Embryonal Central Nervous System Research Articles

Central nervous system embryonal tumor with PLAGL1 amplification: a case report of a novel entity focusing on imaging findings.

The embryonal central nervous system (CNS) tumor with PLAGL1 (pleomorphic adenoma gene-like) amplification is a novel type of pediatric neoplasm with a distinct methylation profile, described for the first time in 2022. It may be located anywhere in the neuroaxis and, as its name implies, it is driven by the amplification and overexpression of one of the PLAG family genes. Although the associated clinical, immunohistopathological, and molecular characteristics are well characterized in the seminal report of this entity, data on the radiological features is still lacking. Here, we present a case report of a 4-year-old girl with a biopsy-proven PLAGL1-amplified brainstem tumor and provide a detailed description of the corresponding conventional neuroimaging characteristics, aiming to better delineate this entity and to increase the awareness of this pathology in the radiological community.

P21.05.B CAPTURING EVOLVING DEFINITIONS OF 12 SELECT RARE CNS TUMORS: A TIMELY REPORT FROM CBTRUS AND NCI-CONNECT

Abstract BACKGROUND Histopathology-specific incidence, prevalence, and survival are essential population-based cancer statistics that describe cancer burden. The National Cancer Institute’s Comprehensive Oncology Network Evaluating Rare CNS Tumors (NCI-CONNECT) aims to improve understanding of tumor biology and patient outcomes for 12 selected rare brain and other central nervous system (CNS) tumor types to improve approaches to care and treatment. These types included atypical teratoid/rhabdoid tumor, brainstem and midline gliomas, choroid plexus tumors, ependymomas, high grade meningiomas, gliomatosis cerebri, medulloblastoma, oligodendrogliomas, pineal region tumors, pleomorphic xanthoastrocytomas, CNS embryonal tumors, NEC/NOS and primary CNS sarcoma. The analysis aimed to estimate the incidence (new cases per year), prevalence (currently living cases), and survival rates for these selected rare brain and other CNS tumor types. MATERIAL AND METHODS The Central Brain Tumor Registry of the United States (CBTRUS) data, which contains data from the Centers for Disease Control and Preventions National Program of Cancer Registries (NPCR) and National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) data, from 2008-2019 were used to calculate average annual age-adjusted incidence rates (AAAIR) per 100,000 population overall and by sex, race/ethnicity, and age. Incidence time trends were calculated for diagnosis years 2004-2019. NPCR survival data from 2001-2018 were used to calculate relative survival (RS) estimates. Estimated prevalence counts as of December 31, 2019 were estimated using incidence from CBTRUS and overall survival rates from SEER. RESULTS Overall AAAIR for all 12 subtypes combined was 1.51 per 100,000 population, with the highest subtype-specific incidence in ependymomas (AAAIR=0.41/100,000). Overall, most subtypes were more common in males and people who are non-Hispanic White. Incidence of all subtypes varied by age. Ependymomas were most prevalent with 19,339 cases; followed by oligodendrogliomas with 15,070 cases. Time trends in incidence varied by subtype, with significant decreases in incidence of gliomatosis cerebri, CNS embryonal tumor, and primary CNS sarcoma. RS for all subtypes combined at 1, 5, and 10 years was 86.6%, 71.9%, and 65.3%, respectively. Ependymomas had the highest RS (1-year=96.1%, 5-years=90.6%, 10-years=86.6%) and primary CNS sarcomas had the lowest RS (1-year=48.2%, 5-years=7.7%, 10-years=5.2%). CONCLUSION Incidence, prevalence, and survival patterns for these 12 selected rare cancer subtypes varied significantly by type. Population based data are critical to guiding effective design of and accrual expectations for clinical trials in rare cancers.

