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Background: Rhabdoid tumors (RT) are aggressive, rare tumors predominantly affecting young children, characterized by biallelic SMARCB1 gene inactivation. While most SMARCB1 alterations are acquired de novo, a third of cases exhibit germline alterations, defining Rhabdoid Tumors Predisposition Syndrome. With the increased sensitivity of next-generation sequencing (NGS), mosaicisms in genes linked to genetic diseases are more detectable. This study focuses on exploring SMARCB1 germline alterations, notably mosaicism in blood samples of children with RT and in parents, using a custom NGS panel., Methods: A cohort of 280 children and 140 parents with germline analysis was studied. Germline DNA from 111 children with RT and 32 parents were reanalyzed with a custom NGS panel with 1500X average depth targeting the SMARCB1 gene to identify intragenic variants not detected with conventional low-sensitivity methods. Follow-up data was obtained for 77 patients., Results: Nine previously undetected mosaicism cases were identified, totaling 17/280 patients with a mosaic variant (6.1%) in the cohort, with variant allele frequencies between 0.9% and 33%, thus highlighting the prior underestimation of its prevalence. Follow-up data showed that 4 out of 7 survivors with mosaic variants developed distinct novel tumors, 2 sharing SMARCB1 alterations with the initial tumor, emphasizing the potential clinical impact of SMARCB1 mosaicism., Conclusions: The hitherto underestimated rate of SMARCB1 mosaicism in RT underscores the need for optimized genetic counseling and oncological monitoring. The findings have significant medical implications, considering the dire prognosis of RT., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Biallelic germline pathogenic variants in one of the four mismatch repair genes (MSH2, MSH6, MLH1 and PMS2) cause a very rare, highly penetrant, childhood-onset cancer syndrome, called constitutional mismatch repair deficiency (CMMRD). The European consortium "Care for CMMRD" (C4CMMRD) was founded in Paris in 2013 to facilitate international collaboration and improve our knowledge of this rare cancer predisposition syndrome. Following initial publications on diagnostic criteria and surveillance guidelines for CMMRD, several partners collaborating within the C4CMMRD consortium have worked on and published numerous CMMRD-related clinical and biological projects. Since its formation, the C4CMMRD consortium held meetings every 1-2 years (except in 2020 and 2021 due to the Covid 19 pandemic). The sixth C4CMMRD meeting was held in Paris in November 2022, and brought together 42 participants from nine countries involved in various fields of CMMRD healthcare. The aim was to update members on the latest results and developments from ongoing research, and to discuss and initiate new study proposals. As previously done for the fifth meeting of the C4CMMRD group, this report summarizes data presented at this meeting., (© 2024. The Author(s).)

Constitutional mismatch repair deficiency (CMMRD), first described 25 years ago, confers an extremely high and lifelong cancer risk, including haematologic, brain, and gastrointestinal tract malignancies, and is associated with several non-neoplastic features. Our understanding of this condition has improved and novel assays to assist CMMRD diagnosis have been developed. Surveillance protocols need adjustment taking into account recent observational prospective studies assessing their effectiveness. Response to immune checkpoint inhibitors and the effectiveness and toxicity of other treatments have been described. An update and merging of the different guidelines on diagnosis and clinical management of CMMRD into one comprehensive guideline was needed. Seventy-two expert members of the European Reference Network GENTURIS and/or the European care for CMMRD consortium and one patient representative developed recommendations for CMMRD diagnosis, genetic counselling, surveillance, quality of life, and clinical management based on a systematic literature search and comprehensive literature review and a modified Delphi process. Recommendations for the diagnosis of CMMRD provide testing criteria, propose strategies for CMMRD testing, and define CMMRD diagnostic criteria. Recommendations for surveillance cover each CMMRD-associated tumour type and contain information on starting age, frequency, and surveillance modality. Recommendations for clinical management cover cancer treatment, management of benign tumours or non-neoplastic features, and chemoprevention. Recommendations also address genetic counselling and quality of life. Based on existing guidelines and currently available data, we present 82 recommendations to improve and standardise the care of CMMRD patients in Europe. These recommendations are not meant to be prescriptive and may be adjusted based on individual decisions., (© 2024. The Author(s).)

Purpose: Describe clinical characteristics and outcome of Li-Fraumeni syndrome (LFS)-associated osteosarcomas., Methods: TP53 germline pathogenic/likely pathogenic variant carriers diagnosed with osteosarcoma in France between 1980 and 2019 were identified via the French Li-Fraumeni database at Rouen University Hospital. Sixty-five osteosarcomas in 52 patients with available clinical and histological data were included. The main clinical characteristics were compared with data from National Cancer Institute's SEER (Surveillance, Epidemiology, and End Results) for patients of the same age group., Results: Median age at first osteosarcoma diagnosis was 13.7 years (range: 5.9-36.7). Compared to unselected osteosarcomas, LFS-associated osteosarcomas occurred more frequently in patients less than 10 years of age (23% vs. 9%), and when compared with osteosarcomas in patients less than 25 years were characterized by an excess of axial (16% vs. 10%) and jaw sites (15% vs. 3%) and histology with predominant chondroblastic component and periosteal subtypes (17% vs. 1%). Metastases incidence (25%) was as expected in osteosarcomas. After the first osteosarcoma treatment, the rate of good histologic response (62%) and the 5-year progression-free survival (55%, 95% confidence interval [CI]: 42.6-71.1) were as expected in unselected series of osteosarcomas, whereas the 5-year event-free survival was 36.5% [95% CI: 25.3-52.7] due to the high incidence of second malignancies reaching a 10-year cumulative risk of 43.4% [95% CI: 28.5-57.5]., Conclusion: In osteosarcoma, young age at diagnosis, axial and jaw sites, histology with periosteal or chondroblastic subtype, and synchronous multifocal tumors should prompt suspicion of a germline TP53 mutation. Standard treatments are effective, but multiple malignancies impair prognosis. Early recognition of these patients is crucial for tailored therapy and follow-up., (© 2024 The Author(s). Pediatric Blood & Cancer published by Wiley Periodicals LLC.)

