bluuebunny/crossref_metadata_2025 huggingface dataset:
RARE-07. Low resting energy expenditure is associated with clinical and radiological hypothalamic damage in children surviving a suprasellar brain tumor
Authors: van Schaik Jiska , Burghard Marcella , Lequin Maarten , van Maren Emiel , van Dijk Anne , Takken Tim , Rehorst Lineke , Bakker Boudewijn , Meijer Lisethe , Hoving Eelco , van Meeteren Netteke Schouten- , Fiocco Marta , Tissing Wim , van Santen Hanneke
Published: June 2022

INTRODUCTION: Children with suprasellar brain damage are at risk for hypothalamic dysfunction (HD). HD may lead to decreased resting energy expenditure (REE) contributing to the development of hypothalamic obesity. Decreased REE, however, is not present in all children with hypothalamic damage. Our aim was to assess which children suspect for HD have low REE, and if REE outcome can be associated with clinical severity of HD or with radiological posterior hypothalamic damage. METHODS: A retrospective cohort study was performed evaluating all children diagnosed with brain injury at risk for HD in whom REE measurement was performed. Measured REE (mREE) was compared to predicted REE (pREE) using amongst others the Schofield equation. Low REE was defined as mREE<90% compared to pREE. Radiologic hypothalamic damage was scored using Muller grading score. The mREE/pREE quotient was associated to a clinical score for HD symptoms and to radiological hypothalamic damage. RESULTS: Sixty-seven children suspected for HD (94% brain tumor diagnosis) with a mean BMI SDS of +2.3 ± 1.0 were included. Of these, 45 (67.2%) had mREE <90% compared to the pREE. Children with severe HD symptoms had a significant lower mean mREE/pREE quotient compared to children with no, mild, or moderate HD symptoms. Mean mREE/pREE quotient of children with posterior hypothalamic damage was significantly lower compared to children with no damage or with anterior damage. Tumor progression or tumor recurrence, severe clinical HD, and panhypopituitarism with DI were significant risk factors for reduced REE. CONCLUSION: Not all children suspect for HD have a low REE. Low REE is associated with clinical and radiological scores for hypothalamic damage. REE measurements in childhood brain tumor survivors may be useful to distinguish between those who may benefit from obesity treatment that increases REE from those who would be better helped using other obesity interventions.
RARE-14. Newborn with hypothalamic hamartoma and Pallister-Hall syndrome
Authors: Flaßkühler Anna Meera , Friedrich Carsten , Beckhaus Julia , Boekhoff Svenja , Fiedler Kai , Becking Mechthild Schulze , Hitz Marc-Philipp , Gieldon Laura , Spranger Stephanie , Bison Brigitte , Hoppe Florian , Müller Hermann L
Published: June 2022

A female full-term newborn of 41 + 2 weeks gestational age with a respiratory adaptation disorder and hypercapnia was transferred from an external maternity clinic to our pediatric intensive care unit. The child is the second child of healthy, non-consanguineous parents. Multiple dysmorphias were noticed at arrival. We identified a choanal atresia/stenosis on both sides in the respiratory tract, a high palate, a submucous cleft palate, a bifid uvula, a laryngeal cleft and a bronchus suis. The child required intubation and ventilation. In addition, we recognized brachydactyly of the hands and feet. The phalanges were not visibly separable. There was nail hypoplasia and rocker bottom feet on both sides. Furthermore, we saw an anal atresia. In routine laboratory work-up, a hypoglycemia and not measurable low TSH serum concentration was noticed. Extended endocrinological laboratory diagnostics revealed a complete pituitary insufficiency. On cranial MRI, a large, iso- to slightly hyperintense space-occupying mass (3.8x3.7x2.5 cm3), originating from the hypothalamus was observed. The brainstem was displaced posteriorly by the mass. The imaging is consistent with a hypothalamic hamartoma. With regard to the present findings, we assumed an underlying genetic cause of the congenital malformations. As a clinical diagnosis, a Pallister-Hall syndrome was suspected. As described in our case, we saw the characteristic features: dysmorphia of the hands and feet, upper respiratory tract, anal atresia, and hypothalamic hamartomas. The Pallister-Hall syndrome is caused by mutations in the GLI3 gene on the 7p13 chromosome. It is inherited in an autosomal dominant manner and its prevalence is unknown. In our patient, a heterozygous, probably pathogenic variant in the GLI3-Gene was proven by Next Generation Sequencing (NGS).
RARE-15. Astroblastoma, MN1 altered comprises two molecularly and clinically distinct subgroups defined by the fusion partners BEND2 and CXXC5
Authors: Schmitt-Hoffner Felix , Gojo Johannes , Mauermann Monika , von Hoff Katja , Sill Martin , Stichel Damian , Capper David , Tauziede-Espariat Arnault , Varlet Pascale , Aldape Kenneth , Abdullaev Zied , Donson Andrew M , Schüller Ulrich , Snuderl Matija , Brandner Sebastian , Łastowska Maria , Trubicka Joanna , Miele Evelina , van der Lugt Jasper , Bunt Jens , Kramm Christof , Zapotocky Michal , Sahm Felix , Korshunov Andrey , Jäger Natalie , Pfister Stefan M , Kool Marcel
Published: June 2022

