Psidium guajava induces cytotoxicity in human malignant glioblastoma cell line: Role of reactive oxygen species

One of the deadliest types of CNS primary brain cancers is glioblastoma multiforme (GBM), and the survival rate of patients is about 7.2%. The standard treatment for GBM is surgical interventions followed by temozolomide. We investigated for the first time, the cytotoxic impacts of Psidium guajava (P. guajava) on the U87 GBM cell line. We measured cell toxicity through the MTT test following 24 h, 48 h, and 72 h treatment with different concentrations of fruit and seed hydroalcoholic extracts of P. guajava (25-400 μg/ml). Lipid peroxidation assay, reactive oxygen species (ROS) production, and apoptosis rate were evaluated 24 h after treatment by extracts of P. guajava. Moreover, to determine the Bax/Bcl-2 and NF-κB genes expression, we performed a real-time polymerase chain reaction (RT-PCR). Our finding demonstrated that 50-400 μg/ml of P. guajava extracts dose-dependently decreased the viability of U87 cells. Also, treatment by extracts increased lipid peroxidation, ROS production, and apoptosis in a dose-dependent manner. Moreover, the RT-PCR demonstrated an up-regulation in Bax\Bcl-2 and NF-κB. Thus, P. guajava inhibited the proliferation of U87 GBM cells and increased apoptosis probably through Bax/Bcl-2 and NF-κB regulation.

Hybrid Techniques of Analyzing MRI Images for Early Diagnosis of Brain Tumours Based on Hybrid Features

Brain tumours are considered one of the deadliest tumours in humans and have a low survival rate due to their heterogeneous nature. Several types of benign and malignant brain tumours need to be diagnosed early to administer appropriate treatment. Magnetic resonance (MR) images provide details of the brain’s internal structure, which allow radiologists and doctors to diagnose brain tumours. However, MR images contain complex details that require highly qualified experts and a long time to analyse. Artificial intelligence techniques solve these challenges. This paper presents four proposed systems, each with more than one technology. These techniques vary between machine, deep and hybrid learning. The first system comprises artificial neural network (ANN) and feedforward neural network (FFNN) algorithms based on the hybrid features between local binary pattern (LBP), grey-level co-occurrence matrix (GLCM) and discrete wavelet transform (DWT) algorithms. The second system comprises pre-trained GoogLeNet and ResNet-50 models for dataset classification. The two models achieved superior results in distinguishing between the types of brain tumours. The third system is a hybrid technique between convolutional neural network and support vector machine. This system also achieved superior results in distinguishing brain tumours. The fourth proposed system is a hybrid of the features of GoogLeNet and ResNet-50 with the LBP, GLCM and DWT algorithms (handcrafted features) to obtain representative features and classify them using the ANN and FFNN. This method achieved superior results in distinguishing between brain tumours and performed better than the other methods. With the hybrid features of GoogLeNet and hand-crafted features, FFNN achieved an accuracy of 99.9%, a precision of 99.84%, a sensitivity of 99.95%, a specificity of 99.85% and an AUC of 99.9%.

Impact of dedicated pediatric neuro-oncological services in a developing country: A single-institution, Pakistani experience

INTRODUCTION

Brain tumors are the most common solid neoplasms and the second most common malignancy in the pediatric age group. Due to the complexity of their management, pediatric central nervous system (CNS) tumors are not a priority in low- and middle-income countries (LMICs).

METHODS

In an attempt to improve the survival rate and overall care, we introduced a dedicated pediatric neuro-oncology service in our institute and evaluated its impact by dividing the pre- and post-era into two cohorts and comparing them: 1998-2013 (16 years: cohort A) and 2014-2019 (6 years: cohort B, after the start of dedicated neuro-oncology services).

RESULTS

We observed that after the implementation of a proper neuro-oncology service, the proportion of patients treated with curative intent increased, and survival improved in cohort B. The patient volume also increased from 15.5 per year in cohort A to 44.8 per year in cohort B. The percentage of children given radiation therapy also increased significantly, while the proportion of children treated with chemotherapy remained stable.

CONCLUSION

A dedicated multidisciplinary team trained and knowledgeable in the specialty of pediatric neuro-oncology can enhance and improve outcomes, and supportive care and help can provide good quality of life to children and their families with brain neoplasms.

Comorbidity Burden in a Cohort of Adolescent and Young Adult Patients Diagnosed with Central Nervous System Tumors and Sarcomas

Purpose: Adolescent and young adult (AYA) oncology patients experience unique biological, behavioral, and socioeconomic challenges, for which provision of care must be tailored. AYAs with central nervous system (CNS) tumors and sarcomas represent a vulnerable population with worse outcomes and potential for serious sequelae from intense multimodal therapy. Comorbidity burden impacts treatment tolerance, adherence, and efficacy, yet has been understudied among these high-risk AYA patients. Methods: Utilizing a validated AYA oncology comorbidity index, we (1) measured comorbid conditions present at diagnosis in AYA-aged patients with CNS tumors and sarcomas and (2) compared baseline comorbidity burden across ascending AYA age groups (15-19, 20-29, and 30-39 years) and with pediatric patients (10-14 years). Results: The cohort included 131 AYAs and 50 pediatric patients. Mean comorbidity score significantly differed between pediatric (0.8) and AYA (1.7) patients, and across ascending age subgroups (0.8 [10-14] < 1.2 [15-19] < 1.7 [20-29] < 2.5 [30-39]). AYAs were significantly more likely than pediatric patients to have ≥2 or ≥3 comorbidities (47% vs. 18%, 24% vs. 6%), with increasing prevalence across ascending age subgroups. Frequency of overweight/obese status, smoking/substance use, obstetric/gynecologic conditions, and cardiovascular comorbidities increased with age. In multivariate analyses adjusting for sex, tumor type, and race, age remained a significant predictor of comorbidity score. Conclusions: AYAs with CNS tumors or sarcomas have a high burden of baseline comorbidities, which increase with age at diagnosis, conferring susceptibility to treatment-related toxicity and mortality. Improving the prognosis for AYAs requires appropriate identification of pre-existing comorbidities and tailoring therapeutic and supportive care accordingly.

Epidemiology of brain tumors among adolescents and young adults in Nigeria

Adolescents and Young Adults (AYA), have distinct endocrine and psychosocial peculiarities. Brain tumors occur less among AYAs, compared to other age groups and with better prognosis. There is however a paucity of literature about brain tumors in AYA in sub-Saharan Africa. We aim to describe the clinical characteristics of brain tumors in AYA across five neurosurgical centers in Nigeria and the associated factors. We report results for older children (10-14 years), adolescents (15-19 years) and young adults (20-24 years). This was a retrospective review of AYA with brain tumors over a 10-year period (2010-2019). Data analysis was by descriptive statistics, Chi square test and multinomial regression at α0.05. There were 104 AYAand the male to female ratio was 1.2:1. Headache (79.8%) and visual symptoms (65.4%) were the most common presenting symptoms. Focal limb weakness (44.1%) occurred less frequently. Median duration of symptoms prior to presentation was 9 months. Glioma was the most common tumor (31, 29.8%) while pituitary adenoma and craniopharyngioma constituted 30.8% of the tumors. Patients with symptom duration of ≤one year were more likely to have infratentorial tumors. There was no significant association between the KPS following intervention and the AYA characteristics. Age group was not significantly associated with any of the presenting symptoms except ataxia, which was significantly higher among the 10 to 14 years group.We have described the epidemiology of brain tumors within AYA in Nigeria and highlighted a need to maximize their care and meet their special needs.

Toward a transitional care from childhood and adolescence to adulthood in surgical neurooncology? A lesson from the Necker-Enfants Malades and the Sainte-Anne Hospitals collaboration

OBJECTIVE

Transitional care in surgical neurooncology is poorly studied. However, this period is pivotal, since it allows the patient to be empowered in his or her disease management. Here, the authors describe the experience of the Necker-Enfants Malades and the Sainte-Anne Hospital collaboration.

