bluuebunny/crossref_metadata_2025 huggingface dataset:
MODL-26. CHILDREN’S BRAIN TUMOR NETWORK: ACCELERATING RESEARCH THROUGH COLLABORATION AND OPEN-SCIENCE
Authors: Lilly Jena , Mason Jennifer , Appert Elizabeth , Heath Allison , Zhu Yuankun , Zhang Bo , Koptyra Mateusz , Santi Mariarita , Pollack Ian , Goldman Stewart , Leary Sarah , Buccoliero Anna , Scagnet Mirko , Haussler David , Hanson Derek , Zhang Jiangguo , Wan Weiqing , Li Chunde , Firestein Ron , Cain Jason , Phillips Joanna , Gupta Nalin , Mueller Sabine , Grant Gerald , Monje-Deisseroth Michelle , Partap Sonia , Greenfield Jeffrey , Rood Brian , Nazarian Javad , Raabe Eric , Jackson Eric , Stapleton Stacie , Lober Robert , Kram David , Storm Phillip , Lulla Rishi , Prados Michael , Resnick Adam , Waanders Angela
Published: December 2020

The Children’s Brain Tumor Network (formerly known as Children’s Brain Tumor Consortium- CBTTC) is a global organization pioneering a model of open-science medical research to improve treatment and discover cures. Started in 2011, our objective was to utilize a regulatory, agreement, and governance architecture to remove existing research barriers that slowed down the pace of research and collaboration. Our network now includes 17 institutions working together to empower research. As of December 2019, over 3,600 subjects have been enrolled resulting in collection of over 45,000 specimens. Clinical data collection is longitudinal and includes medical history, diagnosis, treatment, pathology slides and reports, radiology imaging and reports, and outcome data. The tissue is collected flash-frozen, in freezing media, and fresh for the generation of pre-clinical models including cell lines. Blood is collected from the subject, with blood or saliva collected from the parents for germline comparison. Additionally, the Children’s Brain Tumor Network- Pediatric Brain Tumor Atlas has generated 952 WGS and RNAseq, 221 proteomics, with annotated clinical data. All of this data, both generated raw and processed data, has been made available broadly to the scientific community via cloud-based platforms, including the Gabriella Miller Kids First Data Resource Portal, Cavatica, and PedCbioportal. As of January 2020, we have 45 approved biospecimen requests and 80 genomic/molecular data requests. In summary, the Children’s Brain Tumor Network’s goal is to accelerate the pace of discovery by providing resources and expanding the network of scientists working towards a cure.
MODL-27. MEK INHIBITION WITH TRAMETINIB SLOWS PROGRESSION OF MEDULLOBLASTOMA AND ATYPICAL TERATOID RHABDOID TUMOR IN ORTHOTOPIC XENOGRAFT MURINE MODEL
Authors: Mushrif Sujata , Hung Long , Muthugounder Sakunthala , Asgharzadeh Shahab
Published: December 2020

BACKGROUND

Combination of surgery, chemotherapy, autologous transplantation, irradiation constitutes treatment of CNS embryonal-cell tumors (Medulloblastoma-MBL, atypical teratoid rhabdoid tumor-AT/RT). Targeted agents to improve survival and decrease side effects are necessary. We hypothesize that inhibiting MAPK pathway in MBL and AT/RT may be beneficial.

METHODS

IHC(pERK) was performed on clinical tumors. Trametinib(MEK inhibitor) was tested on MBL(UW228, D283, DAOY); AT/RT(CHLA06, BT12) cell-lines. Luminescent cell-viability assay was done(72 hrs) and with crystal violet assay(10 days). Orthotopic, xenografts of MBL and AT/RT were made in NOD-Scid gamma mice. Mice were given Trametinib daily by gavage for 6 weeks(0.6mg/kg b.w). Western blot was performed on protein from cell lines and tumor xenografts incubated with Trametinib. H&E staining was done on murine tumors.

RESULTS

AT/RT(48%) and MBL(57%); Anaplastic(50%), Desmoplastic(40%), Classic(38%); Group 4(66%), Group 3(20%), SHH(55%), WNT(0%) showed presence of pERK(clinical samples). In-vitro, Trametinib completely abrogated the phosphorylation of ERK at 125nM in AT/RT and 50nM in MBL. The IC50 after 10 days exposure was 10nM for AT/RT and 35nM for MBL. Trametinib treated mice showed delay in tumor growth and significant survival advantage in both AT/RT (p=0.00336) and MBL (p=0.0069). Murine tumors showed decreased proliferation (H&E).

CONCLUSION

Trametinib decreased cell proliferation, increased survival in our murine model in both MBL and AT/RT. Pre-clinical results indicate benefits in subgroups of AT/RT and MBL with active MAPK pathway.
MODL-28. IMMUNE PRIMING WITH INTERFERON-Γ COMBINED WITH EPIGENETIC MODULATION IN PEDIATRIC BRAIN TUMORS
Authors: Crotty Erin , Morris Shelli , Brasel Ken , Girard Emily , Noll Alyssa , Mhyre Andrew , Olson James
Published: December 2020

