Search

The Beckwith–Wiedemann spectrum (BWSp) ranges from isolated lateralized overgrowth (ILO) to classic phenotypes. In this broad clinical spectrum, an epigenetic alteration on chromosome 11p15.5 can be detected. The risk for embryonal tumors is high, especially in patients with lateralized overgrowth (LO). The aim of this study is to investigate epigenetic alterations in 11p15.5 and tumor risk in 87 children with LO. The methylation level of 11p15.5 was examined in the blood of all patients and in skin samples or buccal swabs from 40 patients with negative blood tests; 63.2% of patients were compatible with the ILO phenotype, 18.4% were atypical, and 18.4% were classic. The molecular diagnosis rate was 81.2% for the atypical and classic phenotypes, and 10.9% for the ILO phenotype. In patients with epigenetic alterations, LO was statistically significantly more severe than in test negatives. Tumors developed in six (6.9%) of the total 87 patients with LO; four belonged to the atypical or classical phenotype (12.5%) and two to ILO (3.5%). Three of the four patients with atypical/classical phenotypes had pUPD11, one had IC1-GOM alteration, and two ILO patients were negative. We conclude that LO patients should be monitored for tumor risk even if their epigenetic tests are negative.

Tumor thrombosis of the central venous system in children with embryonal tumors is a rare complication, requiring a comprehensive treatment approach, with chemotherapy and the intervention of a multidisciplinary team of oncologists and cardiac surgeons. The article describes the medical history of a 9-month-old patient with bilateral nephroblastoma and tumor thrombosis of inferior vena cava and right atrium, as well as provides a brief review of the literature. The patient's parents gave their consent to the use of their child's data, including photographs, for research purposes and in publications.

Simple Summary: Individuals treated for brain tumors in childhood are at high risk of cognitive and other late complications. The aim of this nationwide registry study was to explore further education following the nine years of compulsory school in Sweden in teenagers and young adults treated for childhood brain tumors. Individuals treated for embryonal tumors, low grade astrocytomas, optic pathway gliomas, craniopharyngiomas, and neuronal and mixed neuronal-glial tumors, were analyzed separately. All individuals treated for brain tumors were compared to about five times as many matched controls without cancer diagnoses or treatments. Our results demonstrate significant differences between cases and controls regarding attendance in high school, folk high school, and university. Individuals treated for embryonal tumors or optic pathway gliomas attended post-compulsory education less frequently than other analyzed diagnoses. There was a positive correlation between parental education levels and attendance in high school and university for both cases and controls. The risk of late complications after a brain tumor in childhood is high. Both the tumor itself and the treatments give rise to sequelae that affect daily life activities. In this registry study, we explored post-compulsory education, i.e., further education following the nine compulsory years in school, in 452 cases born 1988-1996 and diagnosed with a brain tumor before their fifteenth birthday. They were compared with 2188 individual controls who were not treated for cancer. Significantly fewer teenagers and young adults treated for brain tumors in childhood attended high school or university compared with controls, especially individuals treated for embryonal tumors or optic pathway gliomas. A significantly larger proportion of subjects treated for embryonal tumors and craniopharyngiomas attended folk high schools, a type of post-compulsory school with a more accessible learning environment. For both cases and controls, we observed a positive correlation between parental education levels and attendance in high school and university. In our previous studies we have shown that children treated for brain tumors, as a group, tend to perform worse during their last year of compulsory school compared with their peers, and the current study confirms that these differences remain over time.

Embryonal tumors with multilayered rosettes (ETMR) are highly aggressive tumors occurring in early childhood. Published clinical data refer to retrospective, heterogeneously treated cohorts. Here, we describe the outcome of patients treated according to the prospective P-HIT trial and subsequent HIT2000-interim-registry.Age-stratified treatment included carboplatin/etoposide induction, tandem high-dose chemotherapy ("CARBO/ETO + HDCT"), and response-stratified radiotherapy. Patients with centrally reviewed neuropathological and molecularly confirmed diagnosis of ETMR recruited within the P-HIT trial (2001-2011; n = 19), the HIT2000-interim-registry (2012-2014; n = 12), and earlier HIT trials (n = 4) were selected for analysis.Age-adjusted incidence rate was 1.35 per 1 million children (aged 1-4 years) in the years 2012-2014. Median age at diagnosis for 35 patients was 2.9 years. Metastases at diagnosis were detected in 9 patients. One patient died due to postoperative complications. For 30 patients with non-brainstem tumor location, 5-year progression-free survival (PFS) and overall survival (OS) were 35% and 47% after treatment with CARBO/ETO + HDCT (n = 17), compared to 0% and 8% with other treatments (n = 13, P[OS] = .011). All 4 patients with brainstem tumor died within 10 months after diagnosis. By multivariable analysis, supratentorial location: (HR [PFS]: 0.07 [95%CI: 0.01-0.38], P = .003), localized disease (M0): (HR [OS] M0, no residual tumor: 0.30 [95%CI: 0.009-1.09], P = .068; M0, residual tumor: 0.18 [95%CI: 0.04-0.76], P = .020), and CARBO/ETO + HDCT treatment (HR [OS]: 0.16 [95%CI: 0.05-054], P = .003) were identified as independent prognostic factors. Of 9 survivors, 6 were treated with radiotherapy (craniospinal 4; local 2).Our data indicate improved survival with intensified chemotherapy (CARBO/ETO + HDCT). However, despite intensive treatment, the outcome was poor. Thus, innovative therapies need to be evaluated urgently in an upfront setting.

Central nervous system tumors comprise 26% of cancer in children, representing the most frequent solid neoplasms. Embryonal tumors comprise 15% of them, and they are defined as "small round blue cells" in which morphology is reminiscent of the developing embryonic nervous system. They are the most common high-grade central nervous system neoplasms. Over the years, molecular research has been improving our knowledge concerning these neoplasms, stressing the need for tumor reclassification. Indeed, the revised 2016 fourth edition of the World Health Organization classification introduced genetic parameters in the classification. Specific molecular signatures allow a more accurate risk assessment, leading to proper therapeutic approach and potentially improved prognosis. Holding this new approach, medulloblastoma is noteworthy. The present classification combines the previous histologic classification with a new genetic definition in WNT-activated, sonic hedgehog-activated and non-WNT/non-sonic hedgehog. Molecular data are also a defining feature in the diagnosis of atypical teratoid/rhabdoid tumors and embryonal tumors with multilayered rosettes. However, there are still embryonal tumors that challenge the present World Health Organization classification, and new molecular data have been underlining the need for novel tumor entities. Likewise, recent research has been highlighting heterogeneity in recognized entities. How to translate these molecular developments into routine clinical practice is still a major challenge.

Introduction: Embryonal brain tumors (EBTs) are highly aggressive malignancies predominantly affecting children. They include medulloblastoma (MB), atypical rhabdoid/teratoid tumors (ATRT), pineoblastoma (PB), embryonal tumor multiple rosettes (ETMR)/C19MC-altered tumors, and newly recognized embryonal tumors with FOXR2 activation or BCOR alteration.Areas covered: This review will provide a comprehensive overview and updated of the literature on each of these EBTs. The evolution from location- and histopathology-based diagnosis to more specific and robust molecular-based classification schemes, as well as treatment modalities, will be discussed.Expert commentary: The subgrouping of EBTs with multi-omic profiling has had important implications for risk stratification and discovery of targetable driver pathways. However, these innovations are unlikely to significantly improve survival among high-risk patients until robust preclinical studies are conducted, followed by validation in biology-informed clinical trials.