Clinicopathological and molecular characterization of a case classified by DNA‑methylation profiling as “CNS embryonal tumor with BRD4–LEUTX fusion”

Central Nervous System (CNS) embryonal tumors represent a heterogeneous group of highly aggressive tumors occurring preferentially in children but also described in adolescents and adults. In 2021, the CNS World Health Organization (WHO) classification drastically changed the diagnosis of the other CNS embryonal tumors including new histo-molecular tumor types. Here, we report a pediatric case of a novel tumor type among the other CNS embryonal tumors classified within the methylation class “CNS Embryonal Tumor with BRD4–LEUTX Fusion”. The patient was a 4-year girl with no previous history of disease. For a few weeks, she suffered from headaches, vomiting and mild fever associated with increasing asthenia and loss of weight leading to a global deterioration of health. MRI brain examination revealed a large, grossly well-circumscribed tumoral mass lesion located in the left parietal lobe, contralateral hydrocephalus and midline shift. Microscopic examination showed a highly cellular tumor with a polymorphic aspect. The majority of the tumor harbored neuroectodermal features composed of small cells with scant cytoplasm and hyperchromatic nuclei associated with small “medulloblastoma-like” cells characterized by syncytial arrangement and focally a streaming pattern. Tumor cells were diffusely positive for Synaptophysin, CD56, INI1 and SMARCA4 associated with negativity for GFAP, OLIG-2, EMA, BCOR, LIN28A and MIC-2. Additional IHC features included p53 protein expression in more than 10% of the tumor’s cells and very interestingly, loss of H3K27me3 expression. The Heidelberg DNA-methylation classifier classified this case as “CNS Embryonal Tumor with BRD4:LEUTX Fusion”. RNA-sequencing analyses confirmed the BRD4 (exon 13)–LEUTX (exon 2) fusion with no other molecular alterations found by DNA sequencing. Our case report confirmed that a new subgroup of CNS embryonal tumor with high aggressive potential, loss of H3K27me3 protein expression, BRDA4–LEUTX fusion, named “Embryonal CNS tumor with BRD4–LEUTX fusion”, has to be considered into the new CNS WHO classification.

Proton beam therapy in pediatric patients with central nervous system tumors: method features, clinical data analysis

Introduction. Central nervous system (CNS) tumors are the most common pediatric solid tumor, that need multimodality treatment approach including surgery, intensive chemotherapy (CT) and radiotherapy (RT). Due to toxicity, mostly late, RT has limited use in children, especially those under 3 years of age. The physical characteristics of proton beam therapy (PBT) minimize the risk and types of toxicity compared to photons, making it the preferred choice for pediatric use. Aim – to analyze the experience of PBT in patients under 18 years of age with various types of CNS malignancies, the assessment of risk factors for acute and late toxicity and its clinical manifestations. Materials and methods. A retrospective analysis of 63 courses of PBT performed in 58 patients with CNS malignancies for the period from 2018 to 2022 was carried out on Proton Center of the Sergey Beresin Medical Institute. The manifestations of local and systemic toxicity (predominantly acute) were analyzed, with an assessment of the influence of age, the volume of RT, the use of previous and concomitant CT on the severity of adverse events (AE). Results. In the study cohort, patients with embryonal CNS malignancies predominated (72.3 %). Median age was 5 years 2 months, median follow-up was 15 months. In 36 % of cases, a complete response was achieved by the start of PBT. Patients with craniospinal irradiation (CSI) prevailed (60 %). Among the manifestations of toxicity, AE grade I–II predominated. The most common AE were local reactions (dermatitis (84 %), focal alopecia (96 %)). Among systemic AE, hematological complications (84 %) were the most often occurred. A more pronounced toxicity profile was registered in the group with CSI, while concomitant CT, the patient’s age, previous CT did not significantly affect the severity of most of the assessed AE parameters (p > 0.05). The analysis of late toxic effects was difficult due to the short follow-up period, the cumulative effect of other treatment modalities on the AE’s development. The reported complications included persistent focal alopecia (14 % of cases), endocrinopathies (7 %), neurological manifestations (6 %). One (2 %) child had a severe neurological deficit, secondary epilepsy with psychomotor regression, which can also be associated with the potentiating effect of previous CT and high-dose CT. Conclusion. The analysis of our data and literature review allows to conclude that PBT has relatively low toxicity profile, which is the determining factor for choosing this method of RT in pediatric patients. The main risk factor of AE’s was CSI. The acceptable acute toxicity of repeat PBT makes it possible to be used in pts with disease progression or relapse in case of absence of alternative therapeutic options.

