Molecular subgroups of medulloblastoma: an international meta-analysis of transcriptome, genetic aberrations, and clinical data of WNT, SHH, Group 3, and Group 4 medulloblastomas

The intersections between neuroscience and medulloblastoma

Medulloblastoma (MB) represents the most common malignant central nervous system tumor in childhood. The nervous system plays a critical role in the progression of MB, with interactions between the nervous system and cancer significantly influencing oncogenesis, tumor growth, invasion, stemness, and metabolism. These interactions also regulate angiogenesis, metastatic dissemination, the tumor immune microenvironment, and drug resistance. Investigating the nervous system-MB axis holds promise for identifying diagnostic markers, prognostic biomarkers, and therapeutic targets. It also provides insights into the molecular mechanisms underlying MB and informs the development of novel therapeutic strategies. This review summarizes the latest advancements in understanding the interplay between the nervous system and MB, including the role of glial cells in MB and the potential of drug repurposing targeting nervous system components for MB treatment. These findings underscore promising diagnostic and therapeutic opportunities for MB management. Additionally, we outline future research directions in neurosciences that may pave the way for innovative therapeutic approaches and deepen our understanding of this complex disease.

Molecular classification of medulloblastoma using immunohistochemistry: A single centre study

Medulloblastoma (MB) is the second most common malignant paediatric central nervous system (CNS) tumour. The World Health Organisation (WHO) advocates an integrated pathological and molecular approach to diagnosis. Immunohistochemistry (IHC) has been proven to be a valid surrogate for molecular subtyping in low resource settings. This study aimed to use IHC to classify MB into different molecular subtypes. Patients diagnosed with medulloblastoma between 2011 and 2021 were included in the study. Clinicopathological characteristics, treatment patterns and outcomes were reviewed. Molecular subgrouping into wingless signalling activated (WNT), sonic hedgehog (SHH), and non-WNT/non-SHH was performed by immunohistochemical staining, using β-catenin, Yes-associated protein 1 (YAP1) and GRB2-Associated Binding Protein 1 (GAB1) antibodies. Of the 32 children evaluated, the mean age at diagnosis was 9.9 years with M: F ratio of 1.5:1. Classic (75.8 %) and desmoplastic/nodular (24.2 %) were the only two histopathological variants reported. Non-WNT/non-SHH constituted the majority of cases (54.5 %), followed by SHH (36.4 %) and WNT subgroups (9.1 %). The 5-year overall survival and 5-year progression-free survival was 41 % and 38 % respectively. The 30-day operative mortality rate was 28.1 %. Molecular subgroups determined by immunohistochemistry, can be easily incorporated into routine practice in low resource settings. The overall survival rate in our cohort is lower than thate reported in the literature due to high post-operative mortality and low uptake of adjuvant oncotherapy.

Epidural seeding in medulloblastoma: A rare presentation of tumor seeding

Medulloblastoma is the most common malignant brain tumor in children, known for its high propensity to disseminate through the cerebrospinal fluid (CSF), particularly within the subarachnoid space. Leptomeningeal seeding, where tumor cells attach and proliferate within the leptomeninges, is a common manifestation. However, epidural seeding is an exceptionally rare occurrence, with very few cases documented in the literature. We present the case of an 8-year-old male diagnosed with anaplastic large cell medulloblastoma, who underwent complete tumor resection followed by radiotherapy and chemotherapy. Four years postoperatively, routine imaging revealed multiple thoracic spinal seedings and an epidural lesion at the S2-3 level. Surgical intervention confirmed the mass was confined to the epidural space, without intradural involvement, a notable finding given the rarity of this presentation. The mechanism behind epidural seeding remains unclear, though it was hypothesized that tumor cells may have been introduced during a lumbar puncture performed in the post-diagnosis period. This case contributes to the limited body of literature on epidural seeding in medulloblastoma, highlighting the importance of considering this rare phenomenon in long-term follow-up and surveillance of patients.

Integrative Machine Learning Framework for Enhanced Subgroup Classification in Medulloblastoma

BACKGROUND

Medulloblastoma is the most common malignant brain tumor in children, classified into four primary molecular subgroups: WNT, SHH, Group 3, and Group 4, each exhibiting significant molecular heterogeneity and varied survival outcomes. Accurate classification of these subgroups is crucial for optimizing treatments and improving patient outcomes. DNA methylation profiling is a promising approach for subgroup classification; however, its application is still evolving, with ongoing efforts to improve accessibility and develop more accurate classification methods.

OBJECTIVES

This study aims to develop a supervised machine learning-based framework using Illumina 450K methylation data to classify medulloblastoma into seven molecular subgroups: WNT, SHH-Infant, SHH-Child, Group3-LowRisk, Group3-HighRisk, Group4-LowRisk, and Group4-HighRisk, incorporating age and risk factors for enhanced subgroup differentiation.

METHODS

The proposed model leverages six metagenes, capturing the underlying patterns of the top 10,000 probes with the highest variances from Illumina 450K data, thus enhancing methylation data representation while reducing computational demands.

RESULTS

Among the models evaluated, the SVM achieved the highest performance, with a mean balanced accuracy 98% and a macro-averaged AUC of 0.99 in an independent validation. This suggests that the model effectively captures the relevant methylation patterns for medulloblastoma subgroup classification.

CONCLUSIONS

The developed SVM-based model provides a robust framework for accurate classification of medulloblastoma subgroups using DNA methylation data. Integrating this model into clinical decision making could enhance subgroup-directed therapies and improve patient outcomes.

Accurate identification of medulloblastoma subtypes from diverse data sources with severe batch effects by RaMBat

As the most common pediatric brain malignancy, medulloblastoma (MB) includes multiple distinct molecular subtypes characterized by clinical heterogeneity and genetic alterations. Accurate identification of MB subtypes is essential for downstream risk stratification and tailored therapeutic design. Existing MB subtyping approaches perform poorly due to limited cohorts and severe batch effects when integrating various MB data sources. To address these concerns, we propose a novel approach called RaMBat for accurate MB subtyping from diverse data sources with severe batch effects. Benchmarking tests based on 13 datasets with severe batch effects suggested that RaMBat achieved a median accuracy of 99%, significantly outperforming state-of-the-art MB subtyping approaches and conventional machine learning classifiers. RaMBat could efficiently deal with the batch effects and clearly separate subtypes of MB samples from diverse data sources. We believe RaMBat will bring direct positive impacts on downstream MB risk stratification and tailored treatment design.

Immunohistochemical detection of 5-hydroxymethylcytosine as a prognostic biomarker in non-WNT/Non-SHH medulloblastomas

Although reduced levels of global 5-hydroxymethylcytosine (5hmC) have been observed in medulloblastomas (MBs), it remains unclear whether immunohistochemical (IHC) evaluation of 5hmC can serve as a prognostic biomarker for patients with MB. We performed IHC staining using a 5hmC antibody on a cohort of 114 pediatric MBs, including 69 non-WNT/non-SHH MBs. The 5hmC staining score was evaluated using a 9-point scale based on both the staining intensity and the percentage positive cells. We found that a low 5hmC staining score (< 5 points) was associated with poor outcomes in patients with non-WNT/non-SHH MB (both P < 0.001). Multivariate Cox regression analyses demonstrated the 5hmC staining score was an independent prognostic predictor for progression-free survival (P < 0.001) and overall survival (P = 0.004) in patients with non-WNT/non-SHH MB. Both the receiver operating characteristic curves and calibration curves demonstrated the excellent performance of the nomogram models established based on the Cox regression models. The high predictive accuracy of the nomogram models was confirmed in a validation cohort comprising 32 patients with non-WNT/non-SHH MB. In conclusion, IHC evaluation of 5hmC may serve as a cost-effective and readily accessible approach for the prognostic stratification of patients with non-WNT/non-SHH MB.

