OF VARIABILITY OF PEDIATRIC BRAIN TUMOR IMAGING PROTOCOLS ACROSS INSTITUTIONS: ARE WE FOLLOWING RECOMMENDATIONS?
Authors: kotha Apoorva , Yang David L , Aboian Mariam , Nagaraj Usha D , Bhatia Aashim , Goldman-Yassen Adam Ezra
Published: June 2024

BACKGROUND

Evaluating pediatric brain tumors requires imaging children with tailored MRI protocols. Considerable variation in pediatric brain tumor imaging protocols exist across institutions, which can cause inaccuracies in staging. Although recently consensus guidelines for pediatric brain tumor imaging protocols have been established, adherence to these guidelines across institutions is unknown. Institutions may perceive guidelines as applicable for research purposes rather than routine clinical practice. We aim to explore variability in pediatric brain tumor imaging protocols across institutions and determine the factors influencing guideline divergence.

METHODS AND METHODOLOGY

Faculty at institutions routinely imaging pediatric patients with brain tumors were invited to share brain tumor MRI protocols and complete a structured survey. The survey included multiple choice and open-ended queries concerning practice type, the presence of an institutional imaging protocol for pediatric brain tumors and if the protocol was based on specific consensus recommendations. We assessed if protocols included the 7 minimum recommended MRI sequences by the Children’s Oncology Group (COG) guidelines, including slice thickness and gap.

RESULTS

Twenty emails were sent and responses were received from 12 institutions (the data collection is still ongoing). 2 institutions did not have dedicated protocols for pediatric brain tumors. On average, institutions had 5.7 out of the 7 minimum COG-recommended sequences. All 10 institutions included 3D T1 IR-GRE/TSE, DWI or DTI, and SWI sequences in their protocols. 9 (90%) included post-contrast 3D T1 IR-GRE/TSE, 7 (70%) included T2 TSE/FSE, 7 (70%) included either 3D T2 FLAIR or T2 FLAIR TSE/FSE, and 4 (40%) included T1/TSE/FSE. Across all sequences in all protocols, adherence to recommended imaging parameters was 87% for plane, 71% for slice thickness, and 85% for gap.

CONCLUSION

Significant variability in pediatric brain tumor imaging protocols exists across institutions Standardizing imaging protocols through collaboration is vital in ensuring uniformity in care.
IMMU-01. PIONEERING QUAD-TARGETING CAR T CELL THERAPY IN PEDIATRIC CNS TUMORS – ANALYSIS FROM THE INITIAL PATIENTS TREATED ON THE FIRST-IN-HUMAN PHASE 1 TRIAL BRAINCHILD-04
Authors: Ronsley Rebecca , Choe Michelle , Seidel Kristy , Narayanaswamy Prabha , Pattabhi Sowmya , Wendler Jason , Ho On , Rawlings-Rhea Stephanie , Gust Juliane , Huang Wenjun , Crotty Erin , Leary Sarah , Hauptman Jason , Albert Catherine M , Gardner Rebecca A , Park Julie R , Annesley Colleen , Jensen Michael C , Vitanza Nicholas A
Published: June 2024

BACKGROUND

BrainChild-04 is a first-in-human clinical trial of quad-chimeric antigen receptor (CAR) T cell therapy for children and young adults with central nervous system (CNS) tumors. This trial administers repeated locoregional CAR T cells targeting B7-H3, EGFR, HER2, and IL-13Ralpha2 (“quad-CAR T cells”), leveraging multi-antigen targeting to address the tumor heterogeneity of high-grade CNS tumors.

METHODS

The primary endpoints are feasibility and safety, and secondary endpoints are disease response and correlative studies of CAR T cell activity. The trial utilized a Bayesian Optimal Interval (BOIN) design with three dose regimens (DR). There are 2 arms with weekly delivery for 3 weeks of a 4-week cycle:(A) –diffuse intrinsic pontine glioma (DIPG), (B) –non-pontine diffuse midline glioma (DMG) or other relapsed CNS tumors.

RESULTS

Enrolled patients include DMG N=6, DIPG N=5, other CNS tumors N=4. Of the 15 enrolled patients, 7 have been infused with 8 awaiting infusions. A total of 33 intracranial CAR T doses have been delivered, including Arm A DR 1 (N=1), Arm B DR 1 (N=3), DR2 (N=3). The most common adverse events have been grade 1-2 fever (7/7 patients), grade 1-3 headache (6/7), and grade 1-2 nausea/vomiting (6/7). There have been no DLTs and no cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity(ICANS). CTCAE and tumor inflammation-associated neurotoxicity are both being captured. All treated patients are alive with median follow up time post-initial infusion of 93(14-198) days. CAR T cells were detected by flow cytometric analysis of CSF post-infusion in 14/24 CSF samples. Radiographic response, CSF ct-DNA, targeted mass spectrometry, and cytokine analysis will be presented.

