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Simple Summary Malignant rhabdoid tumors (MRT) are deadly tumors that predominantly affect infants and young children. Even when considering the generally young age of these patients, the treatment of infants below the age of six months represents a particular challenge due to the vulnerability of this patient population. The aim of our retrospective study was to assess the available information on prognostic factors, genetics, toxicity of treatment and long-term outcomes of MRT. We confirmed that, in a cohort of homogenously treated infants with MRT, significant predictors of outcome were female sex, localized stage, absence of a GLM and maintenance therapy, and these significantly favorably influence prognosis. Stratification-based biomarker-driven tailored trials may be a key option to improve survival rates. Abstract Introduction: Malignant rhabdoid tumors (MRT) predominantly affect infants and young children. Patients below six months of age represent a particularly therapeutically challenging group. Toxicity to developing organ sites limits intensity of treatment. Information on prognostic factors, genetics, toxicity of treatment and long-term outcomes is sparse. Methods: Clinical, genetic, and treatment data of 100 patients (aged below 6 months at diagnosis) from 13 European countries were analyzed (2005–2020). Tumors and matching blood samples were examined for SMARCB1 mutations using FISH, MLPA and Sanger sequencing. DNA methylation subgroups (ATRT-TYR, ATRT-SHH, and ATRT-MYC) were determined using 450 k / 850 k-profiling. Results: A total of 45 patients presented with ATRT, 29 with extracranial, extrarenal (eMRT) and 9 with renal rhabdoid tumors (RTK). Seventeen patients demonstrated synchronous tumors (SYN). Metastases (M+) were present in 27% (26/97) at diagnosis. A germline mutation (GLM) was detected in 55% (47/86). DNA methylation subgrouping was available in 50% (31 / 62) with ATRT or SYN; for eMRT, methylation-based subgrouping was not performed. The 5-year overall (OS) and event free survival (EFS) rates were 23.5 ± 4.6% and 19 ± 4.1%, respectively. Male sex (11 ± 5% vs. 35.8 ± 7.4%), M+ stage (6.1 ± 5.4% vs. 36.2 ± 7.4%), presence of SYN (7.1 ± 6.9% vs. 26.6 ± 5.3%) and GLM (7.7 ± 4.2% vs. 45.7 ± 8.6%) were significant prognostic factors for 5-year OS. Molecular subgrouping and survival analyses confirm a previously described survival advantage for ATRT-TYR. In an adjusted multivariate model, clinical factors that favorably influence the prognosis were female sex, localized stage, absence of a GLM and maintenance therapy. Conclusions: In this cohort of homogenously treated infants with MRT, significant predictors of outcome were sex, M-stage, GLM and maintenance therapy. We confirm the need to stratify which patient groups benefit from multimodal treatment, and which need novel therapeutic strategies. Biomarker-driven tailored trials may be a key option.

Cancers 14(5), 1261 (2022). doi:10.3390/cancers14051261, Published by MDPI, Basel

Simple Summary Medulloblastoma is the commonest malignant brain tumour of childhood. Disease relapse following maximal multi-modal therapy including upfront craniospinal irradiation (CSI) is almost always fatal and occurs in approximately 30% of patients. Importantly, patients rarely die of other causes, and consequently relapsed medulloblastoma (rMB) accounts for 10% of all childhood cancer deaths. There is a variety of life-prolonging treatment options at relapse including neurosurgery, re-irradiation, early-phase trials, and chemotherapy. Here, we summarise best practice for investigations including re-biopsy and molecular characterisation of rMB, treatment decision making, and available treatment options. We also highlight advances in the understanding of rMB disease biology and prognostic factors, and look towards future developments such as targeted therapies, liquid biopsies and disease modelling strategies to improve outcomes in this area of unmet clinical need. Abstract Relapsed medulloblastoma (rMB) accounts for a considerable, and disproportionate amount of childhood cancer deaths. Recent advances have gone someway to characterising disease biology at relapse including second malignancies that often cannot be distinguished from relapse on imaging alone. Furthermore, there are now multiple international early-phase trials exploring drug–target matches across a range of high-risk/relapsed paediatric tumours. Despite these advances, treatment at relapse in pre-irradiated patients is typically non-curative and focuses on providing life-prolonging and symptom-modifying care that is tailored to the needs and wishes of the individual and their family. Here, we describe the current understanding of prognostic factors at disease relapse such as principal molecular group, adverse molecular biology, and timing of relapse. We provide an overview of the clinical diagnostic process including signs and symptoms, staging investigations, and molecular pathology, followed by a summary of treatment modalities and considerations. Finally, we summarise future directions to progress understanding of treatment resistance and the biological mechanisms underpinning early therapy-refractory and relapsed disease. These initiatives include development of comprehensive and collaborative molecular profiling approaches at relapse, liquid biopsies such as cerebrospinal fluid (CSF) as a biomarker of minimal residual disease (MRD), modelling strategies, and the use of primary tumour material for real-time drug screening approaches.

