Children's Oncology Group's 2013 blueprint for research: central nervous system tumors

Children's Oncology Group's 2023 blueprint for research: Central nervous system tumors

Tumors of the central nervous system (CNS) are a leading cause of morbidity and mortality in the pediatric population. Molecular characterization in the last decade has redefined CNS tumor diagnoses and risk stratification; confirmed the unique biology of pediatric tumors as distinct entities from tumors that occur in adulthood; and led to the first novel targeted therapies receiving Food and Drug Administration (FDA) approval for children with CNS tumors. There remain significant challenges to overcome: children with unresectable low-grade glioma may require multiple prolonged courses of therapy affecting quality of life; children with high-grade glioma have a dismal long-term prognosis; children with medulloblastoma may suffer significant short- and long-term morbidity from multimodal cytotoxic therapy, and approaches to improve survival in ependymoma remain elusive. The Children's Oncology Group (COG) is uniquely positioned to conduct the next generation of practice-changing clinical trials through rapid prospective molecular characterization and therapy evaluation in well-defined clinical and molecular groups.

Endocrine Late Effects in Childhood Cancer Survivors

Simple Summary

Recent advances in cancer treatment have led to improved survival, with an exponential increase in sequelae among survivors. Around 50% of survivors will experience at least one hormonal disorder, with radiotherapy, hematopoietic stem cell transplantation, and alkylating chemotherapy being the most frequently related. Therefore, lifelong monitoring of childhood cancer survivors at risk is paramount. With this review, we describe in detail the most prevalent endocrine sequelae, considering new approaches such as proton beam therapy and immune-related endocrinopathies with the advent of precision oncology treatment. We hope to encourage oncologists and endocrinologists to develop early detection guidelines that minimize sequelae and have a positive impact on their quality of life.

Abstract

Childhood cancer management has improved considerably over the years, leading to a significant improvement in survival of up to 80%. However, childhood cancer survivors are at the highest risk of developing sequelae resulting from treatment, with endocrine complications being frequently observed among survivors. Multiple predisposing factors for endocrine sequelae have been identified, including age at diagnosis, treatment received, radiation, tumor type, and genetic polymorphisms, which could explain the individual predisposition to develop drug toxicity. Novel agents targeting tumor growth and immune checkpoint inhibitors have recently become the cornerstone for the treatment of different cancers, triggering a myriad of immune-related endocrinopathies. Endocrine sequelae of cancer therapy will have an impact on not only childhood but also on the survival and quality of life of these highly complex patients. Therefore, lifelong monitoring of childhood cancer survivors at risk of endocrine diseases is paramount. Encouraging oncologists and endocrinologists to develop new follow-up and early detection guidelines that minimize sequelae among these patients has become a priority, promoting integration between pediatric and adult units since many sequelae may manifest only after years to decades of follow-up.

Childhood Malignant Brain Tumors: Balancing the Bench and Bedside

Simple Summary

Brain tumors remain the most common childhood solid tumors, accounting for approximately 25% of all pediatric cancers. They also represent the most common cause of cancer-related illness and death in this age group. Recent years have witnessed an evolution in our understanding of the biological underpinnings of many childhood brain tumors, potentially improving survival through both improved risk group allocation for patients to provide appropriate treatment intensity, and novel therapeutic breakthroughs. This review aims to summarize the molecular landscape, current trial-based standards of care, novel treatments being explored and future challenges for the three most common childhood malignant brain tumors—medulloblastomas, high-grade gliomas and ependymomas.

Abstract

Brain tumors are the leading cause of childhood cancer deaths in developed countries. They also represent the most common solid tumor in this age group, accounting for approximately one-quarter of all pediatric cancers. Developments in neuro-imaging, neurosurgical techniques, adjuvant therapy and supportive care have improved survival rates for certain tumors, allowing a future focus on optimizing cure, whilst minimizing long-term adverse effects. Recent times have witnessed a rapid evolution in the molecular characterization of several of the common pediatric brain tumors, allowing unique clinical and biological patient subgroups to be identified. However, a resulting paradigm shift in both translational therapy and subsequent survival for many of these tumors remains elusive, while recurrence remains a great clinical challenge. This review will provide an insight into the key molecular developments and global co-operative trial results for the most common malignant pediatric brain tumors (medulloblastoma, high-grade gliomas and ependymoma), highlighting potential future directions for management, including novel therapeutic options, and critical challenges that remain unsolved.

How well do image-defined risk factors (IDRFs) predict surgical outcomes and survival in patients with neuroblastoma? A systematic review and meta-analysis

INTRODUCTION

Since their introduction to the International Neuroblastoma Risk Group (INRG) staging system in 2009, the role of Image-Defined Risk Factors (IDRFs) in predicting outcomes has been studied in heterogeneous populations with varying results. We conducted a systematic review and meta-analysis in order to determine quantitative measures of precisely how well pre-treatment IDRFs predict surgical outcomes and survival.

METHODS

A systematic review was performed for studies between January 1990 and July 2019 that compared surgical outcomes and/or survival in pediatric neuroblastoma patients with one or more IDRFs to patients without IDRFs. Summary risk ratios (RR) and hazard ratios (HR) were calculated using a random-effects model.

RESULTS

19 retrospective cohort studies were included, representing data from 1132 patients. The risk ratio (RR) of incomplete surgical resection in IDRF-positive patients compared to IDRF-negative patients was 2.45 (95% CI 1.51-3.97). The RR of surgical complications was 2.30 (95% CI 1.46-3.61). The hazard ratio (HR) for 5-year EFS was 2.08 (95% CI 2.93-4.13) while the 5-year HR for OS was 2.44 (95% CI 1.46-4.08).

CONCLUSION

IDRF-positive neuroblastoma patients have a higher risk of incomplete surgical resection, surgical complications, and 5-year mortality and/or relapse. Our results affirm that IDRFs remain a useful prognostic tool for neuroblastoma patients both for short and long-term outcomes.

LEVEL OF EVIDENCE

II.

Fine Particulate Matter Air Pollution and Mortality among Pediatric, Adolescent, and Young Adult Cancer Patients

BACKGROUND

Air pollution is a carcinogen and causes pulmonary and cardiac complications. We examined the association of fine particulate matter pollution (PM_2.5) and mortality from cancer and all causes among pediatric, adolescent, and young adult (AYA) patients with cancer in Utah, a state with considerable variation in PM_2.5.

METHODS

We followed 2,444 pediatric (diagnosed ages 0-14) and 13,459 AYA (diagnosed ages 15-39) patients diagnosed in 1986-2015 from diagnosis to 5 and 10 years postdiagnosis, death, or emigration. We measured average monthly PM_2.5 by ZIP code during follow-up. Separate pediatric and AYA multivariable Cox models estimated the association of PM_2.5 and mortality. Among AYAs, we examined effect modification of PM_2.5 and mortality by stage while controlling for cancer type.