Adult Medulloblastoma: Clinicomolecular Spectrum, An Institutional Experience

Medulloblastoma is uncommon and molecularly lesser known in adults than their pediatric counterparts. This study aims to describe the clinicopathological and molecular characteristics of medulloblastoma in adults. Methods. The clinical, histopathological, and molecular features of 113 medulloblastoma patients of >18 years of age were reviewed. Molecular grouping (wingless pathway activated [WNT]-activated, sonic hedgehog activated [SHH]-activated, non-WNT/non-SHH, Group 3 and non-WNT/non-SHH, Group 4) was done by gene expression profiling. Results. The age-range was 19 to 59 years. The most common histoarchitecture was classic (64%), followed by desmoplastic/nodular (31%) and large cell/anaplastic (5%). The most common molecular group was SHH-activated (65%), followed by WNT-activated (14%), non-WNT/non-SHH, Group 4 (10%), and non-WNT/non-SHH, Group 3 (3%). All desmoplastic/nodular tumors were SHH-activated; while large cell/anaplastic had SHH-activated, WNT-activated and non-WNT/non-SHH, Group 3. TP53-mutant pattern of immunophenotype was observed in 7% (3 SHH-activated; 1 WNT-activated; 1 non-WNT/non-SHH, Group 3; 2 indeterminate). Within the SHH-activated group, TP53-mutant pattern immunophenotype was noted in 3 tumors and 1 was MYCN-amplified. In the WNT-activated group, both monosomy 6 and CTNNB1 mutation were seen in 3 tumors and 3 each had an isolated alteration. Conclusion. SHH-activated medulloblastoma is the most common group and WNT-activated is not rare in adults. Non-WNT/non-SHH, Group 3 though rare is not nonexistent in adults.

Heterozygous Kmt2d loss diminishes enhancers to render medulloblastoma cells vulnerable to combinatory inhibition of LSD1 and OXPHOS

The histone H3 lysine 4 (H3K4) methyltransferase KMT2D (also called MLL4) is one of the most frequently mutated epigenetic modifiers in many cancers, including medulloblastoma (MB). Notably, heterozygous KMT2D loss frequently occurs in MB and other cancers. However, its oncogenic role remains largely uncharacterized. Here, we show that heterozygous Kmt2d loss in murine cerebellar regions promotes MB genesis driven by heterozygous loss of the MB-suppressor gene Ptch via the upregulation of tumor-promoting programs (e.g., oxidative phosphorylation [OXPHOS]). Downregulation of the transcription-repressive tumor suppressor NCOR2 by heterozygous Kmt2d loss, along with Ptch+/--increased MYCN, upregulated tumor-promoting genes. Heterozygous Kmt2d loss substantially diminished enhancer marks (H3K4me1 and H3K27ac) and the H3K4me3 signature, including those for Ncor2. Combinatory pharmacological inhibition of the enhancer-decommissioning H3K4 demethylase LSD1 and OXPHOS significantly reduced the tumorigenicity of MB cells bearing heterozygous Kmt2d loss. Our findings suggest the molecular and epigenetic pathogenesis underlying the MB-promoting effect of heterozygous KMT2D loss.

High B7-H3 protein expression in Medulloblastoma is associated with metastasis and unfavorable patient outcomes

BACKGROUND

Medulloblastoma (MB) is the most common malignant brain tumor in children. Although the 5-year survival rate is approximately 70-80%, the current standard treatment results in severe and long-term side effects. The search for new anticancer immunotherapeutic targets has identified B7-H3 as a promising candidate in various solid tumors. However, the role of B7-H3 in MB remains unclear, and studies reporting its protein expression and association with clinicopathological characteristics are still limited.

METHODS

In this study, B7-H3 protein expression was evaluated by immunohistochemistry in seven non-tumor samples and 43 molecularly characterized MB tissues. Its expression profile was correlated with B7-H3 (CD276) mRNA levels, which were previously determined by nCounter, as well as with the patients' clinical features.

RESULTS

Only 14.3% (1/7) of non-tumor brain and cerebellum tissues showed B7-H3 positivity, whereas 95.6% (41/43) of the MB samples expressed this protein at distinct levels. B7-H3 was found in the cytoplasm and on the membrane of cancer cells. A significant positive correlation was observed between CD276 mRNA and B7-H3 protein levels. Moreover, high expression of B7-H3 protein was associated with worse overall survival and the presence of metastasis at diagnosis.

CONCLUSIONS

This is the first study to associate CD276 mRNA and B7-H3 protein levels in MB, revealing a significant positive correlation. We observed that B7-H3 was overexpressed in MB compared to non-tumor brain tissue. High B7-H3 expression was associated with a worse outcome and with the presence of metastasis at diagnosis.

Therapeutic approaches for targeting the pediatric brain tumor microenvironment

Central nervous system (CNS) tumors are the most frequent solid malignant tumors in pediatric patients and are the leading cause of tumor-related death in children. Treatment for this heterogeneous group of tumors consists of various combinations of safe maximal surgical resection, chemotherapy, and radiation therapy which offer a cure for some children but often cause debilitating adverse late effects in others. While therapies targeting the tumor microenvironment (TME) like immune checkpoint inhibition (ICI) have been successful in treating some cancers, these therapies failed to exhibit treatment efficacy in the majority of pediatric brain tumors in the clinic. Importantly, the pediatric TME is unique and distinct from adult brain tumors and designing therapies to effectively target these tumors requires understanding the unique biology of pediatric brain tumors and the use of translational models that recapitulate the TME. Here we describe the TME of medulloblastoma (MB) and diffuse midline glioma (DMG), specifically diffuse intrinsic pontine glioma (DIPG), and further present the current drug delivery approaches and clinical administration routes targeting the TME in these tumors, including preclinical and clinical studies.

Paediatric extra-axial medulloblastoma presenting with obstructive hydrocephalus and tonsillar herniation: clinical presentation and treatment challenges

Medulloblastoma is the most common paediatric tumour presenting in the posterior fossa. Typically, they are found midline and intra-axially located. Medulloblastomas presenting in an extra-axial location, however, are rare, and of those, they are usually found in the cerebellopontine angle. We present a case of an extra-axial medulloblastoma projecting from the lateral cerebellar hemisphere. As far as we know, there have only been two other cases of a paediatric extra-axial medulloblastoma in the cerebellar hemisphere reported in the literature. After initial medical stabilisation and insertion of an external ventricular drain, further imaging was obtained. MRI demonstrated a heterogeneously enhancing mass with diffusion restriction, a dural tail and a CSF cleft in the left lateral cerebellar hemisphere. A far lateral craniotomy was performed, with the tumour being encountered immediately on dural opening and a defined cleavage plane seen between the tumour and the cerebellar hemisphere. Gross total resection was achieved, and after a short recovery period, adjuvant craniospinal irradiation plus chemotherapy is started. This case illustrates an exceptionally rare location of a relatively common paediatric malignant brain tumour.

AZIN1 level is increased in medulloblastoma and correlates with c-Myc activity and tumor phenotype

BACKGROUND

AZIN1 is a cell cycle regulator that is upregulated in a variety of cancers. AZIN1 overexpression can induce a more aggressive tumor phenotype via increased binding and resultant inhibition of antizyme. Antizyme is a protein that normally functions as an anti-tumor regulator that facilitates the deactivation of several growth-promoting proteins including c-Myc. MYC plays a critical role in medulloblastoma pathogenesis. Its amplification serves as a defining characteristic of group 3 medulloblastomas, associated with the most aggressive clinical course, greater frequency of metastases, and shorter survival times.

METHODS

Medulloblastoma tissues (68 TMA, and 45 fresh tissues, and 31 controls) were stained (fluorescence and immunohistochemical) for AZIN1. Western blotting and ELISA were used to detect the AZIN1 level. Phenotypically aggressive cellular features were measured by increased invasion, colony formation and proliferation. CRISPR-Cas9-mediated AZIN1 knocked-out cells were orthotopically implanted in the cerebellum of nude mice (n = 8/group) with a stereotactic frame. Tumor growth was monitored using the In Vivo Imaging System (IVIS).

RESULTS

Here, we investigated the role of AZIN1 expression in medulloblastoma. We found that overexpression of AZIN1 in medulloblastoma cells induces phenotypically aggressive features. Conducting in vivo studies we found that knocking-out AZIN1 in tumors corresponds with reduced tumor progression and prolonged survival. Clinical specimens are revealing that AZIN1 is highly expressed and directly correlates with MYC amplification status in patients.

CONCLUSION

These data implicate AZIN1 as a putative regulator of medulloblastoma pathogenesis and suggest that it may have clinical application as both a biomarker and novel therapeutic target.

