tbuckley/cabot-search huggingface dataset:
NFS-30. ADJUVANT MEK INHIBITION TO PREVENT REBOUND GROWTH FOLLOWING PARTIAL RESECTION OF PLEXIFORM NEUROFIBROMAS
Authors: Priya P Chan, Molly S Hemenway, Ashley Sabus, Emily Hrycaj, Nathan A Dahl, Leahthan F Domeshek, Brooke M French, Nicholas K Foreman
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Plexiform neurofibromas (PNs) are benign peripheral nerve sheath tumors that occur in patients with neurofibromatosis type I. These tumors can cause significant morbidity leading to functional impairment, pain, and disfigurement. Management of PNs is challenging. Complete surgical resection is often not possible due to tumor growth along vital structures, and rebound growth is frequently experienced following subtotal resection (STR) of PNs. The mitogen-activated protein kinase (MAPK) pathway has been implicated in the growth of PNs, and the use of MAPK enzyme (MEK1/2) inhibitors has been shown to be an effective therapy in the treatment of PNs. Herein, we described our institutional experience using a short course of adjuvant MEK1/2 inhibitors in the treatment of pediatric patients with PNs following STR to prevent rebound growth. METHODS A single-institution retrospective record review of pediatric patients who underwent STR of their PN. RESULTS A total of 35 patients with 39 separate PNs had STR of their PNs. Fourteen PNs were treated with resection alone and 25 PNs were treated with a six-month course of adjuvant MEK1/2 inhibitors following STR. The number of patients requiring additional treatment with surgical resection or medical therapy was 11 of 14 patients (79%) in the resection only group and 6 of 25 patients (24%) in the adjuvant MEK1/2 inhibitor group. The mean time to additional treatment for the resection only group was 22 months, and the mean follow-up time for patients receiving adjuvant MEK1/2 inhibition was 29 months. Skin rash was the most common adverse effect seen with adjuvant MEK1/2 inhibition, and one patient experienced a dose-limiting thrombus. CONCLUSIONS A short course of MEK1/2 inhibitors following STR of PNs is effective in the short-term in preventing rebound growth when compared to STR alone. Treatment is well tolerated and should be considered as adjuvant therapy in pediatric patients.
BIOM-14. UTILITY OF MIRNA-BASED LIQUID BIOPSY AND RADIOGRAPHIC IMAGING IN PEDIATRIC BRAIN TUMOR PATIENTS
Authors: Shehbeel Arif, Peter Madsen, Ariana Familiar, Komal Rathi, Anne Coyle, Jessica Foster, Ammar Naqvi, Ali Nabavizadeh, Phillip B Storm, Madison Hollawell, Mateusz Koptyra, Adam C Resnick
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND MRI is the current gold standard imaging technique for diagnostic evaluation and monitoring of pediatric CNS tumors; however, MRI measures can only provide inference into tumor biology and molecular stratification. miRNAs are an abundant and stable nucleic acid found circulating in blood and cerebrospinal fluid (CSF) and can be utilized as a tumor biomarker. METHODS We hypothesized that correlating miRNA biomarkers with radiological tumor measurements may provide improved diagnostic and monitoring for patients with pediatric brain tumors. Using a cohort of 54 pediatric brain tumors including low grade glioma, ependymoma, germ cell tumor, medulloblastoma, atypical teratoid rhabdoid tumor and high-grade glioma we attempted to combine MRI findings and circulating miRNA data. The miRNA expression was profiled in 33 CSF and 52 plasma samples using the HTG EdgeSeq platform. Clinically acquired, multi-parametric MRI scans at time-points close to liquid biopsy collection were collected retrospectively and used to generate volumetric tumor segmentations. Machine learning methods were implemented to evaluate combinatory features. RESULTS We identified unique miRNA targets that significantly correlated with MRI features, clinical findings, and patient outcomes. In both CSF and plasma, miRNA expression was found to correlate with diagnosis and clinical features including tumor grade and disease burden (p &amp;lt; 0.05). In CSF, miRNA expression was correlated with MRI features including cystic core presence, edema, leptomeningeal disease and tumor location (p &amp;lt;0.05). In plasma, differences in miRNA expression were related to MRI measurements including cystic core volume, location, and leptomeningeal disease (p &amp;lt; 0.05). Combination of miRNA targets for plasma or CSF with imaging-based features significantly improved histology specific multimodal diagnosis predictions. CONCLUSIONS These results demonstrate the potential utility of miRNAs as a pediatric brain tumor biomarker which when combined with imaging features can improve minimally and non-invasive diagnostics and the subsequent management of pediatric brain tumor patients.
