Childhood Medulloblastoma Research Articles

Systematic transcriptomic analysis of childhood medulloblastoma identifies N6- methyladenosine-dependent lncRNA signatures associated with molecular subtype, immune cell infiltration, and prognosis.

Medulloblastoma, the most common malignant pediatric brain tumor, is classified into four main molecular subgroups, but group 3 and group 4 tumors are difficult to subclassify and have a poor prognosis. Rapid point-of-care diagnostic and prognostic assays are needed to improve medulloblastoma risk stratification and management. N6-methyladenosine (m6A) is a common RNA modification and long non-coding RNAs (lncRNAs) play a central role in tumor progression, but their impact on gene expression and associated clinical outcomes in medulloblastoma are unknown. Here we analyzed 469 medulloblastoma tumor transcriptomes to identify lncRNAs co-expressed with m6A regulators. Using LASSO-Cox analysis, we identified a five-gene m6A-associated lncRNA signature (M6LSig) significantly associated with overall survival, which was combined in a prognostic clinical nomogram. Using expression of the 67 m6A-associated lncRNAs, a subgroup classification model was generated using the XGBoost machine learning algorithm, which had a classification accuracy > 90%, including for group 3 and 4 samples. All M6LSig genes were significantly correlated with at least one immune cell type abundance in the tumor microenvironment, and the risk score was positively correlated with CD4+ naïve T cell abundance and negatively correlated with follicular helper T cells and eosinophils. Knockdown of key m6A writer genes METTL3 and METTL14 in a group 3 medulloblastoma cell line (D425-Med) decreased cell proliferation and upregulated many M6LSig genes identified in our in silico analysis, suggesting that the signature genes are functional in medulloblastoma. This study highlights a crucial role for m6A-dependent lncRNAs in medulloblastoma prognosis and immune responses and provides the foundation for practical clinical tools that can be rapidly deployed in clinical settings.

Systematic transcriptomic analysis of childhood medulloblastoma identifies N6-methyladenosine-dependent lncRNA signatures associated with molecular subtype, immune cell infiltration, and prognosis

Medulloblastoma, the most common malignant pediatric brain tumor, is classified into four main molecular subgroups, but group 3 and group 4 tumors are difficult to subclassify and have a poor prognosis. Rapid point-of-care diagnostic and prognostic assays are needed to improve medulloblastoma risk stratification and management. N6-methyladenosine (m6A) is a common RNA modification and long non-coding RNAs (lncRNAs) play a central role in tumor progression, but their impact on gene expression and associated clinical outcomes in medulloblastoma are unknown. Here we analyzed 469 medulloblastoma tumor transcriptomes to identify lncRNAs co-expressed with m6A regulators. Using LASSO-Cox analysis, we identified a five-gene m6A-associated lncRNA signature (M6LSig) significantly associated with overall survival, which was combined in a prognostic clinical nomogram. Using expression of the 67 m6A-associated lncRNAs, a subgroup classification model was generated using the XGBoost machine learning algorithm, which had a classification accuracy > 90%, including for group 3 and 4 samples. All M6LSig genes were significantly correlated with at least one immune cell type abundance in the tumor microenvironment, and the risk score was positively correlated with CD4+ naïve T cell abundance and negatively correlated with follicular helper T cells and eosinophils. Knockdown of key m6A writer genes METTL3 and METTL14 in a group 3 medulloblastoma cell line (D425-Med) decreased cell proliferation and upregulated many M6LSig genes identified in our in silico analysis, suggesting that the signature genes are functional in medulloblastoma. This study highlights a crucial role for m6A-dependent lncRNAs in medulloblastoma prognosis and immune responses and provides the foundation for practical clinical tools that can be rapidly deployed in clinical settings.

Neurocognitive outcomes and functional independence in adult survivors of childhood medulloblastoma diagnosed over three decades.