Minimally invasive surgery (MIS) to resect primary and metastatic pediatric embryonal tumors offers the potential for reduced postoperative morbidity with smaller wounds, less pain, fewer surgical site infections, decreased blood loss, shorter hospital stays, and less disruption to treatment regimens. However, significant controversy surrounds the question of whether a high-fidelity oncologic resection of childhood embryonal tumors with gross total resection, negative margins, and appropriate lymph node sampling can be achieved through MIS. This review outlines the diverse applications of MIS to treat definitively pediatric embryonal malignancies, including this approach to metastatic deposits. It outlines specific patient populations and presentations that may be particularly amenable to the minimally invasive approach. This work further summarizes the current evidence supporting the efficacy of MIS to accomplish a definitive, oncologic resection without compromising relapse-free or overall survival. Finally, the review offers technical considerations to consider in order to achieve a safe and complete resection.

Rhabdomyosarcoma (RMS) arises from abnormal muscle development. We reported previously that Fragile-X-Related 1 (FXR1), essential to normal myogenesis, was highly expressed in RMS relative to other embryonal tumors. This current study explored FXR1 expression across RMS disease characteristics and treatment response.RMS patients ≤18 years (1980-2019; n = 152) were categorized according to tumor histology, PAX/FOXO1 translocation, and vital status. FXR1 protein expression was compared before and after chemotherapy. Impact of FXR1 expression on relapse-free (RFS) and overall survival (OS) was analyzed.FXR1 was most intensely expressed in the cytosol of undifferentiated rhabdomyoblasts. At diagnosis, FXR1 expression was ubiquitous and strong across all disease characteristics and foremost associated with worse RFS in translocation-positive patients (p = 0.0411). Among embryonal and translocation-negative RMS, survivors showed a significantly greater decrease in FXR1 expression after chemotherapy (p 0.001) compared to decedents (p = 0.8). In contrast, alveolar and translocation-positive RMS specimens showed insignificant changes in FXR1 expression across therapy. As expected, alveolar histology, translocation presence, stage, and clinical group associated with worse survival.FXR1 was expressed strongly across RMS specimens at diagnosis regardless of disease or patient characteristics, and particularly in undifferentiated cells. Reduction in FXR1 expression after chemotherapy associated with improved survival for embryonal and translocation-negative RMS patients.

Purpose of review This review aims to give an update on histopathological, molecular and clinical features of central nervous system (CNS) 'embryonal' tumors. Recent findings The taxonomy of previously called 'CNS primitive neuroectodermal tumor' (CNS PNET) has been deeply modified since the discovery of specific molecular profiles for each various sub-entity of these rare, mainly pediatric, tumors. The term 'embryonal tumors' now refers to medulloblastomas, atypical teratoid rhabdoid tumors (AT/RT) and other rare entities, defined by their specific histopathological features together with expression-based or methylation-based profiling; specific gene mutations or fusions characterize some tumor types. In addition, the compilation of large series of molecular data has allowed to dissecting several of these tumor types in molecular subgroups, increasing the number of tumor entities, and leading to an amazingly complex nosology of rare-to-extremely rare malignancies. This rarity precludes from having strong evidence-based therapeutic recommendations, although international efforts are conducted to define the best treatment strategies. Summary Embryonal tumors now correspond to molecularly well defined entities, which deserve further international collaborations to specify their biology and the appropriate burden of treatment, in order to minimize the long-term side-effects of treatment of these overall rare and severe diseases of childhood.

Background: Embryonal tumors represent a heterogeneous entity of brain tumors that need a multidisciplinary treatment including cranio-spinal irradiation (CSI), with a known impact on the acute toxicity. Proton therapy (PT) boasts a reduction in acute hematological toxicity. Methods: We retrospectively examined 20 pediatric patients affected by high-risk medulloblastoma and other rare embryonal brain tumors subjected to CSI with PT from September 2016 to April 2020. Before CSI, all patients received induction chemotherapy, and three patients additionally received two high-dose courses with thiotepa, followed by an autologous haemopoietic stem cell transplantation. We recorded the total white blood cell count, absolute neutrophil count, platelets, and hemoglobin levels for all patients during PT. Results: Leucocytes and neutrophils decreased directly after the beginning of treatment, reaching a complete recovery at the end of treatment. Hemoglobin values remained constant over the treatment course. The median platelet value decreased until reaching a plateau around halfway through therapy, followed by a slow increase. No cases of febrile neutropenia or severe infections were reported. No treatment discontinuation due to hematological toxicity was necessary. Conclusions: CSI with PT was proven to be safe in this setting of pediatric patients. Our study showed that despite all patients having undergone chemotherapy prior to irradiation, no serious hematological toxicity was reported at the end of the treatment with PT, and, therefore, no treatment was discontinued or delayed.

Hyperactivation of Sonic Hedgehog (SHH) signaling pathway drives tumor progression in the largest medulloblastoma subgroup. During cerebellar development, promoters of SHH target genes show inhibitory trimethylation of histone H3 at lysine 27 (H3K27me3), mediated by the Polycomb Repressive Complex 2 (PRC2). Here, we explored the regulation of cerebellar growth and medulloblastoma tumorigenesis by PRC2 complex components EED and EZH2. For developmental studies, we conditionally deleted Eed or Ezh2 in the Atoh1 lineage that gives rise to the cerebellar granule neuron progenitors (CGNP) that are cells of origin for SHH medulloblastomas. For tumor studies, we bred the conditional Eed- or Ezh2-deleted mouse lines with mice genetically engineered to develop SHH medulloblastoma. Our developmental studies showed that Eed was absolutely required for cerebellar growth. Eed-deleted CGNPs underwent aberrant, myocyte-like differentiation and spontaneous apoptosis, resulting in cerebellar hypoplasia. In contrast, Ezh2 deletion produced no developmental phenotype, despite blocking all H3K27me3 in CGNPs. Our tumor studies showed that Eed-deleted medulloblastomas similarly showed aberrant, myocyte differentiation, but unlike CGNPs, did not undergo widespread apoptosis. Eed-deleted medulloblastomas progressed more rapidly than control tumors, indicating that the inappropriate, muscle-like differentiation did not slow tumor growth. Ezh2-deleted medulloblastomas similarly progressed more rapidly than controls. Our data show that the PRC2 complex acts to enforce neuronal lineage commitment in both development and tumorigenesis and to restrain tumor growth in SHH medulloblastoma. Myocyte differentiation in Eed-deleted tumors suggests that PRC2 loss of function may contribute to the medullomyoblastomas that have been observed in patients. The differences in developmental phenotype show that EZH2 and EED functions are non-identical and can be dissociated, while similar increase in tumor progression show tumor suppressive functions for both EED and EZH2.

Introduction KIF11, a mitotic kinesin, is a component responsible for assembly and maintenance of mitotic spindle during mitosis. Tumor cells can upregulate KIF11. Inhibition of KIF11 results monopolar spindle formation, resulting in monoastral mitosis in cells. This activates the spindle assembly checkpoint, cells are arrested and prevented from entering cell cycle, resulting in cell death via apoptosis or necrosis, cell division with aneuploidy or mitotic slippage without division into tetraploid G1 phase. Methods We hypothesized that the effect of KIF11 inhibition on medulloblastoma (MB) is dependent of its p53 mutational status. Results Our findings on Hoechst staining demonstrated a small molecule inhibitor of KIF11 which induced apoptosis in p53-wildtype MB cells at 48h (p Conclusions Our results suggest that when mitotic arrest is induced, p53-mutant MB cells undergo mitotic catastrophe and necrosis while p53-wildtype MB cells predominantly undergo apoptosis.