NFS-02. MEDULLOBLASTOMAS WITH ELP1 PATHOGENIC VARIANTS: A WEAKLY PENETRANT SYNDROME WITH A RESTRICTED SPECTRUM IN A LIMITED AGE WINDOW
Authors: Léa GUERRINI-ROUSSEAU, Julien Masliah-Planchon, Mathilde Filser, Arnault Tauziede-Espariat, Natacha Entz-Werle, Catherine Maugard, Saskia Hopman, Jacob Torrejon-Diaz, Marion Gauthier-Villars, Fatoumata Simaga, Thomas Blauwblomme, Kevin Beccaria, Etienne Rouleau, Marina Dimaria, Jacques Grill, Samuel Abbou, Béatrice Claret, Laurence Brugières, François Doz, Yassine Bouchoucha, Cécile Faure-Conter, Valerie Bonadona, Ludovic Mansuy, Emilie de Carli, Olivier Ingster, Clémentine Legrand, Anne Pagnier, Pascaline Berthet, Damien Bodet, Sophie Julia, Anne-Isabelle Bertozzi, Marjolaine Wilems, Claude-Alain Maurage, Olivier Delattre, Olivier Ayrault, Christelle Dufour, Franck Bourdeaut
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Medulloblastomas (MB) Sonic hedgehog (SHH) subtype are associated with a cancer predisposition syndrome (CPS) in about 15% of cases, the most frequent being related to ELP1 pathogenic variant (PV). The aim of our study is to better evaluate penetrance of this CPS and detail the characteristics of the related tumors. METHODS Twenty-nine ELP1-mutated MB identified in France were retrospectively reviewed. Molecular characteristics of the tumor and clinical features of the patients were collected; whenever possible, the germline DNA from patients and their relatives were sequenced. RESULTS All patients (sex ratio 16/13) presented with SHH-MB, mostly nodular desmoplastic (n=20/28), between 3 and 15 years of age (median 7.3). All mutations are found in the germline when a constitutional DNA sample was available (n=26). Most tumors (93%) showed a biallelic inactivation of PTCH1, other recurrent alterations concerned the TP53 pathway (including 1 somatic TP53 VP) and activation of MYCN/MYCL signaling. We observed that ELP1-mutated MB behave as sporadic cases, with similar distribution within clinical and molecular risk groups of MB, similar outcomes (5y-OS = 85%) and no unusual side effects of treatments. Three patients developed a second tumor (2 high-grade gliomas and 1 thyroid carcinoma) within the irradiation fields. All germline PV were inherited from one asymptomatic parent (11 trio). No specific morphological features were mentioned. Only two index cases from the 29 French patients had a previous familial history of MB (occurring in a cousin), with many asymptomatic carriers. Except the MB, no other cancer was significantly associated with the ELP1 PV. CONCLUSIONS the low penetrance, the ‘at risk’ age window limited to childhood and the narrow tumor spectrum, question the actual benefit of genetic screening in these patients and their family. Our results suggest restricting ELP1 germline sequencing to patients with MB, depending on the parents’ request.
ATRT-18. ALISERTIB USED IN PEDIATRIC ATRT
Authors: Milena Fraustro, Breyonna Maddox, Lilibet Fernandez Valdes, Elizabeth Lopez, Toba Niazi, Ossama Maher, Ziad Khatib
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Atypical rhabdoid tumor (ATRT) is a rare and aggressive primary CNS tumor caused by variants or deletions in the tumor suppressor gene SMARCB1 (aka INI 1). SMARCB1 targets Aurora A kinase (AURKA), an important oncoprotein of the cell cycle. AURKA dysregulation can lead to genomic instability through its oncogenic effects. Alisertib is a selective AURKA inhibitor that has been explored for treatment in various cancers, including pediatric malignancies. METHODS Retrospective chart review of five patients diagnosed with ATRT, treated with Alisertib, at Nicklaus Children’s Hospital from 2019 - 2024. RESULTS of the 5 patients; three were females and two males, with a median age at diagnosis of 2 years. Only one patient had a germline mutation while the rest had somatic mutations. Prior to starting Alisertib therapy, all five patients received chemotherapy per multiple protocols; four patients underwent focal radiation therapy, three patients underwent resection, and two patients underwent tandem autologous transplants. All five patients were treated solely with Alisertib, median dose of 60 mg/m2 PO daily. Two patients had reduced doses during therapy secondary to cytopenia. One patient completed therapy over 13 months with partial response based on imaging. One patient presented progression of disease while on therapy and for that reason treatment was stopped. Three patients continue treatment: two with only Alisertib, one using Avastin and Sirolimus concurrently. CONCLUSIONS Prognosis in patients with ATRT is usually poor given its aggressive nature and high rate of recurrence despite intervention. It is important to note that treatment of ATRT is highly individualized and typically involves a combination of therapeutic modalities. While Alisertib is one of the newest treatment options, there’s limited literature of clinical improvement in patients with ATRT using this treatment. Therefore, further research on novel treatment options is warranted for the future.
