Search Results (341)

Enhancer of zeste homologs inhibitory protein (EZHIP) is a eutherian-specific protein, with poorly defined developmental functions and physiological expression restricted to germ cells. Its aberrant re-expression characterizes posterior fossa ependymoma subtype A and a subset of diffuse midline gliomas with wild-type histone H3—aggressive pediatric brain tumors marked by global loss of the repressive H3 lysine 27 trimethylation (H3K27me3). Functionally analogous to the H3 lysine 27 to methionine (H3K27M) oncohistone, EZHIP inhibits Polycomb repressive complex 2 (PRC2), altering genome-wide H3K27me3 distribution and fate commitment. Unlike H3K27M, EZHIP is epigenetically silenced under physiological conditions yet inducible, suggesting context-dependent oncogenic roles. Its intrinsically disordered structure enables multifunctional interactions and biological versatility. Beyond brain tumors, EZHIP has emerged as an oncogenic driver in osteosarcoma, underscoring broader relevance across cancers. This review integrates current insights into EZHIP—from gene discovery and the mechanism of PRC2 inhibition to its emerging roles in metabolism, DNA repair, 3D chromatin regulation, and development. We outline EZHIP’s clinico-pathological significance in pediatric and adult malignancies, with an emphasis on EZHIP-driven hindbrain tumors. Finally, we discuss therapeutic opportunities, from the direct targeting of intrinsically disordered proteins to the indirect modulation of EZHIP-associated epigenetic and metabolic landscapes, highlighting implications for tumor evolution and precision oncology. Full article

Accurate brain tumor segmentation in both adult and pediatric populations remains a challenge due to substantial differences in brain anatomy, tumor distribution, and subregion size. This study proposes a unified segmentation framework based on nnU-Net, integrating encoder-level self-supervised pretraining with a lightweight, boundary-aware decoder. The encoder is initialized using a large-scale 3D masked autoencoder pretrained on brain MRI, while the decoder is trained with a hybrid loss function that combines region-overlap and boundary-sensitive terms. A harmonized training and evaluation protocol is applied to both the BraTS-GLI (adult) and BraTS-PED (pediatric) cohorts, enabling fair cross-cohort comparison against baseline and advanced nnU-Net variants. The proposed method improves mean Dice scores from 0.76 to 0.90 for adults and from 0.64 to 0.78 for pediatric cases, while reducing HD95 from 4.42 to 2.24 mm and from 9.03 to 6.23 mm, respectively. These results demonstrate that combining encoder-level pretraining with decoder-side boundary supervision significantly enhances segmentation accuracy across age groups without adding inference-time computational overhead. Full article

Thalamic gliomas are among the most challenging pediatric brain tumors due to the delicate functions of the thalamus. Limited surgical intervention leads to the use of adjuvant therapies, including targeted therapy. Thalamic gliomas can be divided into two distinct groups: diffuse midline glioma (DMG) and low-grade glioma (LGG). The most common mutations that can be targeted for treatment are the KIAA1549-BRAF fusion; BRAF V600E mutation; EGFR, FGFR, PDGFR, NTRK, and CDK4/6 mutations; other MAP kinase pathway alterations; and PI3K/AKT/mTOR activation. The bithalamic high-grade glioma especially demonstrates EGFR mutations which makes it a distinct entity. Targeted therapy, including tyrosine kinas inhibitors has been shown to improve the overall survival compared to conventional therapy in certain situations. Demonstrating the mutation carried by the tumor is very critical in this regard. The purpose of this article is to focus on the treatment of thalamic glioma in pediatric patients in light of molecular information. Full article