Case Presentation A 3-year-old female with insignificant past medical history presented with 6 weeks of headaches, emesis, and lethargy. MR imaging identified a heterogeneously enhancing right cerebellar hemispheric mass and obstructive hydrocephalus. Gross total resection was performed without complications; pathology revealed classical WHO grade 4 medulloblastoma (MB). MR imaging of the spine and cerebrospinal fluid testing were negative for disseminated disease. Treatment for standard risk medulloblastoma was initiated, comprising proton craniospinal irradiation with posterior fossa boost and concurrent vincristine, followed by adjuvant chemotherapy with vincristine, lomustine, cisplatin, and cyclophosphamide as standard of care. Next generation sequencing of the tumor tissue performed using a high-multiplex PCR-based NGS panel was negative for alteration of the SMO, PTCH1 and CTBNN1 genes. Further molecular characterization via methylation profiling demonstrated the sonic hedgehog (SHH) molecular subtype. Prior to initiation of chemotherapy, renal ultrasound was performed and identified congenitally absent right kidney; audiology evaluation was unremarkable. Discussion In patients with Gorlin syndrome, cases of unilateral renal agenesis in association with germline SHH-pathway mutations have been reported [1]. SHH signaling is implicated in multiple steps in the development of the urinary system [2]. Outside Gorlin syndrome, however, to the best of our knowledge unilateral renal agenesis coinciding with SHH-driven MB has not been reported. Our patient notably lacks any clinical stigmata of Gorlin syndrome (skeletal abnormalities, skin pits, macrocephaly) and does not exhibit the characteristic germline genetic abnormalities that define GS (PTCH1 mutation or 9q22.3 microdeletion). There are important treatment implications for patients with the constellation of abnormalities we describe here, particularly regarding the requisite frequent monitoring of renal function during multi-agent chemotherapy courses. Our patient tolerated chemoradiation well, and is currently on maintenance chemotherapy with favorable course to date.

Medulloblastoma (MB) accounts for 20% of diagnosed brain tumors in children. Group 3 (G3) MB subtype is the most aggressive. Molecularly, G3 MB is characterized by MYC overexpression, which drives elevated mRNA translation in tumor cells. PERK is an eukaryotic translation initiation factor 2 (eIF2α) kinase that inhibits mRNA translation under endoplasmic reticulum (ER) stress conditions, such as in response to accumulation of unfolded proteins. When unfolded proteins accumulate in the ER, activated PERK phosphorylates eIF2α. This shuts down global translation and triggers integrated stress response (ISR) to help cells adapt through selective translation of mRNA encoding pro-survival proteins. High mRNA expression of PERK correlates with poor survival in G3 MB patients. In vitro, combination of ER or hypoxic stress with PERK knockdown induces apoptosis in MB cells. ISRIB is an ISR inhibitor that maintains translation rates despite eIF2α phosphorylation. Combining ISRIB with stress such as hypoxia induces apoptosis in MB cells and prevents accumulation of key ISR mediators such as ATF4. In addition, combination of ISRIB and hypoxia induces oxidative stress. Current G3 MB treatment regimens include vincristine, a known ISR inducer. Combination of ISRIB with vincristine amplifies vincristine-induced apoptosis, potentially suggesting novel therapeutic approach for MB. Our findings show that inhibition of ISR in G3 MB represents a powerful inducer of cancer cell death.

Medulloblastoma (MB) is a heterogeneous disease in which neoplastic cells and associated immune cells contribute to disease progression. To better understand cellular heterogeneity in MB we used single-cell RNA sequencing, immunohistochemistry and deconvolution of transcriptomic data to profile neoplastic and immune populations in childhood MB samples and MB genetically engineered mouse models (GEMM). Neoplastic cells clustered primarily according to individual sample of origin which is in part due to the effect of chromosomal copy number gains and losses. Harmony alignment of single cell transcriptomic data revealed novel MB subgroup/subtype-associated subpopulations that recapitulate neurodevelopmental processes and are associated with clinical outcomes. This includes photoreceptor-like cells and glutamatergic lineage unipolar brush cells in both GP3 and GP4 subgroups of MB, and a SHH subgroup nodule-associated neuronally-differentiated cell subpopulation. We definitively chart the spectrum of MB immune cell infiltrates, which reveals unexpected degree of myeloid cell diversity. Myeloid subpopulations include subgroup/subtype-associated developmentally-related neuron-pruning as well as antigen presenting myeloid cells. Human MB cellular diversity is recapitulated in subgroup-specific MB GEMM, supporting the fidelity of these models. These findings provide a clearer understanding of both the neoplastic and immune cell heterogeneity in MB and how these impact subgroup/subtype classification and clinical outcome.

Medulloblastoma (MB) is the most common malignant pediatric brain tumor that can be categorized into four major molecular subgroups. Group 3 MB with MYC amplifification (MYCamp-G3-MB) has been shown to be highly aggressive and exhibited worst prognosis, indicating the need for novel effective therapy most urgently. A few epigenetic targeted therapeutic strategies have recently been proven to effectively treat preclinical models of MYCamp-G3-MB, including BET inhibition, HDAC inhibition and SETD8 inhibition, unveiling a promising direction for further investigation. In this study, we carried out systemic bioinformatic analyses of public-available MB datasets as well as functional genomic screening datasets of primary MYCamp-G3-MB lines to search for other potential therapeutic targets within epigenetic modulators. We identifified SSRP1, a subunit of histone-chaperone FACT complex, to be the top drug target candidate as it is highly cancer-dependent in whole-genome CRISPR-Cas9 screening across multiple MYCamp-G3-MB lines; signifificantly upregulated in MYCamp-G3-MB compared to normal cerebellum and most of the rest MB subtypes; its higher expression is correlated with worse prognosis; and it has a blood-brain-barrier penetrable targeted drug that has entered early phase human clinical trials already. Then we utilized RNA-interference approach to verify the cancer-dependency of SSRP1 in multiple MYCamp-G3-MB lines and further confifirmed the therapeutic effificacy of FACT-targeted curaxin drug CBL0137 on treating preclinical models of MYCamp-G3-MB in vitro and in vivo, including an orthotopic intracranial xenograft model. Mechanistically, transcriptome analyses showed CBL0137 preferentially suppressed cell-cycle and DNA-repair related biological processes. Moreover, it selectively disrupted transcription of MYC and NEUROD1, two critical oncogenic transcription factors of MYCamp-G3-MB, via depleting FACT complex from their promoter regions. In summary, our study demonstrates FACT-targeted CBL0137 works effectively on treating MYCamp-G3-MB, presenting another promising epigenetic-targeted therapeutic strategy against the most devastating form of MB.