METHODS

The mixed transitional consultations started in September 2019 in a dedicated space for transitional care, named the "La Suite" department, located in the Necker-Enfants Malades Hospital, Paris, France. The authors organized planned consultations to schedule the clinical and radiological follow-up in the adult neurosurgical department but also emergency consultations to manage tumor recurrence in young adult patients. Transitional care was performed jointly by pediatric and adult neurosurgeons who have developed clinical and research skills in the field of surgical neurooncology. Neuropathological analysis was performed by a neuropathologist who is specialized in pediatric and adult neurooncology.

RESULTS

Fourteen patients benefited from a mixed transitional consultation. All of them accepted to start their management in an adult neurosurgical environment. Eleven patients (78.6%) for whom the disease was controlled benefited from a planned consultation. Three patients (21.4%) required rapid neurosurgical management for a tumor recurrence (n = 2) or for a new primary CNS tumor (n = 1) and benefited from an emergency consultation.

CONCLUSIONS

For adult patients harboring a brain tumor during childhood or adolescence, the authors suggest that neurosurgeons specialized in adult surgical neurooncology with a full knowledge in pediatric neurooncology will combine the required skills to optimize care management for these patients within a dedicated multidisciplinary organization framework.

Smoothened-activating lipids drive resistance to CDK4/6 inhibition in Hedgehog-associated medulloblastoma cells and preclinical models

Medulloblastoma is an aggressive pediatric brain tumor that can be driven by misactivation of the Hedgehog (HH) pathway. CDK6 is a critical effector of oncogenic HH signaling, but attempts to target the HH pathway in medulloblastoma have been encumbered by resistance to single-agent molecular therapy. We identified mechanisms of resistance to CDK6 inhibition in HH-associated medulloblastoma by performing orthogonal CRISPR and CRISPR interference screens in medulloblastoma cells treated with a CDK4/6 inhibitor and RNA-Seq of a mouse model of HH-associated medulloblastoma with genetic deletion of Cdk6. Our concordant in vitro and in vivo data revealed that decreased ribosomal protein expression underlies resistance to CDK6 inhibition in HH-associated medulloblastoma, leading to ER stress and activation of the unfolded protein response (UPR). These pathways increased the activity of enzymes producing Smoothened-activating (SMO-activating) sterol lipids that sustained oncogenic HH signaling in medulloblastoma despite cell-cycle attenuation. We consistently demonstrated that concurrent genetic deletion or pharmacological inhibition of CDK6 and HSD11ß2, an enzyme producing SMO-activating lipids, additively blocked cancer growth in multiple mouse genetic models of HH-associated medulloblastoma. Our data reveal what we believe to be a novel pathway of resistance to CDK4/6 inhibition as well as a novel combination therapy to treat the most common malignant brain tumor in children.

Treatment and Outcomes for Central Nervous System Tumors in Australian Adolescents and Young Adults: A Population-Based National Study

Purpose: While central nervous system (CNS) tumors account for only 10% of adolescent and young adult (AYA) cancers, they are the leading cause of cancer death in this age group. Using national data for Australia, we describe the presentation, treatment, and survival for AYAs diagnosed with CNS tumors. Methods: A population-based study of 15-24 year-olds diagnosed with CNS tumors (low- and high-grade glioma [LGG, HGG], medulloblastoma [MB], primitive neuroectodermal tumors [PNET], ependymoma [EP]) or other (e.g., low-grade neuronal tumor) between 2007 and 2012. Clinical details were extracted from hospital medical records for each patient. Treatment centers were classified as pediatric or adult services. Results: Two hundred seventy-five patients (129 LGG, 77 HGG, 23 MB, 10 PNET, 19 EP, 17 other) were identified, with 17% treated at pediatric hospitals. Symptoms (headache [53%], nausea [31%]) were present for a median of 3 weeks before consulting a health professional. Of LGG patients, 15% had radiotherapy (RT) and 12% chemotherapy (CT). Of HGG patients, 81% had RT and 75% CT. All MB and PNET were managed with surgery, and 74% of MB and 80% of PNET had both RT and CT. Treatment did not differ by treatment center type. Five-year survival for LGG and EP was over 80%, but was 42% for HGG and 20% for PNET. Conclusions: This national, population-based study indicates similar treatment for AYA patients with CNS tumors between pediatric and adult services. Poor outcomes for HGG and PNET patients highlight the need for clinical trials of novel approaches for these tumors.

An epidemiology report for primary central nervous system tumors in adolescents and young adults: a nationwide population-based study in France, 2008-2013

BACKGROUND

Primary central nervous system tumors (PCNST) among adolescents and young adults (AYA, 15-39 y) have rarely been reported. We present a nationwide report of PCNST histologically confirmed in the French AYA population between 2008 and 2013.

METHODS

Patients were identified through the French Brain Tumor Database (FBTDB), a national dataset that includes prospectively all histologically confirmed cases of PCNST in France. Patients aged 15 to 39 years with histologically confirmed PCNST diagnosed between 2008 and 2013 were included. For each of the 143 histological subtypes of PCNST, crude rates, sex, surgery, and age distribution were provided. To enable international comparisons, age-standardized incidence rates were adjusted to the world-standard, European, and USA populations.

RESULTS

For 6 years, 9661 PCNST (males/females: 4701/4960) were histologically confirmed in the French AYA population. The overall crude rate was 8.15 per 100 000 person-years. Overall, age-standardized incidence rates were (per 100 000 person-years, population of reference: world/Europe/USA): 7.64/8.07/8.21, respectively. Among patients aged 15-24 years, the crude rate was 5.13 per 100 000. Among patients aged 25-39 years, the crude rate was 10.10 per 100 000. Age-standardized incidence rates were reported for each of the 143 histological subtypes. Moreover, for each histological subtype, data were detailed by sex, age, type of surgery (surgical resection or biopsy), and cryopreserved samples.

CONCLUSION

These data represent an exhaustive report of all histologically confirmed cases of PCNST with their frequency and distribution in the French AYA population in 2008-2013. For the first time in this age group, complete histological subtypes and rare tumor identification are detailed.

The Power of Human Cancer Genetics as Revealed by Low-Grade Gliomas

The human brain contains a vast number of cells and shows extraordinary cellular diversity to facilitate the many cognitive and automatic commands governing our bodily functions. This complexity arises partly from large-scale structural variations in the genome, evolutionary processes to increase brain size, function, and cognition. Not surprisingly given recent technical advances, low-grade gliomas (LGGs), which arise from the glia (the most abundant cell type in the brain), have undergone a recent revolution in their classification and therapy, especially in the pediatric setting. Next-generation sequencing has uncovered previously unappreciated diverse LGG entities, unraveling genetic subgroups and multiple molecular alterations and altered pathways, including many amenable to therapeutic targeting. In this article we review these novel entities, in which oncogenic processes show striking age-related neuroanatomical specificity (highlighting their close interplay with development); the opportunities they provide for targeted therapies, some of which are already practiced at the bedside; and the challenges of implementing molecular pathology in the clinic.

Stalled developmental programs at the root of pediatric brain tumors

Childhood brain tumors have suspected prenatal origins. To identify vulnerable developmental states, we generated a single-cell transcriptome atlas of >65,000 cells from embryonal pons and forebrain, two major tumor locations. We derived signatures for 191 distinct cell populations and defined regional cellular diversity and differentiation dynamics. Projection of bulk tumor transcriptomes onto this dataset shows that WNT medulloblastomas match the rhombic lip-derived mossy fiber neuronal lineage, embryonal tumors with multilayered rosettes fully recapitulate a neuronal lineage, while Group 2a/b atypical teratoid/rhabdoid tumors may originate outside of the neuroectoderm. Importantly, single-cell tumor profiles reveal highly defined cell hierarchies mirroring transcriptional programs of the corresponding normal lineages. Our findings identify impaired differentiation of specific neural progenitors as a common mechanism underlying these pediatric cancers and provide a rational framework for future modeling and therapeutic interventions.