Treatment of childhood medulloblastoma has evolved to reduce neurotoxicity while improving survival. However, the impact of evolving therapies on late neurocognitive outcomes and adult functional independence remains unknown. Adult survivors of childhood medulloblastoma (n=505; median[minimum-maximum] age, 29[18-46] years) and sibling controls (n=727; 32[18-58] years) from the Childhood Cancer Survivor Study completed surveys assessing neurocognitive problems and chronic health conditions (CHCs). Treatment exposures were categorized as historical (craniospinal irradiation [CSI]≥30 Gy, no chemotherapy), standard-risk (CSI>0 to <30 Gy +chemotherapy) and high-risk (CSI≥30 Gy +chemotherapy) therapy. Latent class analysis identified patterns of functional independence using employment, independent living, assistance with routine/personal care needs, driver's license, marital/partner status. Multivariable models estimated risk of neurocognitive impairment in survivors versus siblings and by treatment exposure group, and associations between neurocognitive impairment, CHCs, and functional independence. Survivors in each treatment exposure group had 4- to 5-fold elevated risk of impaired memory and task efficiency compared to siblings. Contemporary risk-based therapies did not confer lower risk compared to historical therapy. Survivors treated in the 1990s had higher risk of memory impairment (relative risk [RR] 2.24, 95% confidence interval [CI] 1.39-3.60) compared to survivors treated in the 1970s. Sensorimotor, hearing problems and seizures were associated with 33%-34%, 25-26% and 21%-42% elevated risk of task efficiency and memory impairment, respectively. Treatment-related CHCs and neurocognitive impairment were associated with non-independence. Despite treatment changes, long-term survivors of childhood medulloblastoma remain at risk for neurocognitive impairment, which was associated with CHCs. Neurocognitive surveillance after contemporary regimens is imperative.

Medulloblastoma in children with Fanconi anemia: Association with FA-D1/FA-N, SHH type and poor survival independent of treatment strategies.

The outcome of children with medulloblastoma (MB) and Fanconi Anemia (FA), an inherited DNA repair deficiency, has not been described systematically. Treatment is complicated by high vulnerability to treatment-associated side effects, yet structured data are lacking. This study aims to give a comprehensive overview of clinical and molecular characteristics of pediatric FA MB patients. Clinical data including detailed information on the treatment and toxicities of 6 previously unreported FA MB patients were supplemented with data of 16 published cases. We identified 22 cases of children with FA and MB with clinical data available. All MBs with subgroup reporting were SHH-activated (n = 9), confirmed by methylation profiling in 5 patients. FA MB patients exclusively belonged to complementation groups FA-D1 (n = 16) or FA-N (n = 3). Patients were treated with postoperative chemotherapy only (50%) or radiotherapy (RT) ± chemotherapy (27%). Of 23% did not receive adjuvant therapy. Excessive treatment-related toxicities were frequent. Severe hematological toxicity occurred in 91% of patients treated with alkylating chemotherapy, while non-alkylating agents and RT were less toxic. Median overall survival (OS) was 1 year (95%CI: 0.3-1.8). 1-year-progression-free-survival (PFS) was 26.3% ± 10.1% and 1-year-OS was 42.1% ± 11.3%. Adjuvant therapy prolonged survival (1y-OS/1y-PFS 0%/0% without adjuvant therapy vs. 53.3% ± 12.9%/33.3 ± 12.2% with adjuvant therapy, P = .006/P = .086). MB in FA patients is strongly associated with SHH activation and FA-D1/FA-N. Despite the dismal prognosis, adjuvant therapy may prolong survival. Non-alkylating chemotherapy and RT are feasible in selected patients with careful monitoring of toxicities and dose adjustments. Curative therapy for FA MB-SHH remains an unmet medical need.

LMIC-01. SURVIVAL AND PROGNOSTIC FACTORS IN CHILDHOOD MEDULLOBLASTOMA SINGLE TERTIARY CENTER EXPERIENCE FROM KING FAHAD MEDICAL CITY KFMC SAUDI ARABIA