// Simone Treiger Sredni 1, 2, 3 , Anders W. Bailey 1, 3, * , Amreena Suri 1, 3, * , Rintaro Hashizume 4 , Xingyao He 4 , Nundia Louis 4 , Tufan Gokirmak 5 , David R. Piper 5 , Daniel M. Watterson 6 and Tadanori Tomita 1, 2 1 Ann and Robert H. Lurie Children’s Hospital of Chicago, Division of Pediatric Neurosurgery, Chicago, IL 60611, USA 2 Northwestern University, Feinberg School of Medicine, Department of Surgery, Chicago, IL 60611, USA 3 Stanley Manne Children’s Research Institute, Cancer Biology and Epigenomics, Chicago, IL 60614, USA 4 Northwestern University, Feinberg School of Medicine, Department of Neurological Surgery, Chicago, IL 60611, USA 5 Thermo Fisher Scientific, Research and Development, Biosciences Division, Carlsbad, CA 92008, USA 6 Northwestern University, Feinberg School of Medicine, Department of Pharmacology, Chicago, IL 60611, USA * These authors have contributed equally to this work Correspondence to: Simone Treiger Sredni, email: ssredni@luriechildrens.org Keywords: embryonal tumors; CNS; AT/RT; RTK; polyploidy Received: October 10, 2017 Accepted: November 05, 2017 Published: November 24, 2017 ABSTRACT Rhabdoid tumors (RT) are highly aggressive and vastly unresponsive embryonal tumors. They are the most common malignant CNS tumors in infants below 6 months of age. Medulloblastomas (MB) are embryonal tumors that arise in the cerebellum and are the most frequent pediatric malignant brain tumors. Despite the advances in recent years, especially for the most favorable molecular subtypes of MB, the prognosis of patients with embryonal tumors remains modest with treatment related toxicity dreadfully high. Therefore, new targeted therapies are needed. The polo-like kinase 4 (PLK4) is a critical regulator of centriole duplication and consequently, mitotic progression. We previously established that PLK4 is overexpressed in RT and MB. We also demonstrated that inhibiting PLK4 with a small molecule inhibitor resulted in impairment of proliferation, survival, migration and invasion of RT cells. Here, we showed in MB the same effects that we previously described for RT. We also demonstrated that PLK4 inhibition induced apoptosis, senescence and polyploidy in RT and MB cells, thereby increasing the susceptibility of cancer cells to DNA-damaging agents. In order to test the hypothesis that PLK4 is a CNS druggable target, we demonstrated efficacy with oral administration to an orthotropic xenograft model. Based on these results, we postulate that targeting PLK4 with small-molecule inhibitors could be a novel strategy for the treatment of RT and MB and that PLK4 inhibitors (PLK4i) might be promising agents to be used solo or in combination with cytotoxic agents.

// Giovanni Morana 1, * , Cesar Augusto Alves 1, 2, * , Domenico Tortora 1 , Mariasavina Severino 1 , Paolo Nozza 3 , Armando Cama 4 , Marcello Ravegnani 4 , Gabriella D’Apolito 5 , Alessandro Raso 4 , Claudia Milanaccio 6 , Claudia da Costa Leite 2 , Maria Luisa Garre 6 and Andrea Rossi 1 1 Neuroradiology Unit, Istituto Giannina Gaslini, Genova, Italy 2 Radiology Institute, Hospital das Clinicas, Sao Paulo, Brazil 3 Pathology Unit, Istituto Giannina Gaslini, Genova, Italy 4 Neurosurgery Unit, Istituto Giannina Gaslini, Genova, Italy 5 Neuroradiology Unit, Ospedale M. Bufalini, Cesena, Italy 6 Neuro-Oncology Unit, Istituto Giannina Gaslini, Genova, Italy * co-first authorship Correspondence to: Giovanni Morana, email: giovannimorana@gaslini.org Keywords: DWI, CNS embryonal tumors, medulloblastoma, ATRT, relapse Received: February 17, 2017 Accepted: June 16, 2017 Published: July 25, 2017 ABSTRACT Diffusion weighted imaging (DWI) has an established role in primary CNS embryonal tumor (ET) characterization; however, its diagnostic utility in detecting relapse has never been determined. We aimed to compare DWI and conventional MRI sensitivity in CNS ET recurrence detection, and to evaluate the DWI properties of contrast-enhancing radiation induced lesions (RIL). Fifty-six patients with CNS ET (25 with disease relapse, 6 with RIL and 25 with neither disease relapse nor RIL) were retrospectively evaluated with DWI, conventional MRI (including both T2/FLAIR and post-contrast images), or contrast-enhanced MR imaging (CE-MRI) alone. MRI studies were independently reviewed by two neuroradiologists for detection and localization of potential brain relapses. Sensitivity for focal relapse detection was calculated for each image set on a lesion-by-lesion basis. A descriptive per subject analysis was also performed. Evaluation of follow-up MRI studies served as standard of reference. Focal recurrence detection sensitivity of DWI (96%) was significantly higher than conventional MRI (77%) and CE-MRI alone (51%) (p=0.0003 and p

Embryonal tumors are a heterogeneous group of central nervous system (CNS) tumors whose subgroups have varying incidence and outcome. Despite these differences, they are often grouped as a single entity for study purposes. To date, there are no Canadian multi-institutional studies examining the incidence and outcome of all embryonal subtypes. The current study is an observational study reviewing embryonal tumors in all patients less than 36 months of age diagnosed with a CNS tumor in Canada from 1990 to 2005. Embryonal tumors accounted for 26.9% of all CNS tumors. Medulloblastomas were the highest proportion of the embryonal tumors at 61.5%. Atypical teratoid/rhabdoid tumors (AT/RT) had the second highest proportion of embryonal tumors at 18%. The proportion of primitive neuroectodermal tumors (PNET) was 16%, with 2.6 and 1.9% for congenital medulloepithelioma and ependymoblastoma tumors, respectively. AT/RT and PNET were more common in younger age groups. Medulloblastoma became more prevalent with increasing age, with its highest prevalence in the 25 to 36 month age group. Survival rates for our Canadian population at 18 and 24 months were 0.74 and 0.68 for medulloblastoma, 0.64 and 0.60 for PNET, and 0.36 and 0.29 for AT/RT, respectively. Overall, our data are comparable with published international rates for embryonal tumors. These incidence and outcome figures can guide future research into these rare tumors.

Article is dedicated on actual section of modern rehabilitology – organization of rehabilitation of patients of first year of life with oncohematological and immunological diseases. Aim of this study was to analyze the work of innovative direction of rehabilitation/abilitation in department of treatment of children of first year of life in Clinical Rehabilitation Research Center “Russkoe pole” of Dmitry Rogachev Center (Rehabilitation Center). Results of analysis confirm the dominance of embryonal tumors in the structure of diseases among 335 patients admitted to department in 2016. Medical help for patients performing by multidisciplinary team composed of employees of Rehabilitation Center and consultative department of Dmitry Rogachev Center. Volume of involvement of each participant of multidisciplinary team to rehabilitation process is determined by the spectrum of clinical problems of a patient. Results allowed authors to conclude that future integration of programs of recover medicine in practice of pediatric hematologists/oncologists provides both improvement of patients’ life parameters and decreasing of “population load” due to increased number of children and adolescents cured of malignant neoplasms.

BACKGROUND Embryonal tumor with multilayered rosettes (ETMR) is a rare, aggressive embryonal central nervous system tumor characterized by LIN28A expression and alterations in the C19MC locus. ETMRs predominantly occur in young children, have a dismal prognosis, and no definitive treatment guidelines have been established. We report on our experience in nine consecutive patients. METHODS Between 2006 and 2017, nine patients were diagnosed with ETMR. Median age was 25 months (5–38), seven were treated for primary diagnosis, two referred with progressing tumors, seven diagnosed prospectively, two retrospectively, five were located supratentorially, three pineal, one in the brainstem. RESULTS Seven patients had a gross total resection, one a partial resection and one a biopsy at initial diagnosis, followed by second resections at progression. Six patients were treated with intensive chemotherapy regimens including high-dose chemotherapy in three patients and all recurred after a median of 6 months (range 2–11) and all except one patient who died after high-dose chemotherapy, succumbed to their disease after a median of 13 months (range 7–28). Two patients were treated with gross total tumor resection, early focal radiotherapy and concomitant temozolomide followed by temozolomide and intrathecal therapy for one year and both are in continuous complete remission 51 and 46 months after diagnosis. CONCLUSION Gross total resection followed by early focal radiotherapy, temozolomide, and intrathecal chemotherapy seem to be superior to intensive chemotherapy including high-dose chemotherapy. Steady progression was observed in both patients with initial biopsy and PR only despite intensive therapy. Radiotherapy at recurrence/progression was not successful.