Rare embryonal and sarcomatous central nervous system tumours: State-of-the art and future directions

The introduction of molecular methods into the diagnostics of central nervous system (CNS) tumours and the subsequent deciphering of their molecular heterogeneity has resulted in a significant impact on paediatric neurooncology. Particularly in the field of rare embryonal and sarcomatous CNS tumours, novel tumour types have been delineated and introduced in the recent 5th edition of the WHO classification of CNS tumours. The rarity and novelty of these tumour types result in diagnostic and therapeutic challenges. Apart from distinct histopathological and molecular features, these tumour types exhibit characteristic clinical properties and require different therapeutic approaches for optimal patient management. However, based on the limited availability of clinical data, current therapeutic recommendations have to be based on data from small, predominantly retrospective patient cohorts. Within this article, we provide guidance for diagnostic work-up and clinical management of rare CNS embryonal tumours (‘embryonal tumour with multi-layered rosettes’, ETMR; ‘CNS neuroblastoma, FOXR2-activated’, CNS NB-FOXR2; ‘CNS tumour with BCOR-ITD, CNS BCOR-ITD) and rare CNS sarcomatous tumours (‘primary intracranial sarcoma, DICER1-mutant’, CNS DICER1; ‘CIC-rearranged sarcoma’, CNS CIC). By emphasizing the significant consequences on patient management in paediatric CNS tumours, we want to encourage wide implementation of comprehensive molecular diagnostics and stress the importance for joint international efforts to further collect and study these rare tumour types.

Phenotypic characterization of seven individuals with Marbach-Schaaf neurodevelopmental syndrome.

We present the phenotypes of seven previously unreported patients with Marbach-Schaaf neurodevelopmental syndrome, all carrying the same recurrent heterozygous missense variant c.1003C>T (p.Arg335Trp) in PRKAR1B. Clinical features of this cohort include global developmental delay and reduced sensitivity to pain, as well as behavioral anomalies. Only one of the seven patients reported here was formally diagnosed with autism spectrum disorder (ASD), while ASD-like features were described in others, overall indicating a lower prevalence of ASD in Marbach-Schaaf neurodevelopmental syndrome than previously assumed. The clinical spectrum of the current cohort is similar to that reported in the initial publication, delineating a complex developmental disorder with behavioral and neurologic features. PRKAR1B encodes the regulatory subunit R1β of the protein kinase A complex (PKA), and is expressed in the adult and embryonal central nervous system in humans. PKA is crucial to a plethora of cellular signaling pathways, and its composition of different regulatory and catalytic subunits is cell-type specific. We discuss potential molecular disease mechanisms underlying the patients' phenotypes with respect to the different known functions of PKA in neurons, and the phenotypes of existing R1β-deficient animal models.

An Integrated Analysis of Clinical, Genomic, and Imaging Features Reveals Predictors of Neurocognitive Outcomes in a Longitudinal Cohort of Pediatric Cancer Survivors, Enriched with CNS Tumors (Rad ART Pro).