While research on high-incidence tumors such as breast, prostate, and lung cancer has led to significant increases in patient survival in recent years, this has not been the case for low-incidence tumors such as high-grade gliomas, the most common and lethal brain tumors, for which the last significant therapeutic advance dates back to 2005. The high infiltration capacity of these tumors into normal brain tissue essential for both vegetative and relational life, the tumor microenvironment, with poor immunological activity, the multiple resistance mechanisms, and the unattractiveness of research investments due to the limited number of patients have made, and continue to make, the path to achieving significant improvements in the survival of patients with high-grade gliomas long and arduous. The objective of this article is to update the slow but continuous radiotherapeutic progress for adult and pediatric high-grade gliomas to the second half of 2023. We analyzed the progress of preclinical and clinical research on both adult and pediatric high-grade gliomas, with a particular focus on improvements in radiotherapy. Interactions between non-radiant new therapies and radiotherapy were also covered. A literature search was conducted in PubMed using the terms (“glioma* and radio*”) and the time limit of 1 July 2023 to 31 December 2023. The inclusion and exclusion criteria for the review were relevance to advances in radiotherapy for high-grade gliomas in adults and children. Treating patients with advanced disease progression only, using “historical” data as controls, as well as repurposing drugs developed for purposes completely different from their intended use, were the major (but not the only) methods to assess risk of bias in the included studies. The effect measures used in the synthesis or presentation of the results were tabulated and/or displayed in figures. A total of 100 relevant references were reviewed. Advances in preclinical studies and in clinical radiotherapy treatment planning, innovative fractionation, use of radioisotopes/radiopharmaceuticals, radiosensitization procedures, and radiation-induced damage were focused on. While this analysis may be limited by the relatively short publication period, high-grade glioma research remains impacted, especially at the clinical level, by potential issues with trial design, such as treating patients with advanced disease progression, using “historical” data as controls, and repurposing drugs developed for completely different purposes than intended. Addressing these aspects of high-grade glioma research could improve its efficacy, which often remains low despite the associated costs. Full article

Background/Objectives: Although Tumor-Treating Fields (TTFields) therapy is an established treatment modality for adult glioblastoma, clinical data on its efficacy in pediatric brain tumors are extremely scarce. The present study aimed to evaluate the safety of TTFields therapy for pediatric diffuse high-grade glioma (HGG) and to conduct an exploratory analysis of its efficacy. Methods: A prespecified, interim analysis was performed to determine whether the study should be continued on the basis of safety and feasibility data on the first three patients. The target population was children aged 5 to 17 years with newly diagnosed, supratentorial HGG or its first recurrence following frontline therapy. After completion of initial, local treatment for the tumor (surgical removal and/or radiotherapy), all patients received TTFields therapy using Optune^TM for 28 days per course for up to 26 courses until disease progression. Results: The interim analysis, which was completed in October 2022, included three female patients aged 14, 17, and 9 years. All had a histological grade 4 tumor, two of which were radiation-induced, secondary HGG. No serious, treatment-related toxicities or device-related issues were observed. All three patients were able to continue using the device for 75% or more of the time in accordance with the protocol, suggesting that the treatment was feasible. The MRI findings of two patients indicated that the treatment has a potential antitumor effect. Based on these results, the study was resumed and is currently being continued at multiple centers. Conclusions: The initial results of the prespecified, interim analysis demonstrated that TTFields therapy was safe and feasible for children with HGG. This study was funded by the Japan Agency for Medical Research and Development (AMED) and was registered with the Japan Registry of Clinical Trials (jRCTs032200423). Full article

Central nervous system (CNS) tumors consist of a diverse set of malignancies that remain clinically challenging due to their biological complexity, high morbidity, and limited responsiveness to current therapies. A growing body of genomic evidence has revealed that dysregulation of the mitogen-activated protein kinase (MAPK) signaling pathway is a recurrent and unifying characteristic across many pediatric and adult CNS tumor entities. Alterations affecting upstream receptor tyrosine kinases (RTKs), RAS GTPases, RAF kinases, and other associated regulators contribute to MAPK signaling pathway hyperactivation, shaping tumor behavior, therapy response and resistance. These aberrations ranging from hotspot mutations such as BRAF V600E and oncogenic fusions like BRAF–KIAA1549 are particularly enriched in gliomas and glioneuronal tumors, highlighting MAPK signaling as a key oncogenic driver. The expanding availability of molecularly targeted compounds, including selective inhibitors of RAF, MEK and ERK, has begun to transform treatment approaches for specific molecular subtypes. However, the clinical benefit of MAPK-directed therapies is frequently limited by restricted blood–brain barrier (BBB) penetration, intratumoral heterogeneity, parallel pathway reactivation, and an immunosuppressive tumor microenvironment (TME). In this review, we synthesize current knowledge on MAPK pathway alterations in CNS tumors and evaluate the therapeutic landscape of MAPK inhibition, with emphasis on approved agents, emerging compounds, combination strategies, and novel drug-delivery technologies. We also discuss mechanisms that undermine treatment efficacy and highlight future directions aimed at integrating MAPK-targeted therapy into precision-based management of brain tumors. Full article