CNSC-02. PEDIATRIC BRAIN TUMOR CONSORTIUM (PBTC)-056: A PHASE 1 STUDY OF THE ADAM-10 INHIBITOR, INCB007839, IN CHILDREN WITH RECURRENT/PROGRESSIVE HIGH-GRADE GLIOMAS TO TARGET MICROENVIRONMENTAL NEUROLOGIN-3
Authors: Alicia Lenzen, Sonia Partap, Catherine Billups, Tina Young Poussaint, Sameer Farouk Sait, Nathan Robison, Craig C Castellino, James Felker, Clinton Stewart, Jason Fangusaro, Arzu Onar-Thomas, Ira J Dunkel, Katherine E Warren, Michelle Monje
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Pediatric high-grade gliomas (pHGGs), including diffuse intrinsic pontine glioma (DIPG), are a leading cause of central nervous system tumor-related morbidity and mortality in children. Neuronal activity promotes growth of HGGs; one key mechanism is neuronal activity-regulated shedding of neuroligin-3 into the glioma microenvironment, mediated by the protease (A Disintegrin and Metalloprotease) ADAM10. ADAM10 inhibition slows tumor growth in preclinical pHGG models. Here, we report results of the clinical trial PBTC-056 (NCT04295759) evaluating safety and tolerability of INCB007839, an inhibitor of the ADAM 10 and 17 proteases. METHODS Patients aged 3-21 years old with recurrent/progressive pHGGs, including DIPG, were eligible. Additional eligibility criteria included measurable disease and failure of at least 1 standard treatment. One dose level (120mg/m2/dose twice daily [BID]) was tested, and the trial was subsequently amended to require prophylactic anticoagulation with enoxaparin due to an unanticipated toxicity. The primary objective was to assess the safety and tolerability of INCB007839 for children with pHGGs. RESULTS 12 of 13 eligible subjects were evaluable. Median age was 13.5 years (4.9-20.7 years). Diagnoses included: DIPG (54%), glioblastoma multiforme (31%), anaplastic astrocytoma (8%) and CNS primary tumor NOS (8%). All patients were treated at DL1 and remained on study for 1-4 courses. The most common toxicities were lymphopenia, elevated transaminases, and fatigue. There were 3 dose-limiting toxicities: Grade 5 cerebral venous thrombosis (n=1), Grade 3 alanine aminotransferase increase (n=1) and Grade 2 thrombocytopenia (n=1). Ten patients progressed/relapsed during active treatment, 1 patient died on treatment, and 2 patients withdrew (1 prior to starting therapy). CONCLUSIONS INCB007839 was generally well tolerated with a recommended phase 2 dose of 120mg/m2/dose BID and concurrent prophylactic anti-coagulation. These data, combined with foundational preclinical studies targeting neuron-cancer interactions, open the door to possible cancer neuroscience strategies, including combination therapy, for pediatric high-grade gliomas.