BackgroundNeurocognitive deficits in pediatric cancer survivors occur frequently; however, individual outcomes are unpredictable. We investigate clinical, genetic, and imaging predictors of neurocognition in pediatric cancer survivors, with a focus on survivors of central nervous system (CNS) tumors exposed to radiation.MethodsOne hundred eighteen patients with benign or malignant cancers (median diagnosis age: 7; 32% embryonal CNS tumors) were selected from an existing multi-institutional cohort (RadART Pro) if they had: 1) neurocognitive evaluation; 2) available DNA; 3) standard imaging. Utilizing RadART Pro, we collected clinical history, genomic sequencing, CNS imaging, and neurocognitive outcomes. We performed single nucleotide polymorphism (SNP) genotyping for candidate genes associated with neurocognition: COMT, BDNF, KIBRA, APOE, KLOTHO. Longitudinal neurocognitive testing were performed using validated computer-based CogState batteries. The imaging cohort was made of patients with available iron-sensitive (n = 28) and/or T2 FLAIR (n = 41) sequences. Cerebral microbleeds (CMB) were identified using a semi-automated algorithm. Volume of T2 FLAIR white matter lesions (WML) was measured using an automated method based on a convolutional neural network. Summary statistics were performed for patient characteristics, neurocognitive assessments, and imaging. Linear mixed effects and hierarchical models assessed patient characteristics and SNP relationship with neurocognition over time. Nested case-control analysis was performed to compare candidate gene carriers to non-carriers.ResultsCMB presence at baseline correlated with worse performance in 3 of 7 domains, including executive function. Higher baseline WML volumes correlated with worse performance in executive function and verbal learning. No candidate gene reliably predicted neurocognitive outcomes; however, APOE ϵ4 carriers trended toward worse neurocognitive function over time compared to other candidate genes and carried the highest odds of low neurocognitive performance across all domains (odds ratio 2.85, P=0.002). Hydrocephalus and seizures at diagnosis were the clinical characteristics most frequently associated with worse performance in neurocognitive domains (5 of 7 domains). Overall, executive function and verbal learning were the most frequently negatively impacted neurocognitive domains.ConclusionPresence of CMB, APOE ϵ4 carrier status, hydrocephalus, and seizures correlate with worse neurocognitive outcomes in pediatric cancer survivors, enriched with CNS tumors exposed to radiation. Ongoing research is underway to verify trends in larger cohorts.

OTHR-41. Amplification of the PLAG family genes – PLAGL1 and PLAGL2 – is a key feature of a novel embryonal CNS tumor type

Pediatric central nervous system (CNS) tumors differ substantially from their adult counterparts, are marked by considerable molecular and clinical heterogeneity, and diagnosis through histopathology alone can be challenging. Using DNA methylation-based CNS tumor classification in combination with copy number and RNAseq analysis, we identify a rare, novel pediatric CNS tumor type (n=32) which is characterized by focal high-level amplification and consecutive overexpression of one of the PLAG family genes – PLAGL1 or PLAGL2. It is epigenetically divergent from other known tumor types such as high-grade gliomas, medulloblastomas, embryonal tumors, or CNS sarcomas. The wide range of original histopathologic diagnosis rendered attests to their polyphenotypic nature in terms of morphology. We suggest that these tumors may arise from early to intermediate neural progenitor cells with some neuronal commitment. Using ChIPseq data, we show that both PLAGL1 and PLAGL2 act as transcription factors for: i) the oncogenic kinase RET, a potential drug target, that was overexpressed in our cohort; ii) components of the Wnt/β-Catenin pathway; iii) a set of imprinted genes, reported to regulate the imprinted gene network in mouse models, that was deregulated in the PLAGL-amplified tumors. Consequently, a 250-gene expression PLAGL-signature indicated dysregulation of imprinting control and differentiation/development as a prominent feature. We report differences regarding age and sex distribution between PLAGL1- and PLAGL2-amplified tumors and shed light on differences in clinical behavior and outcomes between these subtypes in male and female patients. PLAGL1-amplified tumors were more prevalent in school-age children and teenagers, while PLAGL2-amplified cases occurred in very young patients. Kaplan-Meier analysis showed a trend towards a more favorable outcome in patients with PLAGL1-amplified tumors and in female patients. Survival rates remained constant after 5 years with a five-/ten-year overall survival of 75% for PLAGL1, 24% for PLAGL2, 18% for male patients, and 88% for female patients.

TBIO-02. Mapping the origins of pediatric brain tumors to cell type lineages in the developing cerebellum.

