Search

Purpose: To determine long-term outcomes of a cohort of children with germinoma treated with chemotherapy and radiation therapy without primary tumor boost even in the absence of complete response to chemotherapy. Methods: This retrospective study analyzed the outcome of patients with germinoma consecutively diagnosed and treated at a tertiary care center from January 2000 to December 2021. MRIs were reviewed by two radiologists, blinded to patient data. Tumor location at diagnosis, tumor response to chemotherapy and at completion of radiation therapy and site of relapse were assessed. Tumor response was assessed radiologically by determining the tumor size and response on diffusion-weighted imaging, in addition to biochemical, cytological parameters and neurological status. Results: Of 46 pediatric germinoma patients, 29 children (14 male; median age 12.8 years) received no primary tumor boost. Median follow-up was 63 months (range 9-187 months). Twenty-five children had localized disease and tumor location was suprasellar (n= 11), pineal (n= 10), bifocal (n= 3) and basal ganglia (n= 1) while 4 children had metastatic disease at presentation. All patients completed multi-agent chemotherapy followed by either ventricular irradiation (VI) (23.4 Gy) (n = 23), whole brain (WBI) (23.4 Gy) (n = 5) or craniospinal radiation (CSI) (23.4 Gy) (n= 1). Two children, who had localized disease at presentation and received VI after chemotherapy, relapsed 9 months and 32 months after completion of treatment respectively. No patient had a local relapse. Location of relapse was distant, outside (n= 1) and inside (n= 1) the irradiation field. Five-year PFS was 91% and overall survival (OS) was 100%. Conclusions: In this case series, excellent 5-year PFS and OS rates were achieved with chemotherapy followed by radiation therapy of 23.4 Gy delivered without primary tumor boost. No local relapse was observed despite omitting primary tumor boost in patients with localized and metastatic germinoma.

Low- and middle-income countries sustain the majority of pediatric cancer burden, with significantly poorer survival rates compared to high-income countries. Collaboration between institutions in low- and middle-income countries and high-income countries is one of the ways to improve cancer outcomes.Patient characteristics and effects of a pediatric neuro-oncology twinning program between the Hospital for Sick Children in Toronto, Canada and several hospitals in Karachi, Pakistan over 7 years are described in this article.A total of 460 patients were included in the study. The most common primary central nervous system tumors were low-grade gliomas (26.7%), followed by medulloblastomas (18%), high-grade gliomas (15%), ependymomas (11%), and craniopharyngiomas (11.7%). Changes to the proposed management plans were made in consultation with expert physicians from the Hospital for Sick Children in Toronto, Canada. On average, 24% of the discussed cases required a change in the original management plan over the course of the twinning program. However, a decreasing trend in change in management plans was observed, from 36% during the first 3.5 years to 16% in the last 3 years. This program also led to the launch of a national pediatric neuro-oncology telemedicine program in Pakistan.Multidisciplinary and collaborative efforts by experts from across the world have aided in the correct diagnosis and treatment of children with brain tumors and helped establish local treatment protocols. This experience may be a model for other low- and middle-income countries that are planning on creating similar programs.

The rate limiting enzyme of the polyamine pathway, SAT1, is significantly upregulated in non-cycling GSCs. However, higher SAT1 expression predicts poorer survival in GBM suggesting a role in quiescence and recurrence post-treatment. Treating GSCs with N1N11-Diethylnorspermine (DENSpm) recapitulates SAT1 upregulation and triggers a chemoprotective, long-term reversible growth arrest, while not affecting expression of stem, differentiation, nor senescence-associated markers. Remarkably, DENSpm strongly induces double-stranded RNA in GSCs. Interestingly, S-Adenosyl methionine (SAM) is an essential aminopropyl donor for polyamine biosynthesis. We found a significant correlation between DNA methylation, SAM, and polyamines across GSCs suggesting that SAM depletion may cause epigenetic and post-transcriptional alterations leading to re-activation of endogenous retroviral elements (ERVs) and viral mimicry-driven quiescence. However, while we confirmed DENSpm-induced SAM depletion, we did not detect DNA, histone, nor RNA demethylation. Noteworthy, ERVs are the most accessible transposable elements in GSCs indicative of a poised state. Furthermore, the correlation between expression of ERVs and interferon stimulated genes reveals a spectrum of viral mimicry amongst GSCs. Using a larger cohort of GSCs and hfNSCs, we identified three DENSpm response subgroups. A resistant subgroup comprised of cells able to proliferate through treatment, a reversible one whereby cells become quiescent and readily re-enter cell cycle post-treatment, and an irreversible consisting of cells that enter a deep quiescent state which they cannot escape. Importantly, we found that DENSpm response correlates with the cell's basal inflammatory state and the activity of viral defense pathways. These results indicate that a viral mimicry-driven quiescence may be specific to slower-growing neurodevelopmental GSCs, while more proliferative, inflammatory-poised GSCs are impervious to these additional cues. We propose that polyamine metabolism, glioma stem cell hierarchy and tumour inflammatory context play a central role in regulating quiescence and have important clinical implications in the initial response to treatment, aggressiveness, and ultimately recurrence of GBM.