CONCLUSIONS

Our preliminary experience suggests tolerability of locoregional quad-CAR T therapy at doses evaluated. The trial remains ongoing and these data support continued evaluation of this product to better assess anti-tumor activity in patients with CNS tumors, including DIPG/DMG.
IMMU-02. MODIFYING CAR T CELL EPIGENETIC PROGRAMS TO IMPROVE THEIR PERSISTENCE AGAINST GROUP 3 MEDULLOBLASTOMAS
Authors: Ward Meghan B , Senaoui Linda , Youngblood Ben A , Roussel Martine F , Krenciute Giedre
Published: June 2024

BACKGROUND

Safe, effective therapies are desperately needed to improve outcomes for patients with medulloblastoma (MB), a malignant pediatric brain cancer. Chimeric antigen receptor (CAR)-T cells are a promising therapeutic option as they target T-cell cytotoxicity exclusively to tumor associated antigens. B7-homolog 3 (B7-H3) is an ideal target for CAR-T cell therapy as all MB subtypes express B7-H3 and healthy tissues do not. However, a roadblock to tumor clearance is the inability of B7-H3 CAR-T cells to persist, suggesting that improving persistence will benefit anti-tumor efficacy. The goal of this study was to compare head-to-head knocking out TET2 or DNMT3A negative epigenetic regulators of CAR-T cell persistence against group 3 MB (G3MB), the most malignant MB subtype.

METHODS

We generated B7-H3 CAR-T cells with CD28ζ signaling domain and performed CRISPR/Cas9 knockout (KO) of TET2, DNMT3A, and AAVS1 as a control. We compared resulting CAR-T cell persistence via repeat stimulation assays in vitro against G3MB cell lines with varying B7-H3 antigen density (D341low, HDMB03mid, and D425high). We further compared KO CAR-T cells in vivo against D341low, HDMB03mid, and D425high orthotopic xenografts.

RESULTS

Our data shows that DNMT3A KO, but not TET2 KO, consistently improves the persistence and expansion of CAR-T cells against G3MB in vitro. In vivo, KO of epigenetic regulators moderately improves CAR-T cell therapy against highly aggressive D341low, HDMB03mid, and D425high but is insufficient to elicit curative responses.

CONCLUSIONS

Our study demonstrates that genetic KO of negative epigenetic regulators of CAR-T cell persistence can improve anti-tumor function against G3MB. We conclude that for the B7-H3.CD28ζ CAR, DNMT3A KO is superior for improving persistence over TET2 KO, but that DNMT3A KO is insufficient in vivo. We believe this is due to the aggressive nature of G3MB and we are optimizing in vivo studies for better representation of CAR-T cell persistence.
IMMU-04. THE ROLE OF CHECK POINT INHIBITORS IN PEDIATRIC PRIMARY DIFFUSE LEPTOMENINGEAL MELANOMATOSIS: REPORT OF TWO CASES
Authors: Oren Liat , Vlodavsky Evgeni , Raz Michal , Yaniv Zoar , Benifla Mony , Constantini Shlomi , Arush Myriam Ben , Campino Gadi Adebe
Published: June 2024

BACKGROUND

Primary diffuse leptomeningeal melanomatosis (PDLM), a subtype of malignant melanomas of CNS, is rare, especially in children. PDLM is defined by diffuse invasiveness of the leptomeninges with or without nodules. Clinical manifestations of PDLM are nonspecific, mimicking the diagnosis of meningitis. As PDLM is neither sensitive to chemotherapy nor radiotherapy, the prognosis is extremely poor. Recently, some new therapeutic aspects like immunotherapy, especially immune check point inhibitors (ICI) are emerging. Cases report: First case: A 13 years old boy presented with 4 months of weakness, dysphasia and vomiting. MRI demonstrated diffuse leptomeningeal enhancement of the brain and spine. Brain biopsy confirmed the diagnosis of PDLM, with low PDL1 stains in immunohistochemistry, without targetable alterations on NGS. PET FDG normal. Treatment with ICI (Nivolumab 1 mg/kg/dose and Ipilimumab 3 mg/kg/dose, 4 courses every 21 days) was started. He developed severe complications after the 1st course (ICI enterocolitis, pancreatitis) and progressive disease after 2 courses. Craniospinal radiotherapy was delivered at a dose of 30 Gy. The disease continued to progress; the patient died nine months after diagnosis. Second case: A 7-year-old boy presented with diplopia, headache and vomiting. MRI demonstrated a cranial leptomeningeal enhancement and hypo-intense T1 and hyper-intense T2 signal at bilateral medial frontal cortex area. PET FDG normal. Brain biopsy confirmed the diagnosis of PDLM, with TMB 1.9, NRAS mutation and wild type BRAF by NGS. He started combination of ICI therapy. Three weeks after 1st course of Ipilimumab-Nivolumab he was admitted to PICU with prolonged status epilepticus. MRI demonstrated progression of leptomeningeal disease. Trametinib was deferred by parents and the child succumbed a year from diagnosis.

CONCLUSIONS

We report two cases of pediatric patients with PDLM treated unsuccessfully by immune check point inhibitors, emphasizing the diagnostic and therapeutic challenges in such a rare disease.