Understanding the cellular origins of cerebellar tumors at single cell resolution may help identify novel therapeutic vulnerabilities to overcome current impediments in pediatric neuro-oncology. One approach to answer this important question involves the mapping of tumor profiles onto normal embryonal central nervous system development. Previous attempts in this regard focused on integrating human tumor data with developing mouse cerebellum atlases, however, these approaches were inherently limited due to species-specific differences. In order to address this critical issue, we use a high resolution developing human cerebellum single cell atlas in order to compare to extended bulk and single cell transcriptomes profiles from pediatric solid tumors. In result, we provide novel and confirmatory findings for the cellular association of medulloblastoma SHH, Group3 and Group4 as well as pilocytic astrocytoma, using comprehensive approaches to decipher the cellular composition and map the origins of childhood brain tumors. We also shed light on the cellular origins of posterior fossa ependymoma and radiation-induced glioma (secondary tumor, occurring after medulloblastoma). As a common feature among the tumor similarity to normal cell types, we identify gradients of differentiation, starting from early progenitor cells to more differentiated cell states, observed in all cerebellar tumor entities investigated at single cell level; thus reflecting possible lineages of origin. Pertaining to clinical application, we identified specific developmental genes shared between cerebellar lineages and associated tumors, and tumor-specific genes absent in all cerebellar lineages. These two categories of genes comprise candidate lineage markers for faithful modeling and, if absent from other organ systems after birth, could become an important source of potential therapeutic targets. Importantly, all analysis results are publicly available via an interactive online user interface (brain-match.org) that serves as an open valuable resource for the scientific community.

Embryonal and non-meningothelial mesenchymal tumors of the central nervous system - Advances in diagnosis and prognostication.

The 5th edition of the WHO Classification of Tumours of the Central Nervous System introduces new entities, and provides updated guidance regarding the diagnostic criteria for tumors of the central nervous system (CNS). CNS embryonal tumors and CNS non‐meningothelial mesenchymal tumors can be challenging for practicing pathologists, as the histologic features are not always specific to a particular entity, and integration of microscopic and molecular findings is necessary. This review on CNS embryonal and non‐meningothelial mesenchymal tumors is meant to provide an update with a focus on WHO changes and additions and on recent discoveries with diagnostic, prognostic, and therapeutic implications.

MOMC-1. Employing the Zika Virus to kill paediatric nervous system tumour cells

Malignant paediatric nervous system tumours, such as Medulloblastoma, Neuroblastoma and ATRT commonly harbour tumour cells with stem-like features which are highly tumorigenic and resistant to conventional cancer therapies. These tumours can exhibit high lethality and may result in severe sequelae, including cognitive and motor deficits that significantly affect patients’ quality of life. Oncolytic virotherapy is a novel therapy class that exploits viruses that preferentially infect and destroy tumour cells. These viruses present a unique advantage in targeting highly heterogeneous cancers, such as nervous system tumours, as they possess a secondary mechanism of action through which they induce a tumour-specific immune response. Clinical studies employing oncolytic virotherapy have in general reported low toxicity and minimal adverse effects, deeming oncolytic virotherapy as a potentially attractive and safer intervention against paediatric tumours.The Zika virus (ZIKV) is capable of infecting and destroying neural stem-like cancer cells from human embryonal Central Nervous System (CNS) tumours in vitro and in vivo. Infection of CNS tumour cells with ZIKV effectively inhibits tumour metastasis in mice and, in some cases, induces complete tumour remission. Neuroblastoma arises from immature nerve cells and multiple Neuroblastoma cell lines are susceptible to ZIKV infection and oncolysis. These initial findings have demonstrated the potential for a ZIKV-based virotherapy against paediatric nervous system tumours and warrants examination into the molecular mechanisms through which ZIKV executes its oncolytic ability. My research goal is to elucidate the mechanisms which are of paramount importance for ZIKV-induced oncolysis of brain tumour and Neuroblastoma cells. Utilising global expression omics profiling of ZIKV infection and mapping of viral protein-host protein interactions will identify these mechanisms both at the cellular pathway and molecular levels. These collectively will inform our understanding of how we can employ a future ZIKV-based virotherapy against paediatric nervous system tumours.

