Medulloblastoma

Comparative dosimetric, setup margin, and treatment time analysis between ring gantry and C-Arm linear accelerators for VMAT-based craniospinal irradiation plans

PURPOSE

The purpose of this study is to evaluate the dosimetric and treatment delivery characteristics of volumetric modulated arc therapy technique (VMAT)-based craniospinal axis irradiation (CSI) between ring gantry Halcyon (HAL) and C-arm based Novalis Tx (NTx) linear accelerator. Set-up margin and treatment delivery time for both machines were also taken into account.

MATERIALS AND METHODS

Fifteen patients, 4 females and 11 males treated between March 2019 and February 2022 within the age group 4-56 years simulated in the supine position and were planned for multiple isocentre VMAT technique in ring gantry Halcyon and C-Arm Novalis linear accelerator for 6FFF and 6 MV flatten beam energy. The number of isocenters was the same in both the machines, usually three for adult adolescent age group patients and two for pediatric patients. Total on-couch time and the patient positional shift were captured for each isocenter during each session of treatment. Margins were calculated using Herk's formula of margin = 2.5Σ +0.7σ. Dosimetry, on-couch time, and set-up margin were compared between two competing arms.

RESULTS

Ninety-five percent of PTV coverage (P = 0.333), volume receiving 107% (P = 0.676), total MU (P = 0.818) in both the arms were comparable and statically insignificant. Low-dose spillage such as D20% (P = 0.212) and D50% (P = 0.008) was lesser in HAL comparable to NTx. CI and HI were statically insignificant. Out of 26 organs at risk (OAR), only 3 organs showed a statically significant dose difference. The mean and maximum setup margin in any linear direction was 0.45 and 0.53 cm for HAL and 0.37 and 0.56 cm for NTx and, variation was statistically insignificant (0.23 < P < 0.47). On-couch time was 4.0 ± 5.5 min lesser for HAL and the difference in on-couch time between the two arms was statistically different.

CONCLUSION

Even though the majority of the delivery parameters such as gantry speed, dose rate, beam characteristic (flatten or unflatten), MLC width, and speed between the ring gantry HAL and C-arm NTx linear accelerators were distinctly different, they offered no or minimal difference in the dose distribution and in the setup margin. HAL gives a faster treatment time delivery, which could be crucial for some selective cases such as patients receiving treatment under general anesthesia.

Wnt Signaling in Brain Tumors: A Challenging Therapeutic Target

The involvement of Wnt signaling in normal tissue homeostasis and disease has been widely demonstrated over the last 20 years. In particular, dysregulation of Wnt pathway components has been suggested as a relevant hallmark of several neoplastic malignancies, playing a role in cancer onset, progression, and response to treatments. In this review, we summarize the current knowledge on the instructions provided by Wnt signaling during organogenesis and, particularly, brain development. Moreover, we recapitulate the most relevant mechanisms through which aberrant Wnt pathway activation may impact on brain tumorigenesis and brain tumor aggressiveness, with a particular focus on the mutual interdependency existing between Wnt signaling components and the brain tumor microenvironment. Finally, the latest anti-cancer therapeutic approaches employing the specific targeting of Wnt signaling are extensively reviewed and discussed. In conclusion, here we provide evidence that Wnt signaling, due to its pleiotropic involvement in several brain tumor features, may represent a relevant target in this context, although additional efforts will be needed to: (i) demonstrate the real clinical impact of Wnt inhibition in these tumors; (ii) overcome some still unsolved concerns about the potential systemic effects of such approaches; (iii) achieve efficient brain penetration.

Comparative dosimetric analysis of volumetric modulated arc therapy based craniospinal irradiation plans between Halcyon ring gantry and TrueBeam C-arm linear accelerator

This study evaluates the volumetric modulated arc therapy (VMAT) dosimetric comparison between Halcyon ring gantry and TrueBeam c-arm linear accelerators for craniospinal irradiation (CSI) of the neuro-axis. 25 patients, who received treatment for medulloblastoma and primitive neuro-ectodermal tumors between 2018 and 2021, were planned for VMAT in True Beam (TB), and Halcyon (HAL) linear accelerators using 6 MV unflattened (FFF) photon beams (HALFFF and TBFFF). Dose-volume statistics for the target and organs at risk (OARs) and the total number of monitoring units (MUs) in the treatment plans were compared which included dose received by 95% PTV volume (V95%), volume receiving ≥ 107% dose, homogeneity index (HI), conformity index (PI), MU and dose spillage (D10%, D30%, D50%, D70%, D90%). In all 26 OARs were considered of which five were serial and the remaining were parallel structures. For the former, the dose received by 0.2 cm³, volume = D0.2 cm³) were evaluated and for the latter mean dose were evaluated. Both arms were statistically compared with paired sample t-test with a significant value of ≤ 0.05. 11 patients received treatment with the Halcyon and the rest 14 in the TrueBeam C-arm linear accelerator. Patients in the low- and intermediate-risk category (n = 13) received 23.4 Gy in 13 fractions. The remaining patients were in the high-risk category and received 35 Gy in 21 fractions or 36 Gy in 20 fractions. For HALFFF and TBFFF, PTVV95% were 97.5 ± 0.8% and 97.4 ± 0.9% respectively (p = 0.371) while the V107% were 0.6 ± 0.4% and 0.5 ± 0.5 respectively (p = 0.504). However, the number of monitoring units showed statistical significance (p < 0.001) with values of 1331.9 ± 243.4 MU and 1089 ± 206.7 MU respectively for the HAL and TB plans. The differences in spillage dose were also statistically significant, favouring HAL plans at D30% (p = 0.002), D50% (p < 0.001), D70% (p = 0.039), and D90% (p = 0.01) level except for D10% (p = 0.090). Conformity index also showed statistical significance with PI_HAL = 0.9 ± 0.02 and PI_TB = 0.89 ± 0.03 (p = 0.029). For 10 of the 21 parallel structures, the mean dose differences were statistically significant in favouring of HAL plans. Halcyon based VMAT CSI plans are dosimetrically superior in terms of organ dose, especially for the large organs, and offer lower spillage doses than the TrueBeam plans. Plans generated by both linear accelerators are suitable for the patients' treatments.

Medulloblastomas in Pediatric and Adults

Medulloblastoma is the primary malignant embryonic tumor of the cerebellum and the most common malignant tumor of childhood, accounting up to 25% of all CNS tumors in children, but is extremely rare in adults. Despite the fact that medulloblastomas are one of the most malignant human tumors, it is worthy to note that a great breakthrough has been achieved in our understanding of oncogenesis and the development of real methods of treatment. The main objective of surgical treatment is a maximum resection of tumor with minimal impairment of neurological functions, in order to reduce the volume, remove tumor tissue, get the biopsy, and restore the cerebrospinal fluid flow. The progress of surgical techniques (using a microscope, ultrasound suction), anesthesiology, and intensive care has significantly decreased surgical mortality and increased radicality of tumor removal. Postoperative mortality is less than one percent in most studies, while neurological complications have been reported between 5-10%. Radiotherapy is the main method of treatment in patients older than 3 years, which dramatically improved the recurrence-free survival. Nevertheless, the radiation therapy without systemic chemotherapy leads to a high risk of systemic metastases. After the role of chemotherapy was statistically proven, investigations of the optimal combination of different chemotherapy regimens continued around the world. Currently, 80% of patients can already be cured, however, the quality of life of patients in the long-term period remains quite low, which depends on many factors including endocrinological, cognitive, neurological, and otoneurologic aspects. Thus, the main strategic goal of the development of neuro-oncology is to reduce the doses of radiation therapy to the CNS and the main task of international research is to optimize existing protocols and develop fundamentally new ones based on molecular genetic research in order to improve the quality of life.