Mapping naturally presented T cell antigens in medulloblastoma based on integrative multi-omics

Medulloblastoma is the most frequent malignant primary brain tumor in children. Despite recent advances in integrated genomics, the prognosis in children with high-risk medulloblastoma remains devastating, and new tumor-specific therapeutic approaches are needed. Here, we present an atlas of naturally presented T cell antigens in medulloblastoma. We map the human leukocyte antigen (HLA)-presented peptidomes of 28 tumors and perform comparative immunopeptidome profiling against an in-house benign database. Medulloblastoma is shown to be a rich source of tumor-associated antigens, naturally presented on HLA class I and II molecules. Remarkably, most tumor-associated peptides and proteins are subgroup-specific, whereas shared presentation among all subgroups of medulloblastoma (WNT, SHH, Group 3 and Group 4) is rare. Functional testing of top-ranking novel candidate antigens demonstrates the induction of peptide-specific T cell responses, supporting their potential for T cell immunotherapy. This study is an in-depth mapping of naturally presented T cell antigens in medulloblastoma. Integration of immunopeptidomics, transcriptomics, and epigenetic data leads to the identification of a large set of actionable targets that can be further used for the translation into the clinical setting by facilitating the informed design of immunotherapeutic approaches to children with medulloblastoma.

Mechanisms and therapeutic potential of the hedgehog signaling pathway in cancer

A sort of major malignant disease, cancer can compromise human health wherever. Some mechanisms of the occurrence and evolution of cancer still seem elusive even now. Consequently, the therapeutic strategies for cancer must continually evolve. The hedgehog signaling pathway, a critical mediator in the normal development of numerous organs and the pathogenesis of cancer, is typically quiescent but is aberrantly activated in several malignancies. Extensive research has delineated that the aberrant activity of the hedgehog signaling pathway, whether autocrine or paracrine, is implicated in the initiation and progression of various neoplasms, including medulloblastoma (MB), basal cell carcinoma (BCC) and so on. Thus, notably Smo inhibitors, the opening of inhibitors of the hedgehog signaling pathway has become a topic of research attention. This review aims to summarize four aberrant activation pathways and the influence of hedgehog signaling pathway associated chemicals on tumor formation and development. Additionally, it will explore the therapeutic potential of targeted interventions in the hedgehog signaling pathway for cancer treatment.

Overview of the etiology of childhood cancer and future directions

PURPOSE OF REVIEW

We provide an overview of the etiology of childhood cancer, the state of the literature, and highlight some opportunities for future research, including technological advancements that could be applied to etiologic studies of childhood cancer to accelerate our understanding.

RECENT FINDINGS

Risk factors of childhood cancer were summarized based on demographics and perinatal factors, environmental risk factors, and genetic risk factors. Overall, demographics and perinatal factors are the most well studied in relation to childhood cancer. While environmental risk factors have been implicated, more work is needed to pinpoint specific exposures, identify window(s) of susceptibility, and understand mechanisms. With genome-wide association studies (GWAS), genetic risk factors of eight childhood cancers have emerged, and opportunities remain to conduct GWAS for other cancer types and determine whether risk variants are inherited or de novo. Technological advancements that can shed light into the susceptibility of childhood cancer include metabolomics, using primary teeth as an exposure matrix, and long-read sequencing.

SUMMARY

The development of childhood cancer remains largely not well understood. Collaboration to increase sample size to conduct analyses by histology and/or molecular subtype and application of novel technologies will accelerate our understanding of childhood cancer.

Ferroptosis Transcriptional Regulation and Prognostic Impact in Medulloblastoma Subtypes Revealed by RNA-Seq

Medulloblastoma (MB) is the most common malignant brain tumor in children, typically arising during infancy and childhood. Despite multimodal therapies achieving a response rate of 70% in children older than 3 years, treatment remains challenging. Ferroptosis, a form of regulated cell death, can be induced in medulloblastoma cells in vitro using erastin or RSL3. Using two independent medulloblastoma RNA-sequencing cohorts (MB-PBTA and MTAB-10767), we investigated the expression of ferroptosis-related molecules through multiple approaches, including Weighted Gene Co-Expression Network Analysis (WGCNA), molecular subtype stratification, protein-protein interaction (PPI) networks, and univariable and multivariable overall survival analyses. A prognostic expression score was computed based on a cross-validated ferroptosis signature. In training and validation cohorts, the regulation of the ferroptosis transcriptional program distinguished the four molecular subtypes of medulloblastoma. WGCNA identified nine gene modules in the MB tumor transcriptome; five correlated with molecular subtypes, implicating pathways related to oxidative stress, hypoxia, and trans-synaptic signaling. One module, associated with disease recurrence, included epigenetic regulators and nucleosome organizers. Univariable survival analyses identified a 45-gene ferroptosis prognostic signature associated with nutrient sensing, cysteine and methionine metabolism, and trans-sulfuration within a one-carbon metabolism. The top ten unfavorable ferroptosis genes included CCT3, SNX5, SQOR, G3BP1, CARS1, SLC39A14, FAM98A, FXR1, TFAP2C, and ATF4. Patients with a high ferroptosis score showed a worse prognosis, particularly in the G3 and SHH subtypes. The PPI network highlighted IL6 and CBS as unfavorable hub genes. In a multivariable overall survival model, which included gender, age, and the molecular subtype classification, the ferroptosis expression score was validated as an independent adverse prognostic marker (hazard ratio: 5.8; p-value = 1.04 × 10-9). This study demonstrates that the regulation of the ferroptosis transcriptional program is linked to medulloblastoma molecular subtypes and patient prognosis. A cross-validated ferroptosis signature was identified in two independent RNA-sequencing cohorts, and the ferroptosis score was confirmed as an independent and adverse prognostic factor in medulloblastoma.

Molecular and clinical heterogeneity within MYC-family amplified medulloblastoma is associated with survival outcomes: A multicenter cohort study

BACKGROUND

MYC/MYCN are the most frequent oncogene amplifications in medulloblastoma (MB) and its primary biomarkers of high-risk (HR) disease. However, while many patients' MYC(N)-amplified tumors are treatment-refractory, some achieve long-term survival. We therefore investigated clinicobiological heterogeneity within MYC(N)-amplified MB and determined its relevance for improved disease management.

METHODS

We characterized the clinical and molecular correlates of MYC- (MYC-MB; n = 64) and MYCN-amplified MBs (MYCN-MB; n = 95), drawn from >1600 diagnostic cases.

RESULTS

Most MYC-MBs were molecular group 3 (46/58; 79% assessable) and aged ≥3 years at diagnosis (44/64 [69%]). We identified a "canonical" very high-risk (VHR) MYC-amplified group (n = 51/62; 82%) with dismal survival irrespective of treatment (11% 5-year progression-free survival [PFS]), defined by co-occurrence with ≥1 additional established risk factor(s) (subtotal surgical-resection [STR], metastatic disease, LCA pathology), and commonly group 3/4 subgroup 2 with a high proportion of amplified cells. The majority of remaining noncanonical MYC-MBs survived (i.e. non-group 3/group 3 without other risk features; 11/62 (18%); 61% 5-year PFS). MYCN survival was primarily related to molecular group; MYCN-amplified SHH MB, and group 3/4 MB with additional risk factors, respectively defined VHR and HR groups (VHR, 39% [35/89]; 20% 5-year PFS/HR, 33% [29/89]; 46% 5-year PFS). Twenty-two out of 35 assessable MYCN-amplified SHH tumors harbored TP53 mutations; 9/12 (75%) with data were germline. MYCN-amplified group 3/4 MB with no other risk factors (28%; 25/89) had 70% 5-year PFS.

CONCLUSIONS

MYC(N)-amplified MB displays significant clinicobiological heterogeneity. Diagnostics incorporating molecular groups, subgroups, and clinical factors enable their risk assessment. VHR "canonical" MYC tumors are essentially incurable and SHH-MYCN-amplified MBs fare extremely poorly (20% survival at 5 years); both require urgent development of alternative treatment strategies. Conventional risk-adapted therapies are appropriate for more responsive groups, such as noncanonical MYC and non-SHH-MYCN MB.

Arrested development: the dysfunctional life history of medulloblastoma

Medulloblastoma is a heterogeneous embryonal tumor of the cerebellum comprised of four distinct molecular subgroups that differ in their developmental origins, genomic landscapes, clinical presentation, and survival. Recent characterization of the human fetal cerebellum at single-cell resolution has propelled unprecedented insights into the cellular origins of medulloblastoma subgroups, including those underlying previously elusive groups 3 and 4. In this review, the molecular pathogenesis of medulloblastoma is examined through the lens of cerebellar development. In addition, we discuss how enhanced understanding of medulloblastoma origins has the potential to refine disease modeling for the advancement of treatment and outcomes.

