High-grade gliomas in children

Epidemiologic and histologic characteristics of CNS lesions: a 20-year experience of a tertiary center in Lebanon

Aim:

Report the epidemiologic and histologic characteristics of CNS lesions in the Lebanese population.

Methods:

We conducted a retrospective study evaluating 2025 CNS lesions diagnosed between 1998 and 2017 in the pathology laboratory of a Lebanese tertiary center.

Results:

52.2% of patients were men with a median age of 50 years. The most frequent symptoms were epilepsy (22.5%), headache (20.6%) and motor impairment (19.9%). 90.7% of tumors were primary. Lung (35.6%) and breast (16.5%) were the most frequent primaries of metastases. 46.2% of primary CNS tumors were glial, predominantly astrocytic (56.4%), and (42.5%) were nonglial, predominantly meningeal tumors (58%).

Conclusion:

Compared with Western literature, the Lebanese population is characterized by a younger age of onset of brain tumors, a lower rate of meningiomas and a higher rate of gliomas.

MicroRNA-30a suppresses self-renewal and tumorigenicity of glioma stem cells by blocking the NT5E-dependent Akt signaling pathway

Over the past decade, increasing researches have demonstrated the implication of microRNAs (miRNAs or miRs) in tumorigenicity of glioma stem cells (GSCs). The regulatory functions of miRNAs in GSCs have emerged as potential therapeutic candidates for glioma treatment. Herein, we aim to investigate the role of miR-30a in the proliferation and self-renewal of GSCs and the possible mechanism in relation to ecto-5'-nucleotidase (NT5E)-dependent Akt signaling pathway. RT-qPCR and Western blot analysis were performed to determine the expression of miR-30a and NT5E in glioma tissues and cell lines. GSCs were isolated from glioma cells and identified using flow cytometry. The relationship between miR-30a and NT5E was determined by dual-luciferase reporter gene assay. Gain- and loss-of-function experiments were performed to examine the effects of miR-30a and NT5E on sphere formation, colony formation, and proliferation of GSCs in vitro, as well as orthotopic tumor growth of GSCs in nude mice. Additionally, the Akt signaling pathway was blocked with an Akt inhibitor, LY294002, to investigate its involvement in the regulatory effect of miR30a. miR-30a was poorly expressed in glioma tissues and cell lines as well as GSCs. NT5E, highly expressed in GSCs, was identified as a target of miR-30a. In addition, miR-30a upregulation or NT5E silencing could reduce GSC sphere formation, clone formation, proliferation, and orthotopic tumor growth in nude mice. Moreover, miR-30a inhibited the activation of the Akt signaling pathway by targeting NT5E, and ultimately suppressing the self-renewal and orthotopic tumor growth of GSCs. Our results demonstrate that miR-30a targets NT5E to inhibit the Akt signaling pathway, by which could suppress the self-renewal and orthotopic tumor growth of GSCs. Those findings may provide theoretical basis of miR-30a as a therapeutic target to suppress the glioma progression.

WHO grade has no prognostic value in the pediatric high-grade glioma included in the HERBY trial

BACKGROUND

The World Health Organization (WHO) adult glioma grading system is questionable in pediatric high-grade gliomas (pHGGs), which are biologically distinct from adult HGGs. We took advantage of the neuropathological review data obtained during one of the largest prospective randomized pHGG trials, namely HERBY (NCT01390948), to address this issue in children with newly diagnosed non-brainstem HGG.

METHODS

HGG diagnosis was confirmed by pre-randomization, real-time central pathology review using WHO 2007 criteria, followed by a consensus review blinded to clinical factors and outcomes. We evaluated association between WHO 2007 grade and other clinical/radiological/biological characteristics and the prognostic value of WHO 2007 grade, midline location, and selected biomarkers (Ki-67 index/Olig2/CD34/EGFR/p53/H3F3A K27M mutation) on overall survival.