Glioblastoma is a highly malignant tumour driven by a subset of self-renewing cells termed glioblastoma stem cells. This self-renewal phenotype is largely epigenetically driven, however, the exact epigenetic mechanisms underpinning it are poorly understood. We found that the histone variant macroH2A2 is repressed in a subset of glioblastoma tumours, and that this repression is associated with poorer survival. We interrogate the function of macroH2A2 using in vitro and in vivo patient-derived models. We show that macroH2A2 antagonizes self-renewal and expression of NPC and OPC-like markers, and rewires accessible chromatin by maintaining accessibility at a subset of enhancer elements. We identify small molecules that can upregulate macroH2A2 expression, and find that treatment with a small molecule reduces self-renewal, induces interferon sensitive genes, and a viral mimicry response, effects which are abolished by macroH2A2 knockdown. In summary, we identify macroH2A2 as a repressor of self-renewal in glioblastoma and suggest it may be a novel biomarker and potential marker of therapeutic susceptibility.

OBJECTIVE Gliomas in adolescents and young adults (AYA) are commonly treated with a standard chemo-radiation approach. Molecular alterations have not been comprehensively described to date. METHODS We compiled a multi-institutional cohort of patients diagnosed with glioma between 15-39.9 years over 20 years. Molecular analysis, therapeutic data and outcome was collected. For specific alterations, analysis included patients aged 0-39.9 years. RESULTS A total of 1900 patients with 876 AYA gliomas were included. Ongoing analysis reveals genetic alterations in 95% of available tumours. IDH p.R132H was found in 49% of tumours, while non-canonical IDH mutations were found in 7%. Paediatric-type mutations were found in 33% of AYA tumours with IDH-WT GBM accounting for the remaining 11%. The most common paediatric alterations in AYAs included BRAF p.V600E (11%) and FGFR alterations (7%) while BRAF fusions, H3 p.K27M and H3.3 p.G34R were rarely observed (4%, 4% and 1% respectively). BRAF fused tumours with non-canonical binding partners were enriched in AYAs. Analysis of BRAF-V600E gliomas between ages 0-40 revealed increased tendency for malignant tumours in patients > 20 years suggesting malignant transformation possibly due to higher rate of secondary hits. This resulted in worse overall-survival for AYA patients with BRAF-V600E glioma when compared to children under 20 years (p=0.0032). Ten-year OS of 100%, 90% and 95% was seen for BRAF fused, BRAF-V600E and FGFR-altered AYA low grade glioma respectively, compared to 14% and 25% for BRAF-V600E and FGFR-altered high grade glioma. In contrast, continuous decline was observed in the IDH-mutant gliomas with 10-year OS of 50% which declined to 29% at 15 years. CONCLUSIONS Gliomas in AYA often have non-canonical alterations that may evade standard molecular analysis. They are enriched for paediatric-type alterations with distinct molecularly-based outcomes. These tumours may respond to targeted inhibitors and would benefit from comprehensive diagnostic and therapeutic approaches.