The tumor microenvironment (TME) plays an important role in the development, progression, and treatment response of pediatric cancers, yet remains less elucidated compared to adult malignancies. Pediatric tumors are unique with a low mutational burden, an immature immune landscape, and unique stromal interactions. The resultant “cold” immune microenvironments limits the effectiveness of conventional immunotherapies. This review summarizes the key cellular and non-cellular components of the pediatric TME—including T cells, NK cells, tumor-associated macrophages, cancer-associated fibroblasts, extracellular matrix remodeling, angiogenesis, and hypoxia—and describes how these elements shape tumor behavior and therapy resistance. The role of TME in common pediatric cancers like leukemia, lymphoma, neuroblastoma, brain tumors, renal tumors, and sarcomas is discussed. Emerging therapeutic strategies targeting immune checkpoints, macrophage polarization, angiogenic pathways, and stromal barriers are discussed. Full article

Objectives: Atypical teratoid/rhabdoid tumors (ATRTs) are rare, malignant central nervous system (CNS) neoplasms that predominantly affect infants and young children. While ATRT arises throughout the CNS, its extracranial counterpart, malignant rhabdoid tumor, occurs in other organs. A single-institutional cohort is reviewed to map anatomic distribution of pediatric ATRTs and to integrate a literature review to contextualize ATRT histogenesis from anatomical and embryological perspectives. Methods: A retrospective review was conducted on a cohort of 50 pediatric patients with ATRT treated over 20 years. Demographic, surgical, and neuroimaging data were correlated to define tumor location, extent, and compartmental involvement. A focused literature review synthesized molecular subclassifications and proposed cells of origin/cytogenesis. Results: Of the 50 ATRTs, 18 (36%) were infratentorial, 15 (30%) supratentorial, 11 (22%) in the pineal region, and 6 (12%) in the spinal compartment. Among infratentorial tumors, 10 were centered in the fourth ventricle, with or without extension into the cerebellopontine angle (CPA) cistern; the remainder arose in the CPA. Among ATRTs of the cerebral hemispheres, 3 showed bi-hemispheric involvement crossing the falx cerebri. ATRTs of the pineal region predominantly originated from the superior medullary velum. These topographic data were corelated with embryological and molecular information available in the literature. Conclusions: ATRTs arise across diverse neuroanatomical compartments—including intraparenchymal, intraventricular, extra-axial, and extradural sites—underscoring biological heterogeneity. Inactivation of SMARCB1 is the defining molecular event and principal oncogenic driver, although the upstream mechanisms precipitating these alterations remain incompletely resolved. Molecular subgroups—ATRT-TYR, ATRT-SHH, and ATRT-MYC—display distinct age distributions and anatomic predilections, implicating developmental context in tumor initiation. The characteristic cellular admixture of rhabdoid cells with mesenchymal and/or epithelial differentiation, together with intra- and extra-axial and occasional extradural presentations, supports a model in which at least a subset of ATRTs may originate from neural crest-derived lineages, despite little or no neural crest contribution to brain parenchyma development. Neural plate border progenitors with bipotent features represent a plausible intraparenchymal cell of origin. Definitive resolution of these origins and the mechanisms of SMARCB1 disruption will require integrated approaches. Further investigations are warranted to clarify these mechanisms. Full article

Background/Objectives: Ependymomas are central nervous system (CNS) tumors with marked biological and clinical heterogeneity, particularly in pediatric populations. While the 2021 World Health Organization (WHO) classification emphasizes molecular subgroups—posterior fossa type A (PFA) and B (PFB), supratentorial ZFTA fusion-positive (ST-ZFTA), and YAP1 fusion-positive (ST-YAP)— routine diagnosis is still based on histology and immunohistochemistry (IHC). Recent single-cell RNA sequencing and spatial transcriptomic studies have revealed distinct tumor cell populations, including ependymal-like, astroglial-like, progenitor-like, and stress-associated states. However, a major unresolved issue is whether such heterogeneity can be appreciated and interpreted on conventional pathology slides. Methods: This study examined ependymomas from the Children’s Brain Tumor Network (CBTN), with hematoxylin and eosin (H&E) and IHC for glial fibrillary acidic protein (GFAP) and epithelial membrane antigen (EMA). Tumor regions were stratified into high-cellularity and low-cellularity regions, and staining patterns were correlated with known cellular features from the prior literature. Results: Low-cellularity zones exhibit strong fibrillary GFAP, resembling astroglial or subependymal differentiation. In contrast, high-cellularity zones more often demonstrate variable EMA patterns and GFAP/EMA-negative compartments, consistent with undifferentiated progenitor-like populations. Perinecrotic areas showed increased GFAP and EMA, possibly reflecting stress-associated cellular states and mesenchymal differentiation. Comparisons between PFA and ST-ZFTA tumors revealed that ST-ZFTA ependymomas were significantly more likely to be hypercellular, with a higher frequency of diffuse EMA expression. In contrast, PFA tumors displayed broader variability with stronger GFAP perinuclear staining. Conclusions: These findings support the concept that conventional histology can capture relevant heterogeneity and may complement molecular studies. The recognition of such features may help refine histopathological assessment and provide practical prognostic insights, particularly in resource-limited settings where molecular testing is not universally available. Full article