Abstract BACKGROUND Medulloblastoma (MB) is the most common childhood malignant brain tumor treated with intensive multimodalities therapy including Surgery, Craniospinal Radiation, and chemotherapy. Our study aims to document the clinical courses, prognostic factors, and survival outcomes in Saudi children above three years with Medulloblastoma treated in King Fahad Medical City KFMC. METHODS Retrospective analysis of MB patients diagnosed between January 2009 to January 2022 All patients received Risk-adapted Radiation therapy followed by maintenance chemotherapy,3 patients progressed and died after surgery and were excluded from analysis. RESULTS We identified 145 MB patients 65.5 % were male. median age at Diagnosis 7.00 years (range3-14 years), Age less than 5 years did not have a worse outcome in our cohort. Classic histology was predominant (80%), 42.1% of patients had metastatic disease at presentation; the Median time to start radiation therapy after surgery was 35 days. 51.7% were treated as High-Risk HR MB and Average Risk AR MB 48.3%. 65 cases having molecular testing for MB molecular subgroups. 6 patients 4.1% developed a second malignancy with a median time of 6 years post diagnosis. Multivariate survival analysis showed that progression-free survival was significantly reduced by the extent of surgical resection (P=0.021) and Metastatic MB at diagnosis(P=0.014). At Median follow-up of 7 years, Progression-free survival PFS and overall survival OS for the whole cohort were 72.4% and 71.7% respectively. PFS for AR MB and HR MB was 81.4% and 64.0% respectively. PFS analysis based on molecular subgroup: WNT subgroup 92.3%, SHH 69.2%, Group 4:57.7%:and group 3: 46.2%. CONCLUSIONS Our study is the largest analysis of childhood MB treatment outcomes in Saudi Arabia Defining the poor prognostic factor for these patients and will form the baseline for future pediatric Neuro-Oncology studies in KFMC, which may help to improve the outcome of childhood MB in Saudi Arabia.

QOL-04.IN VIVO MODELLING RECAPITULATES RADIOTHERAPY DELIVERY AND LATE-EFFECT PROFILE FOR CHILDHOOD MEDULLOBLASTOMA

Abstract BACKGROUND Medulloblastoma (MB) is the most common malignant paediatric brain tumour, with 5-year survival rates &amp;gt;70%. Survivors frequently suffer a wide-range of late-effects due to their tumour and its treatment. Cranial radiotherapy (CRT) to the whole-brain, with posterior fossa boost (PFB), underpins treatment for non-infants, however, radiotherapeutic insult to normal brain tissue has deleterious consequences to neurocognitive and physical functioning, and causes accelerated ageing/frailty. Unfortunately, approaches to ameliorate radiotherapy-induced late-effects are lacking and a paucity of appropriate model systems hinders their development. METHODS We have developed a clinically-relevant in vivo model system that recapitulates the radiotherapy dose, delivery and late-effect profile of childhood medulloblastoma, at an equivalent developmental stage. Consistent with human regimens, age-equivalent (postnatal days 28-37) C57Bl/6J mice received targeted, CT image-guided, CRT (human-equivalent 38 Gy, n=12) or CRT with PFB (human-equivalent 49 Gy, n=12), via the small animal radiation research platform (SARRP) and were longitudinally assessed for over a year. Late-effects were compared to a sham-irradiated group (n=12). RESULTS CRT was well tolerated, independent of PFB receipt, and no mice suffered severe acute toxicity. Mice were significantly more frail following irradiation (frailty index; p=0.0002) and had reduced physical functioning; time to fall from a rotating rod and grip strength were significantly lower (rotarod; p=0.026 and grip strength; p=0.006, respectively). Neurocognitive deficits were consistent with those observed in childhood MB survivors; irradiated mice displayed significantly worse working memory (Y-maze; p=0.009) and exhibited spatial memory deficits (Barnes maze; p=0.029). Receipt of PFB did not induce a more severe late-effect profile. CONCLUSION We conclude that our in vivo model of childhood MB radiotherapy recapitulates the late-effect profile of MB survivors. Our clinically-relevant model will facilitate both the elucidation of novel/target mechanisms underpinning MB late-effects and the development of novel interventions for their amelioration.