INTRODUCTION: Radiotherapy with craniospinal irradiation (CSI) is an important part of initial treatment for medulloblastoma in most children. Radiotherapy after recurrence is currently not widely used. This analysis aims to evaluate whether re-irradiation (RT2) may show survival benefits. METHODS: Data for patients with recurrent medulloblastomas from the German HIT-REZ studies was gathered. Patients with RT2 at 1st recurrence were matched by propensity score to an equal number of patients without radiotherapy. Matching variables were sex, initial therapy, time to recurrence, metastatic stage and therapy at 1st recurrence and radiotherapy at subsequent recurrences. The matched cohort was analysed regarding PFS and OS after 1st recurrence. RESULTS: From a cohort of 240 pre-irradiated patients, 106 patients were matched. Patients with RT2 showed improved median PFS [21.0 months (95%-CI: 17.5 – 27.6)] and OS [37.5 months (CI: 30.0 – 59.4)] compared to control patients [(PFS: 12.0 months (CI: 8.1 – 17.7) / OS: 20.1 months (CI: 14.5 – 44.8)]. When stratifying by resection at recurrence (36.8% resected), a survival advantage for RT2 was found in patients without resection in PFS [19.6 (CI: 14.9 – 31.5) vs. 8.0 months (CI: 5.4 – 14.4)] and OS [41.9 (CI: 30.0 – 59.4) vs. 13.3 months (CI: 8.1 – 36.7)]. However, no advantage was found after resection [PFS: 22.5 (CI: 17.5 – 50.4) vs. 19.1 months (CI: 14.1 – 34.3) / OS: 32.3 (CI: 27.6 – NA) vs. 48 months (CI: 23.4 – NA)]. CSI was used in 6 patients without differences in survival to focal RT2. Median PFS after first irradiation was 32.5 months, after RT2 20.9 months. No patients with RT2 were alive past 10 years after 1st recurrence.CONCLUSION: Patients with recurrent medulloblastoma show benefits from RT2 in median PFS and OS. However, no advantage for RT2 was found when resection was also applied at recurrence. Cure after treatment with RT2 was not found in our cohort.

Recurrent medulloblastomas are associated with survival rates n = 30/93) found mainly in molecular subgroup 3 were associated with markedly worse median PFS (HR: 2.34) and OS (HR: 3.26) in regression analyses. A significant survival advantage was found for the use of volume-reducing surgery as well as radiotherapy. Intravenous chemotherapy with carboplatin and etoposide (ivCHT, n = 28/93) showed improved PFS and OS data and the best objective response rate (ORR) was 66.7% compared to oral temozolomide (oCHT, n = 47/93) which was 34.8%. Intraventricular (n = 43) as well as high-dose chemotherapy (n = 17) at first relapse was not related to a significant survival benefit. Although the results are limited due to a non-randomized study design, they may serve as a basis for future treatment decisions in order to improve the patients’ survival.