Ensemble learning based functional independence ability estimator for pediatric brain tumor survivors

A history of brain tumor strongly affects children’s cognitive abilities, performance of daily activities, quality of life, and functional outcomes. In light of the difficulties in cognition, communication, physical skills, and behavior that these patients may encounter, occupational therapists should perform a comprehensive needs-led assessment of their global functioning after recovery. Such an assessment would ensure that the patients receive adequate support and services at school, at home, and in the community. By predicting the functional activity performance of children with a history of brain tumor, clinical workers can determine the progress of their ability recovery and the optimal treatment plan. We selected several features for testing and employed common machine learning models to predict Functional Independence Measure (WeeFIM) scores. The ensemble learning models exhibited stronger predictive performance than did the individual machine learning models. The ensemble learning models effectively predicted WeeFIM scores. Machine learning models can help clinical workers predict the functional assessment scores of patients with childhood brain tumors. This study used machine learning models to predict the WeeFIM scores of patients with childhood brain tumors and to demonstrate that ensemble machine learning models are more suitable for this task than are individual machine learning models.

Medulloblastoma Presenting As Isolated Leptomeningeal Enhancement With No Primary Mass

Medulloblastoma presenting with diffuse leptomeningeal enhancement and no identified intra-parenchymal primary mass is extremely rare. A 14-year-old previously healthy boy presented with a three-week history of symptoms consistent with increased intracranial pressure (ICP). Magnetic resonance imaging (MRI) revealed diffuse leptomeningeal enhancement which prompted consideration of infectious, inflammatory, and neoplastic etiologies. The patient became rapidly unstable requiring the placement of an external ventricular drain (EVD) and induction of a phenobarbital coma for refractory seizures. The “sugar-coated” appearance of the abnormal enhancement and thickened tissues raised concern specifically for malignancy. The patient remained extremely unstable and ultimately required surgical decompression for increased ICP at which time a biopsy was obtained. Despite attempting bridging intra-ventricular chemotherapy, the patient, unfortunately, passed away, just 14 days from the initial presentation. Final pathology later confirmed the diagnosis of medulloblastoma. Awareness of medulloblastoma in the differential of diffuse leptomeningeal enhancement is crucial for early identification and treatment of this rare presentation. This case is the first pediatric report of primary leptomeningeal medulloblastoma without a primary mass involving the large cell/anaplastic variant.

Cerebellar Mutism Syndrome: An Overview of the Pathophysiology in Relation to the Cerebrocerebellar Anatomy, Risk Factors, Potential Treatments, and Outcomes

Cerebellar mutism syndrome (CMS) is one the most disabling postoperative neurological complications after posterior fossa surgery in children. CMS is characterized by a transient mutism with a typical onset demonstrated within 2 days postoperatively accompanied by associated ataxia, hypotonia, and irritability. Several hypotheses for the anatomical basis of pathophysiology and risk factors have been suggested. However, a definitive theory and treatment protocols have not yet been determined. Animal histological and electrophysiological studies and more recent human imaging studies have demonstrated the existence of a compartmentalized representation of cerebellar function, the understanding of which might provide more information on the pathophysiology. Damage to the dentatothalamocortical pathway and cerebrocerebellar diaschisis have been described as the anatomical substrate to the CMS. The risk factors, which include tumor type, brainstem invasion, tumor localization, tumor size, and vermal splitting technique, have not yet been clearly elucidated. The efficacy of potential pharmacological and speech therapies has been studied in small trials. Long-term motor speech deficits and associated cognitive and behavioral disturbances have now been found to be common among CMS survivors, affecting their development and requiring rehabilitation, leading to significant financial effects on the healthcare system and distress to the family. The aim of the present review was to outline the cerebellar anatomy and function and its connections in relationship to the pathophysiology and to refine the risk factors and treatment strategies for CMS.

Development of a prognostic model based on an immunogenomic landscape analysis of medulloblastoma

Medulloblastoma (MB) is one of the most common central nervous system tumors in children. At present, the vital role of immune abnormalities has been proved in tumorigenesis and progression. However, the immune mechanism in MB is still poorly understood. In the present study, 51 differentially expressed immune-related genes (DE-IRGs) and 226 survival associated immune-related genes (Sur-IRGs) were screened by an integrated analysis of multi-array. Moreover, the potential pathways were enriched by functional analysis, such as ‘cytokine–cytokine receptor interaction’, ‘Ras signaling pathway’, ‘PI3K-Akt signaling pathway’ and ‘pathways in cancer’. Furthermore, 10 core IRGs were identified from DE-IRGs and Sur-IRGs. And the potential regulatory mechanisms of core IRGs were also explored. Additionally, a new prognostic model, including 7 genes (HDGF, CSK, PNOC, S100A13, RORB, FPR1, and ICAM2) based on IRGs, was established by multivariable COX analysis. In summary, our study revealed the underlying immune mechanism of MB. Moreover, we developed a prognostic model associated with clinical characteristics and could reflect the infiltration of immune cells.

Aggressive Medulloblastoma-Derived Exosomal miRNAs Promote In Vitro Invasion and Migration of Tumor Cells Via Ras/MAPK Pathway

Medulloblastomas (MBs) are currently divided into 4 molecular subgroups: WNT, SHH, Group 3, and Group 4. Among them, Group 3 MB has the worst prognosis, and 40%-50% of Group 3 cases are already metastatic at the time of diagnosis. Emerging evidence indicates that exosomes drive tumor invasion, but very little is known about exosomes in MBs. In this study, we initially discovered that exosomes isolated from Group 3 MB cell lines altered in vitro behaviors of a less invasive SHH MB cell line and yielded a much more aggressive phenotype. RNA-sequencing analysis revealed 7 exosomal miRNAs with markedly different expression levels between the SHH and Group 3 MB cell lines. They were all predicted to be related to the Ras/MAPK pathway according to the Kyoto Encyclopedia of Genes and Genomes data analysis. Increased expression of miR-181a-5p, miR-125b-5p, and let-7b-5p was further confirmed in Group 3 MB cells with real-time PCR and was shown to increase in vitro invasion and migratory abilities of tumor cells through the activation of ERK in Ras/MAPK pathway. Collectively, our findings suggest that exosomal miRNAs have a critical role in MB progression in vitro and might serve as diagnostic biomarkers and therapeutic targets.

Pretreatment central quality control for craniospinal irradiation in non-metastatic medulloblastoma : First experiences of the German radiotherapy quality control panel in the SIOP PNET5 MB trial

Purpose

Several studies have demonstrated the negative impact of radiotherapy protocol deviations on tumor control in medulloblastoma. In the SIOP PNET5 MB trial, a pretreatment radiotherapy quality control (RT-QC) program was introduced. A first analysis for patients enrolled in Germany, Switzerland and Austria with focus on types of deviations in the initial plan proposals and review criteria for modern radiation technologies was performed.

Methods and patients

Sixty-nine craniospinal irradiation (CSI) plans were available for detailed analyses. RT-QC was performed according to protocol definitions on dose uniformity. Because of the lack of definitions for high-precision 3D conformal radiotherapy within the protocol, additional criteria for RT-QC on delineation and coverage of clinical target volume (CTV) and planning target volume (PTV) were defined and evaluated.

Results

Target volume (CTV/PTV) deviations occurred in 49.3% of initial CSI plan proposals (33.3% minor, 15.9% major). Dose uniformity deviations were less frequent (43.5%). Modification of the RT plan was recommended in 43.5% of CSI plans. Unacceptable RT plans were predominantly related to incorrect target delineation rather than dose uniformity. Unacceptable plans were negatively correlated to the number of enrolled patients per institution with a cutoff of 5 patients (p = 0.001).

Conclusion

This prospective pretreatment individual case review study revealed a high rate of deviations and emphasizes the strong need of pretreatment RT-QC in clinical trials for medulloblastoma. Furthermore, the experiences point out the necessity of new RT-QC criteria for high-precision CSI techniques.

Electronic supplementary material

The online version of this article (10.1007/s00066-020-01707-8) contains supplementary material, which is available to authorized users.

The 100 Most Influential Publications on Medulloblastoma: Areas of Past, Current, and Future Focus

BACKGROUND

This article is the first to identify the most influential articles on medulloblastoma using the citation analysis methodology.