MDB-91. MEDULLOBLASTOMA – MOLECULAR CHARACTERISTICS AND RADIOLOGICAL ASPECTS OF A BRAZILIAN COHORT FROM A SINGLE CENTER

Abstract BACKGROUND Four molecular subgroups of medulloblastoma are distinguished by their genomic, epidemiological, and prognostic characteristics: Wingless (WNT), Sonic hedgehog (SHH), Group 3 and Group 4. Genotypic classification permits individualized therapeutic planning based on risk stratification, thereby improving patient outcome. This study aims to characterize the epidemiological and molecular data of a cohort treated at a single Brazilian center, as well as to correlate the heterogeneous aspects of magnetic resonance imaging (MRI) with the molecular characteristics of this tumor. METHODS The study analyzed 47 medulloblastoma cases, treated at the children’s oncology reference institution of a middle-income country between 2011 and 2021. The medical records, radiological findings and the histological and molecular classification are reviewed. The images were evaluated by an experienced neuroradiologist, blinded to clinical and molecular information. RESULTS Thirty-two out 47 patients met the eligibility criteria and were analyzed. The frequency of molecular groups found was 6.25% Non-SHH/ Non-WNT, 12.50% WNT, 34.38% SHH, 3% Group 3 and 44 % Group 4. The analysis revealed tumor location, presence of hemorrhage/calcification, limits and enhancement patterns are significant for molecular group prediction. SHH shows a significant prevalence in the cerebellar hemisphere, lower presence of hemorrhage/calcification and an ill-defined tumor margins when compared with other subgroups. Group 4 showed significantly less enhancement. CONCLUSIONS In accordance with the frequency observed in studies on childhood medulloblastoma, our series found a significant prevalence of Group 4 and a lack of representativeness of Group 3. Despite the limitations, it was possible to identify radiological tumor characteristics that may predict the molecular subgroup and contribute to a more effective therapeutic approach, thereby reducing the incidence of post-surgical complications.

Radiotherapy for Recurrent Medulloblastoma in Children and Adolescents: Survival after Re-Irradiation and First-Time Irradiation.

Radiotherapy (RT) involving craniospinal irradiation (CSI) is important in the initial treatment of medulloblastoma. At recurrence, the re-irradiation options are limited and associated with severe side-effects. For pre-irradiated patients, patients with re-irradiation (RT2) were matched by sex, histology, time to recurrence, disease status and treatment at recurrence to patients without RT2. A total of 42 pre-irradiated patients with RT2 were matched to 42 pre-irradiated controls without RT2. RT2 improved the median PFS [21.0 (CI: 15.7-28.7) vs. 12.0 (CI: 8.1-21.0) months] and OS [31.5 (CI: 27.6-64.8) vs. 20.0 (CI: 14.0-36.7) months]. Concerning long-term survival after ten years, RT2 only lead to small improvements in OS [8% (CI: 1.4-45.3) vs. 0%]. RT2 improved survival most without (re)-resection [PFS: 17.5 (CI: 9.7-41.5) vs. 8.0 (CI: 6.6-12.2)/OS: 31.5 (CI: 27.6-NA) vs. 13.3 (CI: 8.1-20.1) months]. In the RT-naïve patients, CSI at recurrence improved their median PFS [25.0 (CI: 16.8-60.6) vs. 6.6 (CI: 1.5-NA) months] and OS [40.2 (CI: 18.7-NA) vs. 12.4 (CI: 4.4-NA) months]. RT2 could improve the median survival in a matched cohort but offered little benefit regarding long-term survival. In RT-naïve patients, CSI greatly improved their median and long-term survival.

Late-onset lymphopenia during radiation is associated with an increased risk of tumor recurrence in newly diagnosed pediatric medulloblastoma.

Recent data found a correlation between lymphopenia occurring early during craniospinal radiation therapy (RT) and risk of disease recurrence in newly diagnosed childhood medulloblastoma. However, the population included patients who received chemotherapy prior to or during RT. Here, we investigate the effect of lymphopenia during RT in patients with newly diagnosed pediatric medulloblastoma who were chemotherapy-naïve. We analyzed 79 patients with newly diagnosed medulloblastoma (ages 2-21years) treated between 1997 and 2013 with craniospinal RT. Log-rank tests were used to determine survival differences, and Cox proportional hazards regression was used to assess associations between patient characteristics and lymphopenia with disease recurrence risk. Eighty-three percent of patients (62/75) had grade ≥3 lymphopenia by RT Week 3, with 95% developing grade ≥3 lymphopenia at some point during therapy. There was no difference in incidence of lymphopenia between those who received proton beam RT (93%) versus photon (97%). Twenty-four of 79 (30%) patients developed disease recurrence at an average 27.0months after diagnosis. There was higher risk of disease recurrence in patients with grade ≥3 lymphopenia during RT Week 4 (log-rank p=.016; Cox p=.03) and Week 5 (log-rank p=.024; Cox p=.032); after adjusting for clinical risk group, only grade ≥3 lymphopenia at Week 4 remained prognostic (Cox p=.04). No correlation was found between risk of tumor recurrence and early lymphopenia (RT Weeks 0-3) or absolute lymphocyte count (ALC) below the median at any time during RT. Lymphopenia during RT Weeks 4 and 5 correlates with increased risk of tumor recurrence in pediatric patients with newly diagnosed medulloblastoma.