RESULTS

Real-time central neuropathological review was feasible in a multicenter study, with a mean time of 2.4 days, and led to the rejection of HGG diagnosis in 20 of 163 cases (12.3%). The different grading criteria and resulting WHO grade were not significantly associated with overall survival in the entire population (n = 118) or in midline and non-midline subgroups. H3F3A K27M mutation was significantly associated with poor outcome. No significant prognostic value was observed for grade, even after regrading H3F3A K27M-mutated midline glioma as grade IV (WHO 2016). Midline location and a high Ki-67 index (≥20%) were associated with poor outcome (P = 0.004 and P = 0.04, respectively). A 10% increase in Ki-67 index was associated with a hazard ratio of 1.53 (95% CI: 1.27-1.83; P < 0.0001).

CONCLUSION

Our findings suggest that WHO grade III versus IV has no prognostic value in pediatric HGG.

EZH2, HIF-1, and Their Inhibitors: An Overview on Pediatric Cancers

During the past decades, several discoveries have established the role of epigenetic modifications and cellular microenvironment in tumor growth and progression. One of the main representatives concerning epigenetic modification is the polycomb group (PcG). It is composed of different highly conserved epigenetic effector proteins preserving, through several post-translational modifications of histones, the silenced state of the genes implicated in a wide range of central biological events such as development, stem cell formation, and tumor progression. Proteins of the PcG can be divided in polycomb repressive complexes (PRCs): PRC1 and PRC2. In particular, enhancer of zeste homolog 2 (EZH2), the catalytic core subunit of PRC2, acts as an epigenetic silencer of many tumor suppressor genes through the trimethylation of lysine 27 on histone H3, an essential binding site for DNA methyl transferases and histone deacetylases. A growing number of data suggests that overexpression of EZH2 associates with progression and poor outcome in a large number of cancer cases. Hypoxia inducible factor (HIF) is an important transcription factor involved in modulating cellular response to the microenvironment by promoting and regulating tumor development such as angiogenesis, inflammation, metabolic reprogramming, invasion, and metastatic fate. The HIF complex is represented by different subunits (α and β) acting together and promoting the expression of vascular endothelial growth factor (VEGF), hexokinase II (HKII), receptor for advanced glycation end products (RAGE), carbonic anhydrase (CA), etc., after binding to the hypoxia-response element (HRE) binding site on the DNA. In this review, we will try to connect these two players by detailing the following: (i) the activity and influence of these two important regulators of cancer progression in particular for what concerns pediatric tumors, (ii) the possible correlation between them, and (iii) the feasibility and efficiency to contrast them using several inhibitors.

Phase II, Open-Label, Randomized, Multicenter Trial (HERBY) of Bevacizumab in Pediatric Patients With Newly Diagnosed High-Grade Glioma

Purpose Bevacizumab (BEV) is approved in more than 60 countries for use in adults with recurrent glioblastoma. We evaluated the addition of BEV to radiotherapy plus temozolomide (RT+TMZ) in pediatric patients with newly diagnosed high-grade glioma (HGG). Methods The randomized, parallel group, multicenter, open-label HERBY trial ( ClinicalTrials.gov identifier: NCT01390948) enrolled patients age ≥ 3 years to ≤ 18 years with localized, centrally neuropathology-confirmed, nonbrainstem HGG. Eligible patients were randomly assigned to receive RT + TMZ (RT: 1.8 Gy, 5 days per week, and TMZ: 75 mg/m² per day for 6 weeks; 4-week treatment break; then up to 12 × 28-day cycles of TMZ [cycle 1: 150 mg/m² per day, days 1 to 5; cycles 2 to 12: 200 mg/m² per day, days 1 to 5]) with or without BEV (10 mg/kg every 2 weeks). The primary end point was event-free survival (EFS) as assessed by a central radiology review committee that was blinded to treatment. We report findings of EFS at 12 months after the enrollment of the last patient. Results One hundred twenty-one patients were enrolled (RT+TMZ [n = 59]; BEV plus RT+TMZ [n = 62]). Central radiology review committee-assessed median EFS did not differ significantly between treatment groups (RT+TMZ, 11.8 months; 95% CI, 7.9 to 16.4 months; BEV plus RT+TMZ, 8.2 months; 95% CI, 7.8 to 12.7 months; hazard ratio, 1.44; P = .13 [stratified log-rank test]). In the overall survival analysis, the addition of BEV did not reduce the risk of death (hazard ratio, 1.23; 95% CI, 0.72 to 2.09). More patients in the BEV plus RT+TMZ group versus the RT+TMZ group experienced one or more serious adverse events (n = 35 [58%] v n = 27 [48%]), and more patients who received BEV discontinued study treatment as a result of adverse events (n = 13 [22%] v n = 3 [5%]). Conclusion Adding BEV to RT+TMZ did not improve EFS in pediatric patients with newly diagnosed HGG. Our findings were not comparable to those of previous adult trials, which highlights the importance of performing pediatric-specific studies.