3D genome topology distinguishes molecular subgroups of medulloblastoma

Four main medulloblastoma (MB) molecular subtypes have been identified based on transcriptional, DNA methylation, and genetic profiles. However, it is currently not known whether 3D genome architecture differs between MB subtypes. To address this question, we performed in situ Hi-C to reconstruct the 3D genome architecture of MB subtypes. In total, we generated Hi-C and matching transcriptome data for 28 surgical specimens and Hi-C data for one patient-derived xenograft. The average resolution of the Hi-C maps was 6,833 bp. Using these data, we found that insulation scores of topologically associating domains (TADs) were effective at distinguishing MB molecular subgroups. TAD insulation score differences between subtypes were globally not associated with differential gene expression, although we identified few exceptions near genes expressed in the lineages of origin of specific MB subtypes. Our study therefore supports the notion that TAD insulation scores can distinguish MB subtypes independently of their transcriptional differences.

Application of radiomics for diagnosis, subtyping, and prognostication of medulloblastomas: a systematic review

Applications of radiomics for clinical management of medulloblastomas are expanding. This systematic review aims to aggregate and overview the current role of radiomics in the diagnosis, subtyping, and prognostication of medulloblastomas. The present systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed/MEDLINE were searched using a standardized search term. Articles found within the database from the inception until November 2022 were considered for screening. Retrieved records were screened independently by two authors based on their titles and abstracts. The full text of selected articles was reviewed to finalize the eligibility. Due to the heterogeneity of included studies, no formal data synthesis was conducted. Of the 249 screened citations, 21 studies were included and analyzed. Radiomics demonstrated promising performance for discriminating medulloblastomas from other posterior fossa tumors, particularly ependymomas and pilocytic astrocytomas. It was also efficacious in determining the subtype (i.e., WNT+, SHH+, group 3, and group 4) of medulloblastomas non-invasively. Regarding prognostication, radiomics exhibited some ability to predict overall survival and progression-free survival of patients with medulloblastomas. Our systematic review revealed that radiomics represents a promising tool for diagnosis and prognostication of medulloblastomas. Further prospective research measuring the clinical value of radiomics in this setting is warranted.

Differential regulation of Shh-Gli1 cell signalling pathway on homeodomain transcription factors Nkx2.2 and Pax6 during the medulloblastoma genesis

BACKGROUND

Medulloblastoma is a pediatric malignant brain tumor associated with an aberrantly activated Shh pathway. The Shh pathway acts via downstream effector molecules, including Pax6 and Nkx2.2. Transcription factor Nkx2.2 plays crucial roles during early embryonic patterning and development. In this study, we aimed to determine the role of transcription factor Nkx2.2 in medulloblastoma development.

METHODS AND RESULTS

Here, whole transcriptome levels and suppressive effect of transcription factor Nkx2.2 on Pax6 were assessed using one normal human brain and three surgically removed medulloblastoma samples. Additionally, protein levels of Shh, Gli1, Pax6, and Nkx2.2 and co-expression patterns of Pax6 and Nkx2.2 were assessed in 14 medulloblastoma samples. Quantitative reverse transcription-polymerase chain reaction revealed the suppressive effect of Nkx2.2 on Pax6. D283 cells were treated with the Shh pathway activator, SAG, and Gli1 inhibitor, GANT61, which revealed Pax6-Nkx2.2 regulation. Increased cell proliferation was observed in D283 cells transfected with Nkx2.2 small interfering RNA. Moreover, mRNA expression levels of Shh, Pax6, Nkx2.2, and Gli1 were assessed in Daoy cells transfected with Gli1 and Nkx2.2 small interfering RNAs using quantitative reverse transcription-polymerase chain reaction. Pax6 levels were increased in Nkx2.2 siRNA-transfected cells.

CONCLUSIONS

Aberrantly activated Shh pathway leads to the ectopic expression of Pax6 in granular cells, inducing medulloblastoma development. Moreover, Nkx2.2 transcription factor acts as a suppressor of Pax6 during medulloblastoma development and maintenance. Overall, this study provides novel insights for the development of effective therapeutic strategies and suggests potential targets for medulloblastoma.

Ibrahimi A, Abu Laban D, Maraqa B, Al-Ani A, Al Sharie S, Al-Hussaini M. Clinical and Molecular Characteristics and Outcome of Adult Medulloblastoma at a Tertiary Cancer Center

Background/Objectives: Adult medulloblastoma is a rare entity, with management data extrapolated from pediatric medulloblastoma cases. We aim to report the clinical characteristics, prognostic factors, and treatment outcome of a cohort of adult patients with medulloblastoma. Methods: Fifty-three patients aged ≥ 18 years with medulloblastoma treated at King Hussein Cancer Center between 2007 and 2019 were retrospectively reviewed. Patients' diseases were staged according to modified Chang's staging system. All patients received adjuvant craniospinal irradiation followed by a posterior fossa boost. Baseline disease characteristics, including molecular subgrouping, were tested as prognostic factors of progression-free survival (PFS) and overall survival (OS) by using univariate analysis. Results: Median follow-up was 70 months (range 37.5-104.5 months). Twenty-two tumors were of the SHH-activated subtype. Conversely, WNT-activated and group 4 tumors had three cases each. Only 37.7% of patients died. The mean 3-year, 5-year, and 10-year OS were 85% (75-95%), 74% (62-87%), and 50% (33-75%), respectively. Significant differences in OS were associated with the extent of surgery (p = 0.017), M stage (p = 0.009), and risk status (p < 0.001). Relapses were detected in 28.3% of cases. The 3-year, 5-year, and 10-year PFS were 81% (71-92%), 75% (63-88%), and 66% (52-83%), respectively. Significant differences in PFS were associated with the extent of surgery (p = 0.008) and risk status (p = 0.012). Molecular subgrouping did not correlate with OS or PFS. Conclusions: Our results revealed poor survival of patients with high-risk disease, which may necessitate the intensification of chemotherapy. Molecular subgrouping did not correlate with the outcome in this cohort.

High-throughput neural stem cell-based drug screening identifies S6K1 inhibition as a selective vulnerability in sonic hedgehog-medulloblastoma

BACKGROUND

Medulloblastoma (MB) is one of the most common malignant brain tumors in children. Current treatments have increased overall survival but can lead to devastating side effects and late complications in survivors, emphasizing the need for new, improved targeted therapies that specifically eliminate tumor cells while sparing the normally developing brain.

METHODS

Here, we used a sonic hedgehog (SHH)-MB model based on a patient-derived neuroepithelial stem cell system for an unbiased high-throughput screen with a library of 172 compounds with known targets. Compounds were evaluated in both healthy neural stem cells (NSCs) and tumor cells derived from the same patient. Based on the difference of cell viability and drug sensitivity score between normal cells and tumor cells, hit compounds were selected and further validated in vitro and in vivo.

RESULTS

We identified PF4708671 (S6K1 inhibitor) as a potential agent that selectively targets SHH-driven MB tumor cells while sparing NSCs and differentiated neurons. Subsequent validation studies confirmed that PF4708671 inhibited the growth of SHH-MB tumor cells both in vitro and in vivo, and that knockdown of S6K1 resulted in reduced tumor formation.

CONCLUSIONS

Overall, our results suggest that inhibition of S6K1 specifically affects tumor growth, whereas it has less effect on non-tumor cells. Our data also show that the NES cell platform can be used to identify potentially effective new therapies and targets for SHH-MB.

Predicting response to chemotherapy in brain tumor patients based on MRI features

Chemotherapy in brain tumors is tailored based on tumor type, grade, and molecular markers, which are crucial for predicting responses and survival outcomes. This review summarizes the role of chemotherapy in gliomas, glioneuronal and neuronal tumors, ependymomas, choroid plexus tumors, medulloblastomas, and meningiomas, discussing standard treatment protocols and recent developments in targeted therapies.Furthermore, the studies reporting the integration of MRI-based radiomics and deep learning models for predicting treatment outcomes are reviewed. Advances in MRI-based radiomics and deep learning models have significantly enhanced the prediction of chemotherapeutic benefits, survival prediction following chemotherapy, and differentiating tumor progression with psuedoprogression. These non-invasive techniques offer valuable insights into tumor characteristics and treatment responses, facilitating personalized therapeutic strategies. Further research is warranted to refine these models and expand their applicability across different brain tumor types.