OBJECTIVE

To perform a bibliometric analysis of the 100 most-cited articles on medulloblastoma.

METHODS

Using the Web of Science database, search criteria included the title-specific keyword "medulloblastoma" OR "cerebellar primitive neuroectodermal tumor (PNET)" OR "cerebellar PNET." Publications from 1900 to 2020 labeled "article," "review," "data set," or "clinical trial" were chosen and ranked based on total number of citations in descending order. Each article was evaluated based on the following variables: total citations, average citations per year, first author, institution of first author, title, publication year, country of origin, SCImago Journal Rank, and Scopus SNIP (Source Normalized Impact per Paper).

RESULTS

Our search yielded 4928 articles on medulloblastoma. The 100 most-cited articles ranged from 192 to 2017 across 42 unique journals; Journal of Clinical Oncology accounted for the most publications (16%). Paul A. Northcott was first author of the most articles on the list (n = 7.7%), and the most widely cited article was "Altered neural cell fates and medulloblastoma in mouse patched mutants" by Goodrich et al., published in Science (1997).

CONCLUSIONS

Because medulloblastoma represents the most common form of pediatric cancerous brain tumor, it is important to identify works that have significantly contributed to the body of knowledge regarding this disease. The 100 most-cited medulloblastoma articles comprise a significant collection of data regarding the histopathologic and molecular classification of medulloblastoma as well as clinical outcomes of therapeutics used to treat this disease.

HGF/MET Signaling in Malignant Brain Tumors

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

Evaluation of Prognostic Factors and Role of Participation in a Randomized Trial or a Prospective Registry in Pediatric and Adolescent Nonmetastatic Medulloblastoma - A Report From the HIT 2000 Trial

Purpose

We aimed to compare treatment results in and outside of a randomized trial and to confirm factors influencing outcome in a large retrospective cohort of nonmetastatic medulloblastoma treated in Austria, Switzerland and Germany.

Methods and Materials

Patients with nonmetastatic medulloblastoma (n = 382) aged 4 to 21 years and primary neurosurgical resection between 2001 and 2011 were assessed. Between 2001 and 2006, 176 of these patients (46.1%) were included in the randomized HIT SIOP PNET 4 trial. From 2001 to 2011 an additional 206 patients were registered to the HIT 2000 study center and underwent the identical central review program. Three different radiation therapy protocols were applied. Genetically defined tumor entity (former molecular subgroup) was available for 157 patients.

Results

Median follow-up time was 7.3 (range, 0.09-13.86) years. There was no difference between HIT SIOP PNET 4 trial patients and observational patients outside the randomized trial, with 7 years progression-free survival rates (PFS) of 79.5% ± 3.1% versus 78.7% ± 3.1% (P = .62). On univariate analysis, the time interval between surgery and irradiation (≤ 48 days vs ≥ 49 days) showed a strong trend to affect PFS (80.4% ± 2.2% vs 64.6% ± 9.1%; P = .052). Furthermore, histologically and genetically defined tumor entities and the extent of postoperative residual tumor influenced PFS. On multivariate analyses, a genetically defined tumor entity wingless-related integration site-activated vs non-wingless-related integration site/non-SHH, group 3 hazard ratio, 5.49; P = .014) and time interval between surgery and irradiation (hazard ratio, 2.2; P = .018) were confirmed as independent risk factors.

Conclusions

Using a centralized review program and risk-stratified therapy for all patients registered to the study center, outcome was identical for patients with nonmetastatic medulloblastoma treated on and off the randomized HIT SIOP PNET 4 trial. The prognostic values of prolonged time to RT and genetically defined tumor entity were confirmed.

MicroRNA-31 weakens cisplatin resistance of medulloblastoma cells via NF-κB and PI3K/AKT pathways

BACKGROUND

Medulloblastoma (MB) is a malignant intracranial tumor. Cisplatin is a broad-spectrum antitumor drug. It is important to study the cisplatin resistance of MB cells for the treatment of MB. In this article, we preliminarily studied the cisplatin resistance of microRNA (miR)-31 and the possible mechanism in DAOY and UW228 cells, laying a theoretical foundation for clinical treatment of MB.

METHODS

Following anti-miR-31 and pre-miR-31 transfections, cell viability, BrdU, CyclinD1, and apoptosis levels of DAOY and UW228 cell were detected by CCK8, BrdU, and western blot. Meanwhile, migration, invasion, and western blot assay were respectively used to detect the functions of miR-31 migration and invasion. miR-31 levels were changed by cell transfection and detected by RT-qPCR. Furthermore, the related-proteins of pathways were also detected by western blot.

RESULTS

Anti-miR-31 increased DAOY and UW228 cells viability, BrdU⁺ numbers, and expression of CyclinD1. The migration/invasion rate and expression levels of MMP-9 and vimentin after anti-miR-31 transfection were increased. Furthermore, anti-miR-31 enhanced cells' cisplatin resistance and triggered PI3K/AKT and NF-κB pathways. Pre-miR-31 played opposite roles and promoted the apoptosis.

CONCLUSION

miR-31 regulated cell growth, migration, invasion and cisplatin resistance of MB cells via PI3K/AKT and NF-κB pathways.

Neuropsychological functioning in survivors of childhood medulloblastoma/CNS-PNET: The role of secondary medical complications

OBJECTIVE

To investigate the long-term cognitive consequences of malignant pediatric brain tumor and its treatment, and factors explaining variability in cognitive functioning among survivors. Method: A geographical cohort of survivors of pediatric medulloblastoma (MB) and supratentorial primitive neuroectodermal tumor (CNS-PNET), treated between 1974 and 2013, was invited to participate. Of the 63 surviving patients, 50 (79%) consented to participation. The participants were tested with a battery of neuropsychological tests covering a wide age range. Verbal cognition, nonverbal cognition, processing speed, attention, memory, executive functioning, and manual dexterity were assessed. The participants were between 5:5 and 51:11 years of age at time of assessment. Assessments took place on average 19 years after primary tumor resective surgery. Results: One participant had a severe intellectual disability. For the rest, IQ varied from 52 to 125, with a mean score of 88.0 (SD 19.7). Twenty-eight (56%) of the participants had full-scale IQ scores in the age-average range or above. Gender, age at operation, time since operation, the presence of secondary medical complications, and treatment variables explained 46% of the variability in IQ scores, F(4,44) =  9.5, p<.001. The presence of endocrine insufficiency in combination with either epilepsy and/or hydrocephalus was associated with lowered IQ, lowered processing speed, and memory impairments. Conclusion: Patients treated for childhood MB and CNS-PNET have a lifelong risk of medical sequelae, including impaired cognitive functioning. This study adds to the literature by demonstrating the importance of following neuropsychological functioning closely, especially processing speed, learning, and memory, in survivors who have multiple secondary medical complications.

RBM5 Acts as Tumor Suppressor in Medulloblastoma through Regulating Wnt/β-Catenin Signaling

INTRODUCTION

RBM5 acts as a tumor suppressor gene in lung and breast cancers; however, its role in the pathogenesis of medulloblastoma (MB) remains unclear. We previously identified 4 RBM5 mutations in whole exome sequencing analysis of 40 MB patients. This study examined the role of RBM5 in MB progression.

METHODS

The expression patterns of RBM5 in tissues of 40 MB patients were analyzed using immunohistochemistry. Associations between RBM5 expression and overall survival (OS) were evaluated using Kaplan-Meier analysis. The RBM5 role in Daoy cells' proliferation, migration, and Wnt/β-catenin signaling was analyzed after RBM5 knockdown and overexpression.

RESULTS

The expression level of RBM5 mRNA and protein was significantly lower in MB than that in adjacent normal control tissues, and low RBM5 expression was significantly associated with reduced OS (p = 0.034). RBM5 knockdown induced Daoy and ONS-76 cells proliferation, while RBM5 overexpression repressed cell proliferation and migration in vitro (all p < 0.05). β-Catenin, LEF1, and cyclin D1 mRNA levels were upregulated, while DKK1 expression was downregulated in Daoy cells following RBM5 knockdown.