INTRODUCTION: Malignant rhabdoid tumors (MRT) are highly aggressive neoplasias mostly affecting young children. They are classified as rhabdoid tumors of the central nervous system (ATRT, atypical teratoid rhabdoid tumor), rhabdoid tumors of the kidney (RTK) or extracranial rhabdoid tumors arising from any soft tissue outside the central nervous system (eMRT, extracranial extrarenal MRT). We report a series of four MRTs with cranial nerve involvement. METHODS: Patients were identified from a cohort of 132 patients with MRT (2017 – 2021), as part of the European Rhabdoid Registry (EU-RHAB). Diagnosis of MRT was confirmed immunohistochemically with loss of INI1 expression. Details regarding symptoms at first presentation, diagnostic staging, genetic findings, therapy and the course of disease are reported. REPORT OF CASES/RESULTS: The series contains two MRT affecting the trigeminal nerve and two cases with third cranial nerve involvement. They were two female and two male patients with a median age of 4.7 years (1-159 months) at diagnosis. Location of the main tumor mass differed between being located intra- and extracerebrally. Metastases at diagnosis occurred in one patient, a germ-line mutation in SMARCB1 was present in two patients. Two patients received therapy according to EU-RHAB recommendations with an incomplete resection, conventional chemotherapy enhanced by intraventricular methotrexate and radiotherapy. Both patients are currently alive with no signs of progression, one of them bearing a germ-line mutation. Two patients received palliative treatment after surgery due to rapid progression. Median overall survival was 17.3 (1.4-53.1) months. CONCLUSION: MRT of the cranial nerves affect the peripheral nervous system in close proximity to the brain, thus forming a unique sub-entity between ATRT and eMRT. The selected cases provide insight into the particular challenge regarding clear classification, diagnostics and therapy.

Phosphatidylinositol 4-kinase IIIα (PI4KIIIα/PI4KA/OMIM:600286) is a lipid kinase generating phosphatidylinositol 4-phosphate (PI4P), a membrane phospholipid with critical roles in the physiology of multiple cell types. PI4KIIIα’s role in PI4P generation requires its assembly into a heterotetrameric complex with EFR3, TTC7 and FAM126. Sequence alterations in two of these molecular partners, TTC7 (encoded by TTC7A or TCC7B) and FAM126, have been associated with a heterogeneous group of either neurological (FAM126A) or intestinal and immunological (TTC7A) conditions. Here we show that biallelic PI4KA sequence alterations in humans are associated with neurological disease, in particular hypomyelinating leukodystrophy. In addition, affected individuals may present with inflammatory bowel disease, multiple intestinal atresia and combined immunodeficiency. Our cellular, biochemical and structural modelling studies indicate that PI4KA-associated phenotypical outcomes probably stem from impairment of PI4KIIIα-TTC7-FAM126's organ-specific functions, due to defective catalytic activity or altered intra-complex functional interactions. Together, these data define PI4KA gene alteration as a cause of a variable phenotypical spectrum and provide fundamental new insight into the combinatorial biology of the PI4KIIIα-FAM126-TTC7-EFR3 molecular complex., Salter et al. show that biallelic variants in PI4KA—which encodes the enzymatic core of the PI4KIIIα-TTC7-FAM126 complex—cause a clinically diverse disorder comprising neurological, intestinal and immunological abnormalities.