Systemic interferon-γ (IFNγ) has been shown to induce major histocompatibility complex class I (MHC-I) and T cell infiltration in solid tumors in adult patients, demonstrating a potential strategy to abrogate tumor-intrinsic mechanisms of immune escape. Pediatric brain tumors (PBT) may be particularly sensitive to this approach but have a paucity of immunogenic tumor antigens for presentation on MHC-I. Decitabine and other DNA methyltransferase (DNMT) inhibitors promote expression of oncofetal antigens and endogenous immune responses through epigenetic alterations. We tested the convergence of these immune priming mechanisms using a novel combination of IFNγ and decitabine across a spectrum of PBT. Primary human cell lines (Med-411FH, PBT-05FH, GBM-511FH, CCHMC-GBM-1, CCHMC-GBM-4, ATRT-310FH) and murine transgenic models were treated with IFNγ alone or in combination with decitabine and evaluated expression of cell surface MHC-I and PD-L1, interferon response genes (ISGs), and oncofetal antigens. PBT showed exquisite sensitivity to IFNγ, increasing expression of MHC-1/PD-L1 along with ISGs (TAP1, MX1, IRF1). Decitabine enhanced IFNγ-induced gene expression of oncofetal antigens NY-ESO-1 and MAGE-A1. In a medulloblastoma flank tumor model, MHC-I was increased by 40-fold following intraperitoneal IFNγ treatment (p=0.01), with a 3-fold increase in PD-L1 (p=0.005) compared to untreated controls. Effect on CD8+ T cell killing and validation in humanized models is ongoing. Immune priming of PBT with IFNγ is feasible and results in more substantial MHC-I upregulation compared to hypomethylating agents alone. These results provide a strong rationale for priming prior to checkpoint inhibition as a compelling therapeutic strategy in immunologically-quiescent PBT.
MODL-30. DISSECTING THE ROLE OF MULTI-CILIOGENESIS NETWORK IN CHOROID PLEXUS TUMOR
Authors: Zhao Haotian , Zahran Tasneem
Published: December 2020

The choroid plexus (CP) in brain ventricles consists of a fibro-vascular core encapsulated by epithelial cells that possess clusters of primary cilia on cell surface. CP tumors are rare primary brain neoplasms that most commonly occur in young children. Compared to the benign CP papilloma, choroid plexus carcinoma (CPC) is poorly understood and highly lethal with few treatments available. Molecular, cytogenetics and genomics studies uncovered complex alterations in CPC including frequent chromosomal loss and recurrent focal aberrations, whereas abnormal NOTCH signaling is observed in many CP tumors. We showed that activation of both NOTCH and Sonic Hedgehog (SHH) signaling in mice drives the formation of aggressive CP tumor. Molecular and histology analyses demonstrated that these murine CP tumors closely resemble their human counterparts, which also display aberrant SHH and NOTCH signaling, suggesting they may represent potential therapeutic avenues. Indeed, treatment with vismodegib, an FDA-approved SHH pathway inhibitor, suppresses CP tumor growth. Unlike multi-ciliated CP epithelial cells, tumor cells in these animal models are characterized by a solitary primary cilium. Though key genes of the multi-ciliogenesis circuit driven by Geminin coiled-coil domain-containing protein 1 (GEMC1) are expressed in CP epithelium, GEMC1-dependent transcriptional program is suppressed in NOTCH-driven CP tumors. Importantly, CPCs in humans consist of tumor cells with a solitary primary cilium and exhibit profound defects multi-ciliogenesis program. Together, these results indicate that a solitary primary cilium is crucial for CPC development, whereas multi-ciliogenesis circuit possesses tumor suppressive functions and may represent a novel therapeutic target in CPC.
NFB-01. FUNCTIONAL CHARACTERIZATION OF ATRX LOSS IN NF1-ASSOCIATED GLIOMA AND MPNST
Authors: Yuan Ming , Reilly Karlyne , Pratilas Christine , Heaphy Christopher , Rodriguez Fausto
Published: December 2020

To identify the biologic relevance of ATRX loss in NF1-associated gliomagenesis, we studied the effects of Atrx loss using four previously characterized Nf1+/-Trp53+/- murine glioma lines. Lines 130G#3 and 158D#8 (corresponding to grade IV and III gliomas, respectively) displayed preserved ATRX protein expression compared to NIH-3T3 cells. We studied the effects of Atrx knockdown in these two lines in the presence and absence of the TERT inhibitor, BIRBR1532. Using a telomere-specific FISH assay, we identified increased signal intensity after Atrx knockdown, only in the presence of the TERT inhibitor. These features are reminiscent of ALT, although there were no significant alterations in cell growth. Next, we studied the effect of ATRX loss in MPNST lines ST88-14, NF90-8, STS-26T. These cell lines all expressed ATRX and DAXX. However, STS-26T contained a TERT promoter mutation and ST88-14 had a known SNP in the TERT promoter, while NF90-8 had no alterations. ATRX siRNA knockdown showed no significant effects in cell proliferation or apoptosis. However, ATRX knockdown resulted in rare ultra-bright foci, indicative of ALT. Next, we studied the in vitro effect of the ATR inhibitor VE-821 in MPNST cell lines. Only NF90-8 (lacking TERT alterations) demonstrated a decrease in growth after ATRX knockdown and VE-821 treatment. However, ATRX knockdown alone did not affect sensitivity to carboplatin. Our findings further support a role for ATRX loss with subsequent ALT activation in a biologic subset of NF1-associated malignancies, thereby opening an opportunity for therapeutic targeting of these aggressive tumors using specific classes of drugs.
NFB-03. TRAMETINIB FOR ORBITAL PLEXIFORM NEUROFIBROMAS IN YOUNG CHILDREN WITH NF1
Authors: Toledano Helen , Dotan Gad , Friedland Rivka , Cohen Rony , Yassur Iftach , Toledano Hagit , Constantini Shlomi , Rootman Mika Shapira
Published: December 2020