CONCLUSION

RBM5 may function as a tumor suppressor in MB by regulating Wnt/β-catenin signaling, and its reduced expression is associated with lower OS.

Identification of Core Genes and Pathways in Medulloblastoma by Integrated Bioinformatics Analysis

Medulloblastoma (MB) is one of the most common intracranial malignancies in children. The present study applied integrated bioinformatics to identify potential core genes associated with the pathogenesis of MB and reveal potential molecular mechanisms. Through the integrated analysis of multiple data sets from the Gene Expression Omnibus (GEO), 414 differentially expressed genes (DEGs) were identified. Combining the protein-protein interaction (PPI) network analysis with gene set enrichment analysis (GSEA), eight core genes, including CCNA2, CCNB1, CCNB2, AURKA, CDK1, MAD2L1, BUB1B, and RRM2, as well as four core pathways, including "cell cycle", "oocyte meiosis", "p53 pathway" and "DNA replication" were selected. In independent data sets, the core genes showed superior diagnostic values and significant prognostic correlations. Moreover, in the pan-caner data of the cancer genome atlas (TCGA), the core genes were also widely abnormally expressed. In conclusion, this study identified core genes and pathways of MB through integrated analysis to deepen the understanding of the molecular mechanisms underlying the MB and provide potential targets and pathways for diagnosis and treatment of MB.

Erbb4 Is Required for Cerebellar Developmentand Malignant Phenotype of Medulloblastoma

Medulloblastoma is the most common and malignant pediatric brain tumor in childhood. It originates from dysregulation of cerebellar development, due to an excessive proliferation of cerebellar granule neuron precursor cells (CGNPs). The underlying molecular mechanisms, except for the role of SHH and WNT pathways, remain largely unknown. ERBB4 is a tyrosine kinase receptor whose activity in cancer is tissue dependent. In this study, we characterized the role of ERBB4 during cerebellum development and medulloblastoma progression paying particular interests to its role in CGNPs and medulloblastoma stem cells (MBSCs). Our results show that ERBB4 is expressed in the CGNPs during cerebellum development where it plays a critical role in migration, apoptosis and differentiation. Similarly, it is enriched in the population of MBSCs, where also controls those critical processes, as well as self-renewal and tumor initiation for medulloblastoma progression. These results are translated to clinical samples where high levels of ERBB4 correlate with poor outcome in Group 4 and all medulloblastomas groups. Transcriptomic analysis identified critical processes and pathways altered in cells with knock-down of ERBB4. These results highlight the impact and underlying mechanisms of ERBB4 in critical processes during cerebellum development and medulloblastoma.

GSTP1 polymorphisms sex-specific association with verbal intelligence in survivors of pediatric medulloblastoma tumors

Glutathione S-transferase (GST) single nucleotide polymorphisms (SNPs) have been associated with a lower intellectual quotient (IQ) in medulloblastoma survivors. We investigated the association of GSTP1 polymorphisms with intellectual, neurocognitive skills (e.g., attention span, working memory, and processing speed), and adaptive outcomes for long-term pediatric medulloblastoma survivors. We hypothesized that genetic risk and sex-specific risk would contribute to significantly lower performances across all measures. Eighteen long-term pediatric medulloblastoma survivors completed the Wechsler Abbreviated Scale Intelligence, California Verbal Learning Test-II, Auditory Consonant Trigrams, and Oral Symbol Digit Modality Test. Informants were interviewed with the Scales of Independent Behavior-Revised (SIB-R). After controlling for the false discovery rate, females with a polymorphism performed significantly worse than females without a polymorphism on verbal IQ (p = .005) and SIB-R (p = .012). There was a significant interaction between sex and polymorphism status for verbal IQ (b = -1.8, SE = 0.827, CI: -3.58, -.036). The main effect of this interaction was significant for females (p = .004) and not for males (p = .557). We found large effect sizes between males with the polymorphism and females with the polymorphism across measures of attention span (g = .877), working memory (g = 1.12), and processing speed (g = 1.53). Female medulloblastoma survivors with a GSTP1 polymorphism may have increased vulnerability to deficits in core cognitive skills, IQ, and everyday functional outcomes. Sex-specific genetic risk contributes to the variability in long-term verbal intelligence for medulloblastoma survivors.

Examining the biomarkers and molecular mechanisms of medulloblastoma based on bioinformatics analysis

Medulloblastoma (MB) is the most common malignant brain tumor in children. The aim of the present study was to predict biomarkers and reveal their potential molecular mechanisms in MB. The gene expression profiles of GSE35493, GSE50161, GSE74195 and GSE86574 were downloaded from the Gene Expression Omnibus (GEO) database. Using the Limma package in R, a total of 1,006 overlapped differentially expressed genes (DEGs) with the cut-off criteria of P<0.05 and |log₂fold-change (FC)|>1 were identified between MB and normal samples, including 540 upregulated and 466 downregulated genes. Furthermore, the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were also performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID) online tool to analyze functional and pathway enrichment. The Search Tool for Retrieval of Interacting Genes database was subsequently used to construct a protein-protein interaction (PPI) network and the network was visualized in Cytoscape. The top 11 hub genes, including CDK1, CCNB1, CCNB2, PLK1, CDC20, MAD2L1, AURKB, CENPE, TOP2A, KIF2C and PCNA, were identified from the PPI network. The survival curves for hub genes in the dataset GSE85217 predicted the association between the genes and survival of patients with MB. The top 3 modules were identified by the Molecular Complex Detection plugin. The results indicated that the pathways of DEGs in module 1 were primarily enriched in cell cycle, progesterone-mediated oocyte maturation and oocyte meiosis; and the most significant functional pathways in modules 2 and 3 were primarily enriched in mismatch repair and ubiquitin-mediated proteolysis, respectively. These results may help elucidate the pathogenesis and design novel treatments for MB.

Radiation-induced vascular changes in the intracranial irradiation field in medulloblastoma survivors: An MRI study

BACKGROUND AND PURPOSE

While survival times after treatment of medulloblastoma are increasing, little is known about radiochemotherapy (RCT)-induced cerebrovascular changes. High resolution vessel wall imaging (VWI) sequences are an emerging tool for the evaluation of cerebrovascular diseases. We performed VWI in medulloblastoma long-term survivors to screen for late sequelae of RCT.

MATERIAL AND METHODS

Twenty-two pediatric medulloblastoma survivors (mean age 25.8 years (10-53 years); 16.3 years (mean) post primary RCT (range 1-45 years)) underwent 2D VWI-MRI. Vessel wall thickening, contrast enhancement and luminal narrowing were analyzed. The findings were correlated with the patients' radiation protocols.

RESULTS

Vessel wall changes were observed the intracranial internal carotid artery (ICA) and the vertebrobasilar circulation (VBC) in 14 of 22 patients (63.6%). In multivariate analysis, time after RCT (OR = 1.38, p < 0.05) was strongest independent predictor for development of vessel wall alterations. The dose of radiation was not a relevant predictor.

CONCLUSIONS

With longer follow-up time intracranial vessel wall changes are observed more frequently in medulloblastoma survivors. Thus VWI is a useful tool to monitor vessel wall alterations of cranially irradiated patients, creating the prerequisite for further treatment of late sequelae.