Survival outcomes in pediatric recurrent high-grade glioma: results of a 20-year systematic review and meta-analysis

Recurrent pediatric high-grade glioma is a leading cause of cancer-related death in children. We report results of a systematic review and meta-analysis investigating survival outcome in pediatric patients with recurrent high-grade glioma over the last 20 years. MEDLINE/PubMed, EMBASE, Web of Science and Cochrane Review databases were searched for relevant studies reporting on survival outcomes for pediatric patients with recurrent high-grade glioma treated between 1996 and 2016. Progression-free survival (PFS) and overall survival (OS) were calculated cumulatively over all studies, by therapy subgroup, and by decade of treatment. Random effects models were used to control for heterogeneity as measured by the I² statistic. A total of 17 studies across 4 treatment strategies were included. Eleven investigated traditional chemotherapy, 1 investigated targeted therapy, 3 investigated immunotherapy, and 2 investigated radiotherapy. A total of 129 patients were included with a median age of 10.0 years. Cumulative PFS was 3.5 months (95% CI 2.1-5.0). Cumulative OS was 5.6 months (95% CI 3.9-7.3). OS was 4.0 months (95% CI 1.9-6.1) using traditional chemotherapy, 9.3 months using targeted therapies (95% CI 5.4-13), 6.9 months using immunotherapy (95% CI 2.1-12), and 14 months using reirradiation (95% CI 2.8-25). OS between 1996 and 2006 was 4.2 months (95% CI 2.1-6.2) compared to 8.5 months (95% CI 5.6-11) after 2006. Pediatric patients with recurrent high-grade glioma suffer from poor PFS and OS, regardless of therapy. There may be a trend towards improved OS in the last decade.

Pediatric Basal Ganglia Region Tumors: Clinical and Radiologic Features Correlated with Histopathologic Findings

PURPOSE

To summarize the clinical and radiologic features of pediatric basal ganglia region tumors (PBGRT) in correlation with their histopathologic findings to reduce inappropriate surgery and identify tumors that can benefit from maximal safe resection.

METHODS

The records of 35 children with PBGRT treated in our hospital from December 2011 to December 2015 were analyzed retrospectively. The clinical and radiologic features of these tumors were summarized and correlated with their histopathologic diagnosis.

RESULTS

Our series included 15 astrocytomas and 11 germ cell tumors (GCTs). Basal ganglia astrocytomas were characterized by various clinical presentations and an ill-circumscribed mass with the involvement of surrounding structures on neuroimaging and mostly occurred in the first decade of life (n = 10; 66.7%). Basal ganglia GCT mostly occurred in the second decade of life (n = 8; 72.7%) with hemiparesis as the most common symptom (n = 9; 81.8%). The tumors were located predominantly in the caput of caudate nucleus (n = 8; 72.7%) with hemiatrophy as the typical sign (n = 8; 72.7%). Occasionally, other tumors also could occur in this region, including primitive neuroectodermal tumor (n = 1), atypical teratoid/rhabdoid tumor (n = 1), anaplastic ependymoma (n = 1), lymphoma (n = 1), extraventricular neurocytoma (n = 1), gangliogliomas (n = 2), oligodendroglioma (n = 1), and dysembryoplastic neuroepithelial tumor (n = 1).