Plexiform neurofibromas (PN) in NF1 are diagnosed in early childhood and may grow rapidly during this period. In 10% of patients they involve the orbital-periorbital area and may cause visual problems including glaucoma and visual loss from amblyopia (deprivational, strabismic, or refractive), optic nerve compression or keratopathy. Ptosis, proptosis and facial disfigurement lead to social problems and decreased self-esteem. Complete surgical removal is usually impossible and there is a tendency for regrowth after debulking. Recently inhibitors of the RAS/MAPK pathway have been investigated for their activity in PN. We describe 5 young children with NF1 and PN of the orbital area treated with the MEK inhibitor trametinib followed clinically and by volumetric MRI. Treatment was initiated at mean age 26.8 months (SD ±12.8) and continued for median 25 months (range 17– 48). Reasons for initiating treatment were visual compromise and progressive tumor growth. Doses were as recommended. One child reported decreased orbital pain after one week and another, with involvement of the masseters, had increased ability to chew food. Toxicities were mostly to skin and nails grades 1–2 as expected. Additionally, 60% had debulking surgery of preseptal eyelid tumor in first year of medical treatment. Volumetric MRI measurements showed reduction of 8–26% at 1 year from baseline with a maximal reduction of 45% in two patients at 22 & 45 months. No change in visual function was recorded following treatment initiation. In conclusion, trametinib may decrease tumor size in young children with orbital PN and may prevent progressive disfigurement.
NFB-06. TREATMENT CHALLENGES IN PEDIATRIC GLIOBLASTOMA MULTIFORME WITH CONCURRENT SOMATIC AND GERMLINE NF1 MUTATIONS WITH GERMLINE MISMATCH REPAIR MUTATIONS: TWO UNIQUE CASES
Authors: Baig Muhammed , Mork Maureen , Khatua Soumen , Slopis John , Zaky Wafik , Bingham Racheal , Gupta Sumit , Fuller Greg , Sadighi Zsila
Published: December 2020

INTRODUCTION

We report the first known cases of pediatric glioblastoma (GBM) with prior clinical NF1 diagnoses, one with concurrent germline Lynch syndrome (LS) and NF1, and the other with somatic NF1 mutation and germline constitutional mismatch repair deficiency (CMMRD).

METHODS

Two pediatric GBM cases with prior NF1 clinical diagnoses based on neurocutaneous criteria were reviewed. Next generation sequencing and immunohistochemical staining were used for somatic and germline NF1 and MMR gene mutation detection, and for MMR protein expression, respectively.

RESULTS

Sixteen year old male with prior NF1 clinical diagnosis had resection of right frontal GBM revealing somatic mutations of POLE and PMS2, but not NF1. His father had confirmed LS with MSH2 mutation and no neurocutaneous stigmata. Patient’s germline testing revealed both pathogenic MSH2 plus NF1 mutations confirming LS and NF1. Treatment consisted of chemoradiation with temozolomide followed by adjuvant temozolomide with stable disease at 8 cycles. Nineteen year old male with former NF1 clinical diagnosis had 2 GBMs, first in left midbrain biopsied revealing somatic PMS2 and NF1 mutations underwent radiation then 7 cycles of temozolomide, then new left frontal GBM underwent resection followed by radiation and 5 cycles of pembrolizumab stable at 5th cycle.

CONCLUSION

Children with NF1 stigmata and GBM can have concurrent NF1 and LS, or CMMRD with NF1 somatic mutations. Our patients tolerated alkylating agents, despite risk for secondary malignancies as upfront therapy and at recurrence checkpoint inhibitors. Upfront therapy in GBM with mismatch repair syndrome with checkpoint inhibitors should be studied.
NFB-12. TRAMETINIB THERAPY FOR PEDIATRIC PATIENTS WITH REFRACTORY LOW GRADE GLIOMA OR EXTENSIVE SYMPTOMATIC PLEXIFORM NEUROFIBROMA
Authors: Hounjet Celine D , Ronsley Rebecca , Cheng Sylvia , Rassekh S Rod , Duncan Walter J , Dunham Christopher , Gardiner Jane , Ghag Arvindera , P, Ludemann Jeffrey , Wensley David , Rehmus Wingfield , Sargent Michael A , Evans Naomi , Popovska Vesna , Hukin Juliette
Published: December 2020

OBJECTIVE

Refractory symptomatic plexiform neurofibromas (PNF) and inoperable refractory low grade gliomas (LGG) pose a clinical challenge that may be life threatening. Phase 1 and 2 clinical trials of MEK inhibition with selumetinib in inoperable PNF and LGG have demonstrated promising results in pediatrics, however access has been limited to enrollment on clinical trial. Phase 1 clinical trial for trametinib a MEK 1 and 2 inhibitor has been completed, publication is pending. Thus we have treated a series of children on a compassionate basis with extensive PN or LGG refractory disease with trametinib, as this is available in Canada.

METHODS

We have treated children with trametinib on a compassionate basis in our province since 2017. Review of the clinical data regarding this therapy has been IRB approved.

RESULTS

Two young patients were treated for indication of life threatening extensive PNF and have had tumor shrinkage and improvement of clinical status. Treatment has been complicated by paronychiae, eczema exacerbation, chondrodermatitis nodularis helicis, RSV and influenza B infection and CTCAE grade 2 pneumonia. In spite of the side effects these two patients remain on treatment due to clear benefit from therapy including: improved respiratory compromise, hearing and dysphagia. We will present the data of additional patients treated with trametinib.

CONCLUSION

Trametinib is an effective therapy for life threatening PNF by changing the natural history of tumor growth in young children. Further data is required in terms of tolerance, efficacy and durability of response in such patients in the setting of clinical trials.
NFB-16. mTOROPATHIES AND SUBEPENDYMAL GIANT CELL ASTROCYTOMAS: PREDICTIVE VALUE OF GERMINAL TSC1/2 MUTATIONS SCREENING IN FAMILIAL CASES
Authors: Abdelmoula Nouha Bouayed , Smaoui Walid , Abdelmoula Balkiss , Aloulou Samir , Masmoudi Imen , Bouaziz Imen , Lamloum Ines , Chaari Hadil , Yaich Asma , Dhouib Rafik , Sellami Sonia , Keskes Mariem , Fellah Sourour , Khlifi Khawla , Medhioub Amir , Mhiri Nabil
Published: December 2020