ETMR, an aggressive disease characterised by C19MC alterations, were previously categorised as various histologic diagnoses. The clinical spectrum and impact of conventional multi-modal therapy on this new WHO diagnostic category remains poorly understood as a majority of ~200 cases reported to date lack molecular confirmation. We undertook comprehensive clinico-pathologic studies of a large molecularly confirmed cohort to improve disease recognition and treatment approaches. Amongst 623 CNS-PNETs patients enrolled in the RBTC registry, 159 primary ETMRs were confirmed based on a combination of FISH (125), methylation analysis (88), SNP and RNAseq (32) analyses; 91% had C19MC amplification/gains/fusions, 9% lacked C19MC alterations but had global methylation features of ETMR NOS. ETMRs arose in young patients (median age 26 months) predominantly as localized disease (M0-72%, M2-3 -18%) at multiple locations including cerebrum (60%) cerebellum (18%), midline structures (6%); notably 10% were brainstem primaries mimicking DIPG. Uni-and multivariate analyses of clinical and treatment details of curative regimens available for 110 patients identified metastatic disease (p=0.002), brainstem locations(p=0.005), extent of surgery, receipt of multi-modal therapy including high dose chemotherapy and radiation (P

BACKGROUND Embryonal tumor with multilayered rosettes (ETMR) is an extremely rare entity characterized by LIN28A expression and alterations in the C19MC locus. ETMRs predominantly occur in young children and have a dismal prognosis. We report on our single institution experience in seven consecutive patients. METHODS Between 2006 and 2016, seven patients were diagnosed with ETMR. Diagnosis was established prospectively by characteristic histopathologic features, LIN28A immunostaining and amplification of the C19MC region in five patients and retrospectively confirmed in two additional patients originally diagnosed as central nervous system primitive neuroectodermal tumor. Tumor location was supratentorial in all patients. Median age at diagnosis was 25 months (range 5–38). Male to female ratio was 1:6. RESULTS All patients received gross total tumor resection and four patients were treated with intensive chemotherapy regimens including high-dose chemotherapy in three patients. Four patients recurred after a median of 6 months (range 2–11 months) and all except one patient who died after high-dose chemotherapy, succumbed to their disease after a median of 13 months (range 7–28 months). Consequently, the two most recent patients were treated with gross total tumor resection, primary focal radiotherapy and concomitant temozolomide followed by temozolomide for one year. Due to the high risk of leptomeningeal dissemination intraventricular chemotherapy was administered to all except one patient. Both patients who were treated with primary focal radiotherapy are in continuous complete remission 41 and 36 months after diagnosis. CONCLUSION Gross total resection followed by early focal radiotherapy, temozolomide, and intrathecal chemotherapy seem to be superior to intensive chemotherapy including high-dose chemotherapy.

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare CNS cancer that typically occurs in children younger than 3 years of age. Histologically, AT/RTs are embryonal tumors that contain a rhabdoid component as well as areas with primitive neuroectodermal, mesenchymal, and epithelial features. Compared to other CNS tumors of childhood, AT/RTs are characterized by their rapid growth, short symptomatic prodrome, and large size upon presentation, often leading to brain compression and intracranial hypertension requiring urgent intervention. For decades, the mainstay of care has been a combination of maximal safe surgical resection followed by adjuvant chemotherapy and radiotherapy. Despite advances in each of these modalities, the relative paucity of data on these tumors, their inherently aggressive course, and a lack of molecular data have limited advances in treatment over the past 3 decades. Recent large-scale, multicenter interdisciplinary studies, however, have significantly advanced our understanding of the molecular pathogenesis of these tumors. Multiple clinical trials testing molecularly targeted therapies are underway, offering hope for patients with AT/RT and their families.

Background The less allowable blood loss and tolerance of intraoperative blood loss of children lead to the high rate of massive blood transfusion in the treatment of brain tumor. The surgical concepts of en bloc resection may contribute to the improvement of brain tumor resection. Objective To investigate the effects of en bloc concept on short outcomes of pediatric brain tumors and factors associated with the application of en bloc concept. Methods According to the surgical concept involved, the patients were divided into three subgroups-complete en bloc concept, partial en bloc concept and piecemeal concept. The matching-comparison (piecemeal group and en bloc group formed from the first two subgroups) was conducted based on age, tumor location, lesion volume, and pathological diagnosis to investigate effect of the en bloc concept on the short-term outcomes. Then the patient data after January 2018, when the en bloc concept was routinely integrated into brain tumor surgery in our medical center, were reviewed and analyzed to find out the predictors associated with the application of en bloc concept. Results In the en bloc group, the perioperative outcomes, including hospital stay (p=0.001), PICU stay (p=0.003), total blood loss(p=0.015), transfusion rate(p=0.005) and complication rate(p=0.039), were all significantly improved. The multinomial logistic regression analysis showed that tumor volume and imaging features, like bottom vessel, encasing nerve or pass-by vessel, finger-like attachment, ratio of “limited line” and ratio of “clear line” remained independent factors for the application of en bloc concept in our medical center. Conclusion This study supports the application of complete or partial en bloc concept in the pediatric brain tumor surgery referring to the preoperative imaging features, and compared with piecemeal concept, en bloc concept can improve the short outcomes without significant increases in neurological complication. Large series and Additional supportive evidence are still warranted.

Background International consensus and the 2021 WHO classification recognize eight molecular subtypes among Group 3/4 medulloblastoma (representing ~60% of tumors). However, very few clinical centers worldwide possess the technical capabilities to determine DNA-methylation patterns or other molecular parameters of high-risk for Group 3/4 tumors. As a result, biomarker-driven risk stratification and therapy assignment constitutes a major challenge in medulloblastoma research. Here, we identify an immunohistochemistry (IHC) marker as a clinically tractable method for improved medulloblastoma risk-stratification. Patients and Methods We bioinformatically analyzed published medulloblastoma transcriptomes and proteomes identifying as a potential biomarker TPD52, whose IHC prognostic value was validated across three Group 3/4 medulloblastoma clinical cohorts (n = 387) treated with conventional therapies. Risk stratification and prediction capability were computed utilizing uni- and multivariate survival analysis. Newly developed risk classifiers including TPD52 IHC were compared to state-of-the-art risk stratification schemes in terms of prediction error, area under the time-dependent receiver operating characteristic (ROC) curves and C-statistic. Biomarker-driven prognostic stratification models identified were cross validated in different cohorts. Results TPD52 IHC positivity represents a significant independent predictor of early relapse and death for Group 3/4 medulloblastoma (HRs between 3.67–26.7 [95% CIs between 1.00–706.23], p = 0.05, 0.017 and 0.0058). Cross-validated survival models incorporating TPD52 IHC with clinical features outperformed existing disease risk-stratification schemes, and reclassified ~50% of patients into more appropriate risk categories. Finally, TPD52 immunopositivity is a predictive indicator of poor response to chemotherapy (HR 12.66 [95% CI 3.53–45.40], p < 0.0001), suggesting important implication for therapeutic choices. Conclusion The current study redefines the approach to risk-stratification in Group 3/4 medulloblastoma. Integration of TPD52 IHC in classification algorithms significantly improves outcome prediction and can be rapidly adopted for risk stratification on a global scale, independently of advanced but technically challenging molecular profiling techniques.