Background: Glioblastoma and neuroblastoma are aggressive brain and pediatric tumors with limited treatment options. Vaccinia virus (VV) has demonstrated potent oncolytic and immunomodulatory properties but faces challenges in tumor targeting. Methods: We developed an in vitro co-culture model using mouse microglia (BV2) infected with VV (LIVP strain) to deliver the virus to glioblastoma (U87) and neuroblastoma (SH-SY5Y) cells in both 2D and 3D systems. Our results demonstrated that VV-infected Microglia can efficiently deliver the virus to tumor cells, inducing substantial cytotoxic effects in both 2D and 3D models. Notably, the 3D cultures, which more closely mimic the native tumor microenvironment, exhibited the most pronounced enhancement in oncolysis. Conclusions: This microglia-based delivery strategy enables potent oncolytic activity against brain tumor cells and warrants further exploration in in vivo and combinational therapies. Full article

Pediatric diffuse midline gliomas in the brainstem (bDMGs) are malignant primary brain neoplasms with poor prognosis. Conventional dogma cites that biopsy procedures have risks of devastating injury to the eloquent brainstem and have no direct benefit to affected patients. In recent years, the use of augmented reality (AR) adjuncts has demonstrated potential in providing excellent intraoperative three-dimensional (3D) visualization of intracranial structures. Put together, we hypothesize that the application of AR will be useful as a training tool for brainstem biopsy procedures. Anatomical models of bDMG tumors are created and uploaded to an AR application. The processed data is transferred into designated AR head-mounted devices. Briefly, individual 3D-rendered bDMG images are overlaid with an age-matched, life-sized child mannequin in prone position. A virtual stereotactic brain biopsy needle is deployed by the user into the lesion. At the end of the exercise, each user evaluates their trajectory of choice to assess its accuracy. Overall, the participants reported that the AR platform was useful in reviewing technical nuances for brainstem biopsy in a safe environment. This focused, proof-of-concept study adds to the growing body of literature that AR platforms demonstrate feasibility for neurosurgeons in the understanding of challenging operative neuroanatomy. Full article

Background: Medulloblastoma is an aggressive pediatric brain tumor characterized by marked molecular heterogeneity, which significantly impacts prognosis. The low frequency of genomic mutations in medulloblastoma suggests that alternative mechanisms, such as epigenetic regulation, may play a critical role in its pathogenesis. Methods: Using the EpiFactors database, we investigated the expression of epigenetic regulators in two independent RNA sequencing cohorts [Pediatric Brain Tumor Atlas (PBTA) and Williamson], stratified by molecular subgroups and clinical outcomes. We further analyzed expression heterogeneity at the single-cell level in malignant medulloblastoma cells using single-cell RNA sequencing. Results: Members of the SWI/SNF superfamily were dysregulated across all four molecular subtypes of medulloblastoma. Subtype-specific alterations were also observed: the acetyltransferase complex was shared between Group 3 (with SMARCD3 as a potential marker) and Group 4 (with RBM24 as a potential marker); SWR1, β-catenin/TCF, and protein–DNA complexes were specifically enriched in SHH-MB (with EYA1 and SATB2 as SHH markers); and RSC-type, PRC1, DNA polymerase complexes, and X-chromosome-related factors were enriched in WNT-MB (with FOXA1 and PIWIL4 as WNT markers). An epigenetic score (epi-score), linked to RNA metabolism and S-adenosyl-L-methionine pathways, was developed and identified as an independent adverse prognostic factor. High epi-scores were associated with proliferative, stem-like SHH malignant cells (characterized by G2/M phase, low pseudotime, and high entropy), exhibiting alterations in RNA splicing, DNA recombination, and nuclear division. Conclusions: Expression heterogeneity of epigenetic regulators is closely associated with molecular subgroups and clinical outcomes in medulloblastoma. These findings highlight the role of epigenetic dysregulation in RNA metabolism and tumor progression, particularly in SHH-driven proliferative cells. Full article