mTOR controls several important aspects of cell function particularly in the nervous system. Its hyperactivation has been involved in tuberous sclerosis complex (TSC) and other mTORopathies as well as drug-resistant epilepsy. Mutations in TSC1 and TSC2 genes cause loss of normal inhibition of mTORC1 complex, leading to cell overgrowth and disruptions in synaptogenesis. Many children and adults with TSC harbour neurologic defects especially subependymal giant cell astrocytomas (SEGAs) in the brain. Here, we have performed mutational analysis followed by a genetic counselling for a Tunisian family from Sfax town harboring epileptic seizures associated to a neurocutaneous disorder. Index cases were referred for renal angiolipomas (RAL) associated to seizures crisis and were diagnosed as having TSC. The first 26-year-old patient complained of epilepsy since the age of 22 with left temporal crisis related to cortical tubers near the Heschl’s gyrus. His brother, a 36-year-old man presented more severe epileptic crisis (since 15 years-old), multiples RAL, subependymal nodules, and a rapid evolution of his mTORopathy with tumoral progression of his renal and central nerve lesions: renal cell carcinoma and SEGAs. TSC1 gene mutation screening showed heterozygous two bp deletion at codons 213 and 214 of exon 5. SEGAs are rare, low-grade glioneuronal brain tumors that occur almost exclusively in TSC patients but can lead to nervous complications. We showed through this report, the predictive value of germinal TSC mutations screening in familial cases, because early recognition of the molecular defect may lead to appropriate management of the tumoral progression.
NFB-17. MEK INHIBITOR BINIMETINIB SHOWS CLINICAL ACTIVITY IN CHILDREN WITH NEUROFIBROMATOSIS TYPE 1- ASSOCIATED PLEXIFORM NEUROFIBROMAS: A REPORT FROM PNOC AND THE NF CLINICAL TRIALS CONSORTIUM
Authors: Mueller Sabine , Reddy Alyssa T , Dombi Eva , Allen Jeffrey , Packer Roger , Clapp Wade , Goldman Stewart , Schorry Elizabeth , Tonsgard James , Blakeley Jaishri , Ullrich Nicole J , Gross Andrea , Walsh Karin , Thomas Coretta , Edwards Lloyd , Prados Michael , Korf Bruce , Fisher Michael J
Published: December 2020

BACKGROUND

Plexiform neurofibromas (PNs) can cause significant morbidity. In this phase 2 study, we assessed imaging and functional outcomes to the MEK-inhibitor Binimetinib in pediatric patients with PNs.

METHODS

Children (age 1–17 years) with PN that were progressive or causing significant morbidity were eligible. Binimetinib is dosed twice-daily (starting dose of 32mg/m2) for maximum of 24 four-week courses. Participants with partial response (PR; >20% decrease in PN volume on central MRI review) at cycle 12 may stay on therapy. Participants undergo MRI and functional assessments at baseline and after courses 4, 8, 12, 18 and 24. Functional assessments are based on PN location.

RESULTS

Here we present 1-year response data. Twenty participants (55% male) with median age 12 years (range 2–16 years) enrolled; 19 are evaluable for response. Median baseline tumor volume was 326 ml (range, 8-6661 ml). Fourteen participants (74%) met criteria for PR, with 11 achieving PR by course 5. Median maximal PN volume reduction was 25.5% (range, 9–54%). As of August 2020, 14 participants received at least 12 cycles of Binimetinib; 10 remain on therapy. Off study reasons include treatment associated toxicities (n=2), subject withdrawal (n=2), non-compliance (n=2), prolonged treatment delay (n=1), and lack of response (n=3). Thirteen participants underwent dose reduction. Institution-reported related grade 3 toxicities included dry skin, weight gain, muscle weakness, rash, paronychia, cellulitis, diarrhea, gastric hemorrhage and CPK increase.

CONCLUSIONS

Binimetinib appears reasonably well-tolerated and shows promising activity in children with NF1-associated PNs. Outcomes on functional improvement will be reported at the meeting.
NFB-18. IMMUNE FUNCTION IN CHILDREN TREATED WITH TRAMETINIB
Authors: Moukhaiber Perla , Samolej Anna , Somsri Palita , McCowage Geoffrey
Published: December 2020

BACKGROUND

Trametinib (Tr) has been applied in the treatment of children with various tumor types, often for prolonged periods. Little is known regarding immune function (IF) following prolonged Tr in this age group.

OBJECTIVE

Describe laboratory measures of IF in children on Tr.

METHOD

Patients receiving Tr had low grade glioma with BRAF anomalies (6), or neurofibromatosis-1 (16) with glioma or plexiform neurofibroma. IF was evaluated using leukocyte/lymphocyte counts, immunoglobulin levels, and antibody titres.

RESULTS

22 patients received Tr. 2 also received Dabrafenib. Median age at Tr initiation of Tr was 7.75 years. As of June 2020, 7 patients have had IFT; results are pending on 15. Median duration of Tr therapy at time of IF was 3.5 years (0.8 – 4). In these 7 patients, median white cell count was 6.9 x 10^9/L (4.1 – 12.6), neutrophils 4.2 x 10^9/L (1.8 – 6.8) and lymphocytes 3.2 x 10^9/L (1.4 – 7). IgG levels, B cells and CD8 cytotoxic T cells were normal across 7/7 patients:medians 9.47 g/L (8.62 – 17), 0.51 x 10^9/L (0.2 – 1.26) and 0.58 x 10^9/L (0.25 – 2.03) respectively. CD3 and CD4 T cells: median 2.08 x 10^9/L (0.67 – 4.62) and 1.34 x 10^9/L (0.35 – 2.31), borderline low in 1 heavily pre-treated patient. An adequate immune response was present in all 4 vaccine antigens tested in 5/5 patients.

CONCLUSION

IF appears relatively intact, relevant for immunisation and infection precautions in children on Tr. Data on the complete cohort will be presented.
NURS-10. IMPROVEMENTS IN A BEHAVIORAL TRAINING AND PHARMACOLOGICAL ANXIOLYSIS ALGORITHM FOR INCREASED COMPLIANCE IN PEDIATRIC PATIENTS IN PREPARATION FOR RADIATION THERAPY: A RETROSPECTIVE ANALYSIS
Authors: Tran Judy , Holt Jennifer , Crump Danielle , Shea Anita , Whetzel Lin , Lattimore Andrea , Carson Rebecca , Anderson Roberta
Published: December 2020

BACKGROUND

In the pediatric population, the probability of compliance with radiation involves multifactorial elements. Younger pediatric patients often require anesthesia to ensure accurate delivery of radiotherapy. The purpose of this analysis was to refine our algorithm in pediatric patients to better identify children who would benefit from behavioral training and/or anxiolyxis intervention with the goal of minimizing anesthesia use.