Early Postoperative 18F-FET PET/MRI for Pediatric Brain and Spinal Cord Tumors

Complete resection is the treatment of choice for most pediatric brain tumors, but early postoperative MRI for detection of residual tumor may be misleading because of MRI signal changes caused by the operation. PET imaging with amino acid tracers in adults increases the diagnostic accuracy for brain tumors, but the literature in pediatric neurooncology is limited. A hybrid PET/MRI system is highly beneficial in children, reducing the number of scanning procedures, and this is to our knowledge the first larger study using PET/MRI in pediatric neurooncology. We evaluated if additional postoperative ¹⁸F-fluoro-ethyl-tyrosine (¹⁸F-FET) PET in children and adolescents would improve diagnostic accuracy for the detection of residual tumor as compared with MRI alone and would assist clinical management. Methods: Twenty-two patients (7 male; mean age, 9.5 y; range, 0-19 y) were included prospectively and consecutively in the study and had 27 early postoperative ¹⁸F-FET PET exams performed preferentially in a hybrid PET/MRI system (NCT03402425). Results: Using follow-up (93%) or reoperation (7%) as the reference standard, PET combined with MRI discriminated tumor from treatment effects with a lesion-based sensitivity/specificity/accuracy (95% confidence intervals) of 0.73 (0.50-1.00)/1.00 (0.74-1.00)/0.87 (0.73-1.00) compared with MRI alone: 0.80 (0.57-1.00)/0.75 (0.53-0.94)/0.77 (0.65-0.90); that is, the specificity for PET/MRI was 1.00 as compared with 0.75 for MRI alone (P = 0.13). In 11 of 27 cases (41%), results from the ¹⁸F-FET PET scans added relevant clinical information, including one scan that directly influenced clinical management because an additional residual tumor site was identified. ¹⁸F-FET uptake in reactive changes was frequent (52%), but correct interpretation was possible in all cases. Conclusion: The high specificity for detecting residual tumor suggests that supplementary ¹⁸F-FET PET is relevant in cases where reoperation for residual tumor is considered.

Circulating tumour DNA, microRNA and metabolites in cerebrospinal fluid as biomarkers for central nervous system malignancies

Central nervous system (CNS) malignancies can be difficult to diagnose and many do not respond satisfactorily to existing therapies. Monitoring patients with CNS malignancies for treatment response and tumour recurrence can be challenging because of the difficulty and risks of brain biopsies, and the low specificity and sensitivity of the less invasive methodologies that are currently available. Uncertainty about tumour diagnosis or whether a tumour has responded to treatment or has recurred can cause delays in therapeutic decisions that can impact patient outcome. Therefore, there is an urgent need to develop and validate reliable and minimally invasive biomarkers for CNS tumours that can be used alone or in combination with current clinical practices. Blood-based biomarkers can be informative in the diagnosis and monitoring of various types of cancer. However, blood-based biomarkers have proven suboptimal for analysis of CNS tumours. In contrast, circulating biomarkers in cerebrospinal fluid (CSF), including circulating tumour DNA, microRNAs and metabolites, hold promise for accurate and minimally invasive assessment of CNS tumours. This review summarises the current understanding of these three types of CSF biomarkers and their potential use in neuro-oncologic clinical practice.

Is there an increased risk of spinal relapse in standard-risk medulloblastoma/primitive neuroectodermal tumor patients who receive only a reduced dose of craniospinal radiotherapy?

PURPOSE

Medulloblastoma (MBL) is the most common pediatric brain malignancy. Postoperative radiotherapy to the entire craniospinal axis is the standard-of-care but has linked to long-term morbidity. In this study, we analyzed the implication of reduced dose craniospinal radiotherapy (RT) for survival and pattern of relapse in MBL patients.

MATERIAL AND METHODS

The clinical characteristics of 32 consecutively diagnosed medulloblastoma/primitive neuroectodermal tumor patients were analyzed. After surgical resection, a dose of 23.4 Gy of spinal RT with a posterior fossa boost of 30.6 Gy was prescribed to standard-risk patients, whereas high-risk patients received 36 Gy spinal RT with additional boosts to the posterior fossa up to 54 Gy. Then, both groups received the same chemotherapy protocol.

RESULTS

Five-year OS for standard and high-risk patients was 94 and 50%, respectively. When analyzing prognostic factors, postoperative tumor size is the most important one which affects the OS. Ten patients relapsed during follow-up, and there was no isolated spinal relapse in either group.

CONCLUSION

The risk of isolated spinal relapse does not increase with reduced-dose craniospinal RT, since there is no isolated relapse in either the standard or high-risk groups of patients.

Late effects of craniospinal irradiation for medulloblastomas in paediatric patients

Along with surgery, radiation therapy (RT) remains an essential option to cure patients suffering from medulloblastoma. However, its long-term adverse effects, particularly due to craniospinal irradiation (CSI), which is necessary to eradicate microscopic spread, are a limiting factor. The most frequent sequelae involve neurocognitive and endocrine impairment, which occurs in nearly all patients. Recent progress achieved through genetic and molecular biology offers the possibility to better stratify patients according to risk factors such as age, post-resection tumour residue and metastasis. Thus, new therapeutic studies assess the possibility to reduce radiation dose and/or radiation field size for patients with the most favourable prognosis. New radiotherapy techniques are also used such as Intensity-Modulated Radiotherapy (IMRT), tomotherapy and proton therapy, which aim at reducing the dose delivered to normal tissue. Conventional photon-based therapy has a relatively high exit dose in contrast with proton therapy which causes less damage to surrounding healthy tissue. It is noteworthy that each technique requires a long follow-up in order to prove that late effects could be reduced without compromising survival rates. Dosimetric comparison theoretically suggests that proton therapy may be the superior method for CSI in terms of late effects, but further research is needed to firmly establish this. Whatever the technique used, the great complexity of CSI requires discipline and expertise along with an external quality control online before the first RT session.

Targeting mTOR as a Therapeutic Approach in Medulloblastoma

Mechanistic target of rapamycin (mTOR) is a master signaling pathway that regulates organismal growth and homeostasis, because of its implication in protein and lipid synthesis, and in the control of the cell cycle and the cellular metabolism. Moreover, it is necessary in cerebellar development and stem cell pluripotency maintenance. Its deregulation has been implicated in the medulloblastoma and in medulloblastoma stem cells (MBSCs). Medulloblastoma is the most common malignant solid tumor in childhood. The current therapies have improved the overall survival but they carry serious side effects, such as permanent neurological sequelae and disability. Recent studies have given rise to a new molecular classification of the subgroups of medulloblastoma, specifying 12 different subtypes containing novel potential therapeutic targets. In this review we propose the targeting of mTOR, in combination with current therapies, as a promising novel therapeutic approach.

CSF-ctDNA SMSEQ Analysis to Tailor the Treatment of a Patient with Brain Metastases: A Case Report

Brain metastases are the most common neurological complications of adult cancers, accounting for more than half of brain tumors. The incidence of brain metastases may be increasing due to improved detection of small lesions by advanced imaging technologies. Given the fast evolution of targeted and immunotherapy regimens, it is essential to serially assess brain malignancies during the disease course for disease monitoring and tailoring of the therapeutic management. For such serial and repetitive assessment, cerebrospinal fluid (CSF) could be the biological fluid of choice to supplement cytology examination for the presence or absence of CNS malignancy, as well as provide extensive information on tumor mutational profile for personalization of treatment. The case described here emphasizes the importance of CSF-ctDNA analysis with the CellMax SMSEQ technology that led to treatment adjustment resulting in clinical remission of the patient.

Silencing of Urothelial Carcinoma Associated 1 Inhibits the Proliferation and Migration of Medulloblastoma Cells

Background

UCA1 is a long non-coding RNA that has been found to be aberrantly upregulated in various cancers. The aim of this study was to determine the expression level and function of UCA1 in medulloblastoma, the most common malignant brain tumor during childhood.

Material/Methods

Real-time PCR was used to detect the expression of UCA1 in medulloblastoma specimens and cell lines. Lentiviral-mediated expression of a short hairpin RNA (shRNA) targeting UCA1 or a negative control shRNA was also achieved with the medulloblastoma cell line, Daoy. Cell proliferation and cell cycle progression were subsequently characterized with cell counting kit (CCK)-8 and flow cytometry. Cell migration was examined in wound healing and Transwell migration assays.