Despite a specific histone mutation defining the unique genetic makeup, diffuse midline gliomas are heterogeneous tumors with a wide range of morphologic and molecular spectrum. We investigated the feasibility of using hyperpolarized carbon-13(¹³C) MR metabolic imaging to differentiate distinctive molecular features from two H3K27M-mutant, biopsy-originated diffuse midline glioma xenografts. ¹³C MR metabolic imaging data were acquired on a 3T scanner from 12 rats that had been implanted with SF8628 or SF7761 diffuse midline glioma cells in brainstem, following injection of hyperpolarized [1-¹³C]pyruvate. Despite the two tumors’ similar appearance of T₂-hyperintensity throughout the cerebellum and pons without contrast enhancement, ¹³C metabolic imaging data revealed that SF8627 had significantly higher ratios of lactate to pyruvate, lactate to total carbon, and normalized lactate than SF7761. Elevated lactate levels in SF8628 were associated with large amounts of lactate dehydrogenase (LDH)-A and carbonic anhydrase-IX staining in SF8628 compared to SF7761, which implied that the highly hypoxic condition in SF8628 appeared to contribute to the high level of LDH-A enzyme activity, which, in turn, induced the large conversion from hyperpolarized pyruvate to lactate. Our findings suggest that this advanced metabolic imaging technique may be used for the noninvasive characterization of molecular hypoxia and lactate dehydrogenase-A activity in these pediatric brainstem gliomas. Full article

Diffuse intrinsic pontine glioma (DIPG), or as it is newly redefined, diffuse midline glioma (DMG), remains one of the most horrific diagnoses in pediatric oncology. Aggressive and inaccessible to standard treatments, it is generally considered incurable. Focused ultrasound technology has developed over the last several decades as a noninvasive means to target various types of tumors in both adults and children. Recent advances, particularly in low-intensity focused ultrasound (LIFU), have opened new avenues for enhancing drug delivery and modulating the tumor microenvironment in these challenging tumors. This review provides a comprehensive overview of preclinical and clinical research developments in the use of LIFU for pediatric DMGs. We highlight key findings from animal models demonstrating improved blood–brain barrier (BBB) permeability, increased chemotherapeutic and nanoparticle delivery, and potential immunomodulatory effects of LIFU. Emerging clinical studies, including early-phase safety and feasibility trials, are also discussed, with attention to technical parameters, imaging guidance strategies, and biomarkers of response. The review concludes by addressing the challenges of translating LIFU into routine clinical practice, including device optimization for pediatric anatomy, regulatory hurdles, and the need for standardized treatment protocols. Collectively, these recent advances underscore the promise of LIFU as a minimally invasive, image-guided adjunct to current and future therapies for pediatric DMGs, warranting continued research and collaborative clinical efforts. Full article

Background: Recent advances in childhood cancer treatment and increased survival rates have led to a growing number of adolescents and young adults (AYAs) who are survivors of childhood cancer (CCSs). This study aimed to examine health status, health-related quality of life (HRQoL), and social outcomes in AYA CCSs. Methods: Sixty-two AYAs who were CCSs (treated within the same tertiary Pediatric Hematology–Oncology Department in Crete, Greece) were enrolled in the study. Self-reported HRQoL was assessed using the Short-Form Health Survey (SF-36). Sixty-five never-ill peers constituted the control group. Results: CCSs reach adolescence and young adulthood without significant deviations in HRQoL from their healthy peers. The presence and severity of late effects were significantly correlated with lower scores in physical health. The cancer type seems to play a pivotal role: Langerhans cell histiocytosis survivors displayed significantly lower scores in mental health, and brain tumor survivors scored substantially lower scores in physical functioning. Acute lymphoblastic leukemia survivors reported the highest scores in mental health. Age at diagnosis of neoplasia was negatively correlated with physical functioning. No significant sex differences were identified. Adherence to multiple healthy lifestyle behaviors (regular exercise, abstaining from alcohol consumption and smoking, and using sun protection) and active employment were correlated with significantly higher scores in mental health. Conclusions: Appropriate therapy and regular follow-up after treatment have led to improved clinical and social outcomes, as assessed by CCSs. More efforts are needed to increase awareness of avoiding harmful behaviors that raise the risk of late effects in this specific group. Full article