METHOD

Retrospective data was collected from electronic medical records from 150 pediatric oncology patients <18 years old, treated with photon and proton radiation at our center from August 2016 to December 2019. We identified potential socio-developmental treatment factors thought to impact behavioral compliance and categorized risk factors based on an algorithm to determine risk for noncompliance with radiotherapy.

RESULTS

Six categories demonstrated statistical significance (p<0.05) in their influence on behavioral compliance during radiotherapy: age category (specifically age <7: Odds ratio [OR] 3.0, 95% Confidence Interval [CI] 1.0, 9.1), need for sedation with prior imaging studies (p<0.001), parental premonition of requiring anesthesia for successful treatment (p<0.001), duration of treatment, primary language (p<0.001), and use of total body irradiation (OR 3.1, 95% CI 1.1, 9.3).

CONCLUSION

Identification of pre-radiation risk factors allowed for better recognition of patients at risk for treatment non-compliance and for requiring daily sedation. Future studies should focus on implementing the algorithm prospectively in an effort to identify and direct early intervention with behavioral training and/or anxiolytics to minimize the need for sedation.
PATH-01. MOLECULAR PROFILING OF PAEDIATRIC CENTRAL NERVOUS SYSTEM TUMOURS IN AUSTRALASIA – AN UPDATE ON THE AIM BRAIN AND MNP2.0 PROJECTS
Authors: Algar Elizabeth , Christine White , Kinross Kathryn , Buntine Molly , Jones David , Pfister Stefan , Strong Robyn , Gottardo Nicholas , Hansford Jordan
Published: December 2020

The Access to Innovative Molecular Profiling for Paediatric Brain Cancers (AIM BRAIN) project is a trial testing the feasibility of clinical implementation of diagnostic methylation and molecular profiling for central nervous system (CNS) tumours in Australia and New Zealand. AIM BRAIN builds on an existing study, MNP2.0, and allows cross-validation of results derived from identical samples in separate laboratories in Melbourne, Australia, and DKFZ, Heidelberg, Germany. Parallel methylation profiling (Illumina 850K EPIC array) from co-enrolled cases has revealed excellent concordance between laboratories with 50/51 cases (98%) yielding identical classification using the DKFZ Molecular Neuropathology 2.0 Classifier v11b4. 77/91 (85%) of AIM BRAIN cases classified concordantly by methylation array when compared to their diagnostic histopathology. Of these 77 cases, 16 had classifications below a threshold of 0.90, however still classified correctly. In 14 discordant cases either the histopathology was not well defined, not represented on the classifier, or a very low classification score was obtained. Molecular profiling through MNP2.0 identified 49/167 (29.3%) tumours with gene fusions including BRAF-KIAA1549 (n=29), RELA-C1lorf95 (n=5) and 15 rare or novel fusions. BRAF-KIAA1549 was almost exclusively associated with pilocytic astrocytoma (28/29) and RELA-C1lorf95 with ependymoma. Six pathogenic germline mutations were identified in TP53 (n=2), BRCA1, NF1, LZTR1 and ATM. The incidence of germline predisposition was low (4%) and sex biased towards females (5F:1M), (p<0.08). Our findings confirm methylation profiling as a robust platform for classifying CNS tumours with potential to reveal new CNS tumour entities when combined with molecular profiling.
PATH-04. AN ENHANCED AI-DRIVEN PLATFORM FOR PRECISION MOLECULAR BRAIN TUMOR DIANOSTICS
Authors: Sill Martin , Sahm Felix , Schrimpf Daniel , Capper David , Pfister Stefan M , von Deimling Andreas , Jones David T W
Published: December 2020

Tumors of the CNS represent one of the most complex groups of human cancer, with a vast number of different entities occurring across a spectrum of ages and anatomic locations. This heterogeneity makes accurate diagnosis challenging, with the current gold standard relying on multiple subjective elements. We recently proposed a classification algorithm based on tumor DNA methylation profiling as an objective way to assign samples to over 80 distinct molecular classes. Here we present a substantial update to our machine learning-based algorithm, with more than 170 molecular classes now being represented amongst the 5,915 samples in our reference cohort. These new classes include further subclassification of known groups such as medulloblastoma and ependymoma, as well as multiple new molecular entities described here for the first time. A further improvement is the introduction of a more rationally layered output, making use of ‘families’ of closely-related molecular classes to improve the compatibility with the current WHO classification of CNS tumors. This approach is designed to increase the clinical relevance of the primary output, while also retaining the full information content from the random forest-driven classification. Benchmarking our new algorithm by cross-validation and on an independent validation cohort indicates a retention of the excellent accuracy of diagnosis (error-rate < 4%), with a significant improvement in the proportion of confidently classifiable tumors compared with our previous tool. We believe that this approach, freely accessible through an online web portal, has the potential to enhance diagnostic precision and thereby support clinical care for brain tumor patients.
PATH-14. GENETIC SUSCEPTIBILITY AND OUTCOMES OF PEDIATRIC, ADOLESCENT AND YOUNG ADULT IDH-MUTANT ASTROCYTOMAS
Authors: Bornhorst Miriam , Nobre Liana , Zapotocky Michal , Barseghyan Hayk , Goecks Jeremy , Boue Daniel , Tabori Uri , Hawkins Cynthia , Bouffet Eric , MacDonald Tobey , Schniederjan Matthew , Bronischer Alberto , Orr Brent , Solomon David , Mueller Sabine , Opocher Enrico , Vortmeyer Alexander , Marks Asher , Koschmann Carl , Leung Denise Leung , Mody Rajen , Hwang Eugene , Bhattacharya Surajit , Vilain Eric , Turner Joyce , Kilburn Lindsay , Rood Brian , Packer Roger , Nazarian Javad , Ho Cheng-Ying
Published: December 2020

INTRODUCTION

Previously thought to be rare, recent case series have shown that IDH mutations in young patients are more common than previously described. In this study, we analyzed IDH-mutant tumors to determine clinical significance of these mutations in children, adolescents and young adults.