Background: Constitutional mismatch repair deficiency syndrome (CMMRD) is a rare childhood cancer predisposition syndrome associated with a broad spectrum of malignancies, including non-Hodgkin lymphomas (NHL). Most patients die due to cancer before the age of 20 years. Limited data exist on CMMRD-associated lymphomas and their outcome., Methods: We conducted a retrospective study including all CMMRD-associated NHL patients registered before 2020 in the European and North American databases or reported by members of the European Intergroup for Childhood Non-Hodgkin Lymphoma (EICNHL). Events considered to define event-free survival included relapse/progression, second malignancy (SML), or death, whichever occurred first., Findings: The analysis included 74 patients, with 20 having multiple metachronous NHL. The median age at diagnosis was 9.4 years. Previous malignancies were reported in 36% of the patients, café au lait spots in 96%, and consanguinity in 54%. The initial lymphoma subtypes were 53 T-cell lymphoblastic lymphomas (T-LBL), four B-lymphoblastic lymphomas, and 17 mature B-cell non-Hodgkin lymphoma (B-NHL). All patients were treated with curative intent, with current chemotherapy regimens adapted to their subtype. The median follow-up was 8.7 years. After the first lymphoma, the 5-year event-free and overall survival rates were, respectively, 23.5% [95% confidence interval (CI): 14.9-35.1] and 61.5% [95% CI: 49.6-72.1]. The 5-year cumulative risk of progression/relapse, SML or death as a first event was 20.8%, 52.9%, and 2.7%., Interpretation: Standard treatments for sporadic NHL are effective in most CMMRD-associated NHL cases, but multiple malignancies, including lymphomas, impair prognosis. Future strategies should evaluate the potential of less genotoxic therapies, including immunotherapy, in preventing SMLs while maintaining effective control of NHL., (© 2024 The Author(s). Pediatric Blood & Cancer published by Wiley Periodicals LLC.)

Background: Children with constitutional mismatch repair deficiency (CMMRD) syndrome have an increased risk of high-grade gliomas (HGG), and brain imaging abnormalities. This study analyzes brain imaging features in CMMRD syndrome children versus those with HGG without CMMRD., Methods: Retrospective comparative analysis of brain imaging in 30 CMMRD children (20 boys, median age eight years, 22 with HGG), seven with Lynch syndrome (7 HGG), 39 with type 1 neurofibromatosis (NF1) (four with HGG) and 50 with HGG without MMR or NF1 pathogenic variant ("no-predisposition" patients)., Results: HGG in CMMRD and Lynch patients were predominantly hemispheric (versus midline) compared to NF1 and no-predisposition patients (91% and 86%, vs 25% and 54%, p = 0.004). CMMRD-associated tumors often had ill-defined boundaries (p = 0.008). All CMMRD patients exhibited at least one developmental venous anomaly (DVA), versus 14%, 10%, and 6% of Lynch, NF1, and no-predisposition patients (p < 0.0001). Multiple DVAs were observed in 83% of CMMRD patients, one NF1 patient (3%), and never in other groups (p < 0.0001). Cavernomas were discovered in 21% of CMMRD patients, never in other groups (p = 0.01). NF1-like focal areas of high T2-FLAIR signal intensity (FASI) were more prevalent in CMMRD patients than in Lynch or no-predisposition patients (50%, vs 20% and 0%, respectively, p < 0.0001). Subcortical and ill-limited FASI, possibly involving the cortex, were specific to CMMRD (p < 0.0001) and did not evolve in 93% of patients (13/14)., Conclusion: Diffuse hemispherically located HGG associated with multiple DVAs, cavernomas, and NF1-like or subcortical FASI strongly suggests CMMRD syndrome compared to children with HGG in other contexts., Clinical Relevance Statement: The radiologic suggestion of CMMRD syndrome when confronted with HGGs in children may prompt genetic testing. This can influence therapeutic plans. Therefore, imaging features could potentially be incorporated into CMMRD testing recommendations., Key Points: Using imaging to detect CMMRD syndrome early may improve patient care. CMMRD features include: hemispheric HGG with multiple developmental venous anomalies and NF1-like or subcortical areas with high T2-FLAIR intensity. We propose novel imaging features to improve the identification of potential CMMRD patients., Competing Interests: Compliance with ethical standards Guarantor The scientific guarantor of this publication is V.D.R. Conflict of interest The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article. Statistics and biometry One of the authors has significant statistical expertise. Informed consent Parental agreement on behalf of the patients was prospectively obtained to perform molecular testing of tumor samples. Parental consent for MR imaging analysis was waived for this retrospective observational study. Ethical approval Ethical committee approval was obtained to study the multimodal imaging of children’s brain tumors (EDRACT 2014-A-00541-46). Study subjects or cohorts overlap 26/30 CMMRD patients have been previously published with clinical or biological descriptions, but without in-depth imaging analysis (see Supplementary Table with related published articles). Methodology RetrospectiveObservationalPerformed at three institutions, (© 2024. The Author(s), under exclusive licence to European Society of Radiology.)

Purpose: Supratentorial (ST) ependymoma subgroups are defined by two different fusions with different prognoses. Astroblastomas, MN1-altered, have ependymal-like histopathologic features and represent a differential diagnosis in children. We hypothesized that ZFTA-fused ependymoma and YAP1-fused ependymoma on the one hand, and astroblastoma, MN1-altered, on the other hand, show different MRI characteristics., Methods: We retrospectively analyzed the preoperative imaging of 45 patients with ST ependymoma or astroblastoma between January 2000 and September 2020, blinded to histomolecular grouping. Several characteristics, such as location, tumor volume, calcifications, solid/cystic component, and signal enhancement or diffusion were evaluated. We compared imaging characteristics according to their molecular subtype (ZFTA-fused, YAP1-fused, and astroblastoma, MN1-altered)., Results: Thirty-nine patients were classified as having an ependymoma, 35 with a ZFTA fusion and four with a YAP1 fusion, and six as having an astroblastoma, MN1-altered. YAP1-fused ependymomas were more likely to involve at least 3 lobes than ZFTA-fused ependymomas. Astroblastomas were located in the frontal lobe in 100% of the tumors versus 49% of the ependymomas. Cerebral blood flow by arterial spin labeling was higher in astroblastomas than in ependymomas. There were no differences in the other characteristics between the molecular groups. All the tumors showed common features: intra-axial extra-ventricular tumors, very frequent contrast enhancement (39/43, 91%), a cystic/necrotic component (41/45, 91%), restricted diffusion (32/36, 89%), calcifications (15/18, 83%), and peri-tumoral edema (38/44, 86%)., Conclusion: The distinction between ST ependymoma subtypes and astroblastomas can be guided by several imaging features. These tumors share common imaging features that may help to differentiate ST ependymomas and astroblastomas from other pediatric ST tumors., Competing Interests: Conflict of interest V. Perrod, R. Levy, A. Tauziède-Espariat, C.-J. Roux, K. Beccaria, T. Blauwblomme, J. Grill, C. Dufour, L. Guerrini-Rousseau, S. Abbou, S. Bolle, A. Roux, J. Pallud, C. Provost, C. Oppenheim, P. Varlet, N. Boddaert and V. Dangouloff-Ros declare that they have no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

In paediatric oncology, genomics raises new ethical, legal and psychological issues, as somatic and constitutional situations intersect throughout the care pathway. The discovery of potential predisposition in this context is sometimes carried out outside the usual framework. This article focuses on the views of children, adolescents, and young adults (AYA) with cancer and their parents about their experience with genomic testing. Forty-eight semi-structured interviews were performed with children or AYAs with cancer and one of their parents, before and/or after receiving the genetic test results. The interviews were fully transcribed, coded and thematically analysed using an inductive method. This analysis revealed several themes that are key issues: perceived understanding and consenting, apprehension about the test outcomes (expectations and fears), perception and attitude towards incidental findings. The main expectation was an aetiological explanation. Children and AYAs also emphasised the altruistic meaning of genetic testing, while parents seemed to expect a therapeutic and preventive approach for their child and the rest of the family. Parents were more concerned about a family risk, while patients were more afraid of cancer relapse or transmission to their descendants. Both groups suggested possible feelings of guilt concerning family transmission and imaginary representations of what genomics may allow. Incidental findings were not understood by patients, while some parents perceived the related issues and hesitated between wanting or not to know. A multidisciplinary approach would be an interesting way to help parents and children and AYAs to better grasp the complexity of genetic and/or genomic testing., (© 2024. The Author(s).)