In the recent 5th edition of the WHO classification of CNS tumors, ‘Astroblastoma, MN1 altered’ is recognized a distinct brain tumor type, occurring in children and young adults. Due to its rarity and novelty, little is known about clinical and molecular traits. Therefore, we initiated an international effort and collected tissue samples, clinical and molecular data from 176 patients with Astroblastoma, MN1 altered, identified by their distinct DNA methylation profiles. DNA methylation-based t-SNE clustering analyses revealed that Astroblastoma, MN1 altered tumors form one distinct main cluster (n=158) showing MN1:BEND2 and single cases with EWSR1:BEND2 fusions and a further adjacent, but distinct smaller cluster (n=18) mostly defined by MN1:CXXC5 fusions. Both fusion partner-defined groups show a median age of 12 years but distinct copy-number aberrations, characteristically a gain of chromosome 5 in one third of the CXXC5-fused group and a loss of chromosome 16q in one third of BEND2-fused cases. As previously reported, a vast majority of Astroblastoma, MN1 altered patients are female, which we confirm for the BEND2-fused group (85%). The CXXC5-fused group, however, shows 75% male patients. Interestingly, 9/10 tumors of the few male patients observed in the BEND2-fused group were all located infratentorially or in the spinal cord, whereas almost all female cases show a supratentorial location (85/87). Histologically, the BEND2-fused group was primarily reported as Astroblastoma (39%), whereas in the CXXC5-fused cases, 31% CNS-PNET and only 8% Astroblastoma histologies were originally assigned. Preliminary clinical analyses showed that the BEND2-fused group has a relatively good 5/10-year OS of 97%/89%, but a less favorable 5/10-year PFS of 48%/35%, in line with previous studies. Patients showing CXXC5-fused tumors (n=8) indicated 5/10-year OS and PFS rates of 83%/83% and 60%/60%, respectively. Additional survival and molecular analyses are being conducted to further characterize Astroblastoma, MN1 altered tumors and its molecular subgroups.
RARE-17. Multi-institutional craniopharyngioma cohort highlights need for more comprehensive data collection on comorbidities and quality of life
Authors: Marshall Emily , Crowley Julia , McCormack Shana , Rood Brian , Hankinson Todd , Cheng Sylvia , DeCuypere Michael , Lam Sandi , Goldman Stewart , Ballester Lance , Faig Walter , Velasco Ryan , Arya Kamnaa , Storm Phillip Jay B , Resnick Adam , Prados Michael , Mueller Sabine , Malbari Fatema , Kline Cassie
Published: June 2022

BACKGROUND: Pediatric craniopharyngioma is associated with long-term survival, but tumor- and therapy-related complications often negatively impact quality of life (QoL). Standard treatments include resection and radiation, but institutional practices vary and recurrence rates remain high. In this review, we utilized a cohort from the Children’s Brain Tumor Network (CBTN) to evaluate outcomes for craniopharyngioma. METHODS: CBTN provides clinical and genomic data for pediatric patients diagnosed with primary central nervous system tumors across 25+ institutions. We collected data for 124 patients, ages 0-21, diagnosed with craniopharyngioma between 2012-2020. Variables collected included treatment, recurrence/progression, and comorbidities. RESULTS: Excluding patients without confirmed pathologic diagnosis (n=10) or follow-up data (n=39), 75 patients remained. For initial treatment, most (n=46, 61%) received surgery alone (9 partial, 33 near-total resection). Twenty-six (35%) underwent both surgery and radiation, with 9 receiving both therapies upfront and 17 receiving radiation at progression/recurrence. Four (5%) patients received chemotherapy. Over half of the cohort (n=39, 52%) had at least one progression/recurrence, and four died (5%). Significantly higher rates of progression/recurrence (84% vs. 32%, p=4.0e-5) were identified in patients that had surgery and radiation, compared to surgery alone. Time to recurrence, progression, or death was shorter for the surgery and radiation group (HR=4.1, p<1.0e-4), and for those that underwent partial versus near-total resection (HR=2.7, p=0.1.2e-2). Comorbidities were likely underreported, based on low rates of visual (32%), neuroendocrine (27%), and neurologic (28%) deficits at diagnosis, and 29 patients (39%) with unspecified medical history. CONCLUSIONS: CBTN provides a robust repository of information on treatment and survival of craniopharyngioma patients. However, we found a paucity of data on associated comorbidities and QoL outcomes. We advocate that future datasets and clinical trials routinely collect functional outcomes alongside therapy and survival data, particularly in craniopharyngioma where long-term survival is balanced with future QoL.
RARE-25. Primary Intracranial Ewing Sarcoma in a Child: Case Report
Authors: Custodio John Emmanuel , Baticulon Ronnie , Palabyab Eric Paolo , Golidtum Jared Paul
Published: June 2022

Ewing sarcoma is a rare childhood tumor which accounts for 3% of all pediatric malignancies. More so, primary intracranial involvement with meningeal attachment is even rarer, accounting for only 1% of all Ewing sarcoma. We report a case of a 5-year-old boy who presented with headache, vomiting, and left-sided weakness that rapidly progressed over a period of three months. Cranial MRI showed a 7.1 x 6.7 x 8.6 cm multilobulated, heterogeneously enhancing, mixed solid and cystic extra-axial tumor compressing the frontoparietal lobe and causing significant midline shift. It was attached to the falx and infiltrated the middle third of the superior sagittal sinus. We performed a large right frontoparietal craniotomy to excise the tumor. Because of massive bleeding from the tumor, only a subtotal resection was possible. The bone flap was left out. The patient was discharged fully awake but with right hemiplegia on the fourteenth post-op day. Histopathologic examination revealed a spindle cell neoplasm that exhibited diffuse membranous staining for CD99. Fluorescence in-situ hybridization confirmed EWSR1 gene rearrangement, consistent with Ewing sarcoma. Three months after his surgery, the patient subsequently received 56 Gy of radiation therapy. At twelve months post-op, he remains fully awake and is back in school. He has residual left hemiparesis, but with antigravity movement. A multidisciplinary team involving Pediatric Oncology, Pediatric Neurology, Neurosurgery, Pathology, Radiation Oncology, and Rehabilitation Medicine is essential for patients with rare central nervous system tumors, to maximize effective treatment strategies despite limited resources.
RARE-28. The use of subcutaneous interferon in patients with craniopharyngioma: an institutional retrospective review
Authors: Patil Prabhumallikarjun , Gray Rachel , Goldman-Yassen Adam , Aguilera Dolly , Castellino Robert , Janss Anna , Mazewski Claire
Published: June 2022