NFS-20. DECIPHERING CELLULAR CROSSTALK IN PERIPHERAL NERVOUS SYSTEM TUMORS ASSOCIATED WITH NEUROFIBROMATOSIS TYPE 1 THROUGH SINGLE-CELL RNA SEQUENCING
Authors: Julia Freund, Bernhard Robl, Lisa Gabler, Sarah Machreich, Sibylle Madlener, Alicia Baumgartner, Daniela Lötsch-Gojo, Amedeo Azizi, Johannes Gojo
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Neurofibromatosis Type 1 (NF1) is a genetic disorder characterized by mutations and dysfunctional expression of neurofibromin 1 gene, a critical tumor-suppressor gene. NF1’s complex pathophysiology involves dysregulation of the RAS-MAPK signaling pathway, resulting in sustained MAPK signaling. Among others, the spectrum of clinical features includes low-grade tumors (e.g. plexiform neurofibromas (pNFs)) and malignant peripheral nerve sheath tumors (MPNST). While surgical removal of peripheral nerve tumors is common, total resection is often unattainable. Additionally, approved therapies comprising MEK inhibitors fail to prevent malignization, highlighting the urgent need for novel targets for effective therapies. METHODS To explore novel potential targets across a broad spectrum, we analyzed published scRNA-seq datasets (Kershner et al. 2021, Wu et al. 2022) from human patients, including pNFs and MPNSTs. We further investigated key pathways in vitro with patient-derived cell culture models. RESULTS ScRNA-seq provides insight into complex networks of cell-to-cell interactions that drive the malignant phenotype of cancerous tissues. Due to the rich presence of ECM in NF1 tumors we aimed to investigate cell types contributing to key extracellular matrix (ECM) components and associated signaling pathways. Analysis of 19 NF1 tumor samples revealed consistent presence of Schwann cells (SCs), fibroblasts, endothelial cells, and immune cells. Proliferating cells were found in MPNSTs, while pericytes were exclusive to pNFs. We compared secreted and ECM signaling between the cell types of both tumors. Our analysis discovered, among other findings, collagen signaling, highlighting fibroblasts as emitters and SCs as receivers. We further confirmed these findings through culturing of NF1-derived cells in vitro with and without collagen, observing increased cell proliferation in the presence of collagen. Further experiments and analyses are ongoing. CONCLUSIONS The emphasis on ECM and signaling adds depth to our understanding of NF1 pathogenesis and suggests potential therapeutic targets.
MDB-17. A COMPARISON OF MAGNETIC RESONANCE IMAGING AND CEREBROSPINAL FLUID CYTOLOGY FOR DETECTING LEPTOMENINGEAL METASTASIS IN PATIENTS WITH MEDULLOBLASTOMA
Authors: Zain Peeran, Ryan Phelps, Alexander Aabedi, Edward Fisher, Harmon Khela, Jennifer Rios, Poojan Shukla, Alyssa Reddy, Cassie Kline, Manish K Aghi, Nalin Gupta
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND For medulloblastoma, CSF cytology and MRI together are considered to be superior to either modality alone in identifying leptomeningeal dissemination (LMD). However, MRI has vastly improved since the initial assessment of this approach. METHODS A retrospective medical record review of 130 patients (36.2% female) with medulloblastoma was performed. CSF samples and MR images (6.3% utilized FIESTA) obtained within 1 month of each other from 2000-2023 were analyzed. There were 302 CSF-MRI pairs (range: 1-12 pairs per patient) in total. A 3-tier system (negative, atypical/suspicious, positive) was utilized to account for equivocal findings. RESULTS The mean (SD) age at surgery was 13.2 (13.0) years. Mean (SD) postoperative follow-up time was 7.0 (5.2) years. 71.5% underwent gross or near-total resection, 80.8% received radiotherapy, and 93.1% received chemotherapy. The molecular subtypes were: SHH (24.6%), WNT (4.6%), non-WNT/non-SHH (38.5%), unknown (32.3%). MRI had an 89.8% sensitivity and CSF cytology had a 22.7% sensitivity for detecting LMD that was positive on CSF and/or MRI. MRI was positive in 23.1% of CSF negative cases. CSF was positive in 2.2% of MRI negative cases. For all CSF positive-MRI negative pairs, the CSF samples and MR images were obtained within 10 days of surgery. MRI was positive in 38.9% of CSF atypical cases. CSF was positive in 11.9% of MRI suspicious cases. MRI demonstrated greater or equal ability to CSF in 94.7% of pairs. MRI was more likely to exceed CSF at 3T versus 1.5T (51.3% vs. 27.4%; p&amp;lt;0.01). The overall concordance between CSF cytology and MRI was 61.3%, and this differed by subtype (75.4% SHH vs. 80.0% WNT vs. 52.3% NWNS; p&amp;lt;0.01). CONCLUSIONS Understanding the ability of CSF cytology and MRI to detect LMD is important. While MRI is superior overall, LMD detection varies by MRI Tesla, medulloblastoma subtype, and time since surgery.