METHODS

Through this multi-institution study (10 institutions), we collected 64 IDH1/2-mutant infiltrating astrocytoma specimens from 58 patients aged 4–26 (M:F, 0.4:0.6). Specimens included 46 low-grade (LGG) and 18 high-grade (HGG) astrocytomas. Tumor sequencing data (n=45), germline sequencing data (n=37) and outcome data (n=40) was analyzed.

RESULTS

Similar to adults, most sequenced tumors had a co-mutation in the TP53 gene, while ATRX mutations were less common and primarily seen in HGGs. Approximately 60% (n=21) of patients with germline data available had a mutation in a cancer predisposition gene. Mismatch repair (MMR) mutations were most common (n=12; MSH6 n=9), followed by TP53mutations (n=7). All patients with MMR gene mutations had HGGs and poor progression free (PFS=10% at 2 years, mean TTP=9 months) and overall (OS <30% at 2 years) survival. Despite an OS of 90% at 5 years, many LGG patients had tumor progression/recurrence requiring additional treatment (PFS= 80% at 2 yrs, 40% at 5 yrs, mean TTP=3.5 years). Four LGG tumors (2 with TP53+ATRXloss, 2 with TP53 loss+1p19q co-deletion) underwent malignant transformation.

CONCLUSION

IDH-mutant tumors in pediatric patients are strongly associated with cancer predisposition and increased risk for progression/recurrence or malignant transformation. Routine screening for IDH1/2 mutations in children with grade 2–4 astrocytomas could greatly impact patient management.
PATH-20. METHYLATION ARRAY PROFILING OF PEDIATRIC BRAIN TUMORS; SINGLE CENTRE EXPERIENCE
Authors: Zapotocky Michal , Vicha Ales , Krskova Lenka , Zamecnik Josef , Stolova Lucie , Misove Adela , Vanova Katerina , Koblizek Miroslav , Ramaswamy Vijay , Jones David , Sumerauer David
Published: December 2020

BACKGROUND

Significant heterogeneity of pediatric brain tumors poses major challenge on diagnostics. Therefore, we aimed to evaluate feasibility of methylation array in the diagnostic process.

METHODS

Methylation array (Infinium MethylationEPIC, Illumina) was performed on DNA extracted from fresh frozen tissue from prospective newly diagnosed and selected retrospective patients. Results from Heidelberg classifier (www.molecularneuropathology.org) were compared to the histological diagnosis and further genetic testing was performed to establish integrated morphological/molecular diagnosis.

RESULTS

Within years 2018–2019, we performed methylation array profiling of 102 samples consisting mainly of ependymoma, medulloblastoma high-grade and low-grade glioma. High calibrated score (>0.9) was achieved in 62 patients (61%). In 46 cases (74%) with score >0.9, the histological diagnosis matched the methylation class (MC). In the remaining cases (16) that were classified by histopathology mainly as ependymomas, the methylation profiles were classified as novel molecular entities (HGNET_BCOR, HGNET_MN1, etc.) or different tumor type. In 40 cases (39%) with the score <0.9, six were found to have high normal tissue content. Nine cases had no match in the classifier and 25 were assigned MC with score 0.3 to 0.89. In 20 out of 34 cases with low score, the molecular diagnosis could be confirmed based on copy number variants inferred from the methylation array or using additional testing for gene fusions and mutations.

CONCLUSIONS

Our experience on the first 100+ cases demonstrated that methylation array could be integral part of diagnostic process in order to establish integrated morphological and molecular diagnosis of pediatric brain tumors.
PATH-22. COMPARISON OF SUPERVISED CLASSIFICATION METHODS FOR CENTRAL NERVOUS SYSTEM TUMORS BASED ON DNA-METHYLATION
Authors: Orr Brent , Breuer Alex , Lin Tong , Tran Quynh , Suh Edward , Pounds Stanley
Published: December 2020

Classification of brain tumors using methylation profiling is an important diagnostic advance, reducing subjectivity and improving interpretability of clinical outcome data. Despite the recognized value of methylation profiling in the clinical laboratory, the performance characteristics of different supervised classification models has not been directly compared. We developed 3 methods using methylation profiles to classify CNS tumors: an exact bootstrap k-nearest neighbor (kNN), a multi-layer perceptron neural net (NN), and a random forest classifier (RF). We trained these methods on the publicly available CNS tumor reference cohort (GSE90496) with 2,801 profiles and 91 classes. We evaluated the performance of these methods by leave-out-25% cross-validation. The relative performance of these methods were evaluated in terms of accuracy, precision, and recall for class or class family. The kNN, RF, and NN classifier had an estimate error rate of 10.74%, 4.01%, and 1.89%, respectively for class prediction and an error rate for family prediction of 5.97%, 0.90%, and 0.6%, respectively. At perfect recall for class assignment, the RF and kNN had a precision of 0.96 and 0.89 while the NN reached 0.98. For family assignment, the precision for the three classifiers was almost 1.0 with recall of nearly 0.8. At the recall rate of 1.0, the precision dropped to 0.94, 0.991 and 0.994 for kNN, RF, and NN, respectively. Overall, the NN showed improved performance metrics compared to the kNN and RF in CNS tumor classification for both class and class family assignment.
PATH-25. GENOME-WIDE METHYLATION ANALYSIS CAN SEGREGATE RADIATION-INDUCED GLIOBLASTOMA FROM LATE RECURRENCE OF MEDULLOBLATOMAS
Authors: Hiraki Takamasa , Fukuoka Kohei , Matsushita Yuko , Hibiya Yuko , Honda Satoko , Mori Makiko , Arakawa Yuki , Ichimura Koichi , Kobayashi Masao , Tanami Yutaka , Nakazawa Atsuko , Kurihara Jun , Koh Katsuyoshi
Published: December 2020