Current strategies for managing craniopharyngioma result in significant morbidity. Successful treatment with interferon alfa(INFα) after progression is reported in the literature. This retrospective review details our institutional experience with INFα in craniopharyngioma patients. Method: Between 2000-2021, we treated 81 craniopharyngioma patients. Twenty-two patients received 26 treatment courses of subcutaneous INFα. Twenty-three courses were evaluable for response. Results: Ten patients received upfront INFα after cyst decompression +/- ommaya placement. Progression free survival(PFS) ranged between 7-38mo. Three patients continue on treatment (10+, 12+, 14+mo); seven progressed (four on treatment (7, 9, 25, 38mo), three after treatment (13, 19, 32mo)). At progression, three underwent surgery alone, three underwent surgery and radiation, one resumed INFα. Thirteen patients received INFα after progression. Prior to INFα, eight patients had had surgery, five surgery and radiation. Two in each group had INFα, previously. PFS ranged between 5-82+mo. One patient remains on treatment (5+mo); four continue in follow-up without progression (23+,40+,64+,82+mo) with two patients avoiding radiation to date; eight progressed (three on treatment (6-8mo), five after treatment (16,24,26,46,71mo)). At progression, two underwent surgery alone, three underwent surgery and radiation, one received re-irradiation, two resumed INFα. While receiving INFα, two patients experienced serious adverse events (one intra-tumoral hemorrhage (not attributed to INFα), one suicidal ideation). Both recovered. One tolerated retreatment with INFα. Three additional patients stopped INFα for intolerance, but two received INFα at subsequent progression. No other unanticipated side effects were reported. Conclusion: INFα therapy in patients with both newly diagnosed and progressive craniopharyngioma delayed the need for aggressive surgical resection and/or radiotherapy in some cases. In some patients, INFα resulted in prolonged stabilization of disease delaying or avoiding radiation. Overall, INFα side effects were manageable. These results are encouraging regarding INFα therapy for patients with craniopharyngioma and warrant further evaluation with a clinical trial.
RARE-30. Novel collision tumor of craniopharyngioma and ependymoma in a pediatric patient: a case study
Authors: Gray Rachel , Chien Franklin , Vega Jose Velazquez , Patteson Brooke , Wrubel David , Eaton Bree , Schniederjan Matthew , Mazewski Claire
Published: June 2022

Collision tumors are rare tumors comprised of two distinct histologies. In this case report, we discuss a suprasellar collision tumor consisting of adamantinomatous craniopharyngioma and supratentorial ependymoma in a pediatric patient. Case Presentation: Our patient was a two-year-old female with progressive craniopharyngioma status post cyst decompression with Ommaya reservoir placement, subcutaneous peginterferon, Ommaya taps, and subtotal resection. An MRI three months post-resection showed progression and treatment was started with subcutaneous interferon alfa. After eight weeks, she presented with new onset headaches and vomiting. MRI demonstrated tumor progression with associated obstructive hydrocephalus. She underwent a subtotal resection. Pathology revealed recurrent adamantinomatous craniopharyngioma and a 0.5cm ependymoma with classic histomorphology lacking anaplasia features. The ependymoma was positive for GFAP immunostain and EMA immunohistochemistry highlighted a ‘dot-like’ reaction. The Ki-67 proliferation index was very low (<1%). The limited diagnostic material precluded further genomic characterization of the ependymoma. The previous pathology was reviewed and no ependymoma was identified. Spine MRI was negative for metastatic disease. CSF cytology was negative for malignant cells. Following recovery from surgery, she received 54Gy (RBE) focal proton radiation. Eight months from completion of therapy, surveillance MRI shows stable residual tumor. Genetic work-up for cancer predisposition syndrome is in process despite no strong family history of cancer. Discussion: Due to the patient’s young age at diagnosis, our initial treatment strategy was to delay radiotherapy and utilize other treatment options. Following diagnosis with a collision tumor, the patient proceeded to radiotherapy to manage both tumor components. The role of interferon in the development of a collision tumor in this patient in unknown, but we suspect it to be unrelated. Conclusion: To our knowledge, this is the first documented case of a suprasellar collision tumor comprised of craniopharyngioma and ependymoma. Discovery of the collision tumor impacted the patient’s treatment plan.
DIPG-02. Role of a Bevacizumab-based regime in the treatment of children with diffuse intrinsic pontine glioma (DIPG): a systematic review
Authors: Evans Mia , Gill Ria , Bull Kim
Published: June 2022

BACKGROUND: Diffuse intrinsic pontine glioma (DIPG) is an aggressive paediatric brainstem tumour. There are no effective treatments and median survival is 11.2 months, therefore maintaining quality of life (QOL) is a priority for many families. Bevacizumab, an anti-VEGF IgG antibody, has the potential to improve QOL and survival in DIPG, but has never been evaluated systematically. AIM: To collate the evidence and assess the role of this drug, in the treatment of DIPG. METHODS: MEDLINE, EMBASE, Scopus and Web of Science were searched for relevant studies using terms developed from PICO criteria, including alternatives for Bevacizumab and DIPG. One reviewer screened titles and abstracts, then two reviewers screened full texts. Data were extracted into tables and study quality assessed using MINORS and JBI tools. RESULTS: Searching revealed 1,001 papers; after deduplication 851 remained. After screening of titles and abstracts, 28 full texts were screened, resulting in the inclusion of 11 studies. All studies evaluated more than one outcome. Four studies reported a median overall survival longer than historical data, however, two determined no significant impact. Five studies reported a radiological response in a proportion of participants and two reported no response. Three studies evaluating clinical response, reported improvement in a proportion of patients. Three studies evaluating QOL reported stability or improvement. Four studies evaluating steroid use reported reductions in the proportion of patients receiving steroids. In the treatment of radiation necrosis, Bevacizumab led to clinical improvement in 6/12 patients in 2 studies and permitted a reduction in steroid use in the majority of patients. CONCLUSION: Insufficient evidence means the role of Bevacizumab in the treatment of DIPG is unclear. However, Bevacizumab may be beneficial to some patients. The review highlights the need for further research in this area, particularly randomised controlled trials. More effective therapies are desperately needed.
DIPG-18. Evaluating drug distribution in children with diffuse intrinsic pontine glioma (DIPG) treated with convection-enhanced drug delivery
Authors: Szychot Elwira , Bhagawati Dolin , Gill Steven , Walker David , Hyare Harpreet
Published: June 2022