Potential Importance of Early Focal Radiotherapy Following Gross Total Resection for Long-Term Survival in Children With Embryonal Tumors With Multilayered Rosettes.

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 nine consecutive patients and review the role of initiation/timing of radiotherapy on survival. Between 2006 and 2018, nine patients were diagnosed with ETMR. Diagnosis was confirmed histopathologically, immunohistochemically and molecularly. Median age was 25 months (5–38). Location was supratentorial in five, pineal in three, and brainstem in one. Seven patients had a gross total resection, one a partial resection and one a biopsy at initial diagnosis. Chemotherapy augmented with intrathecal therapy started a median of 10 days (7–20) after surgery. Only two patients who after gross total resection received radiotherapy very early on (six weeks after diagnosis) are alive and in complete remission 56 and 50 months after diagnosis. All remaining patients for whom radiotherapy was deferred until the end of chemotherapy recurred, albeit none with leptomeningeal disease. A literature research identified 228 patients with ETMR. Including our patients only 26 (11%) of 237 patients survived >36 months with no evidence of disease at last follow-up. All but two long-term (>36 months) survivors received radiotherapy, ten of whom early on following gross total resection (GTR). GTR followed by early focal radiotherapy and intrathecal therapy to prevent leptomeningeal disease are potentially important to improve survival of ETMR in the absence of effective targeted therapies.

ETMR-10. EARLY FOCAL RADIOTHERAPY AND TEMOZOLOMIDE FOLLOWING COMPLETE RESECTION APPEAR SUPERIOR TO INTENSIVE CHEMOTHERAPY AND DELAYED RADIOTHERAPY IN CHILDREN WITH EMBRYONAL TUMORS WITH MULTILAYERED ROSETTES (ETMR)

BACKGROUNDEmbryonal 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.METHODSBetween 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.RESULTSSeven 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.CONCLUSIONGross 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.

HGF/MET Signaling in Malignant Brain Tumors.

Hepatocyte growth factor (HGF) ligand and its receptor tyrosine kinase (RTK) mesenchymal-epithelial transition factor (MET) are important regulators of cellular processes such as proliferation, motility, angiogenesis, and tissue regeneration. In healthy adult somatic cells, this ligand and receptor pair is expressed at low levels and has little activity except when tissue injuries arise. In cancer cells, HGF/MET are often overexpressed, and this overexpression is found to correlate with tumorigenesis, metastasis, and poorer overall prognosis. This review focuses on the signaling of these molecules in the context of malignant brain tumors. RTK signaling pathways are among the most common and universally dysregulated pathways in gliomas. We focus on the role of HGF/MET in the following primary malignant brain tumors: astrocytomas, glioblastomas, oligodendrogliomas, ependymomas, and embryonal central nervous system tumors (including medulloblastomas and others). Brain metastasis, as well as current advances in targeted therapies, are also discussed.

Primary sellar neuroblastoma pretending pituitary adenoma: A new case report and review of literature

Introduction Sellar neuroblastoma is hugely rare, only ten cases having been described in the literature. Primary intracranial neuroblastoma mainly occurs in children and arises in the supratentorial parenchyma. These tumors belong to embryonal central nervous system primitive neuroectodermal tumors (PNET). Magnetic resonance imaging (MRI) appearance is non-specific. Management is primary based on surgical resection. Diagnosis relied on histopathological examination. Through this case, it seems relevant to consider neuroblastoma face to MRI atypical aspects of pituitary adenoma. Clinical presentation We report the case of a 58-year-old-man with a 3-year old history of a rapidly growing sellar lesion diagnosed preoperatively as a pituitary non-functioning adenoma. He developed progressive bitemporal hemianopsia and visual field loss. Endocrinal investigations disclosed a functional hyperprolactinemia due to pituitary stalk effect. MRI displayed a sellar and supra-seller mass extension compressing the optic chiasm, with intra-sphenoidal sinus development, skull bone lysis and bilateral cavernous sinus invasion. He underwent near complete surgical removal through an endoscopic transseptal transsphenoidal approach. Histological and immunohistochemical studies yielded a diagnosis of neuroblastoma. Postoperatively his visual deficit improved. Neither endrocinal disturbance nor rhinorrhea occurred. He underwent fractioned radiotherapy a few weeks later. Discussion Primary sellar neuroblastoma could be easily misdiagnosed as pituitary adenoma. Unusual MRI features could lead to consider this diagnosis. The optimal management seems to be surgical resection followed by radiation therapy. Some authors suggested adjuvant chemotherapy in patients with subtotal resection or recurrence however this is no consensual.