RESULTS

Increases in PM_2.5 per 5 μg/m³ were associated with cancer mortality in pediatric lymphomas and central nervous system (CNS) tumors at both time points, and all cause mortality in lymphoid leukemias [HR_5-year = 1.32 (1.02-1.71)]. Among AYAs, PM_2.5 per 5 μg/m³ was associated with cancer mortality in CNS tumors and carcinomas at both time points, and all cause mortality for all AYA cancer types [HR_5-year = 1.06 (1.01-1.13)]. PM_2.5 ≥12 μg/m³ was associated with cancer mortality among breast [HR_5-year = 1.50 (1.29-1.74); HR_10-year = 1.30 (1.13-1.50)] and colorectal cancers [HR_5-year = 1.74 (1.29-2.35); HR_10-year = 1.67 (1.20-2.31)] at both time points. Effect modification by stage was significant, with local tumors at highest risk.

CONCLUSIONS

PM_2.5 was associated with mortality in pediatric and AYA patients with specific cancers.

IMPACT

Limiting PM_2.5 exposure may be important for young cancer patients with certain cancers.See all articles in this CEBP Focus section, "Environmental Carcinogenesis: Pathways to Prevention."

Childhood Cancer Treatments and Associated Endocrine Late Effects: A Concise Guide for the Pediatric Endocrinologist

Endocrine complications are frequently observed in childhood cancer survivors (CCS); in many instances, these complications develop months to years after the completion of cancer therapy. The estimated prevalence of endocrine late effects is 50% among CCS; the main risk factors are external beam radiation that includes key endocrine organs (the hypothalamus/pituitary, thyroid and gonads) and/or alkylating agents. Novel agents targeting tumor growth have increased the options available to a small number of patients albeit with the need for treatment over long periods of time. Some of these agents, such as certain tyrosine kinase inhibitors and immune system modulators have been shown to cause permanent endocrine deficits. This chapter offers a brief summary of the conventional treatment strategies for the most common cancers of childhood and a brief overview of the endocrine late effects most commonly associated with these exposures. The impact of targeted therapies on the endocrine system will also be discussed. The aim of this chapter is to provide basic guidance to the consulting pediatric endocrinologist in preparation for the clinical encounter with a CCS. A more detailed discussion of the management of specific endocrine late effects can be found in the other chapters in this series.

Survival Differences Between Males and Females Diagnosed With Childhood Cancer

Background

Males have worse survival for childhood cancer, but whether this disparity exists among all childhood cancer types is undescribed.

Methods

We estimated sex differences in survival for 18 cancers among children (0–19 years) in Surveillance, Epidemiology, and End Results 18 (2000–2014). We used Kaplan-Meier survival curves (log-rank P values) to characterize sex differences in survival and Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between sex and death for each cancer type. We used an inverse odds weighting method to determine whether the association between sex and death was mediated by stage of disease for solid tumors.

Results

Males had worse overall survival and a higher risk of death for acute lymphoblastic leukemia (HR = 1.24, 95% CI = 1.12 to 1.37), ependymoma (HR = 1.36, 95% CI = 1.05 to 1.77), neuroblastoma (HR = 1.28, 95% CI = 1.09 to 1.51), osteosarcoma (HR = 1.29, 95% CI = 1.08 to 1.53), thyroid carcinoma (HR = 3.25, 95% CI = 1.45 to 7.33), and malignant melanoma (HR = 1.97, 95% CI = 1.33 to 2.92) (all log-rank P values < .02). The association between sex and death was mediated by stage of disease for neuroblastoma (indirect HR = 1.12, 95% CI = 1.05 to 1.19), thyroid carcinoma (indirect HR = 1.24, 95% CI = 1.03 to 1.48), and malignant melanoma (indirect HR = 1.28, 95% CI = 1.10 to 1.49). For these six tumors, if male survival had been as good as female survival, 21% of male deaths and 13% of total deaths after these cancer diagnoses could have been avoided.

Conclusions

Consideration of molecular tumor and clinical data may help identify mechanisms underlying the male excess in death after childhood cancer for the aforementioned cancers.

Intravoxel Incoherent Motion MR Imaging of Pediatric Intracranial Tumors: Correlation with Histology and Diagnostic Utility

BACKGROUND AND PURPOSE

Intravoxel incoherent motion imaging, which simultaneously measures diffusion and perfusion parameters, is promising for brain tumor grading. However, intravoxel incoherent motion imaging has not been tested in children. The purpose of this study was to evaluate the correlation between intravoxel incoherent motion parameters and histology to assess the accuracy of intravoxel incoherent motion imaging for pediatric intracranial tumor grading.

MATERIALS AND METHODS

Between April 2013 and September 2015, 17 children (11 boys, 6 girls; 2 months to 15 years of age) with intracranial tumors were included in this retrospective study. Intravoxel incoherent motion parameters were fitted using 13 b-values for a biexponential model. The perfusion-free diffusion coefficient, pseudodiffusion coefficient, and perfusion fraction were measured in high- and low-grade tumors. These intravoxel incoherent motion parameters and the ADC were compared using the unpaired t test. The correlations between the intravoxel incoherent motion parameters and microvessel density or the MIB-1 index were analyzed using the Spearman correlation test. Receiver operating characteristic analysis was used to evaluate diagnostic performance.

RESULTS

The perfusion-free diffusion coefficient and ADC were lower in high-grade than in low-grade tumors (perfusion-free diffusion coefficient, 0.85 ± 0.40 versus 1.53 ± 0.21 × 10^-3 mm²/s, P < .001; ADC, 1.04 ± 0.33 versus 1.60 ± 0.21 × 10^-3 mm²/s, P < .001). The pseudodiffusion coefficient showed no difference between the groups. The perfusion fraction was higher in high-grade than in low-grade tumors (21.7 ± 8.2% versus 7.6 ± 4.3%, P < .001). Receiver operating characteristic analysis found that the combined perfusion-free diffusion coefficient and perfusion fraction had the best diagnostic performance for tumor differentiation (area under the curve = 0.986).

CONCLUSIONS

Intravoxel incoherent motion imaging reflects tumor histology and may be a helpful, noninvasive method for pediatric intracranial tumor grading.

The role of SOX family members in solid tumours and metastasis

Cancer is a heavy burden for humans across the world with high morbidity and mortality. Transcription factors including sex determining region Y (SRY)-related high-mobility group (HMG) box (SOX) proteins are thought to be involved in the regulation of specific biological processes. The deregulation of gene expression programs can lead to cancer development. Here, we review the role of the SOX family in breast cancer, prostate cancer, renal cell carcinoma, thyroid cancer, brain tumours, gastrointestinal and lung tumours as well as the entailing therapeutic implications. The SOX family consists of more than 20 members that mediate DNA binding by the HMG domain and have regulatory functions in development, cell-fate decision, and differentiation. SOX2, SOX4, SOX5, SOX8, SOX9, and SOX18 are up-regulated in different cancer types and have been found to be associated with poor prognosis, while the up-regulation of SOX11 and SOX30 appears to be favourable for the outcome in other cancer types. SOX2, SOX4, SOX5 and other SOX members are involved in tumorigenesis, e.g. SOX2 is markedly up-regulated in chemotherapy resistant cells. The SoxF family (SOX7, SOX17, SOX18) plays an important role in angio- and lymphangiogenesis, with SOX18 seemingly being an attractive target for anti-angiogenic therapy and the treatment of metastatic disease in cancer. In summary, SOX transcription factors play an important role in cancer progression, including tumorigenesis, changes in the tumour microenvironment, and metastasis. Certain SOX proteins are potential molecular markers for cancer prognosis and putative potential therapeutic targets, but further investigations are required to understand their physiological functions.