BACKGROUND: There is currently no method for evaluating drug distribution and tumour coverage using the convection-enhanced drug delivery (CED) technique in diffuse midline glioma of the pons (previous DIPG). AIMS: To determine an imaging protocol that can be used to assess the distribution of infusate in children with DIPG treated with CED of carboplatin and sodium valproate. METHODS: 12 children with DIPG received between 4–18ml of infusate, through 2 pairs of catheters to encompass tumour volume on 2 days. Volumetric T2W and Diffusion Weighted Imaging (DWI) MRI sequences were performed before and after the first cycle of CED therapy and Apparent Diffusion Coefficient (ADC) maps were calculated. The tumour volume pre and post CED was automatically segmented (ITKSnap) on T2W and ADC on the basis of signal intensity. The ADC maps pre and post infusion were registered and subtracted (FSL) to visualize the infusate distribution. RESULTS: ADC and T2W demonstrated a significant (<0.001) change in mean tumour volume post-infusion (mean ADC volume pre: 19.8ml, post 24.4ml; mean T2W volume pre 19.4ml, post 23.4ml). A significant correlation (p<0.001) was observed for the difference in tumour volume and the actual infused volume (ADC, r=0.76, T2W, r=0.70). There was a significant increase (p<0.001) in mean ADC and mean T2W signal intensity ratio post-infusion, no significant correlation with infusion volume. Finally, pixel-by-pixel subtraction of the ADC maps pre and post infusion visually demonstrated high signal intensity, presumed infusate coverage of the tumour. CONCLUSIONS: Our study provides the preliminary evidence that measurement of change in tumour ADC and T2W MR sequences, has a potential value for quantifying the distribution of infusate delivered by the intermittent CED, which will facilitate the use of CED in future clinical trials.
DIPG-20. Copper chelation therapy targets S-adenosylmethionine (SAM) metabolism and epigenetic regulators in diffuse intrinsic pontine glioma (DIPG)
Authors: Michniewicz Filip , Bell Jessica , Saletta Federica , Watkinson Tayla , Mercatelli Daniele , Giorgi Federico M , Barlow Christopher K , Faridi Pouya , Tsoli Maria , Ziegler David , Vittorio Orazio
Published: June 2022

DIPG is an incurable pediatric brain cancer of the ventral pons characterized by its complex epigenetic profile. Up to 81% of patients present with mutation H3K27M, resulting in the global reduction of H3K27 trimethylation and increased H3K27 acetylation, deregulating gene expression through an aberrant pattern of epigenetic modification. These alterations affect many cellular and metabolic mechanisms, complicating the search for effective targeted therapeutic strategies. Copper is highly abundant in the pons and is essential for normal brain function and development. However, excess copper accumulation is implicated in several neurological diseases and cancers. Incidentally, recent investigations have indicated the H3-H4 dimer can interact with copper acting as a reductase enzyme. Copper chelation therapy is clinically approved for pediatric patients with Wilson’s Disease, improving their neurological symptoms, and is being trialed in several cancers. We therefore hypothesized copper chelation may represent an effective therapeutic strategy for DIPG. Copper chelator tetraethylenepentamine (TEPA) decreased cell growth and induced apoptosis in DIPG cell lines. To understand these results, unbiased RNA-seq and metabolomics analyses were performed, revealing downregulation of EZH2, DNMT1 and DNMT3B, upregulation of KDM6B and the disruption of key enzymes in the S-adenosylmethionine (SAM)-cycle. Importantly, TEPA downregulated SAM, which donates methyl groups for methylation, S-adenosylhomocysteine, its post-methylation product and α-ketoglutarate, a co-factor for KDM6B. Western blots confirmed the reduced expression of EZH2, DNMT1 and DNMT3B, with further blots examining the chromatin cell fraction revealing modulation of H3K27 trimethylation through copper or TEPA stimulation, and reduction of H3K27 acetylation by TEPA. Importantly, in vitro combinations with Panobinostat were synergistic, while in vivo investigations demonstrated TEPA improved survival in an orthotopic patient derived xenograft (PDX) model, showing complete tumor regression in 25% of treated mice. This study indicates a novel use for copper chelators as epigenetic drugs, and their potential as therapeutics for DIPG.
DIPG-21. DIPG cells alter the permeability of the blood-brain barrier in the brainstem leading to treatment failure.
Authors: Ung Caitlin , Upton Dannielle H , Venkat Pooja , Pandher Ruby , Curnis Flavio , Corti Angelo , Nicolazzo Joesph , Mayoh Chelsea , Tsoli Maria , Ziegler David S
Published: June 2022