Multiparametric MRI-Based Interpretable Radiomics Machine Learning Model Differentiates Medulloblastoma and Ependymoma in Children: A Two-Center Study

Rationale and ObjectivesMedulloblastoma (MB) and Ependymoma (EM) in children, share similarities in age group, tumor location, and clinical presentation. Distinguishing between them through clinical diagnosis is challenging. This study aims to explore the effectiveness of using radiomics and machine learning on multiparametric magnetic resonance imaging (MRI) to differentiate between MB and EM and validate its diagnostic ability with an external set. Materials and methodsAxial T2 weighted image (T2WI) and contrast-enhanced T1weighted image (CE-T1WI) MRI sequences of 135 patients from two centers were collected as train/test sets. Volume of interest (VOI) was manually delineated by an experienced neuroradiologist, supervised by a senior. Feature selection analysis and the least absolute shrinkage and selection operator (LASSO) algorithm identified valuable features, and Shapley additive explanations (SHAP) evaluated their significance. Five machine-learning classifiers- extreme gradient boosting (XGBoost), Bernoulli naive Bayes (Bernoulli NB), Logistic Regression (LR), support vector machine (SVM), linear support vector machine (Linear SVC) classifiers were built based on T2WI (T2 model), CE-T1WI (T1 model), and T1+T2WI (T1+T2 model). A human expert diagnosis was developed and corrected by senior radiologists. External validation was performed at Sun Yat-Sen University Cancer Center. Results31 valuable features were extracted from T2WI and CE-T1WI. XGBoost demonstrated the highest performance with an area under the curve (AUC) of 0.92 on the test set and maintained an AUC of 0.80 during external validation. For the T1 model, XGBoost achieved the highest AUC of 0.85 on the test set and the highest accuracy of 0.71 on the external validation set. In the T2 model, XGBoost achieved the highest AUC of 0.86 on the test set and the highest accuracy of 0.82 on the external validation set. The human expert diagnosis had an AUC of 0.66 on the test set and 0.69 on the external validation set. The integrated T1+T2 model achieved an AUC of 0.92 on the test set, 0.80 on the external validation set, achieved the best performance. Overall, XGBoost consistently outperformed in different classification models. ConclusionThe combination of radiomics and machine learning on multiparametric MRI effectively distinguishes between Medulloblastoma and Ependymoma in childhood, surpassing human expert diagnosis in training and testing sets.

Clinical, Molecular Subgroups and Survival Rates Finding of Childhood Medulloblastoma: A Ten Years Moroccan Experience in Pediatric Hematology and Oncology Center.

Clinical, Molecular Subgroups and Survival Rates Finding of Childhood Medulloblastoma: A Ten Years Moroccan Experience in Pediatric Hematology and Oncology Center.

Personalized treatment options of refractory and relapsed medulloblastoma in children: literature review

Medulloblastoma (MB) is the most common malignant tumor of the central nervous system in pediatric patients. Despite the complex anticancer therapy approach, refractory and relapsing forms of the disease remain fatal in most cases and account for approximately 30%. To date, repeated surgery, radiation, and chemotherapy can be used as life-prolonging treatment options; nevertheless, it should be emphasized that there are no standardized approaches based on existing data of molecular variants of MB. It is obvious that only a deep understanding of the biological mechanisms in association with clinical aspects in refractory and relapsing forms of MB would make it possible to personalize second- and subsequent-line therapy in order to achieve maximum efficiency and minimize early and long-term toxicity. The article presents the current understanding of prognostic factors in relapsed/refractory forms of MB, methods of modern diagnostics, as well as existing and perspective treatment options based on the biological and clinical aspects of the disease.