Medulloblastoma (MB) is the most common pediatric central nervous system malignancy. Although the current standard of care leads to ~70% patient survival, the therapies are highly toxic, leading to life-long side effects, and recurrence due to therapeutic resistance is fatal. We sought to investigate mediators of radiation response in mouse models for the Sonic hedgehog (SHH) subgroup MB as well as human cell lines. We previously identified Y-box binding protein 1 (YB1) as a downstream effector of YAP-mediated MB radiation resistance. YB1 is a crucial, yet understudied, protein highly expressed across all 4 subgroups of MB. Through its DNA- and RNA-binding cold shock domain, YB1 mediates both transcriptional and translational changes important for tumor maintenance and therapeutic response. We show that following ionizing radiation, YB1 mediates DNA repair through PARP and that PARP inhibition abrogates YB1-mediated DNA repair in cells overexpressing YB1. Additionally, through its inhibitory effects on p53, YB1 is capable of mediating anti-apoptotic effects in response to genotoxic insult. By targeting YB1 with short hairpin RNA, we show that cells are more amenable to ionizing radiation induced double strand breaks. Additionally, we utilize RNA binding protein immunoprecipitation sequencing to investigate post transcriptional regulation of RNAs bound by YB1. We show that YB1 binds numerous transcripts critical for the identity of early cerebellar progenitor cells, the putative cell of origin for SHH subgroup tumors, in addition to transcripts important for cell cycling and migration.

Medulloblastoma (MB), the most common malignant pediatric brain tumor, often harbor MYC amplifications and arise in the presence of a functional p53 suppressor protein. To elucidate the mechanism behind this inexplicable tumor development we generated an inducible, immunocompetent transgenic mouse model of MYC-driven MB. Tumors driven from the glutamate transporter promoter molecularly resembled aggressive Group 3 MB driven by an enriched photoreceptor program. They developed embryonically in a monoclonal fashion in the presence of a functional unmutated p53 gene. Compared to MYCN-expressing MB driven from the same promoter, we discovered pronounced silencing of the ARF suppressor upstream of p53. We similarly found significant methylation of the ARF promoter in MYC-amplified as compared to MYCN-amplified human MB samples. While MYCN-driven tumor malignancy was more sensitive to ARF depletion, it dramatically increased metastatic spread of MYC-driven tumors. DNMT inhibition could restore ARF levels in MYC-expressing tumors but did not show any therapeutic advantage in tumors in vivo. Computational modeling suggested the HSP90 protein to act as a more specific target and ARF could indeed be restored by the HSP90 inhibitor onalespib that promoted increased survival in our inducible animal model suggesting that HSP90 inhibition could be potentially used in patients affected by MYC-driven ARF-silenced cancer.

Medulloblastoma (MB) is the most common pediatric brain tumor. Of its four distinct molecular subgroups, Group 3 MBs are associated with increased risk of recurrence, metastasis and overall poor patient outcome. In recent years, small molecule inhibitors targeting BMI1 have shown to be efficacious against several types of malignant tumors including pediatric MB. Although in vivo studies provide a promising proof-of-concept for the therapeutic targeting of BMI1 in Group 3 MB, mice that receive treatment eventually succumb to their disease. These results suggest that additional mechanisms may underlie the maintenance of MB and underscores the main obstacle in treating a constantly evolving tumor. After initial preclinical validation of BMI1 inhibitor PTC-596, DNA barcoding clonal tracking technology was leveraged to profile in vivo clonal dynamics of Group 3 MB in response to the established chemoradiotherapy regimen alone and in combination with PTC-596. Comparison of clonal composition of the tumors extracted from the brains and spines post-treatment revealed the persistence of a small number of clones with the ability to escape therapy and drive subsequent tumor expansion. In order to better understand molecular susceptibilities of MB cells post BMI1 inhibition, we undertook an in vitro genome-wide CRISPR/Cas9 screening to identify context-specific MB regulatory pathways to be synergistically targeted along with BMI1. By comparing the results of the in vitro genome wide CRISPR/Cas9 screen to the essential genes in human neural stem cells (hNSCs), we identified several context specific regulators of mTOR, AKT and PLK1 pathways. The combined treatment alongside PTC-596 has demonstrated synergistic efficacy against MB cells with minimal toxicity to hNSCs in vitro and is currently being evaluated in preclinical studies. This study provides the foundation for clinical validation of small-molecule inhibitors synergistic with PTC-596 to improve the durability of remissions and extend survival of patients with treatment-refractory Group 3 MB.

Background Medulloblastoma is a heterogenous disease comprising four molecular subgroups (WNT, SHH, Group 3, and Group 4) with varying outcomes. Excellent long-term survival (>90%) has prompted de-intensification of therapy in WNT-subgroup medulloblastoma globally. FOR-WNT is one such prospective study (CTRI/2017/12/010767) testing the hypothesis that focal conformal radiotherapy (RT) (54Gy/30 fractions/6-weeks) with avoidance of upfront craniospinal irradiation (CSI) followed by standard adjuvant chemotherapy significantly reduces RT-related late toxicity without unduly compromising survival in low-risk WNT-subgroup medulloblastoma (residual tumor Methods Patients with low-risk WNT-subgroup medulloblastoma were enrolled after written informed consent/assent. To ensure patient safety, stopping rules were devised according to group-sequential method. Results Between July 2017 till Feb 2019, seven children of WNT-pathway medulloblastoma were treated with focal conformal RT followed by 6-cycles of adjuvant chemotherapy (cisplatin, cyclophosphamide, and vincristine). One child succumbed to acute renal failure during chemotherapy, while the other 6 patients completed all 6-cycles as planned. Three children were detected with neuraxial failure (supratentorial brain and/or spine) without synchronous local recurrence in the treated tumor-bed on surveillance neuro-imaging between 1.5–2 years from index diagnosis following which the study was terminated prematurely. All 3 children with relapse were treated with salvage CSI (35Gy/21 fractions) with (conformal avoidance of previously treated tumor-bed) plus boost irradiation (10.8-18Gy/6–10 fractions) of metastatic deposits resulting in complete/near complete response and are alive with controlled disease. The other 3 children have not shown any evidence of relapse for over 2-years from index diagnosis and remain on active clinico-radiological surveillance. Conclusion In rigorously defined low-risk WNT-subgroup medulloblastoma, avoidance of upfront CSI is associated with unacceptably high risk of neuraxial failure. A successor study (FOR-WNT 2) incorporating low-dose CSI (18Gy/10 fractions) with similar tumor-bed dose and adjuvant systemic chemotherapy is currently underway.

Medulloblastoma (MB) is the most common pediatric malignant brain tumor and is currently divided into WNT, SHH, Group 3 and Group 4 subtypes. Even with multimodal chemotherapy, radiotherapy and surgery, many children with Group 3 MBs do not survive. We have previously demonstrated an oncogenic role for the RNA-binding protein (RBP) LIN28B in neuroblastoma. LIN28B is a key regulator of let-7 family miRNAs, which in turn inhibit LIN28A/B and other oncogenes. LIN28B has also been found to be upregulated in Wilms tumor, hepatoblastoma, germ cell tumors, leukemia among others. We hypothesize that LIN28B plays an important role in Group 3 MB and that a better understanding of LIN28B and LIN28B-driven networks will reveal novel therapeutic vulnerabilities. LIN28B levels are highest in Group 3 MB patients, and its overexpression is associated with significantly worse survival. Here we demonstrate that down-regulation of LIN28B using shRNA results in significant reduction in cell proliferation by CellTiter-Glo and increased apoptosis by Caspase-Glo (as well as induction of cleaved PARP on immunoblots). In contrast overexpression of LIN28B increases Group 3 cell proliferation and tumor sphere formation The LIN28 inhibitor 1632 also leads to significant reduction in G3 MB cell proliferation. In addition, we find that PDZ-binding kinase (PBK) a downstream target of LIN28B is downregulated when LIN28B is depleted. PBK knock down also leads to decreased proliferation of Group 3 MB cells. Finally RNA-seq profiling following LIN28B depletion reveals additional components of the LIN28B pathway which may be amenable to therapeutic targeting. This work will help define the role for LIN28B in Group 3 MB aggressiveness and establish LIN28B and LIN28B-driven networks as novel therapeutic targets in these patients.