Leptomeningeal dissemination: a sinister pattern of medulloblastoma growth

Leptomeningeal dissemination (LMD) is the defining pattern of metastasis for medulloblastoma. Although LMD is responsible for virtually 100% of medulloblastoma deaths, it remains the least well-understood part of medulloblastoma pathogenesis. The fact that medulloblastomas rarely metastasize outside the CNS but rather spread almost exclusively to the spinal and intracranial leptomeninges has fostered the long-held belief that medulloblastoma cells spread directly through the CSF, not the bloodstream. In this paper the authors discuss selected molecules for which experimental evidence explains how the effects of each molecule on cell physiology contribute mechanistically to LMD. A model of medulloblastoma LMD is described, analogous to the invasion-metastasis cascade of hematogenous metastasis of carcinomas. The LMD cascade is based on the molecular themes that 1) transcription factors launch cell programs that mediate cell motility and invasiveness and maintain tumor cells in a stem-like state; 2) disseminating medulloblastoma cells escape multiple death threats by subverting apoptosis; and 3) inflammatory chemokine signaling promotes LMD by creating an oncogenic microenvironment. The authors also review recent experimental evidence that challenges the belief that CSF spread is the sole mechanism of LMD and reveal an alternative scheme in which medulloblastoma cells can enter the bloodstream and subsequently home to the leptomeninges.

Selective BCL-XL inhibition promotes apoptosis in combination with MLN8237 in medulloblastoma and pediatric glioblastoma cells

Background

CNS tumors, including medulloblastoma and pediatric glioblastoma (pGBM) account for the majority of solid pediatric malignancies. There remains an unmet need to identify novel treatment approaches in poor prognosis and relapsed pediatric brain tumors, where therapeutic options are limited. Small-molecule B-cell lymphoma 2 (BCL-2) family inhibitors may enhance tumor cell killing when combined with conventional and targeted chemotherapeutic agents. We investigated the effect of disrupting BCL-2 and B cell lymphoma-extra large (BCL-XL) protein function using ABT-263, ABT-199 and WEHI-539 in medulloblastoma and pGBM cells following treatment with MLN8237, an Aurora kinase inhibitor under investigation as a novel agent for the treatment of malignant brain tumors.

Methods

Tumor cell growth and viability were determined by MTT/WST-1 assays and flow cytometry. Effects on cell phenotype, cell cycle progression, and ploidy were determined by live cell imaging and DNA content analysis. Apoptosis was determined by annexin V/propidium iodide staining and time-lapse microscopy and confirmed by measuring caspase-3/7 activity and western blotting and by short interfering RNA (siRNA) knockdown of BCL-2 associated X protein/BCL-2 antagonist killer (BAX/BAK).

Results

ABT-263, in combination with MLN8237, reduced mitotic slippage and polyploidy and promoted the elimination of mitotically defective cells via a BAX/BAK-dependent, caspase-mediated apoptotic pathway. The BCL-XL antagonist, WEHI-539, significantly augmented tumor cell killing when used in combination with MLN8237, as well as sensitized resistant brain tumor cells to a novel BAX activator, SMBA1. In addition, siRNA-mediated knockdown of BCL-XL sensitized pGBM and medulloblastoma cells to MLN8237 and mimicked the effect of combination drug treatment.

Conclusion

Selective small-molecule inhibitors of BCL-XL may enhance the efficacy of MLN8237 and other targeted chemotherapeutic agents.

The Children's Oncology Group: Organizational Structure, Membership, and Institutional Characteristics

BACKGROUND

The Children's Oncology Group (COG) is the only organization within the National Cancer Institute's National Clinical Trials Network dedicated exclusively to pediatric cancer research. The purpose of this article is to provide an overview of COG's organizational structure, to characterize its institutional and individual membership, and to summarize enrollments onto COG clinical trials.

METHOD

Data from 2013 to 2015 were compiled from sources internal (Network Operations, Statistics and Data Center, Chair's Office) and external (American Hospital Association, American Nurses Credentialing Center) to COG, to present a comprehensive overview of COG's structure, individual and institutional membership, and group operations.

RESULTS

In 2016, COG comprised 8,785 individuals from 223 member institutions, across seven countries. An average of 9,661 new patients were registered with COG per year over the most recent (2013-2015) 3-year period. Over the same 3-year time frame, there were an average of 16,836 enrollments onto therapeutic (i.e., treatment) and nontherapeutic (e.g., epidemiology, survivorship, biology) trials per year.

CONCLUSIONS

COG institutions have diverse characteristics related to size, geographical location, and infrastructure. Individual membership also reflects diversity with representation from over 28 disciplines and groups. The diversity of COG institutions and individual members allows for unique perspectives and contributions to science unified under a common goal to enroll children/adolescents onto clinical trials. COG's collaborative, multidisciplinary approach to science functions to support the development of research that seeks to continually improve outcomes for children and adolescents with cancer.

Advances in the Surgical Treatment of Neuroblastoma

OBJECTIVE

This study was to review the efficacy of surgical resections in different clinical situations for a better understanding of the meaning of surgery in the treatment of neuroblastoma (NB).

DATA SOURCES

The online database ScienceDirect (201-2018) was utilized. The search was conducted using the keywords "neuroblastoma," "neuroblastoma resection," "neuroblastoma surgery," and "high-risk neuroblastoma."

STUDY SELECTION

We retrospectively analyzed of patients who underwent surgical resections in different clinical situations. The article included findings from selected relevant randomized controlled trials, systematic reviews, and meta-analyses or good-quality observational studies. Abstracts only, letters, and editorial notes were excluded. Full-text articles and abstracts were extracted and reviewed to identify key articles discussing surgery management of NB, which were then selected for critical analysis.

RESULTS

A total of 7800 English language articles were found containing references to NB (201-2018). The 163 articles were searched which were related to the surgical treatment of NB (201-2018). Through the analysis of these important articles, we found that the treatments of NB at low- and intermediate-risk groups were basically the same. High-risk patients remained controversial.

CONCLUSIONS

NB prognosis varies tremendously based on the stage and biologic features of the tumor. After reviewing the relevant literature, patients with low-risk disease are often managed with surgical resection or observation alone with tumors likely to spontaneously regress that are not causing symptoms. Intermediate patients are treated with chemotherapy with the number of cycles depending on their response as well as surgical resection of the primary tumor. High-risk patients remain controversial. Multidisciplinary intensive treatment is essential, especially for patients who received subtotal tumor resection. Minimally invasive surgery for the treatment of NBs without image-defined risk factors in low- to high-risk patients is safe and feasible and does not compromise the treatment outcome. We conclude that ≥90% resection of the primary tumor is both feasible and safe in most patients with high-risk NB. New targeted therapies are crucial to improve survival.