MiR-367 as a therapeutic target in stem-like cells from embryonal central nervous system tumors.

Aberrant expression of the pluripotency factor OCT4A in embryonal tumors of the central nervous system (CNS) is a key factor that contributes to tumor aggressiveness and correlates with poor patient survival. OCT4A overexpression has been shown to up‐regulate miR‐367, a microRNA (miRNA) that regulates pluripotency in embryonic stem cells and stem‐like aggressive traits in cancer cells. Here, we show that (a) miR‐367 is carried in microvesicles derived from embryonal CNS tumor cells expressing OCT4A; and (b) inhibition of miR‐367 in these cells attenuates their aggressive traits. miR‐367 silencing in OCT4A‐overexpressing tumor cells significantly reduced their proliferative and invasive behavior, clonogenic activity, and tumorsphere generation capability. In vivo, targeting of miR‐367 through direct injections of a specific inhibitor into the cerebrospinal fluid of Balb/C nude mice bearing OCT4A‐overexpressing tumor xenografts inhibited tumor development and improved overall survival. miR‐367 was also shown to target SUZ12, one of the core components of the polycomb repressive complex 2 known to be involved in epigenetic silencing of pluripotency‐related genes, including POU5F1, which encodes OCT4A. Our findings reveal possible clinical applications of a cancer stemness pathway, highlighting miR‐367 as a putative liquid biopsy biomarker that could be further explored to improve early diagnosis and prognosis prediction, and potentially serve as a therapeutic target in aggressive embryonal CNS tumors.

Bioinformatics Analysis Reveals Ki-67 Specific microRNA Functions in Pediatric Embryonal Tumors.

Pediatric Central Nervous System (CNS) neoplasms are the second most prevalent tumors of childhood. CNS malignancies are considered as the most notorious type of tumors, due to their anatomic position manifesting an imminent threat to the patients' life. miRNAs are molecules that play a significant role in CNS tumor biology. At the same time diagnostic markers such as Ki-67 have played an important role in CNS tumor diagnosis. In a previous study we have identified several miRNAs, common to different subtypes of pediatric embryonal CNS malignancies as well as, we have identified miRNAs that manifest significant dynamics with respect to their expression and the neoplasmatic subtype. Among the previously reported miRNAs, several have manifested significant differences with respect to Ki-67 expression. Those miRNAs, were further analyzed bioinformatically and related functions were revealed, where some of them confirmed Ki-67 role as a proliferation marker but also predicted novel miRNAs functions in pediatric embryonal tumors.

Molecular pathology of tumors of the central nervous system.