The clinical significance of sub-total surgical resection in childhood medulloblastoma: a multi-cohort analysis of 1100 patients

Medulloblastoma patients with a sub-total surgical resection (STR; >1.5cm2 primary tumour residuum post-surgery) typically receive intensified treatment. However, the association of STR with poor outcomes has not been observed consistently, questioning the validity of STR as a high-risk disease feature. We collected extent of resection (EOR) data from 1110 patients (from UK CCLG centres (n=416, collected between September 1990 and July 2014) and published (n=694) cohorts), the largest cohort of molecularly and clinically annotated tumours assembled to specifically assess the significance of EOR. We performed association and univariable/multivariable survival analyses, assessing overall survival (OS) cohort-wide and with reference to the four consensus medulloblastoma molecular groups and clinical features. STR was reported in 20% (226/1110) of patients. Non-WNT (p=0.047), children <5 years at diagnosis (p=0.021) and metastatic patients (p<0.0001) were significantly more likely to have a STR. In cohort-wide analysis, STR was associated with worse survival in univariable analysis (p<0.0001). Examination of specific disease contexts showed that STR was prognostic in univariate analysis for patients receiving cranio-spinal irradiation (CSI) and chemotherapy (p=0.016) and for patients with Group 3 tumours receiving CSI (p=0.039). STR was not independently prognostic in multivariable analyses; outcomes for patients who have STR as their only risk-feature are as per standard-risk disease. Specifically, STR was not prognostic in non-metastatic patients that received upfront CSI. In a cohort of 1100 molecularly characterised medulloblastoma patients, STR (n=226) predicted significantly lower OS in univariable analysis, but was not an independent prognostic factor. Our data suggest that maximal safe resection can continue to be carried out for patients with medulloblastoma and suggest STR should not inform patient management when observed as a sole, isolated risk-feature. Cancer Research UK, Newcastle Hospitals Charity, Children's Cancer North, British Division of the International Academy of Pathology.

In vivo modeling recapitulates radiotherapy delivery and late-effect profile for childhood medulloblastoma.

Medulloblastoma (MB) is the most common malignant pediatric brain tumor, with 5-year survival rates > 70%. Cranial radiotherapy (CRT) to the whole brain, with posterior fossa boost (PFB), underpins treatment for non-infants; however, radiotherapeutic insult to the normal brain has deleterious consequences to neurocognitive and physical functioning, and causes accelerated aging/frailty. Approaches to ameliorate radiotherapy-induced late-effects are lacking and a paucity of appropriate model systems hinders their development. We have developed a clinically relevant in vivo model system that recapitulates the radiotherapy dose, targeting, and developmental stage of childhood medulloblastoma. Consistent with human regimens, age-equivalent (postnatal days 35-37) male C57Bl/6J mice received computerized tomography image-guided CRT (human-equivalent 37.5 Gy EQD2, n = 12) ± PFB (human-equivalent 48.7 Gy EQD2, n = 12), via the small animal radiation research platform and were longitudinally assessed for > 12 months. CRT was well tolerated, independent of PFB receipt. Compared to a sham-irradiated group (n = 12), irradiated mice were significantly frailer following irradiation (frailty index; P = .0002) and had reduced physical functioning; time to fall from a rotating rod (rotarod; P = .026) and grip strength (P = .006) were significantly lower. Neurocognitive deficits were consistent with childhood MB survivors; irradiated mice displayed significantly worse working memory (Y-maze; P = .009) and exhibited spatial memory deficits (Barnes maze; P = .029). Receipt of PFB did not induce a more severe late-effect profile. Our in vivo model mirrored childhood MB radiotherapy and recapitulated features observed in the late-effect profile of MB survivors. Our clinically relevant model will facilitate both the elucidation of novel/target mechanisms underpinning MB late effects and the development of novel interventions for their amelioration.