Background: Constitutional mismatch repair deficiency (CMMRD) is a cancer predisposition due to biallelic mutations in one of the mismatch repair (MMR) genes associated with early onset of cancers, especially high-grade gliomas. Our aim was to decipher the molecular specificities of these gliomas., Methods: Clinical, histopathological, and whole exome sequencing data were analyzed in 12 children with genetically proven CMMRD and a high-grade glioma., Results: PDL1 expression was present in immunohistochemistry in 50% of the samples. In 9 patients, the glioma harbored an ultra-hypermutated phenotype (104-635 coding single nucleotide variants (SNV) per Mb, median 204). Driver mutations in POLE and POLD1 exonuclease domains were described for 8 and 1 patients respectively and were always present in the mutation burst with the highest variant allele frequency (VAF). The mutational signatures were dominated by MMR-related ones and similar in the different mutation bursts of a same patient without subsequent enrichment of the mutation signatures with POL-driven ones. Median number of coding SNV with VAF above one of the driving polymerase mutation per Mb was 57 (17-191). Our findings suggest that somatic polymerase alterations does not entirely explain the ultra-hypermutant phenotype. SETD2 , TP53 , NF1 , EPHB2 , PRKDC, and DICER1 genes were frequently mutated with higher VAF than the deleterious somatic polymerase mutation., Conclusions: CMMRD-associated gliomas have a specific oncogenesis that does not involve usual pathways and mutations seen in sporadic pediatric or adult glioblastomas. Frequent alterations in other pathways such as MAPK may suggest the use of other targeted therapies along with PD1 inhibitors., Competing Interests: The authors have no commercial association that might pose or create the appearance of a conflict of interest with the information presented in the submitted manuscript., (© The Author(s) 2024. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)

Background: ELP1 pathogenic variants (PV) have been recently identified as the most frequent variants predisposing to Sonic Hedgehog (SHH) medulloblastomas (MB); however, guidelines are still lacking for genetic counseling in this new syndrome., Methods: We retrospectively reviewed clinical and genetic data of a French series of 29 ELP1 -mutated MB., Results: All patients developed SHH-MB, with a biallelic inactivation of PTCH1 found in 24 tumors. Other recurrent alterations encompassed the TP53 pathway and activation of MYCN/MYCL signaling. The median age at diagnosis was 7.3 years (range: 3-14). ELP1 -mutated MB behave as sporadic cases, with similar distribution within clinical and molecular risk groups and similar outcomes (5 y - OS = 86%); no unusual side effect of treatments was noticed. Remarkably, a germline ELP1 PV was identified in all patients with available constitutional DNA ( n  = 26); moreover, all tested familial trio ( n  = 11) revealed that the PVs were inherited. Two of the 26 index cases from the French series had a family history of MB; pedigrees from these patients and from 1 additional Dutch family suggested a weak penetrance. Apart from MB, no cancer was associated with ELP1 PVs; second tumors reported in 4 patients occurred within the irradiation fields, in the usual time-lapse for expected radiotherapy-induced neoplasms., 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 SHH-MB, depending on the parents" request., Competing Interests: None declared., (© The Author(s) 2024. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)

Objective: Adamantinomatous craniopharyngioma mainly affects children. Excessive weight gain is a major long-term complication. The primary objective of this study was to assess long-term weight changes in children treated for craniopharyngioma. The secondary objectives were to identify risk factors for excessive weight gain and to look for associations with hypothalamic damage by the tumour or treatment., Design: Single-centre retrospective cohort study., Method: Children managed for craniopharyngioma at our centre between 1990 and 2019 were included. The body mass index (BMI) standard deviation scores (SDS) at baseline and at last follow-up were compared. Univariate and multivariate analyses were performed in order to identify variables associated with the long-term BMI-SDS variation., Results: The 108 patients had a mean follow-up of 10.4 years. The mean BMI-SDS increase over time was 2.11 (P < .001) overall, 1.21 (P < .001) in the group without hypothalamic involvement by the tumour, and 1.95 (P < .001) in the group managed using intended hypothalamus-sparing surgery. The absence of hypothalamic involvement by the tumour or treatment was significantly associated with less weight gain (P = .046 and P < .01, respectively). After adjustment, factors associated with a BMI-SDS change greater than 2 were female sex (P = .023), tumour involving the hypothalamus (P = .04), and higher baseline BMI (P < .001)., Conclusion: Clinically significant weight gain occurred in nearly all children treated for craniopharyngioma, including those whose hypothalamus was spared by the tumour and intentionally by treatment. However, hypothalamus integrity was associated with less weight gain. Despite hypothalamus-sparing strategies, hypothalamic obesity remains a major concern, indicating a need for novel treatment approaches., Competing Interests: Conflict of interest: The authors declare no conflict of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Endocrinology.)