Embryonal and pineal tumours

Embryonal and pineal tumours represent a diverse group of central nervous system (CNS) neoplasms. While many of the small round blue cell tumours that make up the embryonal neoplasms share similar histologic qualities, there are several morphologic and cytologic characteristics that are useful in distinguishing different tumour types. Similarly, pineal parenchymal tumours represent clinically diverse tumours, ranging from benign to overtly malignant. The most recent iteration of the World Health Organization Classification of CNS Tumours expanded greatly on the significance of molecular alterations in brain tumour diagnostics. In this article, we summarize the salient cytologic and histologic features of CNS embryonal and pineal tumours, and highlight diagnostically relevant molecular alterations within each tumour type.

Radiomics and artificial intelligence applications in pediatric brain tumors

BACKGROUND

The study of central nervous system (CNS) tumors is particularly relevant in the pediatric population because of their relatively high frequency in this demographic and the significant impact on disease- and treatment-related morbidity and mortality. While both morphological and non-morphological magnetic resonance imaging techniques can give important information concerning tumor characterization, grading, and patient prognosis, increasing evidence in recent years has highlighted the need for personalized treatment and the development of quantitative imaging parameters that can predict the nature of the lesion and its possible evolution. For this purpose, radiomics and the use of artificial intelligence software, aimed at obtaining valuable data from images beyond mere visual observation, are gaining increasing importance. This brief review illustrates the current state of the art of this new imaging approach and its contributions to understanding CNS tumors in children.

DATA SOURCES

We searched the PubMed, Scopus, and Web of Science databases using the following key search terms: ("radiomics" AND/OR "artificial intelligence") AND ("pediatric AND brain tumors"). Basic and clinical research literature related to the above key research terms, i.e., studies assessing the key factors, challenges, or problems of using radiomics and artificial intelligence in pediatric brain tumors management, was collected.

RESULTS

A total of 63 articles were included. The included ones were published between 2008 and 2024. Central nervous tumors are crucial in pediatrics due to their high frequency and impact on disease and treatment. MRI serves as the cornerstone of neuroimaging, providing cellular, vascular, and functional information in addition to morphological features for brain malignancies. Radiomics can provide a quantitative approach to medical imaging analysis, aimed at increasing the information obtainable from the pixels/voxel grey-level values and their interrelationships. The "radiomic workflow" involves a series of iterative steps for reproducible and consistent extraction of imaging data. These steps include image acquisition for tumor segmentation, feature extraction, and feature selection. Finally, the selected features, via training predictive model (CNN), are used to test the final model.

CONCLUSIONS

In the field of personalized medicine, the application of radiomics and artificial intelligence (AI) algorithms brings up new and significant possibilities. Neuroimaging yields enormous amounts of data that are significantly more than what can be gained from visual studies that radiologists can undertake on their own. Thus, new partnerships with other specialized experts, such as big data analysts and AI specialists, are desperately needed. We believe that radiomics and AI algorithms have the potential to move beyond their restricted use in research to clinical applications in the diagnosis, treatment, and follow-up of pediatric patients with brain tumors, despite the limitations set out.

Immunoexpression of Survivin and P53 in the Histological Subtypes of Medulloblastoma: A Cross-Sectional Observational Study

Medulloblastoma (MB) is a common malignant intracranial neoplasms in children. The treatment and prognosis of this tumor depends on histology and molecular subtypes. Survivin, implicated in various malignancies, may hold prognostic significance. We investigated survivin and p53 immunoreactivity in different histological subtypes in 20 MB cases from January 2018 to June 2021. Immunohistochemistry revealed survivin expression in 75% (15/20) of cases, with cytoplasmic (10 cases), nuclear (four cases), or combined expression (one case). p53 nuclear expression was present in 35% (7/20) of cases. Classical variant MB exhibited predominant p53 and cytoplasmic survivin expression. Given the association of survivin and p53 expression with poor prognosis, especially in the prevalent classical variant, targeted therapies may hold promise for MB treatment advancement.

Risk-stratification for treatment de-intensification in WNT-pathway medulloblastoma: finding the optimal balance between survival and quality of survivorship

INTRODUCTION

Advances in molecular biology have led to consensus classification of medulloblastoma into four broad molecular subgroups - wingless (WNT), sonic hedgehog (SHH), Group 3, and Group 4, respectively. Traditionally, children >3 years of age, with no/minimal residual tumor (<1.5 cm2) and lack of metastasis were classified as average-risk disease with >80% long-term survival. Younger age (<3 years), large residual disease (≥1.5 cm2), and leptomeningeal metastases either alone or in combination were considered high-risk features yielding much worse 5-year survival (30-60%). This clinico-radiological risk-stratification has been refined by incorporating molecular/genetic information. Contemporary multi-modality management for non-infantile medulloblastoma entails maximal safe resection followed by risk-stratified adjuvant radio(chemo)therapy. Aggressive multi-modality management achieves good survival but is associated with substantial dose-dependent treatment-related toxicity prompting conduct of subgroup-specific prospective clinical trials.

AREAS COVERED

We conducted literature search on PubMed from 1969 till 2023 to identify putative prognostic factors and risk-stratification for medulloblastoma, including molecular subgrouping. Based on previously published data, including our own institutional experience, we discuss molecular risk-stratification focusing on WNT-pathway medulloblastoma to identify candidates suitable for treatment de-intensification to strike the optimal balance between survival and quality of survivorship.

EXPERT OPINION

Prospective clinical trials and emerging biological information should further refine risk-stratification in WNT-pathway medulloblastoma.

Neurosurgical short-term outcomes for pediatric medulloblastoma patients and molecular correlations: a 10-year single-center observation cohort study

This study examined the risk factors for short-term outcomes, focusing particularly on the associations among molecular subgroups. The analysis focused on the data of pediatric patients with medulloblastoma between 2013 and 2023, as well as operative complications, length of stay from surgery to adjuvant treatment, 30-day unplanned reoperation, unplanned readmission, and mortality. 148 patients were included. Patients with the SHH TP53-wildtype exhibited a lower incidence of complications (45.2% vs. 66.0%, odds ratio [OR] 0.358, 95% confidence interval [CI] 0.160 - 0.802). Female sex (0.437, 0.207 - 0.919) was identified as an independent protective factor for complications, and brainstem involvement (1.900, 1.297 - 2.784) was identified as a risk factor. Surgical time was associated with an increased risk of complications (1.004, 1.001 - 1.008), duration of hospitalization (1.006, 1.003 - 1.010), and reoperation (1.003, 1.001 - 1.006). Age was found to be a predictor of improved outcomes, as each additional year was associated with a 14.1% decrease in the likelihood of experiencing a prolonged length of stay (0.859, 0.772 - 0.956). Patients without metastasis exhibited a reduced risk of reoperation (0.322, 0.133 - 0.784) and readmission (0.208, 0.074 - 0.581). There is a significant degree of variability in the occurrence of operative complications in pediatric patients with medulloblastoma. SHH TP53-wildtype medulloblastoma is commonly correlated with a decreased incidence of complications. The short-term outcomes of patients are influenced by various unmodifiable endogenous factors. These findings could enhance the knowledge of onconeurosurgeons and alleviate the challenges associated with patient/parent education through personalized risk communication. However, the importance of a dedicated center with expertise surgical team and experienced neurosurgeon in improving neurosurgical outcomes appears self-evident.

A Radiomic Approach for Evaluating Intra-Subgroup Heterogeneity in SHH and Group 4 Pediatric Medulloblastoma: A Preliminary Multi-Institutional Study

Medulloblastoma (MB) is the most frequent malignant brain tumor in children with extensive heterogeneity that results in varied clinical outcomes. Recently, MB was categorized into four molecular subgroups, WNT, SHH, Group 3, and Group 4. While SHH and Group 4 are known for their intermediate prognosis, studies have reported wide disparities in patient outcomes within these subgroups. This study aims to create a radiomic prognostic signature, medulloblastoma radiomics risk (mRRisk), to identify the risk levels within the SHH and Group 4 subgroups, individually, for reliable risk stratification. Our hypothesis is that this signature can comprehensively capture tumor characteristics that enable the accurate identification of the risk level. In total, 70 MB studies (48 Group 4, and 22 SHH) were retrospectively curated from three institutions. For each subgroup, 232 hand-crafted features that capture the entropy, surface changes, and contour characteristics of the tumor were extracted. Features were concatenated and fed into regression models for risk stratification. Contrasted with Chang stratification that did not yield any significant differences within subgroups, significant differences were observed between two risk groups in Group 4 (p = 0.04, Concordance Index (CI) = 0.82) on the cystic core and non-enhancing tumor, and SHH (p = 0.03, CI = 0.74) on the enhancing tumor. Our results indicate that radiomics may serve as a prognostic tool for refining MB risk stratification, towards improved patient care.