Signaling pathways and mesenchymal transition in pediatric high-grade glioma

Pediatric high-grade gliomas (pHGG), including diffuse intrinsic pontine gliomas (DIPG), are the most lethal types of cancer in children. In recent years, it has become evident that these tumors are driven by epigenetic events, mainly mutations involving genes encoding Histone 3, setting them apart from their adult counterparts. These tumors are exceptionally resistant to chemotherapy and respond only temporarily to radiotherapy. Moreover, their delicate location and diffuse growth pattern make complete surgical resection impossible. In many other forms of cancer, chemo- and radioresistance, in combination with a diffuse, invasive phenotype, are associated with a transcriptional program termed the epithelial-to-mesenchymal transition (EMT). Activation of this program allows cancer cells to survive individually, invade surrounding tissues and metastasize. It also enables them to survive exposure to cytotoxic therapy, including chemotherapeutic drugs and radiation. We here suggest that EMT plays an important, yet poorly understood role in the biology and therapy resistance of pHGG and DIPG. This review summarizes the current knowledge on the major signal transduction pathways and transcription factors involved in the epithelial-to-mesenchymal transition in cancer in general and in pediatric HGG and DIPG in particular. Despite the fact that the mesenchymal transition has not yet been specifically studied in pHGG and DIPG, activation of pathways and high levels of transcription factors involved in EMT have been described. We conclude that the mesenchymal transition is likely to be an important element of the biology of pHGG and DIPG and warrants further investigation for the development of novel therapeutics.

A pediatric brain tumor consortium phase II trial of capecitabine rapidly disintegrating tablets with concomitant radiation therapy in children with newly diagnosed diffuse intrinsic pontine gliomas

BACKGROUND

We conducted a phase II study of oral capecitabine rapidly disintegrating tablets given concurrently with radiation therapy (RT) to assess progression-free survival (PFS) in children with newly diagnosed diffuse intrinsic pontine gliomas (DIPG).

PATIENTS AND METHODS

Children 3-17 years with newly diagnosed DIPG were eligible. Capecitabine, 650 mg/m² /dose BID (maximum tolerated dose [MTD] in children with concurrent radiation), was administered for 9 weeks starting the first day of RT. Following a 2-week break, three courses of capecitabine, 1,250 mg/m² /dose BID for 14 days followed by a 7-day rest, were administered. As prospectively designed, 10 evaluable patients treated at the MTD on the phase I trial were included in the phase II analyses. The design was based on comparison of the PFS distribution to a contemporary historical control (n = 140) with 90% power to detect a 15% absolute improvement in the 1-year PFS with a type-1 error rate, α = 0.10.

RESULTS

Forty-four patients were evaluable for the phase II objectives. Capecitabine and RT was well tolerated with low-grade palmar plantar erythrodyesthesia, increased alanine aminotransferase, cytopenias, and vomiting the most commonly reported toxicities. Findings were significant for earlier progression with 1-year PFS of 7.21% (SE = 3.47%) in the capecitabine-treated cohort versus 15.59% (SE = 3.05%) in the historical control (P = 0.007), but there was no difference for overall survival (OS) distributions (P = 0.30). Tumor enhancement at diagnosis was associated with shorter PFS and OS. Capecitabine was rapidly absorbed and converted to its metabolites.

CONCLUSION

Capecitabine did not improve the outcome for children with newly diagnosed DIPG.

Ependymomas: Prognostic Factors and Outcome Analysis in a Retrospective Series of 33 Patients

Background

The purpose of this study was to evaluate the prognostic factors and outcomes in patients with ependymoma to management plans.

Methods

Between 1997 and 2013, 33 patients with 25 ependymomas (WHO grade II) and eight anaplastic ependymomas (WHO grade III) were pathologically diagnosed. Six were pediatric patients (mean age, 6.15 years; range, 1.3–11 years), while 27 were adults (mean age, 47.5 years; range, 19–70 years). Of those, there were 12 adult patients with totally resected ependymomas without anaplastic pathology and adjuvant treatment. Prognostic factors were assessed in ependymoma patients. Prognostic factors were studied using Kaplan-Meier estimates in subgroups.

Results

For six pediatric patients, the progression-free survival (PFS) was 43.7±13.5 months, and the overall survival (OS) was 58.1±13.7 months. For 27 adult patients, the PFS was 125.6±14.3 months, and the OS was 151.2±12.5 months. Age demonstrated a statistically significant effect on PFS (p=0.03) and OS (p=0.03). In adult ependymomas, the extent of tumor removal significantly affected PFS (p=0.03) and trended towards an effect on OS (p=0.06). Out of 12 patients with totally resected ependymomas without anaplastic pathology and adjuvant treatment, one patient showed tumor recurrence during follow-up (mean, 93.5 months; range, 27.9–162.7 months).

Conclusion

Adult patients with ependymomas were found to have better survival rates compared to pediatric patients. We suggest that totally resected adult ependymomas without anaplastic pathology could be observed without any adjuvant treatment, regardless of the tumor location.

Characterization of 2 Novel Ependymoma Cell Lines With Chromosome 1q Gain Derived From Posterior Fossa Tumors of Childhood

Ependymoma (EPN) is a common brain tumor of childhood that, despite standard surgery and radiation therapy, has a relapse rate of 50%. Clinical trials have been unsuccessful in improving outcome by addition of chemotherapy, and identification of novel therapeutics has been hampered by a lack of in vitro and in vivo models. We describe 2 unique EPN cell lines (811 and 928) derived from recurrent intracranial metastases. Both cell lines harbor the high-risk chromosome 1q gain (1q+) and a derivative chromosome 6, and both are classified as molecular group A according to transcriptomic analysis. Transcriptional enrichment of extracellular matrix-related genes was a common signature of corresponding primary tumors and cell lines in both monolayer and 3D formats. EPN cell lines, when cultured in 3D format, clustered closer to the primary tumors with better fidelity of EPN-specific transcripts than when grown as a monolayer. Additionally, 3D culture revealed ependymal rosette formation and cilia-related ontologies, similar to in situ tumors. Our data confirm the validity of the 811 and 928 cell lines as representative models of intracranial, posterior fossa 1q+ EPN, which holds potential to advance translational science for patients affected by this tumor.

Trimethylation of H3K27 during human cerebellar development in relation to medulloblastoma

Medulloblastoma (MB), the most common malignant childhood brain tumor, encompasses a collection of four clinically and molecularly distinct tumor subgroups, i.e. WNT, SHH, Group 3 and Group 4. These tumors are believed to originate from precursor cells during cerebellar development. Although the exact etiology of these brain tumors is not yet known, histone modifications are increasingly recognized as key events during cerebellum development and MB tumorigenesis. Recent studies show that key components involved in post-translational modifications of histone H3 lysine 27 (H3K27) are commonly deregulated in MB. In this descriptive study, we have investigated the trimethylation status of H3K27, as well as the expression of the H3K27 methylase EZH2 and demethylases KDM6A and KDM6B, during human cerebellum development in relation to MB. H3K27 Trimethylation status differed between the MB subgroups. Moreover, trimethylation of H3K27 and expression of its modifiers EZH2, KDM6A and KDM6B were detected in a spatio-temporal manner during development of the human cerebellum, with consistent high occurrence in the four proliferative zones, which are believed to harbor the precursor cells of the different MB subgroups. Our results suggest that H3K27 trimethylation in MB is deregulated by EZH2, KDM6A and KDM6B. Moreover, we provide evidence that during development of the human cerebellum H3K27me3 and its regulators are expressed in a spatio-temporal manner.

Mortality in Children Receiving Growth Hormone Treatment of Growth Disorders: Data From the Genetics and Neuroendocrinology of Short Stature International Study

CONTEXT

Although pediatric growth hormone (GH) treatment is generally considered safe for approved indications, concerns have been raised regarding potential for increased risk of mortality in adults treated with GH during childhood.

OBJECTIVE

To assess mortality in children receiving GH.