Diffuse Intrinsic Pontine Glioma (DIPG) is an aggressive paediatric high-grade glioma with no effective therapies. The blood-brain barrier (BBB) presents a significant obstacle for delivery of therapeutics into the brain, especially in the brainstem. This study aims to investigate the effect of DIPG cells on the BBB in the brainstem. We hypothesized that the location of DIPG may result in a less permeable BBB than other brain regions. We compared two independent orthotopic models with the same DIPG cells injected in the cortical region or brainstem. We found that treatment with mTOR inhibitor, temsirolimus, significantly extended survival for cortical tumors compared with the same tumor in the brainstem (p=0.0097). Immunohistochemical analysis showed significant reduction of mTOR target, P-p70S6K, in the cortical region compared to brainstem in treated animals, with pharmacokinetic analysis confirming significantly higher temsirolimus levels in the cortical region. These findings suggest that cortical tumors respond better than brainstem tumors, and that a less permeable BBB in brainstem tumors contributes to treatment failure. To understand whether DIPG cells affect the BBB in the brainstem, single-cell RNA sequencing experiments were conducted on vasculature isolated from DIPG and matrigel-injected mice. Gene-ontology overrepresentation analyses identified downregulation in the P38MAPK pathway in endothelial cells from DIPG-injected mice, suggesting the potential for therapeutic manipulation with cytokines. Treatment with SNGR-TNFα, a derivative of an agent successfully used in improving drug penetration in CNS lymphoma patients, in an in vitro BBB/DIPG model significantly reduced transendothelial resistance, and further exploration into the effects on the BBB in vivo is currently being undertaken. Our studies indicate that the intact BBB in the brainstem in DIPG is a major reason for treatment failure, and DIPG cells directly influence the vasculature and response to treatment. This may lead to a novel DIPG treatment strategy and for other brain tumors.
DIPG-22. Modifying the tumor microenvironment with a TIM-3 monoclonal antibody as a therapeutic strategy for DIPGs
Authors: Ausejo-Mauleon Iker , Labiano Sara , De la Nava Daniel , Garcia-Moure Marc , Laspidea Virginia , Becher Oren J , Jiang Li , Filbin Mariella G , Pastor Fernando , Alonso Marta M
Published: June 2022

Diffuse Midline Glioma, encompassing Diffuse Intrinsic Pontine Gliomas (DIPGs), are the most aggressive pediatric brain tumors. Their meager survival has not changed despite the combination of radiotherapy with targeted therapies emphasizing the urgent need for effective treatments. TIM-3 (HAVCR2) is a member of the T-cell immunoglobulin and mucin domain protein family. It is expressed on multiple immune cell types, including T cells, NK cells, myeloid populations, and microglia, regulating adaptive and innate immunity. In silico assessment of TIM-3 expression in DIPG datasets showed a robust expression of this gene. Single-cell sequencing analyses of DIPG biopsies uncover TIM-3 expression, especially in microglia. In vivo efficacy studies showed that treatment with AbTIM-3 significantly increased overall survival in two DIPG immunocompetent orthotopic models, led to long-term survivors (50%), and showed immune memory. TIM-3 treatment led to a significant increase in the tumor microenvironment of microglia, granulocytes, NK, and CD8+ cells and higher levels of IFNγ, GrzB and TNFα corresponding with an NK and T-cell activate phenotypes. Interestingly, there was a decrease in the Treg population which causes an increase in the pro-inflammatory CD8/Treg ratio. CD4, CD8 or NK cell depletion leads to a significant but not a total loss of treatment efficacy. CD4+ and CD8+ cells were aumented in treated draining lymph nodes and expressed higher amounts of pro-inflamattory cytokines than control-mice. Population analysis and depletion experiments demonstrated the relevance of NK, CD4, CD8 and myeloid populations in the response to anti-TIM-3 therapy. Interestingly, the depletion of the different immune populations combined or using immunodeficient Rag2 mice, did not completely abrogate the treatment efficacy. These results suggest the concurrence of an additional mechanism of action that together with the immune response leads to a robust anti-DIPG effect. In conclusion, these data demonstrate that TIM-3 is a potential target for the treatment of DIPG.
DIPG-24. Neurological symptom improvement after re-irradiation in patients with diffuse intrinsic pontine glioma (DIPG): A retrospective analysis of the SIOP-E-HGG/DIPG project.
Authors: Chavaz Lara , Janssens Geert O , Bolle Stephanie , Mandeville Henry , Ramos-Albiac Monica , van Beek Karen , Benghiat Helen , Hoeben Bianca , La Madrid Andres Morales , Seidel Clemens , Kortmann Rolf-Dieter , Hargrave Darren , Gandola Lorenza , Pecori Emilia , van Vuurden Dannis G , Biassoni Veronica , Massimino Maura , Kramm Christof , von Bueren Andre O
Published: June 2022

PURPOSE: To investigate the spectrum of neurological triad improvement in patients with diffuse intrinsic pontine glioma (DIPG) treated by re-irradiation (re-RT) at first progression. METHODS: Re-analysis of the SIOP-E retrospective DIPG cohort by investigating clinical benefits after re-RT with focus on the neurological triad. Patients were divided as "responding" or "non-responding" to re-RT. To assess the interdependence between patients’ characteristics and clinical benefits we used a Chi-Square or Fisher’s Exact test. Survival according to clinical response to re-RT was calculated by the Kaplan-Meier method. RESULTS: As earlier reported, 77% (n = 24/31) of patients had any clinical benefit after re-RT. Among 25/31 well documented patients, 44% (n=11/25) had improvement in cranial nerve palsies, 40% (n=10/25) in long-tract signs, 44% (11/25) in cerebellar signs. Clinical benefits were observed in at least 1, 2 or 3 out of 3 symptoms of the DIPG triad, in 64%, 40% and 24% respectively. Patients irradiated with a dose ≥ 20 Gy versus < 20 Gy may improve slightly better with regards of ataxia (67% versus 23%; P-value = 0.028). The survival from the start of re-RT to death was not different between responding and non-responding DIPG patients (P-value = 0.871). CONCLUSION: A median re-irradiation dose of 20 Gy provides a neurological benefit in two-third of patients with an improvement of at least one symptom of the triad. DIPG patients receiving ≥20 Gy appear to improve slightly better with regards of ataxia, however we need more data to determine whether dose escalation up to 30 Gy provides additional benefit.
DIPG-28. IndolentH3 K27M-mutant diffuse midline glioma
Authors: Damodharan Sudarshawn , Bradley Kristin , Stadler Andrew , Rebsamen Susan , Helgager Jeffrey , Puccetti Diane
Published: June 2022