Functional expression of the proton sensors ASIC1a, TMEM206, and OGR1 together with BKCa channels is associated with cell volume changes and cell death under strongly acidic conditions in DAOY medulloblastoma cells

Fast growing solid tumors are frequently surrounded by an acidic microenvironment. Tumor cells employ a variety of mechanisms to survive and proliferate under these harsh conditions. In that regard, acid-sensitive membrane receptors constitute a particularly interesting target, since they can affect cellular functions through ion flow and second messenger cascades. Our knowledge of these processes remains sparse, however, especially regarding medulloblastoma, the most common pediatric CNS malignancy. In this study, using RT-qPCR, whole-cell patch clamp, and Ca2+-imaging, we uncovered several ion channels and a G protein-coupled receptor, which were regulated directly or indirectly by low extracellular pH in DAOY and UW228 medulloblastoma cells. Acidification directly activated acid-sensing ion channel 1a (ASIC1a), the proton-activated Cl- channel (PAC, ASOR, or TMEM206), and the proton-activated G protein-coupled receptor OGR1. The resulting Ca2+ signal secondarily activated the large conductance calcium-activated potassium channel (BKCa). Our analyses uncover a complex relationship of these transmembrane proteins in DAOY cells that resulted in cell volume changes and induced cell death under strongly acidic conditions. Collectively, our results suggest that these ion channels in concert with OGR1 may shape the growth and evolution of medulloblastoma cells in their acidic microenvironment.

Medulloblastoma in adults: an analysis of clinico-pathological, molecular and treatment factors

BACKGROUND

Medulloblastoma is a highly malignant, embryonal tumor, which is rare in adults, and shows distinct clinical, histopathological, molecular and treatment response features.

METHODS

We retrospectively investigated 44 adults (age 17-48 years) with a histological diagnosis of medulloblastoma, and in 23 immunohistochemistry was used to identify the molecular subgroups. We analyzed demographic, diagnostic, therapeutic and cognitive data, and correlated with PFS (progression-free-survival) and OS (overall survival).

RESULTS

We observed a male prevalence and a median age of 31 years. Symptoms at onset were related to infratentorial location, while myeloradicular and/or cranial nerve involvement was rare. Histological examination showed the classic variant in 75% of patients, the desmoplastic/nodular in 23% and the anaplastic in one. As for molecular diagnosis, 17 patients were SHH and 6 non-WNT/non-SHH (5 group 4 and 1 group 3), while no WNT subgroup was found. The SHH subgroup had a prevalence of high-risk patients and leptomeningeal involvement. Patients underwent gross total or subtotal/partial resection, and craniospinal irradiation, followed in 20 cases by adjuvant chemotherapy. Median OS and PFS were 16.9 and 12 years, respectively. Metastatic disease at presentation and subtotal/partial resection were associated with worse prognosis, while the addition of chemotherapy did not yield a significant advantage over radiotherapy alone. Cognitive impairment in long-term survivors was limited and late relapses occurred in 15% of patients.

CONCLUSIONS

Future studies with adequate sample size and long-term follow-up should prospectively investigate the role of surgery and adjuvant therapies across the different molecular subgroups to see whether a personalized approach is feasible.

Surgical Management of High-Grade Meningiomas

Maximal resection with the preservation of neurological function are the mainstays of the surgical management of high-grade meningiomas. Surgical morbidity is strongly associated with tumor size, location, and invasiveness, whereas patient survival is strongly associated with the extent of resection, tumor biology, and patient health. A versatile microsurgical skill set combined with a cogent multimodality treatment plan is critical in order to achieve optimal patient outcomes. Continued refinement in surgical techniques in conjunction with directed radiotherapeutic and medical therapies will define future treatment.

Melanoma antigens in pediatric medulloblastoma contribute to tumor heterogeneity and species-specificity of group 3 tumors

Background

Medulloblastoma (MB) is the most malignant childhood brain cancer. Group 3 MB subtype accounts for about 25% of MB diagnoses and is associated with the most unfavorable outcomes. Herein, we report that more than half of group 3 MB tumors express melanoma antigens (MAGEs), which are potential prognostic and therapeutic markers. MAGEs are tumor antigens, expressed in several types of adult cancers and associated with poorer prognosis and therapy resistance; however, their expression in pediatric cancers is mostly unknown. The aim of this study was to determine whether MAGEs are activated in pediatric MB.

Methods

To determine MAGE frequency in pediatric MB, we obtained formalin-fixed paraffin-embedded tissue (FFPE) samples of 34 patients, collected between 2008 - 2015, from the Children's Medical Center Dallas pathology archives and applied our validated reverse transcription quantitative PCR (RT-qPCR) assay to measure the relative expression of 23 MAGE cancer-testis antigen genes. To validate our data, we analyzed several published datasets from pediatric MB patients and patient-derived orthotopic xenografts, totaling 860 patients. We then examined how MAGE expression affects the growth and oncogenic potential of medulloblastoma cells by CRISPR-Cas9- and siRNA-mediated gene depletion.

Results

Our RT-qPCR analysis suggested that MAGEs were expressed in group 3/4 medulloblastoma. Further mining of bulk and single-cell RNA-sequencing datasets confirmed that 50-75% of group 3 tumors activate a subset of MAGE genes. Depletion of MAGEAs, B2, and Cs alter MB cell survival, viability, and clonogenic growth due to decreased proliferation and increased apoptosis.

Conclusions

These results indicate that targeting MAGEs in medulloblastoma may be a potential therapeutic option for group 3 medulloblastomas.

Key Points

Several Type I MAGE CTAs are expressed in >60% of group 3 MBs. Type I MAGEs affect MB cell proliferation and apoptosis. MAGEs are potential biomarkers and therapeutic targets for group 3 MBs.

Importance of the Study

This study is the first comprehensive analysis of all Type I MAGE CTAs ( MAGEA , -B , and -C subfamily members) in pediatric MBs. Our results show that more than 60% of group 3 MBs express MAGE genes, which are required for the viability and growth of cells in which they are expressed. Collectively, these data provide novel insights into the antigen landscape of pediatric MBs. The activation of MAGE genes in group 3 MBs presents potential stratifying and therapeutic options.

Abstract Figure

Drivers Underlying Metastasis and Relapse in Medulloblastoma and Targeting Strategies

Medulloblastomas comprise a molecularly diverse set of malignant pediatric brain tumors in which patients are stratified according to different prognostic risk groups that span from very good to very poor. Metastasis at diagnosis is most often a marker of poor prognosis and the relapse incidence is higher in these children. Medulloblastoma relapse is almost always fatal and recurring cells have, apart from resistance to standard of care, acquired genetic and epigenetic changes that correlate with an increased dormancy state, cell state reprogramming and immune escape. Here, we review means to carefully study metastasis and relapse in preclinical models, in light of recently described molecular subgroups. We will exemplify how therapy resistance develops at the cellular level, in a specific niche or from therapy-induced secondary mutations. We further describe underlying molecular mechanisms on how tumors acquire the ability to promote leptomeningeal dissemination and discuss how they can establish therapy-resistant cell clones. Finally, we describe some of the ongoing clinical trials of high-risk medulloblastoma and suggest or discuss more individualized treatments that could be of benefit to specific subgroups.