Supratentorial and Infratentorial Approaches to Pineal Surgery: A Database Analysis

Objectives  Neoplasms involving the pineal gland are rare. When they do occur, tumor resection is anatomically challenging and is traditionally addressed by either a supratentorial or an infratentorial approach. To date, no large, multicenter studies have been performed that systematically analyze outcomes comparing these two approaches. This study aimed to evaluate outcomes for patients undergoing pineal neoplasm resection, comparing supratentorial and infratentorial approaches. Design  Retrospective database review. Setting  Multi-institutional database. Participants  From 2005 to 2016, 60 patients were identified, with 13 undergoing a supratentorial approach and 47 undergoing an infratentorial approach. Main Outcome Measures  Patient demographics, comorbidities, and 30-day postoperative outcomes were investigated using the American College of Surgeons National Surgical Quality Improvement Program database. Demographics, readmission, reoperation, and complication rates were analyzed and compared with previous studies. Results  Patient demographics were similar between these two groups. The overall complication rates for the supratentorial and infratentorial approaches were 30.8 and 17%, respectively, and the difference was not statistically significant. The most common medical complications encountered were respiratory and hematological. Conclusion  As the first multi-institutional database analysis of approaches to the pineal gland, this study provides an analysis of patient demographics, comorbidities, and postoperative complications. After controlling for preoperative risk factors and demographic characteristics, no statistically significant differences in postoperative outcomes were found between infratentorial and supratentorial approaches. The mean readmission, reoperation, and complication rates were found to be 2.1, 8.3, and 20%, respectively. The lack of significant difference between approaches suggests that clinical decision-making should depend upon anatomical considerations and physician preference, although the complications illustrated here may provide some preoperative guidance.

Current epidemiology of cerebrospinal fluid shunt surgery in the UK and Ireland (2004-2013)

OBJECTIVES

To determine current epidemiology and clinical characteristics of cerebrospinal fluid (CSF) shunt surgery, including revisions.

METHODS

A retrospective, multicentre, registry-based study was conducted based on 10 years' data from the UK Shunt Registry, including primary and revision shunting procedures reported between 2004 and 2013. Incidence rates of primary shunts, descriptive statistics and shunt revision rates were calculated stratified by age group, geographical region and year of operation.

RESULTS

41 036 procedures in 26 545 patients were submitted during the study period, including 3002 infants, 4389 children and 18 668 adults. Procedures included 20 947 (51.0%) primary shunt insertions in 20 947 patients, and 20 089 (49.0%) revision procedures. Incidence rates of primary shunt insertions for infants, children and adults were 39.5, 2.4 and 3.5 shunts per 100 000 person-years, respectively. These varied by geographical subregion and year of operation. The most common underlying diagnoses were perinatal intraventricular haemorrhage (35.3%) and malformations (33.9%) in infants, tumours (40.5%) and malformations (16.3%) in children, and tumours (24.6%), post-haemorrhagic hydrocephalus (16.2%) and idiopathic normal pressure hydrocephalus (14.2%) in adults. Ninety-day revision rates were 21.9%, 18.6% and 12.8% among infants, children and adults, respectively, while first-year revision rates were 31.0%, 25.2% and 17.4%. The main reasons for revision were underdrainage and infection, but overdrainage and mechanical failure continue to pose problems.

CONCLUSIONS

Our report informs patients, carers, clinicians, providers and commissioners of healthcare, researchers and industry of the current epidemiology of shunting for CSF disorders, including the potential risks of complications and frequency of revision.

A C-Terminal Fragment of Chlorotoxin Retains Bioactivity and Inhibits Cell Migration

Chlorotoxin was originally isolated from the venom of the Israeli scorpion Leiurus quinquestriatus, and has potential as a tumor imaging agent based on its selective binding to tumor cells. Several targets have been suggested for chlorotoxin including voltage-gated chloride channels, and it has been shown to have anti-angiogenic activity and inhibit cell migration. The structure of chlorotoxin is stabilized by four disulfide bonds and contains β-sheet and helical structure. Interestingly, the reduced form has previously been shown to inhibit cell migration to the same extent as the wild type, but structural analysis indicates that the reduced form of the peptide does not maintain the native secondary structure and appears unstructured in solution. This lack of structure suggests that a short stretch of amino acids might be responsible for the bioactivity. To explore this hypothesis, we have synthesized fragments of chlorotoxin without disulfide bonds. As expected for such small peptides, NMR analysis indicated that the peptides were unstructured in solution. However, the peptide corresponding to the eight C-terminal residues inhibited cell migration, in contrast to the other fragments. Our results suggest that the C-terminal region plays a critical role in the bioactivity of chlorotoxin.

Misactivation of Hedgehog signaling causes inherited and sporadic cancers

The Hedgehog pathway is critical for the development of diverse organs. Misactivation of the Hedgehog pathway can cause developmental abnormalities and cancers, including medulloblastoma, the most common pediatric brain tumor, and basal cell carcinoma, the most common cancer in the United States. Here, we review how basic, translational, and clinical studies of the Hedgehog pathway have helped reveal how cells communicate, how intercellular communication controls development, how signaling goes awry to cause cancer, and how to use targeted molecular agents to treat both inherited and sporadic cancers.

Extracellular Vesicles as Conduits of Non-Coding RNA Emission and Intercellular Transfer in Brain Tumors

Non-coding RNA (ncRNA) species have emerged in as molecular fingerprints and regulators of brain tumor pathogenesis and progression. While changes in ncRNA levels have been traditionally regarded as cell intrinsic there is mounting evidence for their extracellular and paracrine function. One of the key mechanisms that enables ncRNA to exit from cells is their selective packaging into extracellular vesicles (EVs), and trafficking in the extracellular space and biofluids. Vesicular export processes reduce intracellular levels of specific ncRNA in EV donor cells while creating a pool of EV-associated ncRNA in the extracellular space and biofluids that enables their uptake by other recipient cells; both aspects have functional consequences. Cancer cells produce several EV subtypes (exosomes, ectosomes), which differ in their ncRNA composition, properties and function. Several RNA biotypes have been identified in the cargo of brain tumor EVs, of which microRNAs are the most studied, but other species (snRNA, YRNA, tRNA, and lncRNA) are often more abundant. Of particular interest is the link between transforming oncogenes and the biogenesis, cargo, uptake and function of tumor-derived EV, including EV content of oncogenic RNA. The ncRNA repertoire of EVs isolated from cerebrospinal fluid and serum is being developed as a liquid biopsy platform in brain tumors.

Purchases of antidepressants after cancer at a young age in Finland

According to previous studies, childhood cancer survivors have an elevated risk for late mental health effects. However, only few studies exist on young adulthood (YA) cancer survivors' mental health outcomes. In our study, we examined first time antidepressant (AD) medication purchases of childhood and YA cancer patients compared to siblings. The first time AD medication purchases of 7,093 cancer patients aged 0-34 years at diagnosis and a sibling cohort (N = 26,882) were retrieved from the Social Insurance Institution of Finland (Kela) since 1.1.1993. Cancer patients diagnosed between 1.1.1994 and 31.12.2004 were identified from the Finnish Cancer Registry and sibling controls via the Population Registry Centre. Statistical analyses were performed via the Cox regression model, and the hazard ratios (HR) were adjusted for age and gender. Increased hazard ratios for AD purchases were found in the younger (0-19 years at cancer diagnosis) [HR 5.2, 95%CI (3.7-7.2)] and older (age 20-34 years at cancer diagnosis) [HR 4.5, 95%CI (3.9-5.2)] cancer patient groups compared to siblings. The gender effect was similar in patients and controls, showing that females have higher risk for AD purchases than males. Males in the younger patient group had highest HR (5.6) for AD purchases compared to siblings. Patients with sarcoma or CNS tumor in the younger age group and leukemia or CNS malignancy in the older age group had the highest risk for AD medication purchases. The frequency and risk for AD purchases has been increasing during recent decades in both cancer patient age groups compared to siblings. Thus, cancer patients' psychological support should be properly assessed already after primary treatment. Certain diagnostic groups as well as female patients may require more psychological support than others.