Background: Hypermutant gliomas in children are caused by inherited or therapy related replication repair deficiency (RRD), the latter typically following treatment with the alkylating agent temozolomide (TMZ). Recently, immune checkpoint inhibitors (ICIs) revealed clinical responses and prolonged survival in 30% of pediatric-inherited hypermutant gliomas but none of the treatment-related adult hypermutant gliomas. We hypothesized that high-throughput screening of hypermutant and RRD patient derived glioma cell lines from both glioma types (PDGCL) would reveal specific molecular vulnerabilities immediately translatable as targeted therapies to be used in combination with ICIs. Methods: We screened two pediatric hypermutant and RRD PDGCLs (1806, 1260); one pediatric non-hypermutant non-RRD PDGCL (477); an adult non-hypermutant non-RRD PDGCL (189EW); matched recurrent post-TMZ treatment hypermutant RRD PDGCL (248z, 248xy) from patient 189 against a library of 3336 bioactive compounds, including 1500 FDA approved drugs supplemented with 16 additional compounds (BET, PLK1, EZH2, PARP1 inhibitors) at 100nM.Each plate screened contained negative (0.2% DMSO) and positive controls (50nM bortezomib). Cell viability was calculated at 96hr by ATP measurement. Raw values from negative and positive control wells were aggregated and used to calculate Z’-factors for each assay plate, as a measure of assay performance and data quality, with a Z’-factor >0.5 representing high quality data. Only drugs scoring Normalized Percentage of Inhibition (NPI) >50% and z-score>3 were considered potential hits for follow-up evaluation, focusing on those enriched in the pediatric and adult hypermutant PDGCLs. Results: We identified 45 drugs active in all three of the pediatric PDGCLs and 23 common hits in the adult cell lines. Broad target classes were identified such as microtubule associated inhibitors, heat shock protein inhibitors for PDGCLs and proteasome inhibitors for adult cell lines. Unique targets were also identified. Importantly, the inherited and treatment related mismatch repair deficient glioma cells (MMR1260,248z, 248xy) and the hypermutant pediatric cell line (1806) exhibited significant response to PI3K/mTOR inhibitors. Ultrahypermutant RRD cell line and the treatment-related hypermutant cell lines (1806 248z 248xy ) displayed sensitivity to topoisomerase I inhibitors. Preliminary in vitro data confirm sensitivity to topotecan of hypermutant pediatric and adult cell lines. Conclusion: We have identified both mechanism specific and common intrinsic vulnerabilities in hypermutant PDGCLs that can be tested as adjuvant therapies for ICI. Functional validation of the lead candidates is ongoing and will be reported. Citation Format: Laura Scolaro, Nuno Miguel Nunes, Michelle Kushida, David C. Schultz, Sara Cherry, Kanupriya Whig, Peter Dirks, Uri Tabori, John M. Maris. Identification of intrinsic molecular vulnerabilities in inherited and treatment-related hypermutant patient-derived glioma cell line models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB188.

OBJECTIVE: Gliomas in adolescents and young adults (AYA) are commonly treated with a standard chemo-radiation approach based on data from adults. The clinical impact of paediatric-type alterations in these tumours is unknown. METHODS: We compiled a multi-institutional cohort of patients diagnosed with glioma between 15-39.9 years over 20 years. Complete molecular analysis, therapeutic data and outcome was collected. For specific alterations, analysis included patients aged 0-39.9 years. RESULTS: A total of 1900 patients with 876 AYA gliomas were included. Ongoing analysis reveals genetic alterations in 95% of available tumours. IDH-mutant tumours account for only 53%, while paediatric-type mutations were found in 35% of AYA tumours with IDH-WT GBM accounting for the remaining 12%. The most common paediatric alterations in AYAs included BRAF p.V600E (11%) and FGFR alterations (6%) while BRAF fusions, H3 p.K27M and H3.3 p.G34R were rarely observed (4%, 4% and 1% respectively). BRAF fused tumours with non-canonical binding partners were enriched in AYAs. Analysis of BRAF-V600E gliomas between ages 0-40 revealed increased tendency for malignant tumours in patients >20 years suggesting malignant transformation possibly due to higher rate of secondary hits including TP53, CDKN2A and ATRX mutations. This resulted in worse overall-survival for AYA patients with BRAF-V600E glioma when compared to children under 20 years (p=0.0032). Ten-year OS of 100%, 90% and 95% was seen for BRAF fused, BRAF-V600E and FGFR-altered AYA low grade glioma respectively, compared to 14% and 25% for BRAF-V600E and FGFR-altered high grade glioma. In contrast, continuous decline was observed in the IDH-mutant gliomas with 10-year OS of 50% which declined to 29% at 15 years. CONCLUSIONS: Gliomas in AYA are enriched for paediatric-type alterations with distinct molecularly-based outcomes. As these tumours carry different outcomes than childhood glioma and may respond to targeted inhibitors, AYA gliomas would benefit from comprehensive diagnostic and therapeutic approaches.