Results

Levels of UCA1 mRNA were higher in the medulloblastoma specimens (p<0.05) and cell lines (p<0.05) compared to the corresponding nontumor adjacent tissue specimens and a glioblastoma cell line, respectively. For the Daoy cells with silenced UCA1, their proliferation was reduced by 30% compared to the Daoy cells expressing a negative control shRNA (p=0.017). Cell cycle arrest in the G0/G1 phase, resulting in a decreased number of cells in the S phase, as well as reduced cell migration in both wound scratch healing (p=0.001) and Transwell migration assays (p=0.021) were also observed for the Daoy cells with silenced UCA1.

Conclusions

UCA1 was highly expressed in part of medulloblastoma specimens and cell lines examined. In addition, knockdown of UCA1 significantly inhibited the proliferation and migration of medulloblastoma cells in vitro.

Functional expression of calcium-permeable canonical transient receptor potential 4-containing channels promotes migration of medulloblastoma cells

KEY POINTS

The proton sensing ovarian cancer G protein coupled receptor 1 (OGR1, aka GPR68) promotes expression of the canonical transient receptor potential channel subunit TRPC4 in normal and transformed cerebellar granule precursor (DAOY) cells. OGR1 and TRPC4 are prominently expressed in healthy cerebellar tissue throughout postnatal development and in primary cerebellar medulloblastoma tissues. Activation of TRPC4-containing channels in DAOY cells, but not non-transformed granule precursor cells, results in prominent increases in [Ca2+ ]i and promotes cell motility in wound healing and transwell migration assays. Medulloblastoma cells not arising from granule precursor cells show neither prominent rises in [Ca2+ ]i nor enhanced motility in response to TRPC4 activation unless they overexpressTRPC4. Our results suggest that OGR1 enhances expression of TRPC4-containing channels that contribute to enhanced invasion and metastasis of granule precursor-derived human medulloblastoma.

ABSTRACT

Aberrant intracellular Ca2+ signalling contributes to the formation and progression of a range of distinct pathologies including cancers. Rises in intracellular Ca2+ concentration occur in response to Ca2+ influx through plasma membrane channels and Ca2+ release from intracellular Ca2+ stores, which can be mobilized in response to activation of cell surface receptors. Ovarian cancer G protein coupled receptor 1 (OGR1, aka GPR68) is a proton-sensing Gq -coupled receptor that is most highly expressed in cerebellum. Medulloblastoma (MB) is the most common paediatric brain tumour that arises from cerebellar precursor cells. We found that nine distinct human MB samples all expressed OGR1. In both normal granule cells and the transformed human cerebellar granule cell line DAOY, OGR1 promoted expression of the proton-potentiated member of the canonical transient receptor potential (TRPC) channel family, TRPC4. Consistent with a role for TRPC4 in MB, we found that all MB samples also expressed TRPC4. In DAOY cells, activation of TRPC4-containing channels resulted in large Ca2+ influx and enhanced migration, while in normal cerebellar granule (precursor) cells and MB cells not derived from granule precursors, only small levels of Ca2+ influx and no enhanced migration were observed. Our results suggest that OGR1-dependent increases in TRPC4 expression may favour formation of highly Ca2+ -permeable TRPC4-containing channels that promote transformed granule cell migration. Increased motility of cancer cells is a prerequisite for cancer invasion and metastasis, and our findings may point towards a key role for TRPC4 in progression of certain types of MB.

Risk factors for the prognosis of pediatric medulloblastoma: a retrospective analysis of 40 cases

OBJECTIVES:

In this study, we evaluated the association of molecular subtypes, clinical characteristics and pathological types with the prognosis of patients with medulloblastoma.

METHODS:

We analyzed forty patients with medulloblastoma who underwent surgical resection at our center between January 2004 and June 2014. Risk factors associated with survival, disease progression and recurrence were analyzed with a univariate Cox regression analysis, and the identified significant risk factors were further analyzed by Kaplan-Meier survival curves.

RESULTS:

Factors associated with overall survival included M stage (p=0.014), calcification (p=0.012), postoperative treatment, postoperative Karnofsky Performance Scale (KPS) score (p=0.015), and molecular subtype (p=0.005 for WNT and p=0.008 for SHH). Number of symptoms (p=0.029), M stage (p<0.001), and postoperative radiotherapy (p=0.033) were associated with disease progression. Patients with the WNT or SHH subtype had better survival outcomes than patients with non-WNT/SHH subtypes. Risk factors for disease progression-free survival were symptoms >2 and ≥M1 stage without postoperative radiotherapy. The risk of recurrence increased with advanced M stage. Protective factors for recurrence included M0 stage and a combination of chemotherapy and radiotherapy.

CONCLUSION:

We identified the risk factors associated with survival, disease progression and recurrence of medulloblastoma patients. This information is helpful for understanding the prognostic factors related to medulloblastoma.

Highly Conformal Craniospinal Radiotherapy Techniques Can Underdose the Cranial Clinical Target Volume if Leptomeningeal Extension through Skull Base Exit Foramina is not Contoured

AIMS

Craniospinal irradiation (CSI) remains a crucial treatment for patients with medulloblastoma. There is uncertainty about how to manage meningeal surfaces and cerebrospinal fluid (CSF) that follows cranial nerves exiting skull base foramina. The purpose of this study was to assess plan quality and dose coverage of posterior cranial fossa foramina with both photon and proton therapy.

MATERIALS AND METHODS

We analysed the radiotherapy plans of seven patients treated with CSI for medulloblastoma and primitive neuro-ectodermal tumours and three with ependymoma (total n = 10). Four had been treated with a field-based technique and six with TomoTherapy™. The internal acoustic meatus (IAM), jugular foramen (JF) and hypoglossal canal (HC) were contoured and added to the original treatment clinical target volume (Plan_CTV) to create a Test_CTV. This was grown to a test planning target volume (Test_PTV) for comparison with a Plan_PTV. Using Plan_CTV and Plan_PTV, proton plans were generated for all 10 cases. The following dosimetry data were recorded: conformity (dice similarity coefficient) and homogeneity index (D₂ - D₉₈/D₅₀) as well as median and maximum dose (D_2%) to Plan_PTV, V_95% and minimum dose (D_99.9%) to Plan_CTV and Test_CTV and Plan_PTV and Test_PTV, V_95% and minimum dose (D_98%) to foramina PTVs.

RESULTS

Proton and TomoTherapy™ plans were more conformal (0.87, 0.86) and homogeneous (0.07, 0.04) than field-photon plans (0.79, 0.17). However, field-photon plans covered the IAM, JF and HC PTVs better than proton plans (P = 0.002, 0.004, 0.003, respectively). TomoTherapy™ plans covered the IAM and JF better than proton plans (P = 0.000, 0.002, respectively) but the result for the HC was not significant. Adding foramen CTVs/PTVs made no difference for field plans. The mean D_min dropped 3.4% from Plan_PTV to Test_PTV for TomoTherapy™ (not significant) and 14.8% for protons (P = 0.001).

CONCLUSIONS

Highly conformal CSI techniques may underdose meninges and CSF in the dural reflections of posterior fossa cranial nerves unless these structures are specifically included in the CTV.

Time knowledge difficulties following treatment for malignant cerebellar tumors

In children treated for malignant cerebellar tumors, there are only a few studies investigating temporal skills, despite the role of the cerebellum in time processing being generally acknowledged. Children's time knowledge has been defined as the correct representation and use of familiar time units. The present study compares time knowledge in 38 children treated for malignant cerebellar tumors (mean age 11.6 years) with 105 typically-developing (TD) children. The performances on all time knowledge subtests were significantly lower in the tumor group. The results also confirm a lower mean IQ in the children treated for cerebellar tumors, related to slower processing speed and poorer performance on working memory and non-verbal tasks. However, the lower IQ does not explain the considerable difficulties in the acquisition of time knowledge. These results are discussed in the light of the role of the cerebellum in time processing and in the context of two different models of temporal processing: the internal clock model and the neural network state model.