PALC-02. PALLIATIVE RADIOTHERAPY FOR HAEMOSTASIS IN CHILDREN WITH CEREBRAL METASTATIC HAEMORRHAGE
Authors: Elisa Coassin, Angelo Vitullo, Chiara Pilotto, Ilaria Liguoro, Maristella Toniutti, Francesco Tuniz, Marco Vindigni, Enrico Pegolo, Paola Elisa Cogo, Maurizio Mascarin
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Among children, bleeding from brain metastases is rare. Bleeding could be caused by: cancer, treatments and chemotherapy/other drugs such as Bevacizumab, NSAIDs and anticoagulants. We report a case of brain RT after metastases bleeding. METHODS A 14-years-old boy with a negative previous medical history presented to the Emergency Department with seizures and loss of consciousness. Full-body CT scan revealed brain and renal haemorrhages and a right testicular lesion. Serum βhCG was 223,773 mIU/mL. Neurosurgical bleeding control and right orchiectomy were performed: the histopathology revealed a metastatic mixed non-seminomatous germ cell neoplasia of the testis. First-line chemotherapy (4 cycles of Cisplatin/Etoposide/Ifosfamide) and second-line treatments (Paclitaxel/Ifosfamide/Cisplatin and Gemcitabine/Paclitaxel/Oxaliplatin) were performed. Suddenly, he presented with left-sided hyposthenia and partial left hemibody seizure. CT scan revealed 2 haemorrhagic brain lesions, one in each hemisphere. Surgery was not feasible. We started anti-oedema and anti-epileptic therapy, and whole brain RT (WBRT, 36 Gy/12 fx, BEDα/β= 10 Gy= 46.8 Gy). After 5 days from the start, RT had a 7-day stop because of acute oedema and clinical deterioration. Fourth-line chemotherapy was administered with CarboPEB (1st of further 4 cycles), and then WBRT was restarted. At the end of WBRT a stereotactic RT boost to both the haemorrhagic lesions was delivered (20 Gy/10 fx, BEDα/β= 10 Gy= 24.0 Gy). As of today, eight months after the end of therapy, the patient is free from disease and βhCG is negative. CONCLUSION Palliative RT in children is a non-conventional indication, but potentially effective at providing rapid haemostasis, especially in selected cases (surgery not feasible/contraindicated, adult-type histologies, …) and it is ensuring a good tumor control and low-grade acute toxicities. Hypofractionation is suggested to balance patient comfort and treatment effectiveness, especially when life expectancy is short. The optimal RT schedule, dose and fractionations need to be further investigated.
OTHR-26. MINIMALLY-INVASIVE MOLECULAR DIAGNOSIS OF DIFFUSE LEPTOMENINGEAL GLIONEURONAL TUMOR (DLGNT) USING CEREBROSPINAL FLUID CELL-FREE DNA SEQUENCING IN PEDIATRIC AND YOUNG ADULT PATIENTS
Authors: Alexandra M Giantini Larsen, Katherine Hill, Richard Hickman, Tejus A Bale, Bridget Holle, Ingo Mellinghoff, Ira Dunkel, Mark Souweidane, Jeffrey Greenfield, Sameer Farouk Sait, Alexandra M Miller, Matthias A Karajannis
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND Diffuse leptomeningeal glioneuronal tumor (DLGNT) presents with nodular leptomeningeal disease throughout the neuroaxis and is characterized by the presence of KIAA1549::BRAF fusion and chromosome arm 1p deletion. Concomitant gain of chromosome arm 1q is associated with poor prognosis. Diagnosis by meningeal biopsy is often non-diagnostic due to sampling error or yields insufficient material for molecular testing. We hypothesized that analysis of cell free DNA (cfDNA) from cerebrospinal fluid (CSF) could represent a superior diagnostic modality. METHODS We analyzed CSF samples from 9 suspected DLGNT patients, median age of 19.5 years with a 5:4 male:female ratio using MSK-IMPACT, a hybridization capture-based next-generation DNA sequencing panel, including matched germline. RESULTS Prior tissue biopsy was done in 7 patients; 6 were negative for the KIAA1549:BRAF fusion and 1 was positive. Of the 6 biopsies negative for the fusion, analysis of CSF cfDNA detected KIAA1549::BRAF fusion in 3/6 (50%) of patients, who were all subsequently started on MEK inhibitor therapy. The other 3 patients were negative for KIAA1549:BRAF fusion on both biopsy and CSF cfDNA. One patient received biopsy confirmation of KIAA1549::BRAF fusion after CSF cfDNA analysis detected the mutation. In addition, in one patient with prior tissue-confirmed KIAA1549::BRAF fusion, the fusion was not detected in CSF cfDNA during/after treatment with a MEK inhibitor, but additional somatic alterations and DNA copy number profiles were similar to those found in prior biopsies. Additional somatic alterations were identified in ATRX, BCOR, RARA, STAT5A, SPOP, PPM1D, MED12, KMT2C, RECQL andSETD2, including likely oncogenic secondary driver alterations that have not been previously reported in DLGNT. CONCLUSIONS Given the high molecular diagnostic yield and concordance with open biopsy, cfDNA CSF sequencing should be considered as a first line diagnostic maneuver for patients with suspected DLGNT, followed by surgical biopsy only if CSF testing is non-diagnostic.