DESIGN

Prospective, multinational, observational study.

SETTING

Eight hundred twenty-seven study sites in 30 countries.

PATIENTS

Children with growth disorders.

INTERVENTIONS

GH treatment during childhood.

MAIN OUTCOME MEASURE

Standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) using age- and sex-specific rates from the general population.

RESULTS

Among 9504 GH-treated patients followed for ≥4 years (67,163 person-years of follow-up), 42 deaths were reported (SMR, 0.77; 95% CI, 0.56 to 1.05). SMR was significantly elevated in patients with history of malignant neoplasia (6.97; 95% CI, 3.81 to 11.69) and borderline elevated for those with other serious non-GH-deficient conditions (2.47; 95% CI, 0.99-5.09). SMRs were not elevated for children with history of benign neoplasia (1.44; 95% CI, 0.17 to 5.20), idiopathic GHD (0.11; 95% CI, 0.02 to 0.33), idiopathic short stature (0.20; 95% CI, 0.01 to 1.10), short stature associated with small for gestational age (SGA) birth (0.66; 95% CI, 0.08 to 2.37), Turner syndrome (0.51; 95% CI, 0.06 to 1.83), or short stature homeobox-containing (SHOX) gene deficiency (0.83; 95% CI, 0.02 to 4.65).

CONCLUSIONS

No significant increases in mortality were observed for GH-treated children with idiopathic GHD, idiopathic short stature, born SGA, Turner syndrome, SHOX deficiency, or history of benign neoplasia. Mortality was elevated for children with prior malignancy and those with underlying serious non-GH-deficient medical conditions.

The kinesin KIF14 is overexpressed in medulloblastoma and downregulation of KIF14 suppressed tumor proliferation and induced apoptosis

Medulloblastoma (MB) is the most common malignant brain tumor in childhood. At present, there is no well-established targeted drug for majority of patients. The kinesin family member 14 (KIF14) is a novel oncogene located on chromosome 1q and is dysregulated in multiple cancers. The objectives of this study were to evaluate KIF14 expression and chromosome 1q copy number in MB, and to delineate its biological functions in MB pathogenesis. By quantitative RT-PCR and immunohistochemistry, we found KIF14 was overexpressed in MB. Increased KIF14 expression at protein level was strongly associated with shorter progression-free survival (P=0.0063) and overall survival (P=0.0083). Fluorescence in situ hybridization (FISH) analysis confirmed genomic gain of chromosome 1q in 17/93 (18.3%) of MB. Combined genetic and immunohistochemical analyses revealed that 76.5% of MB with 1q gain showed consistent overexpression of KIF14, and a tight link between chromosome 1q gain and KIF14 overexpression (P=0.03). Transient, siRNAs-mediated downregulation of KIF14 suppressed cell proliferation and induced apoptosis in two MB cell lines. Stably KIF14 knockdown by shRNAs inhibited cell viability, colony formation, migration and invasion, and tumor sphere formation in MB cells. We conclude that KIF14 is dysregulated in MB and is an adverse prognostic factor for survival. Furthermore, KIF14 is part of MB biology and is a potential therapeutic target for MB.

The evolution of medulloblastoma therapy to personalized medicine

Recent advances in cancer genomics have revolutionized the characterization and classification of medulloblastomas. According to the current WHO guidelines, medulloblastomas are now classified into the following molecularly defined groups: Wnt signaling pathway (WNT)-activated, sonic hedgehog signaling pathway (SHH)-activated and tumor suppressor protein p53 (TP53)-mutant, SHH-activated and TP53-wildtype, and non-WNT/non-SHH (i.e. group 3 and group 4). Importantly, genomic, epigenomic, and proteomic advances have created a potential paradigm shift in therapeutic options. The challenge now is to (i) translate these observations into new therapeutic approaches and (ii) employ these observations in clinical practice, utilizing the classification following a molecular analysis for diagnosis and application of new subgroup-specific targeted therapeutics.

Molecular mechanisms and therapeutic targets in pediatric brain tumors

Brain tumors are among the leading causes of cancer-related deaths in children. Although surgery, aggressive radiation, and chemotherapy have improved outcomes, many patients still die of their disease. Moreover, those who survive often suffer devastating long-term side effects from the therapies. A greater understanding of the molecular underpinnings of these diseases will drive the development of new therapeutic approaches. Advances in genomics and epigenomics have provided unprecedented insight into the molecular diversity of these diseases and, in several cases, have revealed key genes and signaling pathways that drive tumor growth. These not only serve as potential therapeutic targets but also have facilitated the creation of animal models that faithfully recapitulate the human disease for preclinical studies. In this Review, we discuss recent progress in understanding the molecular basis of the three most common malignant pediatric brain tumors-medulloblastoma, ependymoma, and high-grade glioma-and the implications for development of safer and more effective therapies.

Functional MRI in medulloblastoma survivors supports prophylactic reading intervention during tumor treatment

Development of reading skills is vulnerable to disruption in children treated for brain tumors. Interventions, remedial and prophylactic, are needed to mitigate reading and other learning difficulties faced by survivors. A functional magnetic resonance imaging (fMRI) study was conducted to investigate long-term effects of a prophylactic reading intervention administered during radiation therapy in children treated for medulloblastoma. The fMRI study included 19 reading-intervention (age 11.7 ± 0.6 years) and 21 standard-of-care (age 12.1 ± 0.6 years) medulloblastoma survivors, and 21 typically developing children (age 12.3 ± 0.6 years). The survivors were 2.5 [1.2, 5.4] years after completion of tumor therapies and reading-intervention survivors were 2.9 [1.6, 5.9] years after intervention. Five fMRI tasks (Rapid Automatized Naming, Continuous Performance Test using faces and letters, orthographic and phonological processing of letter pairs, implicit word reading, and story reading) were used to probe reading-related neural activation. Woodcock-Johnson Reading Fluency, Word Attack, and Sound Awareness subtests were used to evaluate reading abilities. At the time of fMRI, Sound Awareness scores were significantly higher in the reading-intervention group than in the standard-of-care group (p = 0.046). Brain activation during the fMRI tasks was detected in left inferior frontal, temporal, ventral occipitotemporal, and subcortical regions, and differed among the groups (p < 0.05, FWE). The pattern of group activation differences, across brain areas and tasks, was a normative trend in the reading-intervention group. Standardized reading scores and patterns of brain activation provide evidence of long-term effects of prophylactic reading intervention in children treated for medulloblastoma.