BACKGROUND: Response-based radiation therapy has been the approach for germinoma after chemotherapy. However, the presence of residual lesions at the end of chemotherapy did not demonstrate a negative impact on progression-free survival (PFS). Similarly, resection of residual tumors after chemotherapy did not show a survival benefit. AIM: Our study objective was to determine long-term outcomes of a cohort who received chemotherapy and radiation therapy without primary tumor boost even in the absence of complete response to chemotherapy. METHOD: This retrospective study analyzed the outcome of germinoma patients diagnosed and treated at a tertiary care center from January 2006 to December 2021. RESULTS: Twenty-nine children (14 male; median age 12.8 years) were identified. Median follow-up was 63 months (range 9-187 months). Twenty children had localized disease and tumor location was suprasellar (n= 9), pineal (n= 10), and bifocal (n= 1) while 9 children had metastatic disease at presentation. All patients completed multi-agent chemotherapy followed by either whole ventricular (WVI) (23.4 Gy) (n = 23), whole brain (WBI) (23.4 Gy) (n = 5) or craniospinal radiation (CSI) (23.4 Gy) (n= 1). Two children, who had localized disease at presentation and received WVI after chemotherapy, relapsed 9 months and 32 months after completion of treatment respectively. None of them had local relapses. Location of relapse was distant, outside (n= 1) and inside (n= 1) the radiation field. Five-year PFS was 93% and overall survival (OS) was 100%. CONCLUSION: In this limited experience, excellent 5-year PFS and OS rates were achieved with chemotherapy followed by radiation therapy delivered without primary tumor boost. This study also demonstrated the absence of local relapse despite omitting primary tumor boost in patients with localized and metastatic germinoma.

Background Intracranial pyogenic complications of sinusitis in children are relatively uncommon but can lead to serious sequelae. The objective of this study was to characterize the clinical, epidemiologic and microbiologic characteristics of children with such complications over a 20-year period (2000- 2019). Methods Single-center retrospective chart review. Cases were identified based on International Classification of Diseases (ICD)-10 diagnostic codes (intracranial abscess or granuloma, extradural and subdural abscess, Pott’s puffy tumor, acute or chronic sinusitis) and by reviewing all microbiological samples of intracranial pus, tissue or fluid. Results 108 cases of clinically and/or radiologically diagnosed sinusitis were included after review of 1591 charts. The majority were adolescents (median age 12, IQR 9-14); 72 were male (67%). The most common presenting symptoms were fever (84%), headache (87%) and symptoms of upper respiratory tract infection (57%). Median symptom duration was 10 days (IQR 5-21) and 55 cases (51%) received oral antibiotics prior to admission. The most frequent complications were epidural empyema (n=50, 46%), subdural empyema (n=46, 43%) and Pott’s puffy tumor (n= 31, 29%). 50% (n=54) underwent neurosurgery, of which 20% (n=11) required multiple craniectomies. 38% (n=41) underwent otolaryngological surgery. Microbiological data from sterile specimens demonstrated single organisms in 36 cases (59%) and polymicrobial growth in 25 cases (41%). The most frequently identified pathogens were Streptococcus anginosus (n=40, 66%) followed by Fusobacterium species (n=10, 16%) and Prevotella species (n=10,16%). Most cases were treated with combination antibiotic therapy (n=68, 63%) and 14% (n=15) with a carbapenem. The median duration of intravenous antibiotic therapy was 51 days (IQR 42-80). One child died and 23% (n=25) suffered neurological sequelae (median follow-up 344 days). 48 cases (44%) occurred between 2014-2019. Conclusion Intracranial complications of sinusitis continue to cause significant morbidity in children. The predominant causative pathogen was Streptococcus anginosus. Polymicrobial infections are common, confirming the need for prolonged broad-spectrum antibiotic treatment. Disclosures Sharon Cushing, MD, MSc, FRCSC, Cochlear Corporation (Research Grant or Support)Cochlear Corporation (Speaker’s Bureau)Interacoustics (Speaker’s Bureau)Plural publishing (Other Financial or Material Support, Royalties: editor: manual of pediatric balance disorders)