It could be difficult to diagnose recurrent medulloblastoma with conventional diagnostic tools because other lesions mimic relapse of the tumor from both a morphological and radiological standpoint, particularly when it happens late. We report two medulloblastoma cases, both of which seemed to develop late-recurrence more than 5 years from the initial surgery. Genome-wide methylation analysis revealed that one of the recurrent tumors was in fact a radiation-induced glioblastoma. The first patient was a 6-year-old female patient who developed a posterior fossa tumor. The pathological diagnosis was medulloblastoma with focal desmoplasia. She was in complete remission for 9 years after the treatment but developed an intradural lesion in her thoracic spine. The lesion was biopsied and pathologically confirmed as recurrence of the tumor. The second patient was a female patient who developed non-metastatic medulloblastoma at the age of 10. She suffered local recurrence 5 years after the diagnosis. Biopsy was performed, and the pathological diagnosis was relapse of the tumor. We performed unsupervised hierarchical clustering of the methylation data from our cases and reference data. In contrast to consistency of methylation profiling and copy number abnormalities between primary and recurrent tumors of case 1, the analysis revealed that the recurrent tumor of case 2 was distinct from medulloblastomas and clustered with “IDH-wild type glioblastomas”, which suggested that the recurrent tumor was radiation-induced glioblastoma. This report highlights the clinical utility of molecular genetic/epigenetic approach to confirm diagnosis of brain tumor recurrence.
PATH-28. MOLECULAR DIAGNOSIS FOR CENTRAL DIAGNOSIS OF BRAIN TUMORS FROM 2016 TO 2019— A REPORT FROM THE JAPAN CHILDREN’S CANCER GROUP (JCCG)
Authors: Nakano Yoshiko , Hirato Junko , Yoshioka Takako , Nobusawa Sumihito , Shoufuda Tomoko , Kitahara Mai , Fukuoka Kohei , Yamasaki Kai , Sakamoto Hiroaki , Nishikawa Ryo , Hara Junichi , Kanemura Yonehiro , Ichimura Koichi
Published: December 2020

INTRODUCTION

Since 2016, the Japan Children’s Cancer Group (JCCG) has established a nationwide network that prospectively provides pathological review and molecular analysis.

METHODS

Patients who were diagnosed with brain tumors between ages 0 and 29 were eligible. The central office at National Center for Child Health and Development served as a hub for the hospitals involved and institutions conducting pathological and molecular analysis, and managed the patients’ clinical information and tumor samples. Histopathology of all cases were centrally reviewed. Routine non-NGS based analyses were conducted based on histological diagnosis and included pyrosequencing for glioma-associated hot spot mutations and PFA/PFB classification for ependymoma, RT-PCR for RELA fusion and BRAF fusion, and nanostring for subgrouping medulloblastoma. In selected cases, methylation analysis, RNA sequencing and exon sequencing of 93 genes were performed in selected cases.

RESULTS

In total, 985 cases were registered to this study in four years. Frozen samples were collected from approximately 80% of cases. The number increased from 152 in 2016 to 326 in 2019. They includes glioma (n=268), medulloblastoma (n=161), ependymoma (n=103), germ cell tumor (n=93), ATRT (n=29) and others. In 55 % of the glioma cases, at least one abnormality was detected by the routine analysis. The detailed analysis for atypical cases identified targetable alternations. DISCUSSION: This nationwide central diagnostic system has now been well established. Current issues and future prospective of the system will be discussed.
PATH-30. EXOSOMES AS A SOURCE OF PLASMA ctDNA TO IDENTIFY POINT MUTATIONS IN PEDIATRIC GLIOMA PATIENTS
Authors: Nobre Liana , Carreiro Isabel Porto , Camacho Aline Helen da Silva , Reis Rafaela , Chimelli Leila , Zalcberg Ilana , Ferman Sima , Ferman Sima , Mor Barbara Monte
Published: December 2020

Surgery consists in the mainstay of treatment in most gliomas, but in many cases, a resection is not feasible. Liquid biopsy is an ideal tool providing a minimally invasive method through plasma or CSF sampling to assess cell-free tumor DNA (ctDNA). Here we explore the feasibility of detecting DNA in plasma exosomes (exoDNA) extracted from glioma patients and further investigate its use in identifying molecular alterations. Exosomes were isolated from 2ml of plasma from 24 patients (13 LGG, 8 HGG, 3 DIPG) and fully characterized by nanoparticle tracking analysis and transmission electron microscopy. DNA was extracted from 13 samples (exoDNA) so far. Five patients had confirmed point mutations in the primary tumor (3BRAFV600E; 1FGFR1N546K; 1H3.3), additionally, 3 samples were collected from clinically diagnosed DIPG patients to inquire H3K27M mutations. DNA was extracted successfully from all exosome samples; a pre-amplification step was needed and direct sequencing was carried out for BRAFV600E. FGFR1N546K and H3K27M mutations were sought in patients with positive tumors. Wildtype BRAF fragment was identified in 12/13samples (1 patient failed sequencing). However, none of the five tumor positive patients nor the DIPG patients had mutations detected at the exo-DNA level. There is growing evidence that CSF may be the ideal source of ctDNA in brain tumor patients, therefore although we could not detect mutations in plasma DNA we are currently analyzing CSF exoDNA and cell-free DNA to evaluate if this proves a successful strategy and weather exoDNA is more representative of the tumor content.
QOL-04. INFLUENCE OF FAMILY, SCHOOL, AND HOSPITAL SYSTEMS IN SUPPORTING SURVIVORS OF PEDIATRIC BRAIN TUMORS WITH NEUROCOGNITIVE LATE EFFECTS
Authors: Moscato Emily , Gies Lisa , Miley Aimee , Salloum Ralph , Wade Shari
Published: December 2020