Objectives: Posterior fossa ependymoma group A (EPN&#95;PFA) and group B (EPN&#95;PFB) can be distinguished by their DNA methylation and give rise to different prognoses. We compared the MRI characteristics of EPN&#95;PFA and EPN&#95;PFB at presentation., Methods: Preoperative imaging of 68 patients with posterior fossa ependymoma from two centers was reviewed by three independent readers, blinded for histomolecular grouping. Location, tumor extension, tumor volume, hydrocephalus, calcifications, tissue component, enhancement or diffusion signal, and histopathological data (cellular density, calcifications, necrosis, mitoses, vascularization, and microvascular proliferation) were compared between the groups. Categorical data were compared between groups using Fisher's exact tests, and quantitative data using Mann-Whitney tests. We performed a Benjamini-Hochberg correction of the p values to account for multiple tests., Results: Fifty-six patients were categorized as EPN&#95;PFA and 12 as EPN&#95;PFB, with median ages of 2 and 20 years, respectively (p = 0.0008). The median EPN&#95;PFA tumoral volume was larger (57 vs 29 cm 3 , p = 0.003), with more pronounced hydrocephalus (p = 0.002). EPN&#95;PFA showed an exclusive central position within the 4th ventricle in 61% of patients vs 92% for EPN&#95;PFB (p = 0.01). Intratumor calcifications were found in 93% of EPN&#95;PFA vs 40% of EPN&#95;PFB (p = 0.001). Invasion of the posterior fossa foramina was mostly found for EPN&#95;PFA, particularly the foramina of Luschka (p = 0.0008). EPN&#95;PFA showed whole and homogeneous tumor enhancement in 5% vs 75% of EPN&#95;PFB (p = 0.0008). All mainly cystic tumors were EPN&#95;PFB (p = 0.002). The minimal and maximal relative ADC was slightly lower in EPN&#95;PFA (p = 0.02 and p = 0.01, respectively)., Conclusion: Morphological characteristics from imaging differ between posterior fossa ependymoma subtypes and may help to distinguish them preoperatively., Clinical Relevance Statement: This study provides a tool to differentiate between group A and group B ependymomas, which will ultimately allow the therapeutic strategy to be adapted in the early stages of patient management., Key Points: • Posterior fossa ependymoma subtypes often have different imaging characteristics. • Posterior fossa ependymomas group A are commonly median or lateral tissular calcified masses, with incomplete enhancement, affecting young children and responsible for pronounced hydrocephalus and invasion of the posterior fossa foramina. • Posterior fossa ependymomas group B are commonly median non-calcified masses of adolescents and adults, predominantly cystic, and minimally invasive, with total and homogeneous enhancement., (© 2023. The Author(s), under exclusive licence to European Society of Radiology.)

Differential diagnosis between constitutional mismatch repair deficiency (CMMRD) and neurofibromatosis type 1 (NF1 ) is crucial as treatment and surveillance differ. We report the case of a girl with a clinical diagnosis of sporadic NF1 who developed a glioblastoma. Immunohistochemistry for MMR proteins identified PMS2 loss in tumour and normal cells and WES showed the tumour had an ultra-hypermutated phenotype, supporting the diagnosis of CMMRD. Germline analyses identified two variants (one pathogenic variant and one classified as variant(s) of unknown significance) in the PMS2 gene and subsequent functional assays on blood lymphocytes confirmed the diagnosis of CMMRD. The large plexiform neurofibroma of the thigh and the freckling were however more compatible with NF1. Indeed, a NF1 PV (variant allele frequencies of 20%, 3% and 9% and in blood, skin and saliva samples, respectively) was identified confirming a mosaicism for NF1. Retrospective analysis of a French cohort identified NF1 mosaicism in blood DNA in 2 out of 22 patients with CMMRD, underlining the existence of early postzygotic PV of NF1 gene in patients with CMMRD whose tumours have been frequently reported to exhibit somatic NF1 mutations. It highlights the potential role of this pathway in the pathogenesis of CMMRD-associated gliomas and argues in favour of testing MEK inhibitors in this context., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The prognosis for Li-Fraumeni syndrome (LFS) patients with medulloblastoma (MB) is poor. Comprehensive clinical data for this patient group is lacking, challenging the development of novel therapeutic strategies. Here, we present clinical and molecular data on a retrospective cohort of pediatric LFS MB patients., Methods: In this multinational, multicenter retrospective cohort study, LFS patients under 21 years with MB and class 5 or class 4 constitutional TP53 variants were included. TP53 mutation status, methylation subgroup, treatment, progression free- (PFS) and overall survival (OS), recurrence patterns, and incidence of subsequent neoplasms were evaluated., Results: The study evaluated 47 LFS individuals diagnosed with MB, mainly classified as DNA methylation subgroup "SHH&#95;3" (86%). The majority (74%) of constitutional TP53 variants represented missense variants. The 2- and 5-year (y-) PFS were 36% and 20%, and 2- and 5y-OS were 53% and 23%, respectively. Patients who received postoperative radiotherapy (RT) (2y-PFS: 44%, 2y-OS: 60%) or chemotherapy before RT (2y-PFS: 32%, 2y-OS: 48%) had significantly better clinical outcome then patients who were not treated with RT (2y-PFS: 0%, 2y-OS: 25%). Patients treated according to protocols including high-intensity chemotherapy and patients who received only maintenance-type chemotherapy showed similar outcomes (2y-PFS: 42% and 35%, 2y-OS: 68% and 53%, respectively)., Conclusions: LFS MB patients have a dismal prognosis. In the presented cohort use of RT significantly increased survival rates, whereas chemotherapy intensity did not influence their clinical outcome. Prospective collection of clinical data and development of novel treatments are required to improve the outcome of LFS MB patients., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Context: Endocrine complications are common in pediatric brain tumor patients., Objective: To describe hypothalamic-pituitary-gonadal axis (HPGA) function in patients treated in childhood for a primary brain tumor more than 5 years earlier, in order to identify risk factors for HPGA impairment., Methods: We retrospectively included 204 patients diagnosed with a primary brain tumor before 18 years of age and monitored at the pediatric endocrinology unit of the Necker Enfants-Malades University Hospital (Paris, France) between January 2010 and December 2015. Patients with pituitary adenoma or untreated glioma were excluded., Results: Among patients with suprasellar glioma not treated by radiotherapy, the prevalence of advanced puberty was 65% overall and 70% when the diagnosis occurred before 5 years of age. Medulloblastoma chemotherapy caused gonadal toxicity in 70% of all patients and in 87.5% of those younger than 5 years at diagnosis. In the group with craniopharyngioma, 70% of patients had hypogonadotropic hypogonadism, which was consistently accompanied by growth hormone deficiency., Conclusion: Tumor type, location, and treatment were the risk main factors for HPGA impairment. Awareness that onset can be delayed is essential to guide information of parents and patients, patient monitoring, and timely hormone replacement therapy., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Context: Craniopharyngioma is a benign brain tumor with frequent local recurrence or progression after treatment. GH replacement therapy (GHRT) is prescribed in children with GH deficiency resulting from childhood-onset craniopharyngioma., Objective: To evaluate whether a shorter delay of GHRT initiation after childhood-onset craniopharyngioma completion therapy increased the risk of a new event (progression or recurrence)., Methods: Retrospective, observational, monocenter study. We compared a cohort of 71 childhood-onset patients with craniopharyngiomas treated with recombinant human GH (rhGH). Twenty-seven patients were treated with rhGH at least 12 months after craniopharyngioma treatment (>12-month group) and 44 patients before 12 months (<12-month group), among which 29 patients were treated between 6 and 12 months (6-12 month group). The main outcome was the risk of tumor new event (progression of residual tumor or tumor recurrence after complete resection) after primary treatment in the >12-month group and in the <12 month or in the 6- to 12-month group patients., Results: In the >12-month group, the 2- and 5-year event-free survivals were respectively 81.5% (95% CI, 61.1-91.9) and 69.4% (95% CI, 47.9-83.4) compared with 72.2% (95% CI, 56.3-83.1) and 69.8% (95% CI, 53.8-81.2) in the <12-month group. The 2- and 5-year event-free survivals were the same in the 6- to 12-month group (72.4%; 95% CI, 52.4-85.1). By log-rank test, the event-free survival was not different between groups (P = .98 and P = .91).The median time for event was not statistically different.In univariate and multivariate analysis, the risk of craniopharyngioma new event was not associated with the GHRT time delay after craniopharyngioma treatment., Conclusions: No association was found between GHRT time delay after childhood-onset craniopharyngioma treatment and an increased risk of recurrence or tumor progression, suggesting GH replacement therapy can be initiated 6 months after last treatment for craniopharyngiomas., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Purpose: The Lynch syndrome (LS)-glioma association is poorly documented. As for mismatch repair deficiency (MMRd) in glioma, a hallmark of LS-associated tumors, there are only limited data available. We determined MMRd and LS prevalence in a large series of unselected gliomas, and explored the associated characteristics. Both have major implications in terms of treatment, screening, and prevention., Methods: Somatic next-generation sequencing was performed on 1,225 treatment-naive adult gliomas referred between 2017 and June 2022. For gliomas with ≥1 MMR pathogenic variant (PV), MMR immunohistochemistry (IHC) was done. Gliomas with ≥1 PV and protein expression loss were considered MMRd. Eligible patients had germline testing. To further explore MMRd specifically in glioblastomas, isocitrate dehydrogenase (IDH)-wild type (wt), we performed IHC, and complementary sequencing when indicated, in a series of tumors diagnosed over the 2007-2021 period., Results: Nine gliomas were MMRd (9/1,225; 0.73%). Age at glioma diagnosis was <50 years for all but one case. Eight were glioblastomas, IDH-wt, and one was an astrocytoma, IDH-mutant. ATRX (n = 5) and TP53 (n = 8) PV were common. There was no TERT promoter PV or EGFR amplification. LS prevalence was 5/1,225 (0.41%). One 77-year-old patient was a known LS case. Four cases had a novel LS diagnosis, with germline PV in MSH2 (n = 3) and MLH1 (n = 1). One additional patient had PMS2 -associated constitutional mismatch repair deficiency. Germline testing was negative in three MSH6-deficient tumors. In the second series of glioblastomas, IDH-wt, MMRd prevalence was 12.5% in the <40-year age group, 2.6% in the 40-49 year age group, and 1.6% the ≥50 year age group., Conclusion: Screening for MMRd and LS should be systematic in glioblastomas, IDH-wt, diagnosed under age 50 years.