Norrin is an atypical WNT ligand that binds the Frizzled-4 (FZD4) and Low-density lipoprotein receptor-related protein (LRP5/6) receptor complex to activate canonical WNT/ β-catenin signaling. Norrin/FZD4 signaling is involved in the regulation of vasculature in several tissues including the retina and for blood-brain barrier function. The role of Norrin in cancer is not very well characterized. Here, we show that NDP, the gene encoding for Norrin, is expressed in a wide range of cancer types, with a particular enrichment in glioblastoma (GBM) and lower grade glioma (LGG). Kaplan-Meier survival analysis of publicly available datasets revealed a significant correlation between NDP expression and survival in GBM, LGG and neuroblastoma. To investigate the function of NDP in GBM, we performed a set of NDP and FZD4 gain and loss of function experiments in patient-derived GBM stem cell (GNS) lines. Recently Achaete-scute homolog 1 (ASCL1) expression was shown to stratify GNS lines into two cohorts with different tumorigenic, proliferation and differentiation dynamics. Surprisingly, we found that NDP manipulation resulted in opposite effects in ASCL1hi versus ASCL1lo lines. NDP inhibited proliferation and sphere formation in ASCL1lo lines through the WNT/ β-catenin pathway, while it stimulated proliferation and sphere formation in ASCL1hi lines independently of the WNT/β-catenin pathway. The NDP/FZD4 effects on growth in both GNS subtypes were recapitulated in xenografts, confirming effects of this pathway on tumor progression in vivo. To gain insight into the cellular and molecular effects of NDP/FZD4 on GNS growth we performed immunocytochemistry (ICC) and RNA-Seq analyses in GNS cells with NDP knockdown. In parallel with our in vitro and in vivo observations, we found that NDP/FZD4 signaling affects GNS proliferation index and cell cycle kinetics and the expression of cell cycle regulatory genes in both GNS subtypes, but in opposite ways. RNA-Seq analysis identified cell cycle regulatory genes and gene sets that are commonly affected by NDP in both GNS types. Interestingly, the analysis also identified several genes and genesets unique to each GNS type, consistent with the divergence of NDP functions between GNS subtypes. Collectively, our results uncover novel functions of NDP in regulating GBM stem cell progression, and that NDP functions in GBM stem cells stratify with ASCL1 expression. Additionally, our results highlight the significance of precision medicine in targeting tumor subtypes based on the molecular signature. Citation Format: Ahmed A. Elsehemy, Hayden Selvadurai, Arturo Ortin-Martinez, Nenad Pokrajac, Yasin Mamatjan, Katherine Rowland, Kenneth Aldape, Peter Dirks, Valerie Wallace. Novel biological roles of the atypical WNT ligand, Norrin, on glioblastoma stem cells segregate with ASCL1 expression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4671.

Verotoxin 1 (VT1) is an E. coli toxin comprising an A subunit with N-glycanase activity, and five smaller B subunits capable of binding to the functional receptor globotriaosylceramide (Galα1-4-Galβ1-4-Glcceramide-Gb3). VT is implicated in hemorrhagic colitis and the more serious hemolytic uremic syndrome. VT1 is active against various tumor cell lines in vitro and in vivo. To extend the anti-cancer spectrum of activity of VT to human brain tumors, in the present analysis we studied the effects of VT on the growth of 6 permanent human astrocytoma cell lines. All astrocytoma cell lines analyzed express Gb3 and were sensitive to VT-1 at a dose of 50 ng/ml, but sensitivity was not proportional to the relative Gb3 concentration. VT induced apoptosis in these cells was shown by electron microscopy. Morphological evidence (nuclear shrinkage and chromatin condensation) of apoptosis could be clearly distinguished 1.5 hrs after toxin addition. Ultrastructural preservation of organelles was observed in conjunction with blebbing of the plasma membrane, condensation of chromatin within the nucleus and nuclear shrinkage. Apoptosis was also induced by the recombinant toxin B subunit alone, suggesting that the ligation of Gb3 is the primary induction mechanism. These studies indicate that verotoxin/Gb3 targetting may provide a novel basis for the inhibition of astrocytoma tumour cell growth.