Single cell coagulomes as constituents of the oncogene-driven coagulant phenotype in brain tumours

Molecular profiling of human cancers revealed a startling diversity in disease-causing mechanisms superseding histological and anatomical commonalities. The emerging molecular subtypes and disease entities are often driven by distinct oncogenic pathways and their effectors, including those acting extracellularly on the vascular and coagulation systems. Indeed, several oncogenic mutations such as those affecting protein-coding genes (RAS, EGFR, PTEN, TP53) and non-coding RNA (microRNA) regulate multiple effectors of the coagulation system (coagulome), including tissue factor, protease activated receptors, clotting factors, mediators of platelet function and fibrinolysis. This is exemplified by differential coagulome profiles in the molecular subtypes of glioblastoma, medulloblastoma and other human tumours. There is mounting clinical evidence that the mutational status of cancer driver genes such as KRAS or IDH1 may influence the risk of venous thromboembolism in patients with colorectal, lung or brain cancers. Notably, single cell sequencing in glioblastoma revealed a remarkable intra-tumoural heterogeneity of cancer cell populations with regard to their individual coagulomes, suggesting a combinatorial and dynamic nature of the global pro-thrombotic phenotype. We suggest that the cellular complexity of specific cancers may define their mechanisms of interactions with the coagulation system, and the risks of thrombosis. Thus, more biologically- based, disease-specific and personalized approaches may be needed to diagnose and manage cancer-related thrombosis.

Anaplasic astrocytoma with exophytic growth in Sylvian fissure in a pediatric patient: a case report

Gliomas are the most frequent supratentorial intracranial tumors in the pediatric population. Usually, they are intra-axial lesions with a characteristic image pattern, however, there are few reported cases of gliomas with exophytic growth. There are no previous reports in the literature of gliomas with exophytic growth in the Sylvian fissure. Fourteen year-old female patient who started with seizures. In imaging studies, a neoplasic mass with an exophytic portion in the left Sylvian fissure was found. Macroscopically, total resection was performed, definitive diagnosis was anaplastic astrocytoma. She presented recurrence and is currently receiving adjuvant treatment. Supratentorial gliomas with exophytic growth are extremely rare. We report the first case in the pediatric population, and we consider it is important to know its imaging and macroscopic characteristics for its initial management and to take it into account as a differential diagnosis of exophytic lesions.

Ventromorphins: A New Class of Small Molecule Activators of the Canonical BMP Signaling Pathway

Here, we describe three new small-molecule activators of BMP signaling found by high throughput screening of a library of ∼600 000 small molecules. Using a cell-based luciferase assay in the BMP4-responsive human cervical carcinoma clonal cell line, C33A-2D2, we identified three compounds with similar chemotypes that each ventralize zebrafish embryos and stimulate increased expression of the BMP target genes, bmp2b and szl. Because these compounds ventralize zebrafish embryos, we have termed them "ventromorphins." As expected for a BMP pathway activator, they induce the differentiation of C2C12 myoblasts to osteoblasts. Affymetrix RNA analysis confirmed the differentiation results and showed that ventromorphins treatment elicits a genetic response similar to BMP4 treatment. Unlike isoliquiritigenin (SJ000286237), a flavone that maximally activates the pathway after 24 h of treatment, all three ventromorphins induced SMAD1/5/8 phosphorylation within 30 min of treatment and achieved peak activity within 1 h, indicating that their responses are consistent with directly activating BMP signaling.

Psychopathological Aspects in Childhood Hematopoietic Stem Cell Transplantation (HSCT): The Perception of Parents and Adolescents

Background: Data about psychosocial sequelae of childhood Hematopoietic Stem Cell Transplantation (HSCT) are limited and the association with a specific donor type or other medical factors is largely unknown (Chang et al., 2012). The aim of the present study was to compare the psychological aspects of pediatric HSCT survivors with healthy peers. A secondary aim was to detect whether parents and children differed in the perception of mental health status. The influence of medical factors on psychological status was also examined. Method: Thirty seven HSCT survivors (23 males) with a mean age of 14.4 years (SD = 3.03; range 8.16-18.33) were recruited. Twenty-six patients underwent an allogenic HSCT (matched unrelated donor, n = 20; matched sibling donor, n = 6) and 11 patients received an autologous HSCT. The children psychological aspects were assessed using the Youth Self Report (YSR) (Achenbach and Rescorla, 2001) and compared to a group of matched healthy peers. At the same time, parents were requested to complete the Child Behavior Checklist 6-18 (Achenbach and Rescorla, 2001). Medical and socio-demographic data were also collected. Results: HSCT survivors reported significantly higher levels of somatic complains (t27 = 3.14; p = 0.004; mean = 3.1) when compared to healthy peers (mean = 1.5). The parent CBCL scores on "child total competence" exceeded the normative clinical cutoff in 48.6% cases. Inter-rater agreement between parent and patient reports was present only in three scales: total competence score (K = 0.06, p = 0.002), somatic complaints (K = 0.21, p = 0.003) and attention problems (k = 0.13; p = 0.02). According to Ancova models, internalizing problems were more frequent in HSCT from family donors (F2 = 3.13; p = 0.06) or in the presence of acute complications (F1 = 11.95; p = 0.003). Conclusion: In contrast to the perception of parents, pediatric HSCT survivors reported good psychological health. However, they complained about more somatic problems as compared with healthy peers. Medical aspects such as donor source and the presence of acute complications should be taken into consideration for the psychological approach in order to improve pediatric HSCT survivor care.

Applying the International Classification of Functioning-Children and Youth Version to Pediatric Neuro-oncology

Given the increased survival rates in patients with pediatric central nervous system tumors, late effects such as treatment- and/or illness-related neurologic sequelae as well as neuropsychological deficits and social difficulties have moved into focus in follow-up care. In order to provide personalized treatment recommendations for pediatric brain tumor survivors, it is crucial not only to assess cognitive impairments but also to measure a patient's functional deficiencies, for example, restricted participation in everyday social activities. Thus, this article introduces the International Classification of Functioning-Children and Youth version (ICF-CY) as a conceptual framework for quantifying functional limitations and informing long-term care in pediatric neuro-oncology. A standardized self-report and proxy-report questionnaire for measuring participation is briefly discussed and specific recommendations based on so-called core sets for clinical practice in pediatric neuro-oncology are provided.

Survival after chemotherapy and stem cell transplant followed by delayed craniospinal irradiation is comparable to upfront craniospinal irradiation in pediatric embryonal brain tumor patients

Pediatric embryonal brain tumor patients treated with craniospinal irradiation (CSI) are at risk for adverse effects, with greater severity in younger patients. Here we compare outcomes of CSI vs. high-dose chemotherapy (HD), stem cell transplant (SCT) and delayed CSI in newly diagnosed patients. Two hundred one consecutive patients treated for medulloblastoma (72 %), supratentorial primitive neuroectodermal tumor (sPNET; 18 %) or pineoblastoma (10 %) at two institutions between 1988 and 2014 were retrospectively identified. Progression free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method and compared by log-rank tests. Adjuvant CSI regimens were used for 56 % of patients (upfront-CSI), and HD/SCT regimens were used in 32 % of patients. HD/SCT patients were significantly younger than those receiving upfront-CSI (2.9 vs. 7.8 years; P < 0.0001). There were no differences in metastases, extent of resection, or CSI dose between upfront-CSI and HD/SCT patients, but median follow-up was shorter in the HD/SCT group (6.2 vs. 3.9 years; P = 0.007). There were no significant outcome differences between upfront-CSI and HD/SCT patients who received CSI as a prophylaxis or following relapse (OS 66 % vs. 61 %, P = 0.13; PFS 67 % vs. 62 %, P = 0.12). Outcomes were equivalent when restricting analyses to HD/SCT patients who received prophylactic CSI prior to relapse (OS 66 % vs. 65 %, P = 0.5; PFS 67 % vs. 74 %, P = 0.8). At last follow-up, 48 % of HD/SCT patients had received neither definitive nor salvage radiotherapy. In this retrospective cohort, outcomes with adjuvant HD/SCT followed by delayed CSI are comparable to upfront-CSI for carefully surveyed pediatric embryonal brain tumor patients. Future prospective studies are required to validate this finding, and also to assess the impact of delayed CSI on neurocognitive outcomes.