Background & Aims: Constitutional mismatch repair deficiency (CMMRD) is a rare recessive childhood cancer predisposition syndrome caused by germline mismatch repair variants. Constitutional microsatellite instability (cMSI) is a CMMRD diagnostic hallmark and may associate with cancer risk. We quantified cMSI in a large CMMRD patient cohort to explore genotype-phenotype correlations using novel MSI markers selected for instability in blood., Methods: Three CMMRD, 1 Lynch syndrome, and 2 control blood samples were genome sequenced to >120× depth. A pilot cohort of 8 CMMRD and 38 control blood samples and a blinded cohort of 56 CMMRD, 8 suspected CMMRD, 40 Lynch syndrome, and 43 control blood samples were amplicon sequenced to 5000× depth. Sample cMSI score was calculated using a published method comparing microsatellite reference allele frequencies with 80 controls., Results: Thirty-two mononucleotide repeats were selected from blood genome and pilot amplicon sequencing data. cMSI scoring using these MSI markers achieved 100% sensitivity (95% CI, 93.6%-100.0%) and specificity (95% CI 97.9%-100.0%), was reproducible, and was superior to an established tumor MSI marker panel. Lower cMSI scores were found in patients with CMMRD with MSH6 deficiency and patients with at least 1 mismatch repair missense variant, and patients with biallelic truncating/copy number variants had higher scores. cMSI score did not correlate with age at first tumor., Conclusions: We present an inexpensive and scalable cMSI assay that enhances CMMRD detection relative to existing methods. cMSI score is associated with mismatch repair genotype but not phenotype, suggesting it is not a useful predictor of cancer risk., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: Ketamine, an N -methyl-D-aspartate receptor antagonist, is effective at relieving adult cancer pain, although there have been very few reports to date regarding its use in children and in adolescents and young adults (AYA). This study assessed the efficacy, safety and opioid-sparing effects of low doses of ketamine added to opioid analgesics to alleviate persistent cancer pain., Methods: This prospective, multicentre, observational trial collected data regarding demographics, pain characteristics, pain score assessment within the first 48 hours of ketamine administration, tolerance and satisfaction from 38 patients aged 2-24 years prescribed with ketamine as an adjuvant antalgic for refractory cancer pain in 10 French paediatric oncology centres., Results: The mean visual analogue scale pain score decreased from 6.7 to 4.3 out of 10 (n=39, p<0.001) from day 1 to day 3 and by at least 2 points in 56% of the patients (n=22) 48 hours after initiation of ketamine. Nine patients experienced poor tolerance (≥2 side effects), all with infusion rates lower than 0.05 mg/kg/hour. None had limiting toxicities. An opioid-sparing effect was highlighted in four patients. Fifty-four per cent of the prescribers and 47% of the patients found the addition of ketamine 'very helpful'., Conclusions: Low doses of ketamine as an adjuvant to opioids significantly reduced the intensity of pain in half of the study population. A tendency towards better pain control is shown, although a lack of statistical power somewhat limits our conclusions, especially in children. Nevertheless, ketamine may be a useful option for improving the treatment of refractory pain in children and AYA with cancer., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Little is known about risks associated with germline SUFU pathogenic variants (PVs) known as a cancer predisposition syndrome., Methods: To study tumour risks, we have analysed data of a large cohort of 45 unpublished patients with a germline SUFU PV completed with 127 previously published patients. To reduce the ascertainment bias due to index patient selection, the risk of tumours was evaluated in relatives with SUFU PV (89 patients) using the Nelson-Aalen estimator., Results: Overall, 117/172 (68%) SUFU PV carriers developed at least one tumour: medulloblastoma (MB) (86 patients), basal cell carcinoma (BCC) (25 patients), meningioma (20 patients) and gonadal tumours (11 patients). Thirty-three of them (28%) had multiple tumours. Median age at diagnosis of MB, gonadal tumour, first BCC and first meningioma were 1.5, 14, 40 and 44 years, respectively. Follow-up data were available for 160 patients (137 remained alive and 23 died). The cumulative incidence of tumours in relatives was 14.4% (95% CI 6.8 to 21.4), 18.2% (95% CI 9.7 to 25.9) and 44.1% (95% CI 29.7 to 55.5) at the age of 5, 20 and 50 years, respectively. The cumulative risk of an MB, gonadal tumour, BCC and meningioma at age 50 years was: 13.3% (95% CI 6 to 20.1), 4.6% (95% CI 0 to 9.7), 28.5% (95% CI 13.4 to 40.9) and 5.2% (95% CI 0 to 12), respectively. Sixty-four different PVs were reported across the entire SUFU gene and inherited in 73% of cases in which inheritance could be evaluated., Conclusion: Germline SUFU PV carriers have a life-long increased risk of tumours with a spectrum dominated by MB before the age of 5, gonadal tumours during adolescence and BCC and meningioma in adulthood, justifying fine-tuned surveillance programmes., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY. Published by BMJ.)