Since the update of the 4th edition of the WHO Classification of Central Nervous System (CNS) Tumors published in 2016, particular molecular characteristics are part of the definition of a subset of these neoplasms. This combined ‘histo-molecular’ approach allows for a much more precise diagnosis of especially diffuse gliomas and embryonal CNS tumors. This review provides an update of the most important diagnostic and prognostic markers for state-of-the-art diagnosis of primary CNS tumors. Defining molecular markers for diffuse gliomas are IDH1/IDH2 mutations, 1p/19q codeletion and mutations in histone H3 genes. Medulloblastomas, the most frequent embryonal CNS tumors, are divided into four molecularly defined groups according to the WHO 2016 Classification: wingless/integrated (WNT) signaling pathway activated, sonic hedgehog (SHH) signaling pathway activated and tumor protein p53 gene (TP53)-mutant, SHH-activated and TP53-wildtype, and non-WNT/non-SHH-activated. Molecular characteristics are also important for the diagnosis of several other CNS tumors, such as RELA fusion-positive subtype of ependymoma, atypical teratoid rhabdoid tumor (AT/RT), embryonal tumor with multilayered rosettes, and solitary fibrous tumor/hemangiopericytoma. Immunohistochemistry is a helpful alternative for further molecular characterization of several of these tumors. Additionally, genome-wide methylation profiling is a very promising new tool in CNS tumor diagnostics. Much progress has thus been made by translating the most relevant molecular knowledge into a more precise clinical diagnosis of CNS tumors. Hopefully, this will enable more specific and more effective therapeutic approaches for the patients suffering from these tumors.

Trends in Pediatric Central Nervous System Tumor Incidence in the United States, 1998-2013.

Brain and other central nervous system (CNS) cancers are the leading cause of U.S. pediatric cancer mortality. Incidence trends can provide etiologic insight. We report trends in incidence rates of pediatric malignant CNS cancers and pilocytic astrocytoma (nonmalignant but historically registered) in the United States. Age-standardized incidence rates and annual percent changes (APC) in rates during 1998 to 2013 were calculated for children aged 0 to 19, stratified by subtype, age, sex, and for gliomas, histology and location. We estimated the absolute change in number of cases diagnosed U.S.-wide during 2013 compared with the expected number of cases had 1998 rates remained stable. Rates of all pediatric malignant CNS cancer combined (n = 18,612) did not change [APC: 0.16; 95% confidence interval (CI): -0.21-0.53]. There were statistically significant changes in several subtypes; however, glioma incidence (n = 10,664) increased by 0.77% per year (95% CI: 0.29-1.26), embryonal cancer rates (n = 5,423) decreased by 0.88% per year (95% CI: -1.33 to -0.43), and pilocytic astrocytoma rates (n = 6,858) increased by 0.89% per year (95% CI: 0.21-1.58). Of the 1,171 malignant tumors and 450 pilocytic astrocytomas diagnosed in U.S. children in 2013, we estimated 120 excess gliomas, 94 excess pilocytic astrocytomas, and 72 fewer embryonal CNS tumors than would be expected had 1998 rates remained stable. The gradual changes in incidence we observed for specific types of pediatric CNS cancers are likely due to a combination of changes in classification and diagnosis and true changes in CNS cancer. Continued surveillance of pediatric CNS tumors should remain a priority, given their significant contribution to pediatric cancer-related deaths.

Bioinformatics and Regression Analyses Manifest Tumor-Specific miRNA Expression Dynamics in Pediatric Embryonal Malignancies.

Pediatric Central Nervous System (CNS) neoplasms are the second most prevalent tumors of childhood. Further on, prognosis of this type of neoplasms still remain poor and the comprehension of the etiology and pathogenesis of the disease still remains scarce. Several reports have identified microRNAs as significant molecules in the development of central nervous system tumors and propose that they might compose key molecules underlying oncogenesis. In a previous study we have identified several miRNAs, common to different subtypes of pediatric embryonal CNS malignancies as well as, we have identified miRNAs that manifest significant dynamics with respect to their expression and the neoplasmatic subtype. Overall, 19 tumor cases from children diagnosed with embryonal brain tumors were investigated. As controls, children who suffered a sudden death underwent autopsy and were not present with any brain malignancy were used (13 samples of varying localization). Our experimental approach included microarrays covering 1211 miRNAs, which appeared to manifest tumor-specific dynamics. In conclusion, it appeared that certain miRNAs are neoplasm specific and in particular, their expression manifests linear dynamics. Thus, the investigation of miRNA expression in pediatric embryonal brain tumors might contribute towards the discovery of tumor-specific miRNA signatures, which could potentially afford the identification of gene-specific biomarkers related to diagnosis, prognosis and patient targeted therapy, as well as help us understand oncogenetic dynamics.