Background Survival in recurrent ependymomas in children and adolescents mainly depends on the extent of resection. Studies on repeated radiotherapy and chemotherapy at relapse have shown conflicting results. Methods Using data from the German multi-center E-HIT-REZ-2005 study, we examined the role of local therapy and the efficacy of chemotherapy with blockwise temozolomide (TMZ) in children and adolescents with recurrent ependymomas. Results Fifty-three patients with a median age of 6.9 years (1.25–25.4) at first recurrence and a median follow-up time of 36 months (2–115) were recruited. Gross- and near-total resection (GTR/NTR) were achieved in 34 (64.2%) patients and associated with a markedly improved 5-year overall survival (OS) of 48.7% vs. 5.3% in less than GTR/NTR. Radiotherapy showed no improvement in OS following complete resection (OS: 70 (CI: 19.9–120.1) vs. 95 (CI: 20.7–169.4) months), but an advantage was found in less than GTR/NTR (OS: 22 (CI: 12.7–31.3) vs. 7 (CI: 0–15.8) months). Following the application of TMZ, disease progression was observed in most evaluable cases (18/21). A subsequent change to oral etoposide and trofosfamide showed no improved response. PF-A EPN were most abundant in relapses (n = 27). RELA-positive EPN (n = 5) had a 5-year OS of 0%. Conclusion The extent of resection is the most important predictor of survival at relapse. Focal re-irradiation is a useful approach if complete resection cannot be achieved, but no additional benefit was seen after GTR/NTR. Longer-term disease stabilization (>6 months) mediated by TMZ occurred in a small number of cases (14.3%).

Accurate pathological diagnosis is crucial for optimal management of patients with cancer. For the approximately 100 known tumour types of the central nervous system, standardization of the diagnostic process has been shown to be particularly challenging - with substantial inter-observer variability in the histopathological diagnosis of many tumour types. Here we present a comprehensive approach for the DNA methylation-based classification of central nervous system tumours across all entities and age groups, and demonstrate its application in a routine diagnostic setting. We show that the availability of this method may have a substantial impact on diagnostic precision compared to standard methods, resulting in a change of diagnosis in up to 12% of prospective cases. For broader accessibility, we have designed a free online classifier tool, the use of which does not require any additional onsite data processing. Our results provide a blueprint for the generation of machine-learning-based tumour classifiers across other cancer entities, with the potential to fundamentally transform tumour pathology.

Background Data on frequency, clinical presentation, and outcome of primary metastatic intracranial ependymoma in children are scarce. Patients and Methods Prospective data on patients younger than 21 years with metastatic intracranial ependymoma at first diagnosis, registered from 2001 to 2014 in the HIT-2000 trial and the HIT-2000 Interim Registry, were analyzed. Results Of 453 registered patients with intracranial ependymoma and central neuropathology review, initial staging included spinal magnetic resonance imaging in all patients and lumbar cerebrospinal fluid (CSF) analysis in 402 patients. Ten patients (2.2%) had metastatic disease, including three with microscopic CSF positivity only (M1 metastasis stage, 0.7% of patients with CSF staging). Location of the primary tumor was supratentorial in four patients (all supratentorial RELA-fused ependymoma [ST-EPN-RELA]) and within the posterior fossa in five patients (posterior fossa ependymoma type A [PF-EPN-A], n = 4; posterior fossa ependymoma not further classifiable, n = 1), and multifocal in one patient. All four patients with ST-EPN-RELA were alive in first or second complete remission (CR) 7.5–12.3 years after diagnosis. All four patients with macroscopic metastases of posterior fossa or multifocal ependymoma died. Three patients with initial M1 stage (ST-EPN-RELA, n = 1; PF-EPN-A, n = 2) received chemotherapy and local irradiation and were alive in second or third CR 3.0–9.7 years after diagnosis. Progression-free and overall survival of the entire cohort at 5 years was 13% (±6%), and 58% (±16%), respectively. Conclusion Primary metastatic disease is rare in children with intracranial ependymoma. Prognosis may depend on molecular subgroup and extent of dissemination, and relevance of CSF analysis for initial staging remains to be clarified. Implications for Practice Childhood ependymoma presenting with metastasis at first diagnosis is very rare with a frequency of 2.4% in this population-based, well-characterized cohort. Detection of microscopic metastases in the cerebrospinal fluid was extremely rare, and impact on prognosis and respective treatment decision on irradiation field remains unclear. Initial metastatic presentation occurs in both supratentorial RELA-fused ependymoma and posterior fossa ependymoma. Prognosis may differ according to extent of metastasis and biological subgroup, with poor prognosis in diffusely spread metastatic posterior fossa ependymoma even after combination therapy with both intensive chemotherapy and craniospinal irradiation, which may help to guide individual therapeutic decisions for future patients.