Introduction Resistance to chemotherapy is a common cause of treatment failure in cancer patients and a major problem facing current cancer research. Targeted modulation of oncogenic signaling pathways may be used to systematically characterize drug resistance mechanisms across tumor entities and may help to identify new therapeutic strategies. Since the transcription factor MYC is aberrantly activated in many cancers including pediatric malignant brain tumors, like medulloblastoma (MB), our study focused on MYC-related drug resistance. Methods and Results We performed high-throughput drug screening using our in-house semi-automated platform and identified the HDAC inhibitor Entinostat as a drug that shows promising effects in MYC-driven MB. Investigating genome-wide dCas9-based transcriptional activation screening, potential drug response modulators, mainly TGFB1/Erk/MKNK1 signaling including neural EGFL like 2 (NELL2), were discovered. For further validation, we stably overexpressed NELL2 in MYC-driven MB cells and treated overexpressing cells and the corresponding control cells with Entinostat. Using PI staining, cell cycle status was tracked. Entinostat treatment led to modest induction of cell death in MYC-driven MB control cells but only slightly increased cell death rate in MYC-driven MB cells with NELL2-overexpression. Conclusion We report that the combination of genetic and pharmacological approaches is a powerful approach to study drug resistance. Our data suggest that activation of the TGFB1/Erk/MKNK1 signaling pathway desensitizes MYC-driven MB cells to Entinostat. Synergistic targeting of TGFB1/Erk/MKNK1 signaling and MYC could therefore provide a novel therapeutic option in this aggressive MB subtype.

Medulloblastoma (MB) is the most common malignant pediatric brain tumor and has the potential for leptomeningeal spread, often responsible for the preponderance of morbidity and mortality in MB patients. Adverse sequelae following high dose craniospinal radiation and aggressive chemotherapies, including neurocognitive deficits and endocrine disorders, impairs patient quality of life and thus call for new therapeutic strategies. Panobinostat is a pan-histone deacetylase (HDAC) inhibitor that has been shown to be effective against MBs in vitro. The objective of the current study is to evaluate the key pharmacokinetic (PK) parameters and the mechanisms influencing the brain penetration of panobinostat in the mouse model, often used in MB preclinical efficacy trials. Pharmacokinetic studies were conducted using FVB wild-type (WT) mice and triple-knockout (TKO, Mdr1a/b–/–Bcrp1–/–) transporter-deficient mice. Panobinostat was administered intravenously (10 mg/kg) and concentrations at selected time points in plasma, brain and spinal cord were determined using LC-MS/MS. PK parameters, including systemic clearances, volumes of distribution, half-lives, and areas-under-the-concentration time curve (AUC) were calculated by using non-compartmental analysis. In WT mice, the CNS penetration was initially limited; however, it increased with time and the brain-to-plasma (B/P) and spinal cord-to-plasma (SC/P) distributional partition coefficients (AUC ratios) were 3.7 and 1.4, respectively. The B/P and SC/P ratios of panobinostat in BBB transporter-deficient TKO mice were 1.7- and 2.3-fold higher than those in WT mice, respectively. Our data suggest that P-glycoprotein (P-gp) and/or breast cancer resistance protein (Bcrp) efflux transporters, localized in BBB, may influence the delivery of panobinostat to tumors in the brain following systemic intravenous administration. These systemic and CNS distributional parameters will inform future preclinical efficacy studies of panobinostat for MB. As such, studies investigating other administration routes that can bypass the BBB, such as the intrathecal injection of novel formulations, are ongoing.

Background Medulloblastoma is one of the most common malignant childhood brain tumors and is managed by maximal surgical resection followed by cranio-spinal irradiation and adjuvant chemotherapy. The estimates for survival have not significantly improved over the last two decades, and survivors have an increased risk of poor quality of life. Disease relapse occurs in around 30% of children and survival is less than 20%. Laser interstitial thermal therapy (LITT) is a minimally invasive approach that has been increasingly used to treat brain lesions, particularly for high-risk surgeries. While LITT has been described in a variety of primary brain tumors, including glioblastoma multiforme and metastatic brain tumors, there have been few reports of LITT for recurrent medulloblastoma. Case Description We describe a case of an 11-year-old female with recurrent medulloblastoma first treated at age 5. She initially underwent gross total resection complicated by severe posterior fossa syndrome followed by chemotherapy and radiation (per ACNS0332). She was unfortunately found to have a new enhancing lesion on surveillance imaging 6 years later, and a biopsy confirmed recurrent tumor. Due to morbidity from initial surgery, the family did not wish to pursue further open resection but agreed to proceed with laser ablation as an alternative. She continues on Avastin/irinotecan/TMZ. Surveillance MRI nearly a year later shows a significant reduction in tumor size and enhancement. Conclusion Recurrent medulloblastoma is a highly aggressive tumor that conveys a poor prognosis. LITT offers a less invasive procedure that may serve as an adjunct in treating recurrent tumor or as palliation. Longer term follow-up and additional cases will help understand the efficacy of LITT in recurrent medulloblastoma.

Background Pineoblastoma (PB) is a rare embryonal brain tumour most often diagnosed in young children. To date, no clinical trials have been conducted specific to pediatric PB. Collaborative studies performed over the past 30 years have included PB in studies accruing for other embryonal tumours, primarily medulloblastoma (MB), but also including the entity formerly known as CNS-PNET and atypical teratoid rhabdoid tumors. Each of these studies have included only a small number of children with PB, making clinical features difficult to interpret and determinants of outcome difficult to ascertain. Patients and Methods Published centrally reviewed series with sufficient treatment and outcome data from North American and Australian cases were pooled. To investigate associations between variables, Fisher’s exact and Wilcoxon-Mann-Whitney tests, and Spearman correlations were used as appropriate. Kaplan-Meier plots, log-rank tests, and Cox proportional hazards models were used in survival analysis. Results We describe a 30-year review of the reported clinical features of PB and a pooled centrally reviewed, cohort analysis of cases (n=178) from the Children’s Oncology Group (COG) (n=82) groups and several published, centrally reviewed institutional series (n=96). We find young children Conclusion Given the relative scarcity of this tumor and the emerging data on subgroups of pineoblastoma, prospective, collaborative international studies will be vital to improving the long-term survival of these patients.

“Head Start” 4 (HS 4) is a prospective randomized clinical trial that tailors treatment based on medulloblastoma molecular subgroups and response to induction chemotherapy to compare the efficacy of one versus three (tandem) cycles of myeloablative therapy. Advances in RNA and DNA profiling have identified four core molecular subgroups of medulloblastoma with prognostic significance: Sonic Hedgehog (SHH) subtype, WNT subtype, Group 3, and Group 4. In HS 4 trial, we utilize a combination of histopathology and immunohistochemistry (pathology/IHC), as well as chromosomal microarray analysis (CMA) utilizing OncoScanTM (Thermo Fisher) to classify medulloblastoma samples into either SHH, WNT, or non-WNT/non-SHH (Group 3/4) subgroups at the time of diagnosis. NanoString based 22-gene assay is performed retrospectively to test concordance. We have pathology/IHC, CMA, and NanoString data on 26 infants and young children with medulloblastoma enrolled on HS 4. Pathology/IHC was able to assign samples to SHH, WNT, and non-WNT/non-SHH subgroups in all but two cases: one case was classified as Group 3, and the second as SHH by both CMA and NanoString. CMA was indeterminate in six cases, of which, pathology/IHC was able to assign all six samples aforementioned three subgroups. NanoString was indeterminate in two cases: one case was classified as SHH by CMA and pathology/IHC, and the second case was indeterminate by CMA but was assigned as non-WNT/non-SHH on pathology/IHC. There is excellent correlation between NanoString and combination of histopathology and CMA for core medulloblastoma subgrouping on HS 4. Methylation studies are ongoing.