CONCLUSIONS

Astrocytoma and GCT are the most common PBGRTs. Low-grade astrocytomas could benefit from maximal surgical resection, whereas GCTs merit neoadjuvant chemoradiation therapy followed by second-look surgery. We advocate routine testing of tumor markers and analysis of their clinical and radiologic features to optimize the therapeutic strategy.

Pediatric Brain Tumors: Current Knowledge and Therapeutic Opportunities

Great progress has been made in many areas of pediatric oncology. However, tumors of the central nervous system (CNS) remain a significant challenge. A recent explosion of data has led to an opportunity to understand better the molecular basis of these diseases and is already providing a foundation for the pursuit of rationally chosen therapeutics targeting relevant molecular pathways. The molecular biology of pediatric brain tumors is shifting from a singular focus on basic scientific discovery to a platform upon which insights are being translated into therapies.

Expression and Prognostic Significance of p53 in Glioma Patients: A Meta-analysis

Glioma is a brain tumor deriving from the neoplastic glial cells or neuroglia. Due to its resistance to anticancer drugs and different disease progress of individuals, patients with high-grade glioma are difficult to completely cure, leading to a poor prognosis and low overall survival. Therefore, there is an urgent need to look for prognostic and diagnostic indicators that can predict glioma grades. P53 is one of the widely studied biomarkers in human glioma. The purpose of this study was to comprehensively evaluate the significance of p53 expression in glioma grades and overall survival. We searched commonly used electronic databases to retrieve related articles of p53 expression in glioma. Overall, a total of 21 studies including 1322 glioma patients were finally screened out. We observed that the frequency of p53 immuno-positivity was higher in high-grade patients than that in low-grade category (63.8 vs. 41.6 %), and our statistic analysis indicated that p53 expression was associated with pathological grade of glioma (OR 2.93, 95 % CI 1.87-4.60, P < 0.00001). This significant correction was also found in 1-, 3- and 5-year overall survival. However, no positive relationship was found between age, sex, tumor size and p53 expression in patients with glioma. In conclusion, our results suggested that p53 immunohistochemical expression might have an effective usefulness in predicting the prognosis in patients with glioma.

Improving Care in Pediatric Neuro-oncology Patients: An Overview of the Unique Needs of Children With Brain Tumors

Brain tumors represent the most common solid tumors in childhood, accounting for almost 25% of all childhood cancer, second only to leukemia. Pediatric central nervous system tumors encompass a wide variety of diagnoses, from benign to malignant. Any brain tumor can be associated with significant morbidity, even when low grade, and mortality from pediatric central nervous system tumors is disproportionately high compared to other childhood malignancies. Management of children with central nervous system tumors requires knowledge of the unique aspects of care associated with this particular patient population, beyond general oncology care. Pediatric brain tumor patients have unique needs during treatment, as cancer survivors, and at end of life. A multidisciplinary team approach, including advanced practice nurses with a specialty in neuro-oncology, allows for better supportive care. Knowledge of the unique aspects of care for children with brain tumors, and the appropriate interventions required, allows for improved quality of life.

Pediatric glioblastoma: a single institution experience

PURPOSE

The aim of this study was to evaluate characteristics of childhood glioblastoma multiforme, effectiveness of treatment modalities, and detect factors related to outcome.

METHODS

A detailed analysis was performed on a series of 15 patients treated between 2000 and 2013, based on their clinical, radiologic, pathologic, treatment, and follow-up data.

RESULTS

Median survival time of children with glioblastoma was 13.5 months. One- and 2-year overall survival probabilities were 66.7 and 20 %, respectively. There were no significant differences in survival based on patients' gender, age, disease presentation with or without epileptic seizures, signs/symptoms of increased intracranial pressure, or tumor location. The presence of neurological deficit initially, as well as prior to radiotherapy, which was quantified by neurologic function score (NFS), had an impact on overall survival. Children with NFS 0 lived longer compared to others (p = 0.001). Survival of children that underwent gross total resection was longer than that of children that underwent subtotal resection (p = 0.030). Mean survival time of children with gross total resection was 73.5 months, compared to 13 months in children with subtotal resection. There was no significant correlation between outcome and type of radiotherapy. In four patients with gigantocellular glioblastoma, we found no evidence of a better prognosis. Two long-term survivors were recorded. Both of them underwent gross total resection and were assigned a NFS 0.