RalA is overactivated in medulloblastoma

Medulloblastoma (MDB) represents a major form of malignant brain tumors in the pediatric population. A vast spectrum of research on MDB has advanced our understanding of the underlying mechanism, however, a significant need still exists to develop novel therapeutics on the basis of gaining new knowledge about the characteristics of cell signaling networks involved. The Ras signaling pathway, one of the most important proto-oncogenic pathways involved in human cancers, has been shown to be involved in the development of neurological malignancies. We have studied an important effector down-stream of Ras, namely RalA (Ras-Like), for the first time and revealed overactivation of RalA in MDB. Affinity precipitation analysis of active RalA (RalA-GTP) in eight MDB cell lines (DAOY, RES256, RES262, UW228-1, UW426, UW473, D283 and D425) revealed that the majority contained elevated levels of active RalA (RalA-GTP) as compared with fetal cerebellar tissue as a normal control. Additionally, total RalA levels were shown to be elevated in 20 MDB patient samples as compared to normal brain tissue. The overall expression of RalA, however, was comparable in cancerous and normal samples. Other important effectors of RalA pathway including RalA binding protein-1 (RalBP1) and protein phosphatase A (PP2A) down-stream of Ral and Aurora kinase A (AKA) as an upstream RalA activator were also investigated in MDB. Considering the lack of specific inhibitors for RalA, we used gene specific silencing in order to inhibit RalA expression. Using a lentivirus expressing anti-RalA shRNA we successfully inhibited RalA expression in MDB and observed a significant reduction in proliferation and invasiveness. Similar results were observed using inhibitors of AKA and geranyl-geranyl transferase (non-specific inhibitors of RalA signaling) in terms of loss of in vivo tumorigenicity in heterotopic nude mouse model. Finally, once tested in cells expressing CD133 (a marker for MDB cancer stem cells), higher levels of RalA activation was observed. These data not only bring RalA to light as an important contributor to the malignant phenotype of MDB but introduces this pathway as a novel target in the treatment of this malignancy.

A chemical screen for medulloblastoma identifies quercetin as a putative radiosensitizer

Treatment of medulloblastoma in children fails in approximately 30% of patients, and is often accompanied by severe late sequelae. Therefore, more effective drugs are needed that spare normal tissue and diminish long-term side effects. Since radiotherapy plays a pivotal role in the treatment of medulloblastoma, we set out to identify novel drugs that could potentiate the effect of ionizing radiation.Thereto, a small molecule library, consisting of 960 chemical compounds, was screened for its ability to sensitize towards irradiation. This small molecule screen identified the flavonoid quercetin as a novel radiosensitizer for the medulloblastoma cell lines DAOY, D283-med, and, to a lesser extent, D458-med at low micromolar concentrations and irradiation doses used in fractionated radiation schemes. Quercetin did not affect the proliferation of neural precursor cells or normal human fibroblasts. Importantly, in vivo experiments confirmed the radiosensitizing properties of quercetin. Administration of this flavonoid at the time of irradiation significantly prolonged survival in orthotopically xenografted mice. Together, these findings indicate that quercetin is a potent radiosensitizer for medulloblastoma cells that may be a promising lead for the treatment of medulloblastoma in patients.

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.

Molecular insights into pediatric brain tumors have the potential to transform therapy

High-throughput genomic technologies have shed light on the biologic heterogeneity of several pediatric brain tumors. The biology of the four common pediatric brain tumors-namely medulloblastoma; ependymoma; high-grade glioma (HGG), including diffuse intrinsic pontine glioma; and low-grade glioma-is highlighted in this CCR Focus article. The discovery that medulloblastoma consists of four different subgroups, namely WNT, SHH, Group 3, and Group 4, each with distinct clinical and molecular features, has affected the treatment of children with medulloblastoma. Prospective studies have documented the efficacy of SMO inhibitors in a subgroup of patients with SHH medulloblastoma. Efforts are ongoing to develop specific therapies for each of the subgroups of medulloblastoma. Similar efforts are being pursued for ependymoma, HGG, and diffuse intrinsic pontine glioma where the disease outcome for the latter two tumors has not changed over the past three decades despite several prospective clinical trials. Developing and testing targeted therapies based on this new understanding remains a major challenge to the pediatric neuro-oncology community. The focus of this review is to summarize the rapidly evolving understanding of the common pediatric brain tumors based on genome-wide analysis. These novel insights will add impetus to translating these laboratory-based discoveries to newer therapies for children diagnosed with these tumors.

Medulloblastoma: recurrence and metastasis

Medulloblastoma is the most common malignant brain tumor of childhood. Although there is now long-term survival or cure for the majority of children, the survivors bear a significant burden of complications due, at least in part, to the intense therapies given to ensure eradication of the tumor. Significant efforts have been made over the years to be able to distinguish between patients who do and do not need intensive therapies. This review summarizes the history and current state of clinical risk stratification, pathologic diagnosis and genetics. Recent developments in correlation between genetics and pathology, genome-wide association studies and the biology of medulloblastoma metastasis are discussed in detail. The current state of clinical treatment trials are reviewed and placed into the perspective of potential novel therapies in the near term.

Differences in parent-provider concordance regarding prognosis and goals of care among children with advanced cancer

PURPOSE

Concordance between parents of children with advanced cancer and health care providers has not been described. We aimed to describe parent-provider concordance regarding prognosis and goals of care, including differences by cancer type.

PATIENTS AND METHODS

A total of 104 pediatric patients with recurrent or refractory cancer were enrolled at three large children’s hospitals. On enrollment, their parents and providers were invited to complete a survey assessing perceived prognosis and goals of care. Patients’ survival status was retrospectively abstracted from medical records. Concordance was assessed via discrepancies in perceived prognosis, statistics, and McNemar’s test. Distribution of categorical variables and survival rates across cancer type were compared with Fisher’s exact and log-rank tests, respectively.

RESULTS

Data were available from 77 dyads (74% of enrolled). Parent-provider agreement regarding prognosis and goals of care was poor (kappa, 0.12 to 0.30). Parents were more likely to report cure was likely (P < .001). The frequency of perceived likelihood of cure and the goal of cure varied by cancer type for both parents and providers (P < .001 to .004). Relatively optimistic responses were more common among parents and providers of patients with hematologic malignancies, although there were no differences in survival.

CONCLUSION

Parent-provider concordance regarding prognosis and goals in advanced pediatric cancer is generally poor. Perceptions of prognosis and goals of care vary by cancer type. Understanding these differences may inform parent-provider communication and decision making.

Ovarian function in survivors of childhood medulloblastoma: Impact of reduced dose craniospinal irradiation and high-dose chemotherapy with autologous stem cell rescue

BACKGROUND

Data on ovarian function (OvF) in medulloblastoma (MB) survivors is limited, with most studies describing outcomes in survivors treated with craniospinal irradiation (CSI) doses >24 Gy ± standard chemotherapy. The objective of the current study is to report on OvF: (i) across a range of CSI doses; and (ii) following high-dose chemotherapy with autologous stem cell rescue (ASCR).

PROCEDURE

Retrospective review of female MB survivors who were diagnosed in childhood and followed at Memorial Sloan Kettering Cancer Center. Patients were divided into three groups: (i) CSI ≤24 Gy +/- standard chemotherapy; (ii) CSI ≥35 Gy +/- standard chemotherapy; and (iii) high-dose chemotherapy with ASCR +/- CSI.

RESULTS

Primary ovarian dysfunction (POD) occurred in 2/17 subjects in group 1, 3/9 subjects in group 2 and 5/5 subjects in group 3 (P < 0.01). Normalization of function was noted in four subjects with POD. Persistent POD requiring hormone replacement (POF) was observed in 1/17 subjects in group 1, 2/9 in group 2, and 3/5 in group 3 (P = 0.02). Neither age at treatment nor type of standard chemotherapy correlated with risk of POD or POF.

CONCLUSIONS

Both POD and POF appear to occur in a small proportion of patients who are treated with contemporary doses of CSI +/- standard chemotherapy. However, ovarian dysfunction requiring hormone replacement therapy is common following high-dose chemotherapy associated with ASCR. These findings will assist clinicians in counseling patients regarding fertility preservation and risk of impaired ovarian function/future fertility. Pediatr Blood Cancer 2015;62:317-321. © 2014 Wiley Periodicals, Inc.