Background Medulloblastoma (MB) is one of the most common malignant pediatric CNS tumors. Patients with Group 3 MBs harboring MYC amplification exhibit low survival rates. Surviving patients suffer from therapy-induced sequelae, which calls for new targeted therapy strategies. We and others have previously shown the sensitivity of MYC-amplified MB to class I histone deacetylase (HDAC) inhibition. After demonstrating that the MYC target gene PLK1 is significantly downregulated upon class I HDACi treatment, we hypothesized that inhibition of both HDACs and PLK1 could have synergistic effects. Methods Cell metabolic activity changes upon HDAC and PLK1 inhibitor treatment were measured in MYC-amplified and non-amplified MB cell lines, as well as in an additional MYC-inducible cell line. The interaction effect of both inhibitors was determined by computation of the combination index (CI) using the Chou-Talalay method. Results were validated assessing cell viability, cell cycle, and apoptosis induction. Transcription profile changes after combination treatment were evaluated. Results MYC-amplified MB cell lines were more sensitive than non-amplified cell lines to PLK1i treatment, showing IC50 in clinically achievable concentration ranges. Inhibition of class I HDACs and PLK1 synergistically reduced cell metabolic activity in lower concentrations in MYC-amplified compared to non-amplified MB cell lines. We also observed a significant loss of viability and cells in G1 phase, as well as induction of apoptosis after combination treatment in MYC-amplified cells. MYC target gene sets were significantly downregulated in the MYC-amplified cell line HD-MB03 after treatment with combination. We demonstrated reduction of MYC protein levels upon PLK1i treatment. In vivo evaluation of combination treatment using orthotopic Group 3 MYC-amplified MB PDX models is ongoing. Conclusion Our data suggest that MYC-amplification is a predictive marker for PLK1i treatment in MB. The combination of HDACi and PLKi could be a candidate therapy for future clinical trials for MYC-amplified group 3 MB.

Introduction Medulloblastoma (MB) is the most common malignant brain tumour in children. The most frequent molecular subgroup, Group 4 (MBGrp4) accounts for ~35/40% of cases, however it has the least understood underlying biology. Clinical outcomes are heterogeneous in MBGrp4 and are not accounted for by established clinico-pathological risk factors. There is now a requirement for a comprehensive study of MBGrp4, considering established clinico-pathological features and novel molecular biomarkers to enhance risk-stratification and identify novel therapeutic targets. Methods A clinically-annotated, retrospective MBGrp4 discovery cohort (n = 420) was generated from UK CCLG institutions, collaborating European centres and SIOP-UKCCSG-PNET3 and HIT-SIOP-PNET4 clinical trials. Contemporary, multi-omics profiling was performed. Focal and arm level copy number aberrations (CNAs) were determined from molecular inversion probe (MIP) or DNA methylation array which additionally provided next generation non-WNT/non-SHH (Grp3/Grp4) subtype classifications. Targeted next-generation DNA sequencing was performed to overlay the mutational landscape. Survival modelling was carried out with patients >3 years old who received craniospinal irradiation. Results MBGrp4 subtypes were assigned to 88% of tumours with available data. Subtype VIII was strongly associated with i17q (p Conclusion Comprehensive genetic and epigenetic profiling in this large retrospective cohort has improved our understanding of the molecular and clinical heterogeneity within MBGrp4. Incorporation of molecular biomarkers improved risk-stratification for MBGrp4.

Medulloblastoma (MB) is the most common malignant brain tumor of childhood. Despite major advances in our understanding of the biology of MB, novel treatments remain urgently needed. Using a chemical-genomics driven drug repositioning strategy, we identified the cardiac glycoside family of compounds as potential treatments for Group 3 MB. We subsequently demonstrated that single-agent treatment with digoxin prolongs survival in a patient-derived xenograft model (PDOX) of Group 3 MB to a degree comparable to radiation therapy, a mainstay in the treatment of MB. Finally, we examined the mechanism of digoxin-mediated cell killing using RNA-seq. This work identified LHX9, a member of the LIM homeobox family of transcription factors, as the gene most significantly down-regulated following treatment (Huang and Injac et al, Sci Trans Medicine, 2018). Homologs of LHX9 play key roles in cerebellar development via spatially and temporally restricted expression and LHX9 has been proposed as a core transcription factor (TF) in the regulatory circuitry of Group 3 tumors. Loss of function of other core TFs has been shown to impact MB growth. The role of LHX9 in MB, however, has not been previously experimentally evaluated. We now report that knockdown of LHX9 in MB-derived cell lines results in marked growth inhibition. RNA-seq analysis of LHX9-depleted cells showed changes which included alterations in extracellular matrix-receptor interactions and TGFb signaling. These findings raise the possibility that loss of LHX9 plays a major role in digoxin-mediated cell killing and that LHX9 represents a key dependency required for the growth of Group 3 MB. Clinical targeting of core TFs would represent a novel approach to targeting this devastating disease.

Background To investigate the influence of different MRI features on survival in patients with medulloblastoma. Methods A total of 171 patients were included in the study, including 131 pediatric and 40 adults (> 18 years). A set of 16 pre-defined semantic MRI features was analyzed using T1W (pre and post-contrast), T2W, and diffusion-weighted imaging (additional sequences as available). Patients with a definitive event (recurrence) or a minimum follow up of 12 months (in case of no recurrence) were included in the current analysis. All patients were treated and followed up according to standard institutional practice. Log-rank test was used for univariate analysis (UVA) and Cox regression for multivariate analysis (MVA). Results The molecular subgroups were as follows: WNT-27 children, 7 adults; SHH-31 children, 29 adults; group 3–32 children, 3 adults; and group 4–41 children, 1 adult. The median follow up was 45 months (range 1 to 137 months). For all the patients, on UVA the recurrence-free survival (RFS) was significantly (p Conclusion Several MRI features can be linked with survival in patients with medulloblastoma, with a specific impact on individual molecular subgroups. Considering the entire population, non-central location on the vertical aspect, tumors away from brainstem, calcification are risk factors associated with inferior outcomes.

Medulloblastoma (MB) is the most common paediatric malignant brain tumour and is classified into four distinct molecular subgroups (WNT, SHH, G3 and G4), each of them further subdivided into subtypes with different prognosis and responses to therapy. Deregulation of chromatin modifier genes plays an essential role in MB, particularly in the G4 subgroup, the least understood of all subgroups, despite being the most common and associated with poor prognosis. A BMI1High; CHD7Low molecular signature identifies patients with poor survival within this subgroup. We show that BMI1High; CHD7Low mediates a novel epigenetic regulation of inositol metabolism in both G4 MB cells and patients. These tumours display hyperactivation of the AKT/mTOR pathway which leads to energetic rewiring characterized by enhanced glycolytic capacity and reduced mitochondrial function. We demonstrate that inositol administration counteracts this metabolic alteration, impairs MB proliferation in vitro and significantly extends survival in an in vivo pre-clinical model. Moreover, inositol synergises with cisplatin, a chemotherapy agent currently used in MB treatment, enhancing its therapeutic effect in vivo. Importantly, cerebellar neural stem cells bearing the BMI1High; CHD7Low signature do not show metabolic adaptation and are thus resistant to inositol treatment, highlighting a fundamental difference between normal and neoplastic metabolism in the developing cerebellum. In summary, we have identified an actionable vulnerability in a pre-clinical setting modelling a molecularly defined group of MB patients, the translational value of which can now be explored in signature-matched clinical trials in MB.