CONCLUSIONS

Gross total resection is essential for longer overall survival among pediatric patients with glioblastoma and offers a possibility for long-term survival. Severity of neurologic symptoms quantified by NFS can be considered as a potential predictor of outcome.

A pilot study of bevacizumab-based therapy in patients with newly diagnosed high-grade gliomas and diffuse intrinsic pontine gliomas

Although bevacizumab has not proven effective in adults with newly diagnosed high-grade gliomas (HGG), feasibility in newly diagnosed children with diffuse intrinsic pontine gliomas (DIPG) or HGG has not been reported in a prospective study. In a safety and feasibility study, children and young adults with newly diagnosed HGG received radiotherapy (RT) with bevacizumab (10 mg/kg: days 22, 36) and temozolomide (75-90 mg/m(2)/day for 42 days) followed by bevacizumab (10 mg/kg, days 1, 15), irinotecan (125 mg/m(2), days 1, 15) and temozolomide (150 mg/m(2)/day days 1-5). DIPG patients did not receive temozolomide. Telomerase activity, quality of life (QOL), and functional outcomes were assessed. Among 27 eligible patients (15 DIPG, 12 HGG), median age 10 years (range 3-29 years), 6 discontinued therapy for toxicity: 2 during RT (grade 4 thrombocytopenia, grade 3 hepatotoxicity) and 4 during maintenance therapy (grade 3: thrombosis, hypertension, skin ulceration, and wound dehiscence). Commonest ≥grade 3 toxicities included lymphopenia, neutropenia and leukopenia. Grade 3 hypertension occurred in 2 patients. No intracranial hemorrhages occurred. For DIPG patients, median overall survival (OS) was 10.4 months. For HGG patients, 3-year progression free survival and OS were 33 % (SE ± 14 %) and 50 % (SE ± 14 %), respectively. All 3 tested tumor samples, demonstrated histone H3.3K27M (n = 2 DIPG) or G34R (n = 1 HGG) mutations. QOL scores improved over the course of therapy. A bevacizumab-based regimen is feasible and tolerable in newly diagnosed children and young adults with HGG and DIPG.

The potential for epigenetic analysis of paediatric CNS tumours to improve diagnosis, treatment and prognosis

Tumours of central nervous system (CNS) origin are the second most prevalent group of cancers in children, yet account for the majority of childhood cancer-related deaths. Such tumours show diverse location, cell type of origin, disease course and long-term outcome, both across and within tumour types, making treatment problematic and contributing to the relatively modest progress in reducing mortality over recent decades. As technological advances begin to reveal the genetic landscape of all cancers, it is becoming increasingly clear that genetic disruption represents only one 'layer' of molecular disruption associated with disease aetiology. Obtaining a full understanding of tumour behaviour requires an understanding of the cellular and molecular pathways disrupted during tumourigenesis, particularly in relation to gene expression. The utility of such an approach has allowed stratification of cancers such as medulloblastoma into subgroups based on molecular features, with potential to refine risk prediction. Given that epigenetic disruption is a universal feature of all human cancers, it is logical to speculate that interrogating epigenetic marks may help to further define the molecular profile, and therefore the clinical trajectory, of tumours. An integrated approach to build a molecular 'signature' of individual tumours that incorporates traditional morphological and demographic information, genetic and transcriptome analysis, in addition to epigenomics (DNA methylation and non-coding RNA analysis), offers tremendous promise to (i) inform treatment approach, (ii) facilitate accurate early identification (preferably at diagnosis) of variable risk groups (both good and poor prognosis groups), and (iii) track disease progression in childhood CNS tumours.