Direct Implantation of Patient Brain Tumor Cells into Matching Locations in Mouse Brains for Patient-Derived Orthotopic Xenograft Model Development

Background: Despite multimodality therapies, the prognosis of patients with malignant brain tumors remains extremely poor. One of the major obstacles that hinders development of effective therapies is the limited availability of clinically relevant and biologically accurate (CRBA) mouse models. Methods: We have developed a freehand surgical technique that allows for rapid and safe injection of fresh human brain tumor specimens directly into the matching locations (cerebrum, cerebellum, or brainstem) in the brains of SCID mice. Results: Using this technique, we successfully developed 188 PDOX models from 408 brain tumor patient samples (both high-and low-grade) with a success rate of 72.3% in high-grade glioma, 64.2% in medulloblastoma, 50% in ATRT, 33.8% in ependymoma, and 11.6% in low-grade gliomas. Detailed characterization confirmed their replication of the histopathological and genetic abnormalities of the original patient tumors. Conclusions: The protocol is easy to follow, without a sterotactic frame, in order to generate large cohorts of tumor-bearing mice to meet the needs of biological studies and preclinical drug testing.

The OTX2 Gene Induces Tumor Growth and Triggers Leptomeningeal Metastasis by Regulating the mTORC2 Signaling Pathway in Group 3 Medulloblastomas

Medulloblastoma (MB) encompasses diverse subgroups, and leptomeningeal disease/metastasis (LMD) plays a substantial role in associated fatalities. Despite extensive exploration of canonical genes in MB, the molecular mechanisms underlying LMD and the involvement of the orthodenticle homeobox 2 (OTX2) gene, a key driver in aggressive MB Group 3, remain insufficiently understood. Recognizing OTX2's pivotal role, we investigated its potential as a catalyst for aggressive cellular behaviors, including migration, invasion, and metastasis. OTX2 overexpression heightened cell growth, motility, and polarization in Group 3 MB cells. Orthotopic implantation of OTX2-overexpressing cells in mice led to reduced median survival, accompanied by the development of spinal cord and brain metastases. Mechanistically, OTX2 acted as a transcriptional activator of the Mechanistic Target of Rapamycin (mTOR) gene's promoter and the mTORC2 signaling pathway, correlating with upregulated downstream genes that orchestrate cell motility and migration. Knockdown of mTOR mRNA mitigated OTX2-mediated enhancements in cell motility and polarization. Analysis of human MB tumor samples (N = 952) revealed a positive correlation between OTX2 and mTOR mRNA expression, emphasizing the clinical significance of OTX2's role in the mTORC2 pathway. Our results reveal that OTX2 governs the mTORC2 signaling pathway, instigating LMD in Group 3 MBs and offering insights into potential therapeutic avenues through mTORC2 inhibition.

The pivotal role of irradiation-induced apoptosis in the pathogenesis and therapy of medulloblastoma

BACKGROUND

Medulloblastoma (MB) is a rare primitive neuroectodermal tumors originating from the cerebellum. MB is the most common malignant primary brain tumor of childhood. MB originates from neural precursor cells in distinctive regions of the rhombic lip, and their maturation occurs in the cerebellum or the brain stem during embryonal development. Also, apoptosis is a programmed cell death associated with numerous physiological as well as pathological regulations.

RECENT FINDINGS

Irradiation (IR)-induce apoptosis triggers cell death, with or without intervening mitosis within a few hours of IR and these share different morphologic alteration such as, loss of normal nuclear structure as well as degradation of DNA. Moreover, MB is strikingly sensitive to DNA-damaging therapies and the role of apoptosis a key treatment modality. Furthermore, in MB, the apoptotic pathways are made up of several triggers, modulators, as well as effectors. Notably, IR-induced apoptotic mechanisms in MB therapy are very complex and they either induce radiosensitivity or inhibit radioresistance leading to potential effective treatment strategies for MB.

CONCLUSION

This review explicitly explores the pivotal roles of IR-induced apoptosis in the pathogenesis and therapy of MB.

Extra-axial cerebellopontine angle nodular medulloblastoma mimicking meningioma: a case report with literature review

Introduction

Medulloblastoma, a highly malignant embryonal tumor predominantly found in the pediatric population, typically arises within the cerebellum. This case report holds particular importance due to the rarity of medulloblastoma within the cerebellopontine angle (CPA). The distinct anatomical challenge posed by the CPA complex neurovascular structures, along with the absence of pathognomonic clinical or radiographic features, highlights the unique diagnostic and management challenge of this case.

Case presentation

A 5-year-old boy presented with mild, progressively worsening headaches on CT/MRI imaging, which revealed a solid mass in the left CPA. Radiologically, the lesion closely resembled a CPA meningioma. The patient underwent a left retrosigmoid suboccipital craniectomy, utilizing a modified park bench position and careful burrhole creation. Intraoperatively, the tumor exhibited well-defined margins, firm adherence to cranial nerves, and complex tissue characteristics. Postoperatively, histopathological analysis identified nodular medulloblastoma, WHO grade IV, with immunohistochemical markers confirming its subtype.

Discussion

This case highlights the critical role of surgical intervention in addressing rare tumors, emphasizing the need for multidisciplinary collaboration in both diagnosis and management to achieve a favorable outcome. Uncommon tumor locations, such as the CPA, require tailored approaches, and the utilization of advanced diagnostic techniques, including immunohistochemistry, aids in accurate subtype classification.

Conclusion

This case highlights the critical role of surgical intervention in addressing rare tumors, emphasizing the need for multidisciplinary collaboration in both diagnosis and management to achieve a favorable outcome.

Heterogeneity and tumoral origin of medulloblastoma in the single-cell era

Medulloblastoma is one of the most common malignant pediatric brain tumors derived from posterior fossa. The current treatment includes maximal safe surgical resection, radiotherapy, whole cranio-spinal radiation and adjuvant with chemotherapy. However, it can only limitedly prolong the survival time with severe side effects and relapse. Defining the intratumoral heterogeneity, cellular origin and identifying the interaction network within tumor microenvironment are helpful for understanding the mechanisms of medulloblastoma tumorigenesis and relapse. Due to technological limitations, the mechanisms of cellular heterogeneity and tumor origin have not been fully understood. Recently, the emergence of single-cell technology has provided a powerful tool for achieving the goal of understanding the mechanisms of tumorigenesis. Several studies have demonstrated the intratumoral heterogeneity and tumor origin for each subtype of medulloblastoma utilizing the single-cell RNA-seq, which has not been uncovered before using conventional technologies. In this review, we present an overview of the current progress in understanding of cellular heterogeneity and tumor origin of medulloblastoma and discuss novel findings in the age of single-cell technologies.

Childhood, adolescent, and adult primary brain and central nervous system tumor statistics for practicing healthcare providers in neuro-oncology, CBTRUS 2015-2019

Background

The Central Brain Tumor Registry of the United States (CBTRUS), in collaboration with the Centers for Disease Control and Prevention (CDC) and National Cancer Institute (NCI), is the largest aggregation of histopathology-specific population-based data for primary brain and other central nervous system (CNS) in the US. CBTRUS publishes an annual statistical report which provides critical reference data for the broad neuro-oncology community. Here, we summarize the key findings from the 2022 CBTRUS annual statistical report for healthcare providers.

Methods

Incidence data were obtained from the CDC's National Program of Cancer Registries (NPCR) and NCI's Surveillance, Epidemiology, and End Results Program for 52 central cancer registries (CCRs). Survival data were obtained from 42 NPCR CCRs. All rates are per 100 000 and age-adjusted using the 2000 US standard population. Overall median survival was estimated using Kaplan-Meier models. Survival data for selected molecularly defined histopathologies are from the National Cancer Database. Mortality data are from the National Vital Statistics System.

Results

The average annual age-adjusted incidence rate of all primary brain and other CNS tumors was 24.25/100 000. Incidence was higher in females and non-Hispanics. The most commonly occurring malignant and predominately non-malignant tumors was glioblastoma (14% of all primary brain tumors) and meningioma (39% of all primary brain tumors), respectively. Mortality rates and overall median survival varied by age, sex, and histopathology.

Conclusions

This summary describes the most up-to-date population-based incidence, mortality, and survival, of primary brain and other CNS tumors in the US and aims to serve as a concise resource for neuro-oncology providers.