Advancements in the treatment of pediatric acute leukemia and brain tumor - continuous efforts for 100% cure

Treatment outcomes of pediatric cancers have improved greatly with the development of improved treatment protocols, new drugs, and better supportive measures, resulting in overall survival rates greater than 70%. Survival rates are highest in acute lymphoblastic leukemia, reaching more than 90%, owing to risk-based treatment through multicenter clinical trials and protocols developed to prevent central nervous system relapse and testicular relapse in boys. New drugs including clofarabine and nelarabine are currently being evaluated in clinical trials, and other targeted agents are continuously being developed. Chimeric antigen receptor-modified T cells are now attracting interest for the treatment of recurrent or refractory disease. Stem cell transplantation is still the most effective treatment for pediatric acute myeloid leukemia (AML). However, in order to reduce treatment-related death after stem cell transplantation, there is need for improved treatments. New drugs and targeted agents are also needed for improved outcome of AML. Surgery and radiation therapy have been the mainstay for brain tumor treatment. However, chemotherapy is becoming more important for patients who are not eligible for radiotherapy owing to age. Stem cell transplant as a means of high dose chemotherapy and stem cell rescue is a new treatment modality and is often repeated for improved survival. Drugs such as temozolomide are new chemotherapeutic options. In order to achieve 100% cure in children with pediatric cancer, every possible treatment modality and effort should be considered.

Prospective longitudinal assessment of sensorineural hearing loss with hyperfractionated radiation therapy alone in patients with average-risk medulloblastoma

Background

To report on sensorineural hearing loss (SNHL) in a cohort of patients treated with hyperfractionated radiation therapy (HFRT) without upfront platinum-based chemotherapy in average-risk medulloblastoma.

Methods

Hearing thresholds were assessed by ear-specific pure-tone audiograms at stimulus frequencies of 0.25, 0.5, 1, 2, 4, and 8 kilohertz. Audiometric assessments were done serially longitudinally at baseline, between 6-12 months after HFRT, and annually thereafter. Pure-tone audiograms were analyzed and graded according to Brock pediatric ototoxicity grading criteria.

Results

Five of 20 (25%) children had communicatively and developmentally significant SNHL (Brock grade 2 or worse) even before starting radiotherapy. On follow-up, new-onset Brock grade 2 or worse ototoxicity was documented in 6 previously normal ears. Eleven patients had preserved hearing in both ears on last audiometric follow-up. Compared with baseline testing, post-HFRT audiometry at 2-3 years showed modest decline in hearing threshold across all frequencies. Age at diagnosis and sex did not significantly impact hearing, while higher cochlear doses trended towards worse hearing outcomes. Tumors that extended more towards one side expectedly showed significant worsening in the ipsilateral ear. There was a differential impact of treatment on the right and left ears with the right ear (and not the left ear) showing significantly worse hearing thresholds in the low-to-intermediate speech frequency range over time.

Conclusion

The use of HFRT for craniospinal irradiation and conformal tumor bed boost without upfront platinum-based chemotherapy in children with average-risk medulloblastoma results in preserved hearing in a large proportion of patients in the audible speech range.

Fractionated stereotactic radiosurgery for recurrent ependymoma in children

Outcomes for children with relapsed ependymoma are poor. Re-irradiation is a potentially viable salvage option in these patients. Data were reviewed for 12 patients (median age 5.6 years) with relapsed ependymoma who received fractionated stereotactic radiosurgery (fSRS) following maximal surgical resection from 1995 to 2012. Four patients experienced a second recurrence, including 2 in-field and 2 distant failures. Median time to second recurrence (32 months) was significantly longer than time to first recurrence (24 months) (p = 0.008). Three-year local control was 89 %, and median event free survival from fSRS was 3.4 years. Radiation necrosis was observed in 6 patients, 3 who were symptomatic. In conclusion, fSRS offers durable response with a tolerable toxicity profile in children with recurrent EPN.

Genetic drivers of metastatic dissemination in sonic hedgehog medulloblastoma

Leptomeningeal dissemination (LMD), the metastatic spread of tumor cells via the cerebrospinal fluid to the brain and spinal cord, is an ominous prognostic sign for patients with the pediatric brain tumor medulloblastoma. The need to reduce the risk of LMD has driven the development of aggressive treatment regimens, which cause disabling neurotoxic side effects in long-term survivors. Transposon-mediated mutagenesis studies in mice have revealed numerous candidate metastasis genes. Understanding how these genes drive LMD will require functional assessment using in vivo and cell culture models of medulloblastoma. We analyzed two genes that were sites of frequent transposon insertion and highly expressed in human medulloblastomas: Arnt (aryl hydrocarbon receptor nuclear translocator) and Gdi2 (GDP dissociation inhibitor 2). Here we show that ectopic expression of Arnt and Gdi2 promoted LMD in mice bearing Sonic hedgehog (Shh)-induced medulloblastomas. We overexpressed Arnt and Gdi2 in a human medulloblastoma cell line (DAOY) and an immortalized, nontransformed cell line derived from mouse granule neuron precursors (SHH-NPD) and quantified migration, invasiveness, and anchorage-independent growth, cell traits that are associated with metastatic competence in carcinomas. In SHH-NPD cells. Arnt and Gdi2 stimulated all three traits. In DAOY cells, Arnt had the same effects, but Gdi2 stimulated invasiveness only. These results support a mechanism whereby Arnt and Gdi2 cause cells to detach from the primary tumor mass by increasing cell motility and invasiveness. By conferring to tumor cells the ability to proliferate without surface attachment, Arnt and Gdi2 favor the formation of stable colonies of cells capable of seeding the leptomeninges.

A meta-analysis of parental smoking and the risk of childhood brain tumors

OBJECTIVE

Previous studies regarding the association between parental smoking and the risk of childhood brain tumors (CBT) have reported inconsistent results. We performed a meta-analysis to summarize evidence on this association and to quantify the potential dose-response relationship.

METHODS

A systematic literature search was conducted in the Medline and Embase databases. The summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated. Dose-response meta-analysis was also performed for studies that reported categorical risk estimates for a series of smoking exposure levels.

RESULTS

A total of 17 studies fulfilled the inclusion criteria. In the meta-analyses, the summary RRs (95% CIs) of CBT for maternal smoking during pregnancy, paternal smoking during pregnancy, maternal smoking before pregnancy, and paternal smoking before pregnancy were 0.96 (0.86-1.07), 1.09 (0.97-1.22), 0.93 (0.85-1.00), and 1.09 (1.00-1.20), respectively. Dose-response meta-analysis also showed no significant association between parental smoking and the risk of CBT.

CONCLUSIONS

Findings from our meta-analysis indicate that parental smoking may not be associated with a risk of CBT.

Role of SOX family of transcription factors in central nervous system tumors

SOX genes are developmental regulators with functions in the instruction of cell fate and maintenance of progenitor's identity during embryogenesis. They play additional roles during tissue homeostasis and regeneration in adults particularly in the Central Nervous System (CNS). In the last years a growing number of evidences has shown that mutations and dysfunction of SOX factors are implicated in several human diseases, including a variety of cancers. In this review, we will summarize the current knowledge about SOX family in CNS tumors and their role in the origin and maintenance of the subpopulation of cancer stem cells in these tumors.