Background: In developed countries, cancer remains the leading cause of pediatric death from illness after the neonatal period., Objective: To describe the end-of-life care characteristics of children and adolescents with solid tumors (ST) or hematologic malignancies (HM) who died from tumor progression in the Île-de-France area., Methods: This is a regional, multicentric, retrospective review of medical files of all children and adolescents with cancer who died over a 1-year period. Extensive data from the last 3 months of life were collected., Results: A total of 99 eligible patients died at a median age of 9.8 years (range, 0.3-24 years). The most frequent terminal symptoms were pain (n = 86), fatigue (n = 84), dyspnea (n = 49), and anorexia (n = 41). Median number of medications per patient was 8 (range, 3-18). Patients required administration of opioids (n = 91), oxygen (n = 36), and/or sedation (n = 61). Decision for palliative care was present in all medical records and do-not-resuscitate orders in 90/99 cases. Symptom prevalence was comparable between children and adolescents with ST and HM. A wish regarding the place of death had been expressed for 64 patients and could be respected in 42 cases. Death occurred in hospital for 75 patients., Conclusions: This study represents a large and informative cohort illustrating current pediatric palliative care approaches in pediatric oncology. End-of-life remains an active period of care requiring coordination of multiple care teams.

Context: Endocrine complications are common in pediatric brain tumor patients., Objective: We aimed to describe the endocrine follow-up of patients with primary brain tumors., Methods: This is a noninterventional observational study based on data collection from medical records of 221 patients followed at a Pediatric Endocrinology Department., Results: Median age at diagnosis was 6.7 years (range, 0-15.9), median follow-up 6.7 years (0.3-26.6), 48.9% female. Main tumor types were medulloblastoma (37.6%), craniopharyngioma (29.0%), and glioma (20.4%). By anatomic location, 48% were suprasellar (SS) and 52% non-suprasellar (NSS). Growth hormone deficiency (GHD) prevalence was similar in both groups (SS: 83.0%, NSS: 76.5%; P = 0.338), appearing at median 1.8 years (-0.8 to 12.4) after diagnosis; postradiotherapy GHD appeared median 1.6 years after radiotherapy (0.2-10.7). Hypothyroidism was more prevalent in SS (76.4%), than NSS (33.9%) (P < 0.001), as well as ACTH deficiency (SS: 69.8%, NSS: 6.1%; P < 0.001). Early puberty was similar in SS (16%) and NSS (12.2%). Hypogonadotropic hypogonadism was predominant in SS (63.1%) vs NSS (1.3%), P < 0.001, and postchemotherapy gonadal toxicity in NSS (29.6%) vs SS (2.8%), P < 0.001. Adult height was lower for NSS compared to target height (-1.0 SD, P < 0.0001) and to SS patients (P < 0.0001). Thyroid nodules were found in 13/45 patients (28.8%), including 4 cancers (4.8-11.5 years after radiotherapy). Last follow-up visit BMI was higher in both groups (P = 0.0001), and obesity incidence was higher for SS (46.2%) than NSS (17.4%)., Conclusion: We found a high incidence of early-onset endocrine disorders. An endocrine consultation and nutritional evaluation should be mandatory for all patients with a brain tumor, especially when the tumor is suprasellar or after hypothalamus/pituitary irradiation., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Purpose of Review: Brain tumors are the most frequent solid cancer in the pediatric population. Owing to the rarity of environmental clues about their origin, it is tempting to consider these neoplasms as developmental processes gone awry. Our review will explore the heuristic power of this hypothesis and the influence of these findings on the clinical management., Recent Finding: A more accurate description of cancer predisposition syndrome has shown their frequent association with developmental abnormalities. Several genes involved in pediatric brain tumor oncogenesis are involved in developmental processes. Modeling of several pediatric brain tumor in cerebral organoids, mimicking embryonal stage of brain development, indicates that early events during brain development create the conditions necessary for their oncogenesis., Summary: The onset of multiple brain tumor types early in life suggests a functional relationship between brain development and oncogenesis. A growing body of evidence seems to support the hypothesis that some of the main developmental steps in the brain can be highjacked by the tumors during their initiation. Collaborations between neuroscientists and oncologists should provide room for improvement in the knowledge for these neoplasms., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

The cIMPACT-NOW Update 7 has replaced the WHO nosology of "ependymoma, RELA fusion positive" by "Supratentorial-ependymoma, C11orf95-fusion positive". This modification reinforces the idea that supratentorial-ependymomas exhibiting fusion that implicates the C11orf95 (now called ZFTA) gene with or without the RELA gene, represent the same histomolecular entity. A hot off the press molecular study has identified distinct clusters of the DNA methylation class of ZFTA fusion-positive tumors. Interestingly, clusters 2 and 4 comprised tumors of different morphologies, with various ZFTA fusions without involvement of RELA. In this paper, we present a detailed series of thirteen cases of non-RELA ZFTA-fused supratentorial tumors with extensive clinical, radiological, histopathological, immunohistochemical, genetic and epigenetic (DNA methylation profiling) characterization. Contrary to the age of onset and MRI aspects similar to RELA fusion-positive EPN, we noted significant histopathological heterogeneity (pleomorphic xanthoastrocytoma-like, astroblastoma-like, ependymoma-like, and even sarcoma-like patterns) in this cohort. Immunophenotypically, these NFκB immunonegative tumors expressed GFAP variably, but EMA constantly and L1CAM frequently. Different gene partners were fused with ZFTA: NCOA1/2, MAML2 and for the first time MN1. These tumors had epigenetic homologies within the DNA methylation class of ependymomas-RELA and were classified as satellite clusters 2 and 4. Cluster 2 (n = 9) corresponded to tumors with classic ependymal histological features (n = 4) but also had astroblastic features (n = 5). Various types of ZFTA fusions were associated with cluster 2, but as in the original report, ZFTA:MAML2 fusion was frequent. Cluster 4 was enriched with sarcoma-like tumors. Moreover, we reported a novel anatomy of three ZFTA:NCOA1/2 fusions with only 1 ZFTA zinc finger domain in the putative fusion protein, whereas all previously reported non-RELA ZFTA fusions have 4 ZFTA zinc fingers. All three cases presented a sarcoma-like morphology. This genotype/phenotype association requires further studies for confirmation. Our series is the first to extensively characterize this new subset of supratentorial ZFTA-fused ependymomas and highlights the usefulness of ZFTA FISH analysis to confirm the existence of a rearrangement without RELA abnormality., (© 2021. The Author(s).)