Factors Affecting the Prognosis of Children with Medulloblastoma: A Single Institution Retrospective Analysis of 40 Cases

Few studies have investigated the factors associated with the prognosis of children with medulloblastoma. This retrospective observational study evaluated the association of molecular subtype, clinical characteristics, and pathological types with the outcomes of children with medulloblastoma. This study included 40 patients with medulloblastoma who underwent surgical resection at the Affiliated Children's Hospital of Fudan University between January 2004 and June 2014. The primary outcome was overall survival (OS). Risk factors associated with survival, disease progression, and recurrence were analyzed by univariate Cox regression analysis; the identified significant risk factors were further analyzed by Kaplan-Meier survival curves. Immunohistochemistry analysis of Yes-associated protein 1 (YAP1) and GRB2-associated protein 1 (GAB1) was used for medulloblastoma subtype identification; 20% of tumors were the WNT subtype, and 32.5% were the SHH subtype, with the remainder being non-SHH/WNT. Factors associated with OS included M stage, calcification, cerebrospinal fluid fistula, postoperative treatment (radiotherapy, chemotherapy, or both), postoperative Karnofsky Performance Scale score, and molecular subtype (P < 0.044). Patients with the WNT subtype had better survival outcomes (hazard ratio [HR] = 0.16, 95% confidence interval [CI]: 0.05–0.58). Number of symptoms, M stage, and postoperative radiotherapy were associated with disease progression (P ≤ 0.033). The risk of recurrence increased with advanced M stage (HR = 30.71; 95% CI: 3.92—240.44, P = 0.001). Patients receiving both chemotherapy and radiotherapy were less likely to have a recurrence (P = 0.040). Molecular subtyping of medulloblastoma was more predictive of survival than histopathology in patients undergoing adjuvant therapy.

Ganglioglioma Arising From Desmoplastic Medulloblastoma: A Case Report and Review of Literature

We describe a case of medulloblastoma maturating into ganglioglioma during therapy. A 10-month-old boy was diagnosed with a desmoplastic medulloblastoma and was treated with gross total resection followed by induction chemotherapy. A recurrence in the tumor bed during therapy was managed with focal radiation therapy and consolidation chemotherapy. After further progression, the recurrent tumor was resected completely. The histopathology revealed a benign ganglioglioma with no residual medulloblastoma. This case raises the possibility that a malignant medulloblastoma can differentiate into a benign tumor and suggests that differentiation therapy may have value in the treatment of medulloblastoma.

Quality of survival and cognitive performance in children treated for medulloblastoma in the PNET 4 randomized controlled trial

Background

The relationship between direct assessments of cognitive performance and questionnaires assessing quality of survival (QoS) is reported to be weak-to-nonexistent. Conversely, the associations between questionnaires evaluating distinct domains of QoS tend to be strong. This pattern remains understudied.

Methods

In the HIT-SIOP PNET4 randomized controlled trial, cognitive assessments, including Full Scale, Verbal and Performance IQ, Working Memory, and Processing Speed, were undertaken in 137 survivors of standard-risk medulloblastoma from 4 European countries. QoS questionnaires, including self-reports and/or parent reports of the Behavior Rating Inventory of Executive Function (BRIEF), the Health Utilities Index, the Strengths and Difficulties Questionnaire, and the Pediatric Quality of Life Inventory, were completed for 151 survivors. Correlations among direct cognitive assessments, QoS questionnaires, and clinical data were examined in participants with both assessments available (n = 86).

Results

Correlations between direct measures of cognitive performance and QoS questionnaires were weak, except for moderate correlations between the BRIEF Metacognition Index (parent report) and working memory (r = .32) and between health status (self-report) and cognitive outcomes (r = .35-.44). Correlations among QoS questionnaires were moderate to strong both for parent and self-report (r = .39-.76). Principal Component Analysis demonstrated that questionnaires and cognitive assessments loaded on 2 separate factors.

Conclusions

We hypothesize that the strong correlations among QoS questionnaires is partially attributable to the positive/negative polarity of all questions on the questionnaires, coupled with the relative absence of disease-specific questions. These factors may be influenced by respondents' personality and emotional characteristics, unlike direct assessments of cognitive functioning, and should be taken into account in clinical trials.

The expression of FAT1 is associated with overall survival in children with medulloblastoma

PURPOSE

The FAT1 gene is involved in some cancers; however, its role in medulloblastoma is less clear. This study investigated the effects of FAT1 expression on the prognosis of medulloblastoma patients.

METHODS

Whole exome sequencing was undertaken in 40 medulloblastoma patient samples. FAT1 mRNA and protein expression levels in normal and brain tumor tissues were determined by fluorescence quantitative PCR and immunohistochemistry, respectively. The association of FAT1 expression with overall survival (OS) was examined by Kaplan-Meier curve analysis with a log-rank test. Following lentiviral-mediated FAT1 knockdown using shRNA in Daoy cells, proliferation, Wnt signaling, and β-catenin protein expression were determined.

RESULTS

Eight FAT1 missense mutations were detected in 7 patients. FAT1 mRNA expression in tumors was significantly lower than in adjacent normal tissue (p = 0.043). The OS of patients with high FAT1 protein expression was significantly longer than that of patients with low FAT1 protein expression (median survival time: 24.3 vs 4.8 months, respectively; p = 0.002). shFAT1 cells had significantly higher proliferation rates than shControl cells (p≤0.028). Furthermore, the mRNA expression of LEF1, β-catenin, and cyclin D1 was significantly upregulated in shFAT1-Daoy cells (p≤0.018).

CONCLUSIONS

Low FAT1 expression was associated with poor prognosis in children with medulloblastoma. Furthermore, FAT1 may act on Wnt signaling pathway to exert its antitumor effect.

Fast imaging employing steady-state acquisition (FIESTA) MRI to investigate cerebrospinal fluid (CSF) within dural reflections of posterior fossa cranial nerves

OBJECTIVE

There is no consensus approach to covering skull base meningeal reflections-and cerebrospinal fluid (CSF) therein-of the posterior fossa cranial nerves (CNs VII-XII) when planning radiotherapy (RT) for medulloblastoma and ependymoma. We sought to determine whether MRI and specifically fast imaging employing steady-state acquisition (FIESTA) sequences can answer this anatomical question and guide RT planning.

METHODS

96 posterior fossa FIESTA sequences were reviewed. Following exclusions, measurements were made on the following scans for each foramen respectively (left, right); internal acoustic meatus (IAM) (86, 84), jugular foramen (JF) (83, 85) and hypoglossal canal (HC) (42, 45). A protocol describes measurement procedure. Two observers measured distances for five cases and agreement was assessed. One observer measured all the remaining cases.

RESULTS

IAM and JF measurement interobserver variability was compared. Mean measurement difference between observers was -0.275 mm (standard deviation 0.557). IAM and JF measurements were normally distributed. Mean IAM distance was 12.2 mm [95% confidence interval (CI) 8.8-15.6]; JF was 7.3 mm (95% CI 4.0-10.6). The HC was difficult to visualize on many images and data followed a bimodal distribution.

CONCLUSION

Dural reflections of posterior fossa CNs are well demonstrated by FIESTA MRI. Measuring CSF extension into these structures is feasible and robust; mean CSF extension into IAM and JF was measured. We plan further work to assess coverage of these structures with photon and proton RT plans. Advances in knowledge: We have described CSF extension beyond the internal table of the skull into the IAM, JF and HC. Oncologists planning RT for patients with medulloblastoma and ependymoma may use these data to guide contouring.

Core deficits and quality of survival after childhood medulloblastoma: a review

Background

Medulloblastoma is the most common malignant central nervous system tumor in children. Treatment most often includes surgical resection, craniospinal irradiation, and adjuvant chemotherapy. Although survival has improved dramatically, the tumor and its treatments have devastating long-term side effects that negatively impact quality of survival (QoS). The objective was to review the literature on QoS following childhood medulloblastoma.

Methods

This narrative review is based on a Medline database search and examination of the reference lists of papers selected.