OBJECTIVE

Pediatric brain tumor survivors (PBTS) are at risk for developing neurocognitive late effects that may interfere with academic and adaptive functioning. To mitigate the potential impact, some PBTS may implement strategies independently, while others may rely on system-level support from family, school, or hospital systems. Given the limited knowledge on survivor and family perspectives of these supports, we conducted a mixed-methods study involving PBTS and their caregivers to examine the influence of family, educational, and hospital supports, and identify areas of unmet need. PARTICIPANTS AND

METHODS

PBTS (N=56,Mage=18.12,range=10–25) completed questionnaires on academic accommodations. Medical chart reviews provided diagnosis and treatment information. A subset of families, who did not significantly differ from the larger sample on demographics, completed qualitative interviews (N=25). Three coders identified themes separately for parents and survivors and reached consensus (kappa’s > .78) using thematic content analysis.

RESULTS

Families emphasized the role of family support, including providing individualized help, setting up a structured learning environment, and suggesting metacognitive strategies. Parents also emphasized how they have adjusted their expectations. At school, 53% reported an individualized education plan. Formal accommodations (e.g., modified coursework, small group instruction, extra time) were helpful, yet some noted barriers, including embarrassment and lack of follow-through. Survivors emphasized the value of informal accommodations. Families described unmet needs related to connecting with other survivors, navigating community and educational resources, and transitioning to adulthood.

CONCLUSIONS

PBTS seem to rely on systems-level supports to mitigate neurocognitive effects. Future work should strengthen communication between systems and adult transition services.
QOL-11. COMPARISON OF TREATMENT BURDEN RATING SCALES ON NEUROCOGNITIVE OUTCOMES IN A MIXED SAMPLE OF PEDIATRIC BRAIN TUMOR SURVIVORS
Authors: Baig Muhammad , Olsthoorn Ineke , Yang Grace , Zaky Wafik , Stavinoha Peter
Published: December 2020

BACKGROUND

Predicting neurocognitive outcomes in pediatric brain tumor (PBT) patients is challenging. Rarity of PBT makes inclusion of detailed risk factors (e.g., treatment modality, intensity, individual complications) difficult when sample sizes are small. The Neurological Predictor Scale (NPS) summarizes complications and treatment factors associated with neurocognitive risks and has modest validation. Recently, the Pediatric Neuro-Oncology Rating of Treatment Intensity (PNORTI) was developed to evaluate the impact of treatment intensity on psychosocial outcomes but has not been compared to neurocognitive outcomes. This study compared the NPS and PNORTI in terms of relationship to neurocognitive outcomes known to be at risk in PBT survivors.

METHODS

88 PBT survivors’ neuropsychological outcomes were retrospectively analyzed in relation to the NPS and PNORTI. Variables of interest included IQ, working memory, and processing speed.

RESULTS

NPS associated with lower IQ (rs=-.476, p=.001), lower working memory (rs=-.323, p=.010), and lower processing speed (rs=-.389, p=.007) in patients diagnosed at a younger age, but only processing speed for children diagnosed after age 7 years (rs=-.262, p=.036). PNORTI was not correlated with neurocognitive variables for either group.

CONCLUSION

NPS has value in predicting neurocognitive outcomes, though much more in a younger age at diagnosis group compared to older patients. The PNORTI did not demonstrate predictive value for these neurocognitive domains in our sample. Given the potential clinical and research value of a summary rating of treatment burden relating to long-term outcome, future research should include relationship to psychosocial outcomes and quality of life.
QOL-12. CLINICAL SIGNIFICANCE OF RADIATION-INDUCED CEREBROVASULAR DISEASE IN CHILDHOOD BRAIN TUMOR SURVIVORS
Authors: Remes Tiina , Suo-Palosaari Maria , Ritari Niina , Puosi Riina , Koskenkorva Päivi , Sutela Anna , Toiviainen-Salo Sanna-Maria , Arikoski Pekka , Arola Mikko , Hovén Emma , Lähteenmäki Päivi , Lönnqvist Tuula , Riikonen Pekka , Sirkiä Kirsti , Rantala Heikki , Harila Marika , Ojaniemi Marja , Harila-Saari Arja
Published: December 2020

BACKGROUND

Childhood brain tumor survivors have a high risk of early cerebrovascular disease, but currently its clinical significance is unknown.

METHODS

In a nation-wide study, we investigated 68 childhood brain tumor survivors treated with radiotherapy by using magnetic resonance imaging (MRI) and neuropsychological examination after median follow-up time of 20.6 years (range 5.0 – 33.1 years) since radiotherapy. Associations between imaging markers of cerebrovascular disease, white matter hyperintensities and the results of neuropsychological examination were investigated.

RESULTS

Majority (65 %) of the survivors was diagnosed with cerebrovascular disease at median age of 27.1 years (range16.2 – 43.8 years). The presence of imaging markers of cerebrovascular disease or white matter hyperintensities was associated with poorer performance in verbal (VIQ) and performance (PIQ) intelligent quotient, working and semantic memory, executive functions, visuospatial ability, and immediate and general auditive memory (P < 0.05). Survivors with microbleeds performed worse in PIQ, processing speed, executive functions, and visuospatial ability (P <0.05). Lacunar infarcts were associated with difficulties in visuospatial ability (P <0.05). Survivors with white matter hyperintensities in MRI had higher impairment of working and semantic memory, visuospatial ability, and general auditive memory (P < 0.05). Cerebrovascular and small-vessel disease burden associated with poorer neurocognitive performance.

CONCLUSION

The imaging markers of cerebrovascular disease and white matter hyperintensities were related to poorer cognitive performance in radiation-treated long-term survivors of childhood brain tumor. Longitudinal studies are urgently needed to investigate how cerebrovascular disease and related cognitive impairment progress in the survivors.