Medulloblastoma in children: a case report and literature review

Medulloblastoma in children: a case report and literature review

Translation of non-canonical open reading frames as a cancer cell survival mechanism in childhood medulloblastoma

A hallmark of high-risk childhood medulloblastoma is the dysregulation of RNA translation. Currently, it is unknown whether medulloblastoma dysregulates the translation of putatively oncogenic non-canonical open reading frames (ORFs). To address this question, we performed ribosome profiling of 32 medulloblastoma tissues and cell lines and observed widespread non-canonical ORF translation. We then developed a stepwise approach using multiple CRISPR-Cas9 screens to elucidate non-canonical ORFs and putative microproteins implicated in medulloblastoma cell survival. We determined that multiple lncRNA-ORFs and upstream ORFs (uORFs) exhibited selective functionality independent of main coding sequences. A microprotein encoded by one of these ORFs, ASNSD1-uORF or ASDURF, was upregulated, associated with MYC-family oncogenes, and promoted medulloblastoma cell survival through engagement with the prefoldin-like chaperone complex. Our findings underscore the fundamental importance of non-canonical ORF translation in medulloblastoma and provide a rationale to include these ORFs in future studies seeking to define new cancer targets.

MiRNA-211 maintains metabolic homeostasis in medulloblastoma through its target gene long-chain acyl-CoA synthetase 4

The prognosis of childhood medulloblastoma (MB) is often poor, and it usually requires aggressive therapy that adversely affects quality of life. microRNA-211 (miR-211) was previously identified as an important regulator of cells that descend from neural cells. Since medulloblastomas primarily affect cells with similar ontogeny, we investigated the role and mechanism of miR-211 in MB. Here we showed that miR-211 expression was highly downregulated in cell lines, PDXs, and clinical samples of different MB subgroups (SHH, Group 3, and Group 4) compared to normal cerebellum. miR-211 gene was ectopically expressed in transgenic cells from MB subgroups, and they were subjected to molecular and phenotypic investigations. Monoclonal cells stably expressing miR-211 were injected into the mouse cerebellum. miR-211 forced expression acts as a tumor suppressor in MB both in vitro and in vivo, attenuating growth, promoting apoptosis, and inhibiting invasion. In support of emerging regulatory roles of metabolism in various forms of cancer, we identified the acyl-CoA synthetase long-chain family member (ACSL4) as a direct miR-211 target. Furthermore, lipid nanoparticle-coated, dendrimer-coated, and cerium oxide-coated miR-211 nanoparticles were applied to deliver synthetic miR-211 into MB cell lines and cellular responses were assayed. Synthesizing nanoparticle-miR-211 conjugates can suppress MB cell viability and invasion in vitro. Our findings reveal miR-211 as a tumor suppressor and a potential therapeutic agent in MB. This proof-of-concept paves the way for further pre-clinical and clinical development.Graphical

Evolution of Systemic Therapy in Medulloblastoma Including Irradiation-Sparing Approaches.

The management of medulloblastoma in children has dramatically changed over the past four decades, with the development of chemotherapy protocols aiming at improving survival and reducing long-term toxicities of high-dose craniospinal radiotherapy. While the staging and treatment of medulloblastoma were until recently based on the modified Chang's system, recent advances in the molecular biology of medulloblastoma have revolutionized approaches in the management of this increasingly complex disease. The evolution of systemic therapies is described in this review.

NCOG-24. RISK-ADAPTED TREATMENT STRATEGIES WITH PRE-IRRADIATION CHEMOTHERAPY IN PEDIATRIC MEDULLOBLASTOMA: OUTCOMES FROM THE POLISH PEDIATRIC NEURO-ONCOLOGY GROUP

Abstract Craniospinal irradiation (CSI) has been a major component of the standard of care treatment backbone of childhood medulloblastoma. However, chemotherapy regimens have varied based on protocol, patient age, and molecular subtyping. In one of the largest studies to date, we analyze treatment outcomes in children with newly-diagnosed medulloblastoma treated with pre-irradiation chemotherapy followed by risk-adapted radiotherapy and maintenance chemotherapy. A total of 153 patients from the Polish Pediatric Neuro-oncology Group were included in the analysis. Median age at diagnosis was 8.0 years. Sixty-seven patients were classified as standard risk and 86 as high risk. Overall survival (OS) and event-free survival (EFS) for standard-risk patients at 5 years (± standard error) were 87 ± 4.3% and 84 ± 4.6% respectively, while 5-year OS and EFS for high-risk patients were 81 ± 4.3% and 79 ± 4.5% respectively. This study demonstrates promising survival outcomes in patients treated with pre-irradiation chemotherapy followed by risk-adapted CSI and adjuvant chemotherapy. Such an approach may be useful in cases where initiation of radiotherapy may need to be delayed, a common occurrence in many institutions globally.