Non-random aneuploidy specifies subgroups of pilocytic astrocytoma and correlates with older age

Pilocytic astrocytoma (PA) is the most common brain tumor in children but is rare in adults, and hence poorly studied in this age group. We investigated 222 PA and report increased aneuploidy in older patients. Aneuploid genomes were identified in 45% of adult compared with 17% of pediatric PA. Gains were non-random, favoring chromosomes 5, 7, 6 and 11 in order of frequency, and preferentially affecting non-cerebellar PA and tumors with BRAF V600E mutations and not with KIAA1549-BRAF fusions or FGFR1 mutations. Aneuploid PA differentially expressed genes involved in CNS development, the unfolded protein response, and regulators of genomic stability and the cell cycle (MDM2, PLK2),whose correlated programs were overexpressed specifically in aneuploid PA compared to other glial tumors. Thus, convergence of pathways affecting the cell cycle and genomic stability may favor aneuploidy in PA, possibly representing an additional molecular driver in older patients with this brain tumor.

Application of Nanomedicine to the CNS Diseases

Drug delivery to the brain is a challenge because of the many mechanisms that protect the brain from the entry of foreign substances. Numerous molecules which could be active against brain disorders are not clinically useful due to the presence of the blood-brain barrier. Nanoparticles can be used to deliver these drugs to the brain. Encapsulation within colloidal systems can allow the passage of nontransportable drugs across this barrier by masking their physicochemical properties. It should be noted that the status of the blood-brain barrier is different depending on the brain disease. In fact, in some pathological situations such as tumors or inflammatory disorders, its permeability is increased allowing very easy translocation of carriers. This chapter gathers the promising results obtained by using nanoparticles as drug delivery systems with the aim to improve the therapy of some CNS diseases such as brain tumor, Alzheimer's disease, and stroke. The data show that several approaches can be investigated: (1) carrying drug through a permeabilized barrier, (2) crossing the barrier thanks to receptor-mediated transcytosis pathway in order to deliver drug into the brain parenchyma, and also (3) targeting and treating the endothelial cells themselves to preserve locally the brain tissue. The examples given in this chapter contribute to demonstrate that delivering drugs into the brain is one of the most promising applications of nanotechnology in clinical neuroscience.

Anticancer activity of taraxerol acetate in human glioblastoma cells and a mouse xenograft model via induction of autophagy and apoptotic cell death, cell cycle arrest and inhibition of cell migration

The aim of the present study was to investigate the in vitro and in vivo anticancer and apoptotic effects of taraxerol acetate in U87 human glioblastoma cells. The effects on cell cycle phase distribution, cell cycle-associated proteins, autophagy, DNA fragmentation and cell migration were assessed. Cell viability was determined using the MTT assay, and phase contrast and fluorescence microscopy was utilized to determine the viability and apoptotic morphological features of the U87 cells. Flow cytometry using propidium iodide and Annexin V-fluorescein isothiocyanate demonstrated the effect of taraxerol acetate on the cell cycle phase distribution and apoptosis induction. Western blot analysis was performed to investigate the effect of the taraxerol acetate on cell cycle-associated proteins and autophagy-linked LC3B-II proteins. The results demonstrated that taraxerol acetate induced dose- and time-dependent cytotoxic effects in the U87 cells. Apoptotic induction following taraxerol acetate treatment was observed and the percentage of apoptotic cells increased from 7.3% in the control cells, to 16.1, 44.1 and 76.7% in the 10, 50 and 150 µM taraxerol acetate-treated cells, respectively. Furthermore, taraxerol acetate treatment led to sub-G₁ cell cycle arrest with a corresponding decrease in the number of S-phase cells. DNA fragments were observed as a result of the gel electrophoresis experiment following taraxerol acetate treatment. To investigate the inhibitory effects of taraxerol acetate on the migration of U87 cell, a wound healing assay was conducted. The number of cells that migrated to the scratched area decreased significantly following treatment with taraxerol acetate. In addition, taraxerol acetate inhibited tumor growth in a mouse xenograft model. Administration of 0.25 and 0.75 µg/g taraxerol acetate reduced the tumor weight from 1.2 g in the phosphate-buffered saline (PBS)-treated group (control) to 0.81 and 0.42 g, respectively. Similarly, 0.25 and 0.75 µg/g taraxerol acetate injection reduced the tumor volume from 1.3 cm³ in the PBS-treated group (control) to 0.67 and 0.25 cm³, respectively.

Extracellular Vesicles in Brain Tumor Progression

Brain tumors can be viewed as multicellular 'ecosystems' with increasingly recognized cellular complexity and systemic impact. While the emerging diversity of malignant disease entities affecting brain tissues is often described in reference to their signature alterations within the cellular genome and epigenome, arguably these cell-intrinsic changes can be regarded as hardwired adaptations to a variety of cell-extrinsic microenvironmental circumstances. Conversely, oncogenic events influence the microenvironment through their impact on the cellular secretome, including emission of membranous structures known as extracellular vesicles (EVs). EVs serve as unique carriers of bioactive lipids, secretable and non-secretable proteins, mRNA, non-coding RNA, and DNA and constitute pathway(s) of extracellular exit of molecules into the intercellular space, biofluids, and blood. EVs are also highly heterogeneous as reflected in their nomenclature (exosomes, microvesicles, microparticles) attempting to capture their diverse origin, as well as structural, molecular, and functional properties. While EVs may act as a mechanism of molecular expulsion, their non-random uptake by heterologous cellular recipients defines their unique roles in the intercellular communication, horizontal molecular transfer, and biological activity. In the central nervous system, EVs have been implicated as mediators of homeostasis and repair, while in cancer they may act as regulators of cell growth, clonogenicity, angiogenesis, thrombosis, and reciprocal tumor-stromal interactions. EVs produced by specific brain tumor cell types may contain the corresponding oncogenic drivers, such as epidermal growth factor receptor variant III (EGFRvIII) in glioblastoma (and hence are often referred to as 'oncosomes'). Through this mechanism, mutant oncoproteins and nucleic acids may be transferred horizontally between cellular populations altering their individual and collective phenotypes. Oncogenic pathways also impact the emission rates, types, cargo, and biogenesis of EVs, as reflected by preliminary analyses pointing to differences in profiles of EV-regulating genes (vesiculome) between molecular subtypes of glioblastoma, and in other brain tumors. Molecular regulators of vesiculation can also act as oncogenes. These intimate connections suggest the context-specific roles of different EV subsets in the progression of specific brain tumors. Advanced efforts are underway to capture these events through the use of EVs circulating in biofluids as biomarker reservoirs and to guide diagnostic and therapeutic decisions.

Metastatic medulloblastoma in adults: outcome of patients treated according to the HIT2000 protocol

BACKGROUND

Due to the rarity of metastatic medulloblastoma in adults, knowledge about the efficacy and toxicity of intensified chemotherapy and radiotherapy is limited.

PATIENTS AND METHODS

Adults with disseminated medulloblastoma registered in the HIT2000 trial as observational patients and treated according to one of two different treatment regimens were analysed. The sandwich strategy MET-HIT2000AB4 consists of postoperative chemotherapy, hyperfractionated craniospinal radiotherapy, and maintenance chemotherapy; while the HIT'91 maintenance strategy consists of postoperative craniospinal radiotherapy, and maintenance chemotherapy.

RESULTS

Twenty-three patients (median age: 30.7years), diagnosed from November 2001 to July 2009, and treated in 18 institutions in Germany and Austria, were eligible. The median follow-up of surviving patients was 3.99years. The 4-year event-free survival (EFS) and overall survival (OS)±standard error (SE) were 52%±12% and 91%±6%, respectively. The survival was similar in both treatment groups (HIT'91 maintenance strategy, n=9; MET-HIT2000AB4 sandwich strategy, n=14). Patients with large cell/anaplastic medulloblastoma relapsed and died (n=2; 4-year EFS/OS: 0%) and OS differed compared to patients with classic (n=11; 4-year EFS/OS: 71%/91%) and desmoplastic medulloblastoma (n=10; 4-year EFS/OS: 48%/100%), respectively (p=0.161 for EFS and p=0.033 for OS). Treatment-induced toxicities consisted mainly of neurotoxicity (50% of patients, ⩾ °II), followed by haematotoxicity and nephrotoxicity/ototoxicity. The professional outcome appeared to be negatively affected in the majority of evaluable patients (9/10).

CONCLUSIONS

Treatment of adults with metastatic medulloblastoma according to the intensified paediatric HIT2000 protocol was feasible with acceptable toxicities. EFS rates achieved by both chemotherapeutic protocols were favourable and appear to be inferior to those obtained in older children/adolescents with metastatic disease.