Background: Smoothened inhibitors (SMOi) have shown activity in Sonic Hedgehog (SHH) medulloblastoma, however this therapeutic class was not developed in children due to severe effects reported on growth. We hereby report long-term follow-up of young patients treated with SMOi for recurrent medulloblastoma., Methods: Clinical data on response and toxicity from patients treated with vismodegib or sonidegib from 2011 to 2019 for a SHH medulloblastoma were retrospectively reviewed. Methylation analysis and whole exome sequencing were performed whenever possible., Results: All patients with a somatic PTCH1 mutation responded to SMOi (6/8), including 2 prolonged complete responses. One patient was free of disease 8.2 years after treatment. SMOi was challenged again for 3 patients. Two of them had a response, one with SMOi alone, the other one in combination with temozolomide despite previous progression under monotherapy. SMO resistance mutations were found in patients from biopsy at relapse. Combination with temozolomide or surgery plus radiotherapy was associated with very long disease control in 2 patients. The most severe adverse events were myalgia and growth plate fusion with metaphyseal sclerosis. Normal growth velocity was recovered for 1 patient although her final height was below estimated target height., Conclusions: Targeting SMO in mutated PTCH1 is an interesting strategy for long-term responses. Combination of SMOi with chemotherapy or surgery and local radiotherapy is an appealing strategy to prevent early resistance and diminish SMOi exposure, especially in young patients. Inhibition of SHH pathway causes growth and development impairment but partial recovery of the growth velocity is possible., (© The Author(s) 2021. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)

Background: High-risk medulloblastoma is defined by the presence of metastatic disease and/or incomplete resection and/or unfavorable histopathology and/or tumors with MYC amplification. We aimed to assess the 3-year progression-free survival (PFS) and define the molecular characteristics associated with PFS in patients aged 5-19 years with newly diagnosed high-risk medulloblastoma treated according to the phase II trial PNET HR+5., Methods: All children received postoperative induction chemotherapy (etoposide and carboplatin), followed by 2 high-dose thiotepa courses (600 mg/m2) with hematological stem cell support. At the latest 45 days after the last stem cell rescue, patients received risk-adapted craniospinal radiation therapy. Maintenance treatment with temozolomide was planned to start between 1-3 months after the end of radiotherapy. The primary endpoint was PFS. Outcome and safety analyses were per protocol (all patients who received at least one dose of induction chemotherapy)., Results: Fifty-one patients (median age, 8 y; range, 5-19) were enrolled. The median follow-up was 7.1 years (range: 3.4-9.0). The 3 and 5-year PFS with their 95% confidence intervals (95% CI) were 78% (65-88) and 76% (63-86), and the 3 and 5-year OS were 84% (72-92) and 76% (63-86), respectively. Medulloblastoma subtype was a statistically significant prognostic factor (P-value = 0.039) with large-cell/anaplastic being of worse prognosis, as well as a molecular subgroup (P-value = 0.012) with sonic hedgehog (SHH) and group 3 being of worse prognosis than wingless (WNT) and group 4. Therapy was well tolerated., Conclusions: This treatment based on high-dose chemotherapy and conventional radiotherapy resulted in a high survival rate in children with newly diagnosed high-risk medulloblastoma., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Childhood malignancies are rarely related to known environmental exposures, and it has become increasingly evident that inherited genetic factors play a substantial causal role. Large-scale sequencing studies have shown that approximately 10% of children with cancer have an underlying cancer predisposition syndrome. The number of recognised cancer predisposition syndromes and cancer predisposition genes are constantly growing. Imaging and laboratory technologies are improving, and knowledge of the range of tumours and risk of malignancy associated with cancer predisposition syndromes is increasing over time. Consequently, surveillance measures need to be constantly adjusted to address these new findings. Management recommendations for individuals with pathogenic germline variants in cancer predisposition genes need to be established through international collaborative studies, addressing issues such as genetic counselling, cancer prevention, cancer surveillance, cancer therapy, psychological support, and social-ethical issues. This Review represents the work by a group of experts from the European Society for Paediatric Oncology (SIOPE) and aims to summarise the current knowledge and define future research needs in this evolving field., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Given the very poor prognosis for children with recurrent medulloblastoma, we aimed to identify prognostic factors for survival post-relapse in children with childhood medulloblastoma. We retrospectively collected clinico-biological data at diagnosis and main clinical characteristics at relapse of children newly diagnosed with a medulloblastoma between 2007 and 2017 at Gustave Roussy and Necker Hospital. At a median follow-up of 6.6 years (range, 0.4-12.3 years), relapse occurred in 48 out 155 patients (31%). The median time from diagnosis to relapse was 14.3 months (range, 1.2-87.2 months). Relapse was local in 9, metastatic in 22 and combined (local and metastatic) in 17 patients. Second-line treatment consisted of chemotherapy in 31 cases, radiotherapy in 9, SHH-inhibitor in four and no treatment in the remaining four. The 1-year overall survival rate post-relapse was 44.8% (CI 95%, 31.5% to 59.0%). While molecular subgrouping at diagnosis was significantly associated with survival post-relapse, the use of radiotherapy at relapse and time to first relapse (>12 months) might also have a potential impact on post-relapse survival.

Background: Previous pilot studies have shown the feasibility of preoperative chemotherapy in patients with medulloblastoma, but benefits and risks compared with initial surgery have not been assessed., Methods: Two therapeutic strategies were retrospectively compared in 92 patients with metastatic medulloblastoma treated at Gustave Roussy between 2002 and 2015: surgery at diagnosis (n = 54, group A) and surgery delayed after carboplatin and etoposide-based neoadjuvant therapy (n = 38, group B). Treatment strategies were similar in both groups., Results: The rate of complete tumor excision was significantly higher in group B than in group A (93.3% vs 57.4%, P = 0.0013). Postoperative complications, chemotherapy-associated side effects, and local progressions were not increased in group B. Neoadjuvant chemotherapy led to a decrease in the primary tumor size in all patients; meanwhile 4/38 patients experienced a distant progression. The histological review of 19 matched tumor pairs (before and after chemotherapy) showed that proliferation was reduced and histological diagnosis feasible and accurate even after neoadjuvant chemotherapy. The 5-year progression-free and overall survival rates were comparable between groups. Comparison of the longitudinal neuropsychological data showed that intellectual outcome tended to be better in group B (the mean predicted intellectual quotient value was 6 points higher throughout the follow-up)., Conclusion: Preoperative chemotherapy is a safe and efficient strategy for metastatic medulloblastoma. It increases the rate of complete tumor excision and may improve the neuropsychological outcome without jeopardizing survival., Key Points: 1. Preoperative chemotherapy increases the rate of complete tumor removal.2. No additional risk (toxic or disease progression) is linked to the delayed surgery.3. Preoperative chemotherapy could have a positive impact on the neuropsychological outcome of patients., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Neuro-Oncology.)