The prognosis for pediatric ependymoma remains unaffected by recent discovery. Upfront therapy is maximal surgical resection followed by radiation and the utility of histologic diagnosis remains unreliable. Nine molecular subgroups and possible genetic drivers of ependymoma have been identified, but the implementation of these findings into targeted therapy and stratified clinical trials has not occurred. It is imperative that researchers work collaboratively to move discovery towards clinical testing. Heterogeneity of ependymoma requires that we collect a large amount of data; progress in the field is dependent on deep analysis of this information. As we further subclassify ependymoma, it will be important to have a large patient population for enrollment onto clinical trials, which will maximize data collection and the amount of materials available for experimentation and analysis. Researchers in the United States, Europe, and Japan propose an international ependymoma research collaborative which aims to synthesize research across sites, foster drug discovery, and prove strategies to integrate clinical and molecular diagnostics into biology-based therapy. Our goal is to maximize information and materials from existing bio and data repositories and not to ‘re-create the wheel’. We envision PEDS as an open science platform and present this concept at ISPNO to invite our colleagues to harmonize efforts towards pediatric ependymoma discovery.

Korrespondenz zu 10.1016/j.ijrobp.2019.08.005

In general patients with congenital rhabdoid tumors (RT) are considered to be incurable and often treated using a primarily palliative approach. METHODS: A pro- and retrospective collection of 42 patients from EU-RHAB, France and Moscow (2006 to 2016) diagnosed within the first 28 days of life was evaluated. Genetic and clinical evaluation included SMARCB1 and/or SMARCA4 (FISH, MLPA, sequencing) mutation analysis and immunohistochemistry. 48% (20/42) were treated according to the EU-RHAB recommendations, 7% (3/42) following the pilot approach Rhabdoid 2007, 33% (14/42) with individual schedules and 12% (5/42) received no chemotherapy. RESULTS: 40.5% (17/42) of patients presented with extracranial RT, 33.5% (14/42) with AT/RT and the remainder 26% (11/42) demonstrated synchronous tumors. Metastases at diagnosis were present in 52% (22/42). A germ-line mutation (GLM) was detected in 66% (25/38) and associated with a poor prognosis (4.2 ± 4.1% vs. 48 ± 16.4%, p

The 'Individualized Therapy for Relapsed Malignancies in Childhood' (INFORM) precision medicine study is a nationwide German program for children with high-risk relapsed/refractory malignancies, which aims to identify therapeutic targets on an individualised basis. In a pilot phase, reported here, we developed the logistical and analytical pipelines necessary for rapid and comprehensive molecular profiling in a clinical setting. Fifty-seven patients from 20 centers were prospectively recruited. Malignancies investigated included sarcomas (n = 25), brain tumours (n = 23), and others (n = 9). Whole-exome, low-coverage whole-genome, and RNA sequencing were complemented with methylation and expression microarray analyses. Alterations were assessed for potential targetability according to a customised prioritisation algorithm and subsequently discussed in an interdisciplinary molecular tumour board. Next-generation sequencing data were generated for 52 patients, with the full analysis possible in 46 of 52. Turnaround time from sample receipt until first report averaged 28 d. Twenty-six patients (50%) harbored a potentially druggable alteration with a prioritisation score of 'intermediate' or higher (level 4 of 7). Common targets included receptor tyrosine kinases, phosphoinositide 3-kinase-mammalian target of rapamycin pathway, mitogen-activated protein kinase pathway, and cell cycle control. Ten patients received a targeted therapy based on these findings, with responses observed in some previously treatment-refractory tumours. Comparative primary relapse analysis revealed substantial tumour evolution as well as one case of unsuspected secondary malignancy, highlighting the importance of re-biopsy at relapse. This study demonstrates the feasibility of comprehensive, real-time molecular profiling for high-risk paediatric cancer patients. This extended proof-of-concept, with examples of treatment consequences, expands upon previous personalised oncology endeavors, and presents a model with considerable interest and practical relevance in the burgeoning era of personalised medicine.