Late new morbidity in survivors of adolescent and young-adulthood brain tumors in Finland: a registry-based study

BACKGROUND

Brain tumors (BTs) in adolescence and young adulthood (AYA) differ from those in childhood or late adulthood. However, research concerning late effects in this particular survivor group is limited. This study evaluates late morbidity of survivors diagnosed in AYAs.

METHODS

We identified from the Finnish Cancer Registry all survivors diagnosed with BT at the ages 16-24 years between 1970 and 2004 (N = 315) and used data from the Hospital Discharge Registry to evaluate their late (≥5 y after diagnosis) morbidity requiring treatment in a specialized health care setting. A sibling cohort of BT patients diagnosed before the age of 25 years was used as a comparison cohort (N = 3615).

RESULTS

The AYA BT survivors had an increased risk for late-appearing endocrine diseases (HR, 2.9; 95% CI, 1.1-8.0), psychiatric disorders (HR, 2.0; 95% CI, 1.2-3.2), diseases of the nervous system (HR, 9; 95% CI, 6.6-14.0), disorders of vision/hearing loss (HR, 3.6; 95% CI, 1.5-8.5), diseases of the circulatory system (HR, 4.9; 95% CI, 2.9-8.1), and diseases of the kidney (HR, 5.9; 95% CI, 2.5-14.1). Survivors with irradiation had an increased risk for diseases of the nervous system compared with non-irradiated survivors (HR, 3.3; 95% CI, 1.8-6.2). The cumulative prevalence for most of the diagnoses remained significantly increased for survivors even 20 years after cancer diagnosis.

CONCLUSIONS

The AYA BT survivors have an increased risk of morbidity for multiple new outcomes for ≥5 years after their primary diagnosis. This emphasizes the need for structured late-effect follow-up for this patient group.

Delayed diagnosis of childhood low-grade glioma: causes, consequences, and potential solutions

PURPOSE

Diagnosis of childhood brain tumors is delayed more than diagnosis of other pediatric cancers. However, the contribution of the most common pediatric brain tumors, lowgrade gliomas (LGG), to this delay has never been investigated.

METHODS

We retrospectively reviewed cases of childhood LGG diagnosed from January 1995 through December 2005 at our institution. The pre-diagnosis symptom interval (PSI) was conservatively calculated, and its association with race, sex, age, tumor site, tumor grade, and outcome measures (survival, disease progression, shunt use, seizures, extent of resection) was analyzed. Cases of neurofibromatosis type 1 were reported separately.

RESULTS

The 258 children had a median follow-up of 11.1 years, and 226 (88 %) remained alive. Greater pre-diagnosis symptom interval (PSI) was significantly associated with grade I (vs. grade II) tumors (p = 0.03) and age >10 years at diagnosis (p = 0.03). Half of the 16 spinal tumors had a PSI > 6 months. PSI was significantly associated with progression (p = 0.02) in grade I tumors (n = 195) and in grade I tumors outside the posterior fossa (n = 134, p = 0.03). Among children with grade I tumors, median PSI was longer in those who had seizures (10.3 months) than in those who did not (2.5 months) (p = 0.09).

CONCLUSIONS

Delayed diagnosis of childhood LGG allows tumor progression. To reduce time to diagnosis, medical curricula should emphasize inclusion of LGG in the differential diagnosis of CNS neoplasm.

Epigenetic dysregulation: a novel pathway of oncogenesis in pediatric brain tumors

A remarkably large number of "epigenetic regulators" have been recently identified to be altered in cancers and a rapidly expanding body of literature points to "epigenetic addiction" (an aberrant epigenetic state to which a tumor is addicted) as a new previously unsuspected mechanism of oncogenesis. Although mutations are also found in canonical signaling pathway genes, we and others identified chromatin-associated proteins to be more commonly altered by somatic alterations than any other class of oncoprotein in several subgroups of childhood high-grade brain tumors. Furthermore, as these childhood malignancies carry fewer non-synonymous somatic mutations per case in contrast to most adult cancers, these mutations are likely drivers in these tumors. Herein, we will use as examples of this novel hallmark of oncogenesis high-grade astrocytomas, including glioblastoma, and a subgroup of embryonal tumors, embryonal tumor with multilayered rosettes (ETMR) to describe the novel molecular defects uncovered in these deadly tumors. We will further discuss evidence for their profound effects on the epigenome. The relative genetic simplicity of these tumors promises general insights into how mutations in the chromatin machinery modify downstream epigenetic signatures to drive transformation, and how to target this plastic genetic/epigenetic interface.

Chromosome band 7q34 deletions resulting in KIAA1549-BRAF and FAM131B-BRAF fusions in pediatric low-grade Gliomas

The majority of pediatric low-grade gliomas (LGGs) are characterized by constitutive activation of the mitogen-activated protein kinase (MAPK) pathway through various mechanisms including BRAF mutations, inactivation of NF1, and KIAA1549-BRAF and FAM131B-BRAF fusions. The KIAA1549-BRAF fusion typically results from a 2.0 Mb tandem duplication in chromosome band 7q34. In the present study, single nucleotide polymorphism (SNP)-based array analysis of three LGGs demonstrated deletions in 7q34 that resulted in a BRAF fusion. Case 1 was likely a pilocytic astrocytoma (PA) with three deletions in 7q33q34 and an exon 15-9 KIAA1549-BRAF fusion. SNP array analysis of case 2, a possible dysembryoplastic neuroepithelial tumor (DNT), revealed a 2.6 Mb deletion, which included the 5' end of BRAF and extended to the 3' end of FAM131B. In case 3, deletions involving BRAF and FAM131B were observed in both a primary and a recurrent PA. RNA-based sequence analysis of cases 2 and 3 confirmed a fusion between FAM131B exon 2 and BRAF exon 9. The presence of fusion transcripts in these three LGGs highlights the utility of SNP array analysis to identify deletions that are suggestive of fusion proteins. BRAF fusions can result from multiple non-overlapping deletions, suggesting various complex mechanisms of formation.

Drug and cell encapsulation: alternative delivery options for the treatment of malignant brain tumors

Malignant brain tumors including glioblastoma are incurable cancers. Over the last years a number of promising novel treatment approaches have been investigated including the application of inhibitors of receptor tyrosine kinases and downstream targets, immune-based therapies and anti-angiogenic agents. Unfortunately so far the major clinical trials in glioblastoma patients did not deliver clear clinical benefits. Systemic brain tumor therapy is seriously hampered by poor drug delivery to the brain. Although in glioblastoma, the blood brain barrier is disrupted in the tumor core, the major part of the tumor is largely protected by an intact blood brain barrier. Active cytotoxic compounds encapsulated into liposomes, micelles, and nanoparticles constitute novel treatment options because they can be designed to facilitate entry into the brain parenchyma. In the case of biological therapeutics, encapsulation of therapeutic cells and their implantation into the surgical cavity represents another promising approach. This technology provides long term release of the active compound at the tumor site and reduces side effects associated with systemic delivery. The proof of principle of encapsulated cell factories has been successfully demonstrated in experimental animal models and should pave the way for clinical application. Here we review the challenges associated with the treatment of brain tumors and the different encapsulation options available for drugs and living cells, with an emphasis on alginate based cell encapsulation technology.

Diagnostic application of high resolution single nucleotide polymorphism array analysis for children with brain tumors

Single nucleotide polymorphism (SNP) array analysis is currently used as a first tier test for pediatric brain tumors at The Children's Hospital of Philadelphia. The results from 100 consecutive patients are summarized in the present report. Eighty-seven percent of the tumors had at least one pathogenic copy number alteration. Nineteen of 56 low grade gliomas (LGGs) demonstrated a duplication in 7q34, which resulted in a KIAA1549-BRAF fusion. Chromosome band 7q34 deletions, which resulted in a FAM131B-BRAF fusion, were identified in one pilocytic astrocytoma (PA) and one dysembryoplastic neuroepithelial tumor (DNT). One ganglioglioma (GG) demonstrated a 6q23.3q26 deletion that was predicted to result in a MYB-QKI fusion. Gains of chromosomes 5, 6, 7, 11, and 20 were seen in a subset of LGGs. Monosomy 6, deletion of 9q and 10q, and an i(17)(q10) were each detected in the medulloblastomas (MBs). Deletions and regions of loss of heterozygosity that encompassed TP53, RB1, CDKN2A/B, CHEK2, NF1, and NF2 were identified in a variety of tumors, which led to a recommendation for germline testing. A BRAF p.Thr599dup or p.V600E mutation was identified by Sanger sequencing in one and five gliomas, respectively, and a somatic TP53 mutation was identified in a fibrillary astrocytoma. No TP53 hot-spot mutations were detected in the MBs. SNP array analysis of pediatric brain tumors can be combined with pathologic examination and molecular analyses to further refine diagnoses, offer more accurate prognostic assessments, and identify patients who should be referred for cancer risk assessment.