Ependymoblastoma of the brainstem: MRI findings and differential diagnosis

Ependymoblastoma (EBL) is a rare malignant CNS tumor of early childhood, listed as a subgroup of primitive neuroectodermal tumors (PNET) in the 2007 WHO Classification of Tumours of the Central Nervous System. Histologically, EBL can be defined by multilayered, mitotically active "ependymoblastic" rosettes with central lumen as a histological hallmark. The prognosis seems to be far inferior to other embryonal CNS tumors, and known clinical and MRI characteristics of EBL are based on scattered case reports. We present and discuss two uncommon cases of histopathologically confirmed ependymoblastoma that both seem to originate from the brainstem.

Molecular sub-group-specific immunophenotypic changes are associated with outcome in recurrent posterior fossa ependymoma

Better understanding of ependymoma (EPN) biology at relapse is needed to improve therapy at this critical event. Convincing data exist defining transcriptionally distinct posterior fossa (PF) sub-groups A and B at diagnosis. The clinical and biological consequence of these sub-groups at recurrence has not yet been defined. Genome and transcriptome microarray profiles and clinical variables of matched primary and first recurrent PF EPN pairs were used to identify biologically distinct patterns of progression between EPN sub-groups at recurrence. Key findings were validated by histology and immune function assays. Transcriptomic profiles were partially conserved at recurrence. However, 4 of 14 paired samples changed sub-groups at recurrence, and significant sub-group-specific transcriptomic changes between primary and recurrent tumors were identified, which were predominantly immune-related. Further examination revealed that Group A primary tumors harbor an immune gene signature and cellular functionality consistent with an immunosuppressive phenotype associated with tissue remodeling and wound healing. Conversely, Group B tumors develop an adaptive, antigen-specific immune response signature and increased T-cell infiltration at recurrence. Clinical distinctions between sub-groups become more apparent after first recurrence. Group A tumors were more often sub-totally resected and had a significantly shorter time to subsequent progression and worse overall survival. Minimal tumor-specific genomic changes were observed for either PF Groups A or B at recurrence. Molecular sub-groups of PF EPN convey distinct immunobiologic signatures at diagnosis and recurrence, providing potential biologic rationale to their disparate clinical outcomes. Immunotherapeutic approaches may be warranted, particularly in Group A PF EPN.

Potential Pediatric Applications of PET/MR

Medical imaging with multimodality and whole-body technologies has continuously improved in recent years. The advent of combined modalities such as PET/CT and PET/MR offers new tools with an exact fusion of molecular imaging and high-resolution anatomic imaging. For noninvasive pediatric diagnostics, molecular imaging and whole-body MR have become important, especially in pediatric oncology. Because it has a lower radiation exposure than PET/CT, combined PET/MR is expected to be of special use in pediatric diagnostics. This review focuses on possible pediatric applications of PET/MR hybrid imaging, particularly pediatric oncology and neurology but also the diagnosis of infectious or inflammatory diseases.

Late toxicity following craniospinal radiation for early-stage medulloblastoma

BACKGROUND

The purpose of this study is to review late toxicity following craniospinal radiation for early-stage medulloblastoma.

MATERIAL AND METHODS

Between 1963 and 2008, 53 children with stage M0 (n = 50) or M1 (n = 3) medulloblastoma were treated at our institution. The median age at diagnosis was 7.1 years (range 1.2-18.5). The median craniospinal irradiation (CSI) dose was 28.8 Gy (range 21.8-38.4). The median total dose, including boost, was 54 Gy (range 42.4-64.8 Gy). Since 1963, the CSI dose has been incrementally lowered and the high-risk boost volume reduced. Twenty-one patients (40%) received chemotherapy in their initial management, including 12 who received concurrent chemotherapy. Late sequelae were evaluated by analyzing medical records and conducting phone interviews with surviving patients and/or care-takers. Complications were graded using the NCI Common Terminology Criteria for Adverse Events, version 4.0.

RESULTS

The median follow-up for all patients was 15.4 years (range 0.4-44.4) and for living patients it was 24 years (range 5.6-44.4). The overall survival, cause-specific survival, and progression-free survival rates at 10 years were 67%, 67%, and 71%, respectively. Sixteen patients (41% of patients who survived five years or more) developed grade 3 + toxicity; 15 of these 16 patients received a CSI dose > 23.4 Gy. The most common grade 3 + toxicities for long-term survivors are hearing impairment requiring intervention (20.5%) and cognitive impairment (18%) prohibiting independent living. Four patients developed secondary (non-skin) malignancies, including three meningiomas, one rhabdomyosarcoma, and one glioblastoma multiforme. Three patients (5.6%) died from treatment complications, including radionecrosis, severe cerebral edema, and fatal secondary malignancy.

CONCLUSION

Ongoing institutional and cooperative group efforts to minimize radiation exposure are justified given the high rate of serious toxicity observed in our long-term survivors. Follow-up through long-term multidisciplinary clinics is important and warranted for all patients exposed to radiotherapy in childhood.

Therapeutic opportunities for medulloblastoma come of age

In this issue of Cancer Cell, Kool and colleagues reveal clear genetically defined subclasses of the sonic hedgehog (SHH) subclass of medulloblastoma. This molecular dissection of the SHH subclass is not simply a cutting-edge advance; the data have profound impact on clinical trial design and decision-making.

Overcoming resistance to Sonic Hedgehog inhibition by targeting p90 ribosomal S6 kinase in pediatric medulloblastoma

BACKGROUND

Molecular subtyping has allowed for the beginning of personalized treatment in children suffering from medulloblastoma (MB). However, resistance inevitably emerges against these therapies, particularly in the Sonic Hedgehog (SHH) subtype. We found that children with SHH subtype have the worst outcome underscoring the need to identify new therapeutic targets.

PROCEDURE

High content screening of a 129 compound library identified agents that inhibited SHH MB growth. Lead molecular target levels, p90 ribosomal S6 kinase (RSK) were characterized by immunoblotting and qRT-PCR. Comparisons were made to human neural stem cells (hNSC). Impact of inhibiting RSK with the small molecule BI-D1870 or siRNA was assessed in growth assays (monolayer, neurosphere, and soft agar). NanoString was used to detect RSK in a cohort of 66 patients with MB. To determine BI-D1870 pharmacokinetics/pharmacodynamics, 100 mg/kg was I.P. injected into mice and tissues were collected at various time points.

RESULTS

Daoy, ONS76, UW228, and UW426 MB cells were exquisitely sensitive to BI-D1870 but unresponsive to SHH inhibitors. Anti-tumor growth corresponded with inactivation of RSK in MB cells. BI-D1870 had no effect on hNSCs. Inhibiting RSK with siRNA or BI-D1870 suppressed growth, induced apoptosis, and sensitized cells to SHH agents. Notably, RSK expression is correlated with SHH patients. In mice, BI-D1870 was well-tolerated and crossed the blood-brain barrier (BBB).

CONCLUSIONS

RSK inhibitors are promising because they target RSK which is correlated with SHH patients as well as cause high levels of apoptosis to only MB cells. Importantly, BI-D1870 crosses the BBB, acting as a scaffold for development of more long-lived RSK inhibitors.