INTRODUCTION: H3 K27M-mutant diffuse midline glioma (DMG) is an aggressive central nervous system tumor that is universally fatal with a median survival of 8-12 months after diagnosis. Here we present a patient who was incidentally found to have a lesion within the right thalamus on brain magnetic resonance imaging (MRI). Twelve years later, she was found to have a brain mass within the same area with pathology consistent with an H3 K27M-mutant DMG. CASE DESCRIPTION: A 14-year-old female presented with new onset left-sided numbness and weakness, blurry vision and a right-sided temporal headache. Her past medical history is significant for severe persistent asthma and anoxic brain injury secondary to a cardiopulmonary arrest at 2-years-of-age due to an asthma exacerbation. She has had multiple MRIs of her brain since her initial insult which initially showed the presence of a T2/FLAIR hyper-intense lesion within the right medial thalamus in addition to chronic central nervous system changes. The right thalamic lesion was stable in size between images obtained at 2-years and 4-years of age. Her current physical exam is significant for decreased strength to her left upper and lower extremities. Brain MRI with and without contrast is obtained with partial effacement of the third ventricle due to mass effect from an enlarging mass from the right thalamus. Biopsy of the lesion demonstrated an H3 K27M-mutant DMG, WHO grade IV. Our patient went on to receive palliative radiation therapy with 59.4 Gy over 33 fractions. DISCUSSION: This case illustrates an unusual presentation of an H3 K27M-mutant DMG with an indolent course, diagnosed twelve years after the initial MRI finding. This proposes the possibility of multiple factors playing a role in the oncogenesis of these aggressive tumors and that further research is warranted.
DIPG-34. Life and End-of-Life after Diffuse Intrinsic Pontine Glioma diagnosis
Authors: Pejenaute Idoya Serrano , López-Almaráz Ricardo , Echebarria Aizpea , Adán Rosa , De Pedro Jimena , Gonzalez Paula , Sanchez Jesús , López-Bayón Julio , Astigarraga Itziar , García-Ariza Miguel
Published: June 2022

INTRODUCTION AND OBJECTIVES: Despite advances in pediatric oncology, Diffuse Intrinsic Pontine Glioma’s (DIPG) life expectancy remains <10% at 2 years, and the mean survival time is 8-10 months from diagnosis. Its location associates multiple symptoms of complex management that condition their quality of life. The aim is to review our experience in the clinical course of the disease and the involvement of palliative care (PC). METHODS: Single-centre retrospective study of patients <18 years diagnosed with DIPG between 2011-2022. A review of the electronic medical record was carried out, recording demographic data, oncological treatments, PC and advance care planning (ACP). RESULTS: We registered 14 patients (2 alive). Median age at diagnosis was 6.4 years (range 3.5-11.9). Median survival from diagnosis was 9.6 months (range 0.5-18) and 3.8 months from progression (range 0.1-12). At diagnosis, 92% received oncological treatment (radiotherapy 75%, chemotherapy 41%, oncolytic viruses 21%, partial resection 8%). After progression, 4 patients received metronomic chemotherapy or re-irradiation and in the last month of life 2 received chemotherapy. In the last 3 months of life, 64% were admitted at least once for progression or end-of-life. In the last month, all received oral dexamethasone. Follow-up by PC team was provided in 64%, with first contact in the last month of life in 36%. ACP was recorded in 4 patients, all of them followed up for PC. Death occurred at home in 33%, hospital in 58%. Palliative sedation was used in 5 patients. CONCLUSIONS: Despite the known prognosis of DIPG, some patients continue receiving oncological treatment after progression and in the last month of life. Contact with PC teams occurred mainly at advanced disease stage. Median survival of children with DIPG is below one year, with multiple symptoms in the progression phase. Therefore, early follow-up by PC teams is recommended.
DIPG-38. Significant tumor regression of H3K27M-mutated diffuse midline glioma of the brainstem with panobinostat: a case report.
Authors: Partap Sonia , Abadilla Natasha , Farahzadi Thrithi , Monje Michelle
Published: June 2022

INTRODUCTION: Diffuse midline glioma is a fatal CNS tumor that chiefly occurs in children. To date, standard of care has been limited to local field radiation. A histone mutation in H3K27M is seen in 80% of diffuse midline gliomas of the brainstem, also called diffuse intrinsic pontine glioma (DIPG). Panobinostat, a potent inhibitor of histone deacetylases, has shown moderate efficacy in DIPG/DMGs in preclinical models, and a dose-finding clinical trial (PBTC-047) is ongoing. We report on a case of a child with biopsy-proven H3K27M-mutated DMG of the brainstem treated off-trial with panobinostat monotherapy after radiation. METHODS: This is a case report of a 12-year-old female with H3K27M-mutated DMG of the medulla and cerebellum that exhibited gadolinium-enhancement on MRI. The patient was treated with 54 Gy focal photon radiation to the tumor field over six weeks after biopsy demonstrating the H3.3K27M mutation (H3F3A), as well as mutations in TP53, PIK3R1 and AXSL1 genes. She was not eligible for PBTC-047 due to uncontrolled hypertension. She received panobinostat as per the ongoing PBTC protocol at a dose of 28 mg/m2 given on Monday, Wednesday, and Friday on alternating weeks. She received three 28-day cycles over three months. RESULTS: The patient tolerated the therapy well, with minimal adverse reactions of low-grade abdominal pain and constipation. MRI imaging after three cycles revealed an 80% reduction in tumor volume. Together with this radiographic response, she exhibited improvement in left-sided motor strength and improved left facial sensation. Due to an unrelated need for oral surgery, panobinostat was held. MRI imaging six weeks after cessation of panobinostat revealed extensive relapse with supratentorial and spinal disease. CONCLUSION: Systemic panobinostat may demonstrate anti-tumor efficacy in some cases of H3K27M-mutated DMG. Future work is required to determine factors predictive of favorable response.
DIPG-39. New preclinical models for Diffuse Midline Glioma
Authors: Klenner Marbod , Freidel Pia , Filbin Mariella G , Beck Alexander
Published: June 2022