Compartments in medulloblastoma with extensive nodularity are connected through differentiation along the granular precursor lineage

Medulloblastomas with extensive nodularity are cerebellar tumors characterized by two distinct compartments and variable disease progression. The mechanisms governing the balance between proliferation and differentiation in MBEN remain poorly understood. Here, we employ a multi-modal single cell transcriptome analysis to dissect this process. In the internodular compartment, we identify proliferating cerebellar granular neuronal precursor-like malignant cells, along with stromal, vascular, and immune cells. In contrast, the nodular compartment comprises postmitotic, neuronally differentiated malignant cells. Both compartments are connected through an intermediate cell stage resembling actively migrating CGNPs. Notably, we also discover astrocytic-like malignant cells, found in proximity to migrating and differentiated cells at the transition zone between the two compartments. Our study sheds light on the spatial tissue organization and its link to the developmental trajectory, resulting in a more benign tumor phenotype. This integrative approach holds promise to explore intercompartmental interactions in other cancers with varying histology.

Developmental basis of SHH medulloblastoma heterogeneity

Many genes that drive normal cellular development also contribute to oncogenesis. Medulloblastoma (MB) tumors likely arise from neuronal progenitors in the cerebellum, and we hypothesized that the heterogeneity observed in MBs with sonic hedgehog (SHH) activation could be due to differences in developmental pathways. To investigate this question, here we perform single-nucleus RNA sequencing on highly differentiated SHH MBs with extensively nodular histology and observed malignant cells resembling each stage of canonical granule neuron development. Through innovative computational approaches, we connect these results to published datasets and find that some established molecular subtypes of SHH MB appear arrested at different developmental stages. Additionally, using multiplexed proteomic imaging and MALDI imaging mass spectrometry, we identify distinct histological and metabolic profiles for highly differentiated tumors. Our approaches are applicable to understanding the interplay between heterogeneity and differentiation in other cancers and can provide important insights for the design of targeted therapies.

Liquid Biopsies for Monitoring Medulloblastoma: Circulating Tumor DNA as a Biomarker for Disease Progression and Treatment Response

Pediatric brain tumors, including medulloblastoma (MB), represent a significant challenge in clinical oncology. Early diagnosis, accurate monitoring of therapeutic response, and the detection of minimal residual disease (MRD) are crucial for improving outcomes in these patients. This review aims to explore recent advancements in liquid biopsy techniques for monitoring pediatric brain tumors, with a specific focus on medulloblastoma. The primary research question is how liquid biopsy techniques can be effectively utilized for these purposes. Liquid biopsies, particularly the analysis of circulating tumor DNA (ctDNA) in cerebrospinal fluid (CSF), are investigated as promising noninvasive tools. This comprehensive review examines the components of liquid biopsies, including ctDNA, cell-free DNA (cfDNA), and microRNA (miRNA). Their applications in diagnosis, prognosis, and MRD assessment are critically assessed. The review also discusses the role of liquid biopsies in categorizing medulloblastoma subgroups, risk stratification, and the identification of therapeutic targets. Liquid biopsies have shown promising applications in the pediatric brain tumor field, particularly in medulloblastoma. They offer noninvasive means of diagnosis, monitoring treatment response, and detecting MRD. These biopsies have played a pivotal role in subgroup classification and risk stratification of medulloblastoma patients, aiding in the identification of therapeutic targets. However, challenges related to sensitivity and specificity are noted. In conclusion, this review highlights the growing importance of liquid biopsies, specifically ctDNA analysis in CSF, in pediatric brain tumor management, with a primary focus on medulloblastoma. Liquid biopsies have the potential to revolutionize patient care by enabling early diagnosis, accurate monitoring, and MRD detection. Nevertheless, further research is essential to validate their clinical utility fully. The evolving landscape of liquid biopsy applications underscores their promise in improving outcomes for pediatric brain tumor patients.

Pediatric-Like Brain Tumors in Adults

Pediatric brain tumors are different to those found in adults in pathological type, anatomical site, molecular signature, and probable tumor drivers. Although these tumors usually occur in childhood, they also rarely present in adult patients, either as a de novo diagnosis or as a delayed recurrence of a pediatric tumor in the setting of a patient that has transitioned into adult services.Due to the rarity of pediatric-like tumors in adults, the literature on these tumor types in adults is often limited to small case series, and treatment decisions are often based on the management plans taken from pediatric studies. However, the biology of these tumors is often different from the same tumors found in children. Likewise, adult patients are often unable to tolerate the side effects of the aggressive treatments used in children-for which there is little or no evidence of efficacy in adults. In this chapter, we review the literature and summarize the clinical, pathological, molecular profile, and response to treatment for the following pediatric tumor types-medulloblastoma, ependymoma, craniopharyngioma, pilocytic astrocytoma, subependymal giant cell astrocytoma, germ cell tumors, choroid plexus tumors, midline glioma, and pleomorphic xanthoastrocytoma-with emphasis on the differences to the adult population.

Somatic Versus Germline: A Case Series of Three Children With ATM-Mutated Medulloblastoma

Somatic versus Germline-A Case Series of Three Children with ATM- mutated Medulloblastoma.

Genomic tumor evolution dictates human medulloblastoma progression

Background

Medulloblastoma (MB) is the most common high-grade pediatric brain tumor, comprised of 4 main molecular subgroups-sonic-hedgehog (SHH), Wnt, Group 3, and Group 4. Group 3 and Group 4 tumors are the least characterized MB subgroups, despite Group 3 having the worst prognosis (~50% survival rate), and Group 4 being the most prevalent. Such poor characterization can be attributed to high levels of inter- and intratumoral heterogeneity, making it difficult to identify common therapeutic targets.

Methods

In this study, we generated single-cell sequencing data from 14 MB patients spanning all subgroups that we complemented with publicly available single-cell data from Group 3 patients. We used a ligand-receptor analysis tool (CellChat), expression- and allele-based copy-number variation (CNV) detection methods, and RNA velocity analysis to characterize tumor cell-cell interactions, established a connection between CNVs and temporal tumor progression, and unraveled tumor evolution.

Results

We show that MB tumor cells follow a temporal trajectory from those with low CNV levels to those with high CNV levels, allowing us to identify early and late markers for SHH, Group 3, and Group 4 MBs. Our study also identifies SOX4 upregulation as a major event in later tumor clones for Group 3 and Group 4 MBs, suggesting it as a potential therapeutic target for both subgroups.

Conclusion

Taken together, our findings highlight MB's inherent tumor heterogeneity and offer promising insights into potential drivers of MB tumor evolution particularly in Group 3 and Group 4 MBs.

Chronic AMPK inactivation slows SHH medulloblastoma progression by inhibiting mTORC1 signaling and depleting tumor stem cells

We show that inactivating AMPK in a genetic medulloblastoma model depletes tumor stem cells and slows progression. In medulloblastoma, the most common malignant pediatric brain tumor, drug-resistant stem cells co-exist with transit-amplifying cells and terminally differentiated neuronal progeny. Prior studies show that Hk2-dependent glycolysis promotes medulloblastoma progression by suppressing neural differentiation. To determine how the metabolic regulator AMPK affects medulloblastoma growth and differentiation, we inactivated AMPK genetically in medulloblastomas. We bred conditional Prkaa1 and Prkaa2 deletions into medulloblastoma-prone SmoM2 mice and compared SmoM2-driven medulloblastomas with intact or inactivated AMPK. AMPK-inactivation increased event-free survival (EFS) and altered cellular heterogeneity, increasing differentiation and decreasing tumor stem cell populations. Surprisingly, AMPK-inactivation decreased mTORC1 activity and decreased Hk2 expression. Hk2 deletion similarly depleted medulloblastoma stem cells, implicating reduced glycolysis in the AMPK-inactivated phenotype. Our results show that AMPK inactivation disproportionately impairs medulloblastoma stem cell populations typically refractory to conventional therapies.

PRMT5 as a Potential Therapeutic Target in MYC-Amplified Medulloblastoma

MYC amplification or overexpression is most common in Group 3 medulloblastomas and is positively associated with poor clinical outcomes. Recently, protein arginine methyltransferase 5 (PRMT5) overexpression has been shown to be associated with tumorigenic MYC functions in cancers, particularly in brain cancers such as glioblastoma and medulloblastoma. PRMT5 regulates oncogenes, including MYC, that are often deregulated in medulloblastomas. However, the role of PRMT5-mediated post-translational modification in the stabilization of these oncoproteins remains poorly understood. The potential impact of PRMT5 inhibition on MYC makes it an attractive target in various cancers. PRMT5 inhibitors are a promising class of anti-cancer drugs demonstrating preclinical and preliminary clinical efficacies. Here, we review the publicly available preclinical and clinical studies on PRMT5 targeting using small molecule inhibitors and discuss the prospects of using them in medulloblastoma therapy.