Background: The optimal therapeutic strategy for relapsing intracranial germ cell tumours (IGCTs) has not been clearly established., Methods: Relapses of IGCTs, occurring from 01/01/1990 to 31/12/2014, were retrieved from the Societe Française d'Oncologie Pediatrique-TGM 90, 92 and GCT 96 protocols, and from the National Childhood Solid Tumour Registry. Refractory IGCTs were excluded., Results: Forty-four relapsing IGCTs were identified: 14 were initially treated for histologically proven germinomas (germinoma group), 5 for non-histologically proven germinomas (putative germinoma group) and 25 for non-germinomatous germ cell tumours (NGGCTs) (NGGCT group). In the germinoma group, the 5-year event-free survival (EFS) and overall survival (OS) were 79% (95% confidence interval [CI]: 47-93) and 86% (95% CI: 54-96), respectively. Only one of the 11 patients treated with reirradiation experienced a further relapse. A trend of better EFS was observed for relapses at sites that were not initially involved: 5-year EFS of 100% versus 67% (95% CI: 28-88), p = 0.09. In the putative germinoma group, 4 of 5 patients experienced a further event, leading to 2 deaths. In the NGGCT group, the 5-year EFS and OS were 56% (95% CI: 35-73) and 60% (95% CI: 38-76), respectively. A significant improvement in outcomes after high-dose chemotherapy (HDC) was observed: 5-year OS of 72% (95% CI: 46-87) versus 29% (95% CI: 4-61), p = 0.006., Conclusion: Relapsing germinomas are highly curable; reirradiation appears to play a key role. Histological proof at initial diagnosis if markers are negative is crucial. Despite inferior outcomes relapsing, NGGCTs can be cured in a significant proportion of cases provided intensive treatment including HDC is applied., Competing Interests: Conflict of interest statement None declared., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Medulloblastomas may occur in a predisposition context, including familial adenomatosis polyposis. Medulloblastomas related to a germline pathogenic variant of adenomatous polyposis coli (APC) remain rare and poorly described. Their similarities with sporadic WNT medulloblastomas still require description., Methods: We performed a multicentric retrospective review of 12 patients treated between 1988 and 2018 for medulloblastoma with an identified or highly suspected (personal or familial history) APC germline pathogenic variant. We report personal and familial history APC gene pathogenic variants whenever available: clinical and histologic characteristics of the medulloblastoma, treatments, and long-term outcome, including second tumor and late sequelae., Results: Medulloblastomas associated with APC pathogenic variants are mainly classic (11/11 patients, 1 not available), nonmetastatic (10/12 patients) medulloblastomas, with nuclear immunoreactivity for ß-catenin (9/9 tested cases). Ten of 11 assessable patients are disease free with a median follow-up of 10.7 years (range, 1-28 y). Secondary tumors included desmoid tumors in 7 patients (9 tumors), 1 thyroid carcinoma, 2 pilomatricomas, 1 osteoma, 1 vertebral hemangioma, and 1 malignant triton in the radiation field, which caused the only cancer-related death in our series., Conclusions: Medulloblastomas associated with an APC pathogenic variant have an overall favorable outcome, even for metastatic tumors. Yet, long-term survival is clouded by second tumor occurrence; treatment may play some role in some of these second malignancies. Our findings raise the question of applying a de-escalation therapeutic protocol to treat patients with APC germline pathogenic variants given the excellent outcome, and reduced intensity of craniospinal irradiation may be further evaluated., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Purpose: The identification of a heritable tumor predisposition often leads to changes in management and increased surveillance of individuals who are at risk; however, for many rare entities, our knowledge of heritable predisposition is incomplete., Methods: Families with childhood medulloblastoma, one of the most prevalent childhood malignant brain tumors, were investigated to identify predisposing germline mutations. Initial findings were extended to genomes and epigenomes of 1,044 medulloblastoma cases from international multicenter cohorts, including retrospective and prospective clinical studies and patient series., Results: We identified heterozygous germline mutations in the G protein-coupled receptor 161 ( GPR161 ) gene in six patients with infant-onset medulloblastoma (median age, 1.5 years). GPR161 mutations were exclusively associated with the sonic hedgehog medulloblastoma (MB SHH ) subgroup and accounted for 5% of infant MB SHH cases in our cohorts. Molecular tumor profiling revealed a loss of heterozygosity at GPR161 in all affected MB SHH tumors, atypical somatic copy number landscapes, and no additional somatic driver events. Analysis of 226 MB SHH tumors revealed somatic copy-neutral loss of heterozygosity of chromosome 1q as the hallmark characteristic of GPR161 deficiency and the primary mechanism for biallelic inactivation of GPR161 in affected MB SHH tumors., Conclusion: Here, we describe a novel brain tumor predisposition syndrome that is caused by germline GPR161 mutations and characterized by MB SHH in infants. Additional studies are needed to identify a potential broader tumor spectrum associated with germline GPR161 mutations.

Background: Pediatric neurofibromatosis type 1 (NF1)-associated optic pathway gliomas (OPGs) exhibit different clinico-radiological features, treatment, and outcome compared with sporadic OPGs. While NF1-associated OPGs are caused by complete loss-of-function of the NF1 gene, other genetic alterations of the RAS-MAPK pathway are frequently described in the sporadic cases. We identified a group of patients who presented OPGs with typical radiological features of NF1-associated OPGs but without the NF1 diagnostic criteria. We aim to investigate into the possible molecular mechanisms underlying this "NF1-like" pediatric OPGs presentation., Methods: We analyzed clinico-radiological features of 16 children with NF1-like OPGs and without NF1 diagnostic criteria. We performed targeted sequencing of the NF1 gene in constitutional samples ( n  = 16). The RAS-MAPK pathway major genes were sequenced in OPG tumor samples ( n  = 11); BRAF FISH and IHC analyses were also performed., Results: In one patient's blood and tumor samples, we identified a NF1 nonsense mutation (exon 50: c.7285C>T, p.Arg2429*) with ~8% and ~70% VAFs, respectively, suggesting a mosaic NF1 mutation limited to the brain (segmental NF1). This patient presented signs of neurodevelopmental disorder. We identified a somatic alteration of the RAS-MAPK pathway in eight tumors: four BRAF activating p.Val600Glu mutations, three BRAF:KIAA oncogenic fusions, and one putative gain-of-function complex KRAS indel inframe mutation., Conclusions: NF1-like OPGs can rarely be associated with mosaic NF1 that needs specific constitutional DNA analyses for diagnosis. Further studies are warranted to explore unknown predisposition condition leading to the NF1-like OPG presentation, particularly in patients with the association of a neurodevelopmental disorder., (© The Author(s) 2019. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)