Malignant brain tumors are the leading cause of childhood death in Germany, with Diffuse Midline Glioma (DMG) being the most lethal of all paediatric brain tumors. Current treatment strategies are limited to irradiation which prolongs survival only by a few months. Preclinical studies have identified effective drug candidates, but translation into the clinic remains a major obstacle. It is known that interactions between tumor cells and components of the TME (tumor microenvironment), such as cell to cell contacts between malignant and non-malignant cells or secreted factors, can increase therapy resistance and progression of brain tumors. However, these important factors are not present in most conventional cell culture models for drug testing. Consequently, there is a need for more realistic DMG models to improve the relevance and translational potential of current drug screening. Therefore, the goal of this study was to develop a new DMG model for drug testing, consisting of induced pluripotent stem cell (iPSC) derived human brain cells and patient derived DMG cells to better mimic the complex tumor microenvironment. We co-cultured three-dimensional cerebral organoids with DMG tumor spheres resulting in the formation of DMG-Brain-Organoids (DBO). Preliminary results show that co-culture induces distinct tumor cell subpopulations corresponding to those detected in DMG tumors by single cell RNA sequencing (Filbin et al., 2018). These subpopulations mainly differ in their proliferative capacity and their differential response to clinical interventions may be critical for therapeutic success. DBOs subjected to drug treatments (single or combination) were sectioned and individual therapy effects on tumor cell subpopulations and proliferative capacity were monitored using multiplexed immunofluorescence imaging. By observing drug effects in a realistic setup, we hope to improve the predictive power of our preclinical drug screens and to find new combination therapies for DMG.
DIPG-40. Combined pharmacological and genetic screening to identify dependencies and combinations in ACVR1-mutant diffuse midline glioma
Authors: Rogers Rebecca , Carvalho Diana , Grabovska Yura , Fernandez Elisabet , Izquierdo Elisa , Mackay Alan , Jones Chris
Published: June 2022

Somatic mutations in ACVR1, which encodes the serine/threonine kinase ALK2, are found in 20-25% of DMG-H3K27 patients. Treatment of ACVR1-mutant patient-derived models with multiple chemotypes of ALK2 inhibitors (ALK2i) results in reduced cell viability in vitro and extended survival in orthotopic xenografts in vivo but, as single agents, these inhibitors were unable to achieve a complete anti-tumour response. Recently we reported that combinatorial treatment of ACVR1-mutant DIPG cells with vandetanib (RTK inhibitor) and everolimus (mTOR/ABC transporter inhibitor) was synergistic both in vitro and in vivo and was shown to be a feasible combination to trial clinically in this setting. To identify specific dependencies in ACVR1-mutant cells which may be translatable with novel synergistic drug combinations alongside ALK2i, we have implemented both candidate and unbiased drug and genetic screening approaches. Using a panel of patient-derived ACVR1-mutant and wild-type models, we identified synergy between multiple chemotypes of ALK2i (M4K2009/LDN-214117) and PI3K/mTOR (AZD8055/everolimus) and MEK inhibitors (trametinib), reflecting the common co-segregation of PIK3CA/PIK3R1 alterations in these tumours. Whole-genome CRISPR/Cas9 screening of ACVR1-mutant SU-DIPG-IV cells in combination with two ALK2i (M4K2009/LDN-193189), confirmed a specific MTOR genetic dependency, as well as for the protein phosphatase regulatory subunit PPP2R1A, known to play a role in MAPK pathway activation. Additional hits include the serine/threonine kinase PKMYT1, a negative regulator of the G2/M checkpoint via a functionally redundant phosphorylation of CDK1/CCNB1 alongside WEE1; confirmatory drug assays with the WEE1 inhibitor AZD1775 resulted in a synergistic interaction with ALK2i in ACVR1-mutant cells. Hits were integrated with DepMap using ‘gene-effect’ scores (Chronos) enabling filtering of common essential genes. Preliminary pathway enrichment analysis (MAGeCKFlute) identified ALK2i-specific vulnerabilities involving TGFB1/SMAD signalling and histone deacetylation. These data highlight functionally rational and novel combinatorial possibilities for children with ACVR1-mutant DMG, with systematic preclinical assessment required for prioritisation for the clinic.
DIPG-47. TSO500ctDNA sequencing reveals oncogenic mutations and copy number variations in the liquid biome of children with diffuse midline glioma
Authors: Bonner Erin R , Harrington Robin , Eze Augustine , Bornhorst Miriam , Kline Cassie N , Dawood Adam , Das Biswajit , Chen Li , Pauly Rini , Williams P Mickey , Karlovich Chris , Peach Amanda , Howell D'Andra , Doroshow James , Kilburn Lindsay , Packer Roger J , Mueller Sabine , Nazarian Javad
Published: June 2022