BET bromodomain inhibition of MYC-amplified medulloblastoma

PURPOSE

MYC-amplified medulloblastomas are highly lethal tumors. Bromodomain and extraterminal (BET) bromodomain inhibition has recently been shown to suppress MYC-associated transcriptional activity in other cancers. The compound JQ1 inhibits BET bromodomain-containing proteins, including BRD4. Here, we investigate BET bromodomain targeting for the treatment of MYC-amplified medulloblastoma.

EXPERIMENTAL DESIGN

We evaluated the effects of genetic and pharmacologic inhibition of BET bromodomains on proliferation, cell cycle, and apoptosis in established and newly generated patient- and genetically engineered mouse model (GEMM)-derived medulloblastoma cell lines and xenografts that harbored amplifications of MYC or MYCN. We also assessed the effect of JQ1 on MYC expression and global MYC-associated transcriptional activity. We assessed the in vivo efficacy of JQ1 in orthotopic xenografts established in immunocompromised mice.

RESULTS

Treatment of MYC-amplified medulloblastoma cells with JQ1 decreased cell viability associated with arrest at G1 and apoptosis. We observed downregulation of MYC expression and confirmed the inhibition of MYC-associated transcriptional targets. The exogenous expression of MYC from a retroviral promoter reduced the effect of JQ1 on cell viability, suggesting that attenuated levels of MYC contribute to the functional effects of JQ1. JQ1 significantly prolonged the survival of orthotopic xenograft models of MYC-amplified medulloblastoma (P < 0.001). Xenografts harvested from mice after five doses of JQ1 had reduced the expression of MYC mRNA and a reduced proliferative index.

CONCLUSION

JQ1 suppresses MYC expression and MYC-associated transcriptional activity in medulloblastomas, resulting in an overall decrease in medulloblastoma cell viability. These preclinical findings highlight the promise of BET bromodomain inhibitors as novel agents for MYC-amplified medulloblastoma.

Are pediatric brain tumors on the rise in the USA? Significant incidence and survival findings from the SEER database analysis

INTRODUCTION

Central nervous system tumors are the second most common form of cancer in children between the ages of 1 and 19 years. We aimed to provide the most recent data on the incidence and survival of these tumors in the USA and to assess the literature.

METHODS

Frequency, rates, and survival sessions were calculated using the November 2008 submission for the US Surveillance Epidemiology and End Results Program. Data were collected and analyzed for children and adolescents aged 1 to 19 years with primary brain tumors.

RESULTS

We found that the incidence rate of all pediatric brain tumors has been on a gradual but steady increase from 1973 to 2008 (p < 0.001). The average annual increase was 1.37 %. Our survival analysis of the individual tumors revealed that the 5-year overall survival for children diagnosed between 1974 and 1978 with medulloblastoma was 43.7 %. However, this increased to 62.8 % for children diagnosed between 1999 and 2003. A similar survival trend was also observed when all the other pediatric brain cancer histologies were collectively analyzed (p < 0.001).

CONCLUSIONS

From our study, we can conclude that contrary to previous reports indicating a plateau in the incidence rates of pediatric brain tumors since the mid-1980s, there has been an increase from 1973 to 2008. Potential causes include environmental carcinogens, but more research is needed to investigate the factors behind this sustained rise in incidence over the years.

The adolescent and young adult with cancer: state of the art--brain tumor

The management of adolescents and young adults with brain tumors, which consist of many different histologic subtypes, continues to be a challenge. Better outcome with a decrease of the side effects of the disease and therapy and improvement of quality of life has been demonstrated in recent decades for some tumors. Significant differences in survival and cure are also observed between adult and pediatric tumors of the same histologic grade. Genetic, developmental, and environmental factors likely influence the type of tumor and response observed, even though no clear pathologic features differentiate these lesions among children, adolescents, and adults. Similarly, treatment strategies are not identical among these populations; most patients receive surgery, followed by radiation therapy and multiagent chemotherapy. Advances in understanding the biology underlying the distribution of tumors in adolescents and young adults may influence the development of prospective trials. A more individualized view of these tumors will likely influence stratification of patients in future studies as well as selection for targeted agents. Accordingly, outcomes may improve and long-term morbidities may decrease.

Chromatin remodeling defects in pediatric and young adult glioblastoma: a tale of a variant histone 3 tail

Primary brain tumors occur in 8 out of 100 000 people and are the leading cause of cancer-related death in children. Among brain tumors, high-grade astrocytomas (HGAs) including glioblastoma multiforme (GBM) are aggressive and are lethal human cancers. Despite decades of concerted therapeutic efforts, HGAs remain essentially incurable in adults and children. Recent discoveries have revolutionized our understanding of these tumors in children and young adults. Recurrent somatic driver mutations in the tail of histone 3 variant 3 (H3.3), leading to amino acid substitutions at key residues, namely lysine (K) 27 (K27M) and glycine 34 (G34R/G34V), were identified as a new molecular mechanism in pediatric GBM. These mutations represent the pediatric counterpart of the recurrent mutations in isocitrate dehydrogenases (IDH) identified in young adult gliomas and provide a much-needed new pathway that can be targeted for therapeutic development. This review will provide an overview of the potential role of these mutations in altering chromatin structure and affecting specific molecular pathways ultimately leading to gliomagenesis. The distinct changes in chromatin structure and the specific downstream events induced by each mutation need characterizing independently if progress is to be made in tackling this devastating cancer.

Family factors associated with academic achievement deficits in pediatric brain tumor survivors

PURPOSE

The purpose of this study is to examine whether parental education, socioeconomic status, or family environment moderate the extent of academic achievement deficits in pediatric brain tumor survivors (PBTS) relative to classmate case-controls. PBTS are known to be at risk for cognitive and academic impairment; however, the degree of impairment varies. Prior research has focused on treatment risk, and efforts to examine the protective role of family resources and relationships have been lacking.

METHODS

Pediatric brain tumor survivors (N = 164), ages 8-15 and 1-5 years posttreatment, were recruited at five treatment centers in the United States and Canada. A case-control classmate, matched for age, gender, and race, was recruited for each survivor. The Wide Range Achievement Test, a demographic form, and the Family Environment Scale were administered in families' homes. Treatment data were abstracted from medical charts.

RESULTS

Pediatric brain tumor survivors demonstrated lower achievement than classmate-controls in reading, spelling, and arithmetic. Parental education and socioeconomic status were associated with levels of achievement demonstrated by PBTS but did not account for discrepancies between PBTS and classmate-controls. Deficits in achievement relative to classmate-controls, across all academic domains, were greater for survivors in families lower in support and higher in conflict. These associations remained after controlling for age at diagnosis, time since treatment, and whether treatment had involved chemotherapy, focal, or whole brain radiation.

CONCLUSIONS

These results support the development of interventions to enhance family functioning as well as educational resources as part of intervention and rehabilitation services to optimize academic progress in children who have been treated for brain tumors.