Results

Frequent problems after medulloblastoma treatment include medical complications, such as long-term neurological and sensory (hearing loss) impairments; endocrine deficits, including growth problems; and secondary tumors. Neurocognitive impairment is repeatedly reported, with decreasing cognitive performances over time. Although all cognitive domains may be affected, low processing speed, attention difficulties, and working memory difficulties are described as the core cognitive deficits resulting from both cerebellar damage and the negative effect of radiation on white matter development. Long-term psychosocial limitations include low academic achievement, unemployment, and poor community integration with social isolation. Important negative prognostic factors include young age at diagnosis, conventional craniospinal radiotherapy, presence of postoperative cerebellar mutism, and perioperative complications. The influence of environmental factors, such as family background and interventions, remains understudied.

Conclusion

Future studies should focus on the respective impact of radiation, cerebellar damage, genomic and molecular subgroup parameters, and environmental factors on cognitive and psychosocial outcomes. Long-term (probably lifelong) follow-up into adulthood is required in order to monitor development and implement timely, suitable, multi-disciplinary rehabilitation interventions and special education or support when necessary.

Sox2: regulation of expression and contribution to brain tumors

Tumors of the CNS are composed of a complex mixture of neoplastic cells, in addition to vascular, inflammatory and stromal components. Similar to most other tumors, brain tumors contain a heterogeneous population of cells that are found at different stages of differentiation. The cancer stem cell hypothesis suggests that all tumors are composed of subpopulation of cells with stem-like properties, which are capable of self-renewal, display resistance to therapy and lead to tumor recurrence. One of the most important transcription factors that regulate cancer stem cell properties is SOX2. In this review, we focus on SOX2 and the complex network of signaling molecules and transcription factors that regulate its expression and function in brain tumor initiating cells. We also highlight important findings in the literature about the role of SOX2 in glioblastoma and medulloblastoma, where it has been more extensively studied.

Clinical characteristics and abandonment and outcome of treatment in 67 Chinese children with medulloblastoma

OBJECT The purpose of this study was to explore the clinical features and outcome of medulloblastoma in Chinese children. The authors analyze the reasons that treatment is abandoned and attempt to provide evidence-based recommendations for improving the prognosis of medulloblastoma in this population. METHODS A total of 67 pediatric cases of newly diagnosed medulloblastoma were included in this study. All of the children were treated at Xinhua Hospital between January 2007 and June 2013. The authors retrospectively analyzed the clinical data, treatment modalities, and outcome. The male-to-female ratio was 2:1, and the patients' median age at diagnosis was 51.96 months (range 3.96-168.24 months). The median duration of follow-up was 32 months (range 3-70 months). RESULTS At the most recent follow-up date, 31 patients (46%) were alive, 30 (45%) had died, and 6 (9%) had been lost to follow-up. The estimated 3-year overall survival and progression-free survival, based on Kaplan-Meier analysis, were 55.1% ± 6.4% and 45.6% ± 6.7%, respectively. Univariate analysis showed that standard-risk group (p = 0.009), postoperative radiotherapy (RT) combined with chemotherapy (p < 0.001), older age (≥ 3 years) at diagnosis (p = 0.010), gross-total resection (p = 0.012), annual family income higher than $3000 (p = 0.033), and living in urban areas (p = 0.008) were favorable prognostic factors. Multivariate analysis revealed that postoperative RT combined with chemotherapy was an independent prognostic factor (p < 0.001). The treatment abandonment rate in this cohort was 31% (21 of 67 cases). CONCLUSIONS There was a large gap between the outcome of medulloblastoma in Chinese children and the outcome in Western children. Based on our data, treatment abandonment was the major cause of therapeutic failure. Parents' misunderstanding of medulloblastoma played a major role in abandonment, followed by financial and transportation difficulties. Establishment of multidisciplinary treatment teams could improve the prognosis of medulloblastoma in Chinese children.

Shedding light on adult medulloblastoma: current management and opportunities for advances

Few evidence-based guidelines are available for the treatment of adult medulloblastoma, an extremely rare disease. Therapeutic regimens, typically modeled following pediatric protocols, consist of surgical resection followed by radiotherapy with or without adjuvant chemotherapy. Because of the rarity of this disease in adults, any treatment undertaken is based mainly on small and retrospective studies. Unlike pediatric patients, adults with medulloblastoma have been treated according to risk-adapted therapeutic strategies in only a few prospective studies. Overall, approximately 30% of patients experience recurrence and die of disease-related causes. Although the patients could respond to second-line treatments, the prognosis of patients with recurrence remains dismal. An important challenge for the future will be the biologic characterization of medulloblastoma in adults, with the identification of specific genetic patterns of patients with different prognosis and different response to targeted treatments.

Chemotherapy increases long-term survival in patients with adult medulloblastoma--a literature-based meta-analysis

BACKGROUND

Adult medulloblastoma is a potentially curable malignant entity with an incidence of 0.5-1 per million. Valid data on prognosis, treatment, and demographics are lacking, as most current knowledge stems from retrospective studies. Surgical resection followed by radiotherapy are accepted parts of treatment regimes; however, established prognostic factors and data clarifying the role of chemotherapy are missing.

METHODS

We investigated 227 publications from 1969-2013, with 907 identifiable, individual patients being available for meta-analysis. Demographic data, risk stratification, and treatment of these patients were similar to previous cohorts.

RESULTS

The median overall survival (mOS) was 65 months (95% CI: 54.6-75.3) , the 5-year overall survival was 50.9% with 16% of the patients dying more than 5 years after diagnosis. Incomplete resection, clinical and radiological signs for brainstem infiltration, and abstinence from radiotherapy were predictive of worse outcome. Metastatic disease at tumor recurrence was identified as a new prognostic factor, while neither metastasis at initial diagnosis nor desmoplastic/classic histology was correlated with survival. Patients receiving chemotherapy first-line survived significantly longer (mOS: 108 mo, 95% CI: 68.6-148.4) than patients treated with radiation alone (mOS: 57 mo, 95% CI: 39.6-74.4) or patients who received chemotherapy at tumor recurrence. This effect was not biased by tumor stage or decade of treatment. Importantly, (neo)adjuvant chemotherapy also significantly increased the chance for long-term survival (>5 y) compared with radiotherapy alone or chemotherapy at tumor recurrence.

CONCLUSIONS

This meta-analysis clarifies relevant prognostic factors and suggests that chemotherapy as part of first-line therapy improves overall survival and increases the proportion of patients with long-term survival.

Detection of tumor-derived DNA in cerebrospinal fluid of patients with primary tumors of the brain and spinal cord

Cell-free DNA shed by cancer cells has been shown to be a rich source of putative tumor-specific biomarkers. Because cell-free DNA from brain and spinal cord tumors cannot usually be detected in the blood, we studied whether the cerebrospinal fluid (CSF) that bathes the CNS is enriched for tumor DNA, here termed CSF-tDNA. We analyzed 35 primary CNS malignancies and found at least one mutation in each tumor using targeted or genome-wide sequencing. Using these patient-specific mutations as biomarkers, we identified detectable levels of CSF-tDNA in 74% [95% confidence interval (95% CI) = 57-88%] of cases. All medulloblastomas, ependymomas, and high-grade gliomas that abutted a CSF space were detectable (100% of 21 cases; 95% CI = 88-100%), whereas no CSF-tDNA was detected in patients whose tumors were not directly adjacent to a CSF reservoir (P < 0.0001, Fisher's exact test). These results suggest that CSF-tDNA could be useful for the management of patients with primary tumors of the brain or spinal cord.

New perspectives in the treatment of adult medulloblastoma in the era of molecular oncology

Medulloblastoma is the most common central nervous system tumor in children, while it is extremely rare in adults. Multimodal treatment involving surgery, radiotherapy and chemotherapy can improve the prognosis of this disease, and recent advances in molecular biology have allowed the identification of molecular subgroups (WNT, SHH, Groups 3 and 4), each of which have different cytogenetic, mutational and gene expression signatures, demographics, histology and prognosis. The present review focuses on the state of the art for adult medulloblastoma treatment and on novel molecular advances and their future implications in the treatment of this disease.