BACKGROUND: Molecular profiling of childhood CNS tumors is critical for diagnosis and clinical management, yet tissue access is restricted due to sensitive neuroanatomical locations. Moreover, CNS tumors including diffuse midline glioma (DMG) exhibit mutational heterogeneity and clonal evolution, which cannot be captured by upfront diagnostic biopsy alone. To address the lack of tumor visibility, and tprovide opportunity for longitudinal sampling, we validated and optimized a commercially available deep sequencing platform for analysis of circulating tumor DNA (TSO500ctDNATM). METHODS: In a proof-of-concept study, we defined the sensitivity, specificity, and clinical relevance of our novel ctDNA platform via analysis of paired tissue, CSF, and blood from children with DMG (n=10). Paired samples were assessed for concordance and sequencing results were compared to digital droplet PCR (ddPCR) detection of prognostic H3K27M mutation. RESULTS: DMG associated mutations in genes including H3-3A, H3C2, TP53, and ACVR1 were detected in ctDNA, including in CSF samples with low (<5ng) starting DNA input. Of 9 H3K27M mutations identified in tumor, 8 were present in CSF and 3 in plasma/serum, for a positive percent agreement with tumor results of 89% and 33%, respectively. Among CSF samples, H3.3K27M was detected in 6/6 cases, and H3.1K27M in 2/3 cases, with variant allele frequencies comparable to ddPCR results. CNVs including PDGFRA, KIT, and MDM4 gains were detected in CSF and paired tumor. Low frequency events including ACVR1, PIK3CA activating mutations and KRAS amplification were detected in CSF but absent from paired tumor, indicating tissue heterogeneity. Strategies to optimize ctDNA detection, including optimization of ctDNA isolation and adjustment of library QC metrics, were identified. CONCLUSION: Targeted ctDNA deep sequencing is feasible, can inform on clinically relevant tumor mutation and CNV profiling, and provides an opportunity for longitudinal monitoring of tumor genomic evolution in the liquid biome of children with CNS tumors.
DIPG-49. International preclinical drug discovery and biomarker program informing an adoptive combinatorial trial for DMG
Authors: Nazarian Javad , Dun Matthew , Kilburn Lindsay , Waszak Sebastian , Vitanza Nicholas , Franson Andrea , Prados Mike , Raabe Eric , Firestein Ron , Beck Alexander , Saratsis Amanda , Rotblat Barak , van Vuurder Dannis , Foster Jessica , Hulleman Esther , Kline Cassie , Gupta Nalin , Cain Jason , Koschmann Carl , Muller Sabine
Published: June 2022

INTRODUCTION: DMG-ACT (DMG- multi-arm Adaptive and Combinatorial Trial) will implement an innovative clinical trial design of combinatorial arms for patients with DMG at all disease stages, that is adaptive to pre-clinical and correlate data generated in eight collaborating institutions. The goal of the team is to rapidly identify and validate i) promising drugs and drug combinations for clinical use, and ii) predictive biomarkers of promising drugs. METHODS: In vitro (n=30) and in vivo (n=8) models of DMG across fourteen institutions were used to assess single and combination treatment of over 80 drugs and drug combinations. Predictive biomarkers of response for top candidate drugs were identified using extensive molecular assays including proteomics, CRISPR, RNAseq, ELISA, FACS, and IHC. RESULTS: Inhibitory concentration (IC50) of all drugs were established and validated across all participating sites. In vivo validation of single and combination drug assays confirmed drug efficacy as increased survival for: ONC201 (p=0.01), ONC206 (p=0.01), ONC201+ONC206 (p=0.02), ONC201+panobinostat (p=0.01). Marizomib was highly toxic in murine PDX and zebrafish larvae assays. Murine pharmacokinetic analysis showed peak brain levels of ONC201, and ONC206 above pre-clinical IC50 concentrations. Molecular testing and analyses of existing drug screen across 578 cancer cells validated mitochondrial stress and additional proteins, as the main targets induces by ONC201/6. CONCLUSION: Thorough preclinical testing in a multi-site laboratory setting identified promising therapeutics for DMGs, resulting in launch of two clinical trials (PNOC022, ONOC023). Validation of identified biomarkers are ongoing using clinical specimen as well as in vivo PDX models.
DIPG-55. Increasing the drug-tumor resonance time in DMG murine models significantly extends survival
Authors: Power Erica , Zhang Liang , Rechberger Julian , Oh Juhee , Elmquist William , Daniels David
Published: June 2022

H3K27-altered diffuse midline glioma (DMG) is a uniformly lethal CNS cancer that predominately occurs in children. In the last decade, while studies revealing the molecular underpinnings of the disease have paved the way for novel therapeutic strategies, this tumor remains a death sentence. Our lab and others have identified numerous drugs of high interest for treating this devasting disease, however, every trial has failed to show benefit. Is our failure to translate these laboratory findings due to the fact we have not found the right drugs or treatment regimens yet? Or is this a failure to get the drugs to the tumor? Or is this simply a very bad disease to treat? The answer is likely multifactorial. Our lab, in collaboration with others, have strong data to show that simply getting drugs to the tumor will not result in a positive benefit. Most drugs are rapidly cleared from their target space. Utilizing techniques that increase the drug-tumor resonance time is necessary to translate our basic science findings to our patients. Picking the right drug and the delivery mechanism is not enough for a positive effect. Here, we assessed the efficacy of a previously identified inhibitor, alisertib, delivered by short-term convection-enhanced delivery or a continuous osmotic pump and found that continuous, direct delivery results in a significant increase in survival (p = 0.0002). Furthermore, long-term survivors showed a decreased tumor burden and on-target drug effects. These data support that translation into patients must consider three factors: 1) selection of a potent therapy, 2) selection of the proper delivery method for that therapy, 3) modulation to ensure that the therapy remains in the targeted tissue long enough for desired effect. Keeping these basic tenets at the forefront of development may finally lead to a more effective treatment strategy for this devastating disease