Pediatric high-grade astrocytomas: a distinct neuro-oncological paradigm

Brain tumors are the leading cause of cancer-related death in children. High-grade astrocytomas (HGAs), in particular, are lethal in children across all ages. Integrative genome-wide analyses of the tumor's genome, transcriptome and epigenome, using next-generation sequencing technologies and genome-wide DNA methylation arrays, have provided valuable breakthroughs in our understanding of the pathogenesis of HGAs across all ages. Recent profiling studies have provided insight into the epigenetic nature of gliomas in young adults and HGAs in children, particularly with the identification of recurrent gain-of-function driver mutations in the isocitrate dehydrogenase 1 and 2 genes (IDH1/2) and the epigenetic influence of their oncometabolite 2-hydroxyglutarate, as well as mutations in the histone 3 variant 3 gene (H3F3A) and loss-of-function mutations in the histone 3 lysine 36 trimethyltransferase gene (SETD2). Mutations in H3F3A result in amino acid substitutions at residues thought to directly (K27M) or indirectly (G34R/V) affect histone post-translational modifications, suggesting they have the capacity to affect the epigenome in a profound manner. Here, we review recent genomic studies, and discuss evidence supporting the molecular characterization of pediatric HGAs to complement traditional approaches, such as histology of resected tumors. We also describe newly identified molecular mechanisms and discuss putative therapeutic approaches for HGAs specific to pediatrics, highlighting the necessity for the evolution of HGA disease management approaches.

Future of Clinical Genomics in Pediatric Oncology

The somatic genomic alterations in pediatric cancers to some extent overlap with those seen in adult cancers, but the exact distribution throughout the genome and the types and frequency of alterations differ. The ultimate goal of genomic research in children, as with adults, is translation to the clinic to achieve more accurate diagnosis, more precise risk stratification, and more effective, less toxic therapy. The genomic features of pediatric malignancies and pediatric-specific issues in clinical investigation may make translating genomic discoveries to the clinic more difficult. However, through large-scale molecular profiling of pediatric tumors, continued coordinated efforts to evaluate novel therapies in the pediatric population, thoughtful phase II and III trial design, and continued drug development, genomically based therapies will become more common in the pediatric oncology clinic in the future.

Identification of small molecule activators of BMP signaling

Bone Morphogenetic Proteins (BMPs) are morphogens that play a major role in regulating development and homeostasis. Although BMPs are used for the treatment of bone and kidney disorders, their clinical use is limited due to the supra-physiological doses required for therapeutic efficacy causing severe side effects. Because recombinant BMPs are expensive to produce, small molecule activators of BMP signaling would be a cost-effective alternative with the added benefit of being potentially more easily deliverable. Here, we report our efforts to identify small molecule activators of BMP signaling. We have developed a cell-based assay to monitor BMP signaling by stably transfecting a BMP-responsive human cervical carcinoma cell line (C33A) with a reporter construct in which the expression of luciferase is driven by a multimerized BMP-responsive element from the Id1 promoter. A BMP-responsive clone C33A-2D2 was used to screen a bioactive library containing ∼5,600 small molecules. We identified four small molecules of the family of flavonoids all of which induced luciferase activity in a dose-dependent manner and ventralized zebrafish embryos. Two of the identified compounds induced Smad1, 5 phosphorylation (P-Smad), Id1 and Id2 expression in a dose-dependent manner demonstrating that our assays identified small molecule activators of BMP signaling.

Epidemiology of primary brain tumors in childhood and adolescence in Kuwait

The relatively high frequency of primary brain tumors (PBT) observed in childhood and adolescence in Kuwait has necessitated this epidemiological study. It is based on the records of the Department of Pathology, Al-Sabah Hospital, which examined all brain tumor biopsies done in this age group in Kuwait between 1995 and 2011. During this period, 75 boys (49%) boys and 77 (51%) girls had histologically confirmed PBT. They comprised 122 children (0-14 years) and 30 adolescents (15-19 years). The boys/girls ratio was 1.03 in childhood and 0.76 in adolescence. The age-adjusted incidence rate was 11.2/ million person-years. Early childhood (0-4 years) had the peak frequency of tumors (33%), highest adjusted age-specific incidence rate (3.8/million person-years) of all tumors and the least boys/girls rates ratio (0.38) for astrocytic tumors. Low grade and high grade tumors peaked in 5-9 and 0-4 years respectively. Risk factors (hereditary syndromes or previous radio-therapy) were identified in three patients. Three (2%) tumors were congenital. High grade tumors comprised 47% of childhood and 23% of adolescence PBT. The most common tumors in childhood were astrocytoma (37%), embryonal tumors (31%), ependymoma (8%), and in adolescence astrocytoma (27%), pituitary adenoma (23%) and glioblastoma (13%). Embryonal tumors formed 44% of PBT in early childhood. Gliomas constituted 54% and 43% of all PBT, but 25% and 57% of high grade tumors in childhood and adolescence respectively. Most common tumor locations were cerebellum (47%), ventricles (19%) and cerebral lobes (17%) in childhood and pituitary (30%), cerebellum (27%) and 13% each for cerebral lobes and ventricles in adolescence. Approximately 57% of childhood and 23% of adolescence PBT were infratentorial. In conclusion, despite the high relative frequency of PBT before the age of 20 years in Kuwait, its incidence rate is apparently low. Compared with Western countries, Kuwait has a lower incidence of malignant gliomas, but a higher frequency of cerebellar and intraventricular tumors. Embryonal tumors are remarkably common in early childhood.

Frequent ATRX mutations and loss of expression in adult diffuse astrocytic tumors carrying IDH1/IDH2 and TP53 mutations

Gliomas are the most common primary brain tumors in children and adults. We recently identified frequent alterations in chromatin remodelling pathways including recurrent mutations in H3F3A and mutations in ATRX (α-thalassemia/mental-retardation-syndrome-X-linked) in pediatric and young adult glioblastoma (GBM, WHO grade IV astrocytoma). H3F3A mutations were specific to pediatric high-grade gliomas and identified in only 3.4 % of adult GBM. Using sequencing and/or immunohistochemical analyses, we investigated ATRX alterations (mutation/loss of expression) and their association with TP53 and IDH1 or IDH2 mutations in 140 adult WHO grade II, III and IV gliomas, 17 pediatric WHO grade II and III astrocytomas and 34 pilocytic astrocytomas. In adults, ATRX aberrations were detected in 33 % of grade II and 46 % of grade III gliomas, as well as in 80 % of secondary and 7 % of primary GBMs. They were absent in the 17 grade II and III astrocytomas in children, and the 34 pilocytic astrocytomas. ATRX alterations closely overlapped with mutations in IDH1/2 (p < 0.0001) and TP53 (p < 0.0001) in samples across all WHO grades. They were prevalent in astrocytomas and oligoastrocytomas, but were absent in oligodendrogliomas (p < 0.0001). No significant association of ATRX mutation/loss of expression and alternative lengthening of telomeres was identified in our cohort. In summary, our data show that ATRX alterations are frequent in adult diffuse gliomas and are specific to astrocytic tumors carrying IDH1/2 and TP53 mutations. Combined alteration of these genes may contribute to drive the neoplastic growth in a major subset of diffuse astrocytomas in adults.

Differences in molecular genetics between pediatric and adult malignant astrocytomas: age matters

The microscope - the classical tool for the investigation of cells and tissues - remains the basis for the classification of tumors throughout the body. Nowhere has this been more true than in the grading of astrocytomas. In spite of the fact that our parents warned us not to judge a book by its cover, we have continued to assume that adult and pediatric malignant gliomas that look the same, will have the same mutations, and thus respond to the same therapy. Rapid advances in molecular biology have permitted us the opportunity to go inside the cell and characterize the genetic events that underlie the true molecular heterogeneity of adult and pediatric brain tumors. In this paper, we will discuss some of the important clinical differences between pediatric and adult gliomas, with a focus on the molecular analysis of these different age groups.

Pediatric neuro-oncology: current status and future directions

Tumors of the central nervous system (CNS) are the most common solid malignancies in childhood and are the leading cause of cancer-related death in this age group. While an ongoing improvement in overall prognosis has been achieved in the last few decades, current therapeutic approaches still confer significant morbidities, especially for the very young. The traditional strategies of surgery, radiotherapy and conventional cytotoxic chemotherapy need to be further refined while newer approaches, including molecularly targeted agents, hold the promise of better responses, improved outcomes and reduced toxicities. This article discusses treatment standards, the focus of current clinical investigations and the future promise of novel, biologically based approaches for the most common pediatric CNS tumors: primitive neuroectodermal tumors including medulloblastomas, ependymomas and astrocytomas (both low-grade and high-grade glioma).