A preliminary study on the mechanism of VASH2 in childhood medulloblastoma

To study the differences in VASH2 expression in pediatric medulloblastoma (MB) tumor tissues of different molecular subtypes, to analyze the correlation between VASH2 and the molecular subtypes of medulloblastoma, clinicopathological data, and prognosis, and to explore the specific mechanism of VASH2’s role in SHH medulloblastoma cell lines DAOY. We analyzed 47 pediatric medulloblastoma cases admitted to the Department of Pediatric Neurosurgery of the First Affiliated Hospital of Xinjiang Medical University from January 2011 to December 2019, and the expression levels of YAP1 and GAB1 in these tumor tissues were detected by immunohistochemistry (IHC) and molecularly typed (WNT-type, SHH-type, and non-WNT/SHH-type). The correlation between VASH2 and molecular typing of medulloblastoma was analyzed. We also analyzed the medulloblastoma dataset in the GEO database (GSE30074 and GSE202043) to explore the correlation between VASH2 and the prognosis of medulloblastoma patients, as well as performed a comprehensive GO enrichment analysis specifically for the VASH2 gene to reveal the underlying biological pathways of its complex molecular profile. We used vasopressin 2 (VASH2) as a research target and overexpressed and knocked down VASH2 in SHH medulloblastoma cell lines DAOY by lentiviral vectors in vitro, respectively, to investigate its role in SHH medulloblastoma cell lines DAOY cell proliferation, apoptosis, migration, invasion and biological roles in the cell cycle. (1) Among 47 pediatric medulloblastoma cases, 8 were WNT type, 29 were SHH type, and 10 were non-WNT/SHH type. the positive rate of VASH2 was highest in the SHH type with a 68.97% positive rate, followed by non-WNT/SHH and lowest in the WNT type. The results of the multifactorial analysis showed that positive expression of VASH2 was associated with medulloblastoma molecular subtype (SHH type), site of tumor development (four ventricles), and gender (male), P < 0.05. (2) The results of cellular experiments showed that overexpression of VASH2 increased the invasion and migration ability of medulloblast Daoy, while knockdown of VASH2 inhibited the invasion and Overexpression of VASH2 upregulated the expression of Smad2 + 3, Smad4, Mmp2 and the apoptotic indicators Bcl-2 and Caspase3, while knockdown of VASH2 suppressed the expression of Smad2 + 3 and Mmp2, and silenced the expression of Smad4 and the apoptotic indicators Bcl2, Caspase3 expression. Flow cytometric cycle analysis showed that VASH2 overexpression increased the S phase in the Daoy cell cycle, while VASH2 knockdown decreased the S phase in the SHH medulloblastoma cell lines DAOY cell cycle. Bioinformatics analysis showed that there was no statistically significant difference between the expression of VASH2 genes in the GSE30074 and GSE202043 datasets and the prognosis of the patients, but the results of this dataset analysis suggested that we need to continue to expand the sample size of the study in the future. The results of the GO enrichment analysis showed that the angiogenic pathway was the most significantly enriched, and the PPI interactions network of VASH2 was obtained from the STRING database. Using the STRING database, we obtained the PPI interaction network of VASH2, and the KEGG enrichment analysis of VASH2-related genes showed that VASH2-related genes were related to the apoptosis pathway, and therefore it was inferred that VASH2 also affects the development of tumors through apoptosis. We found for the first time that the positive expression rate of VASH2 was closely associated with SHH-type pediatric medulloblastoma and that VASH2 was involved in the invasion, migration, cell cycle, and apoptotic capacity of SHH medulloblastoma cell lines DAOY by affecting downstream indicators of the TGF-β pathway. This suggests that it is involved in the progression of pediatric medulloblastoma, and VASH2 is expected to be a diagnostic and therapeutic target for SHH-type pediatric medulloblastoma.