Epidemiology, diagnosis, and optimal management of glioma in adolescents and young adults

Second-look surgery in postoperative pediatric low-grade glioma

OBJECTIVE

To review the literature on second-look surgery in pediatric low-grade gliomas (LGG) with a view to presenting both sides of the picture of re-exploration.

METHODS

Collection of material from recent literature on pediatric LGG. This was a retrospective review of these publications.

RESULTS

There are a number of publications recommending second-look surgery in selected cases, provided morbidity of the second surgery is minimum, and indeed some in which there is improvement in the neurodeficit after the second resection.

CONCLUSION

There seems a fair balance of articles recommending and dissuading the practice of second-look surgery, but in our limited experience we have found it useful in selected patients.

High Expression of KIFC1 in Glioma Correlates with Poor Prognosis

OBJECTIVE

Kinesin family member C1 (KIFC1), a non-essential kinesin-like motor protein, has been found to serve a crucial role in supernumerary centrosome clustering and the progression of several human cancer types. However, the role of KIFC1 in glioma has been rarely reported. Thus, the present study aimed to investigate the role of KIFC1 in glioma progression.

METHODS

Online bioinformatics analysis was performed to determine the association between KIFC1 expression and clinical outcomes in glioma. Immunohistochemical staining was conducted to analyze the expression levels of KIFC1 in glioma and normal brain tissues. Furthermore, KIFC1 expression was knocked in the glioma cell lines, U251 and U87MG, and the functional roles of KIFC1 in cell proliferation, invasion and migration were analyzed using cell multiplication, wound healing and Transwell invasion assays, respectively. The autophagic flux and expression levels matrix metalloproteinase-2 (MMP2) were also determined using imaging flow cytometry, western blotting and a gelation zymography assay.

RESULTS

The results revealed that KIFC1 expression levels were significantly upregulated in glioma tissues compared with normal brain tissues, and the expression levels were positively associated with tumor grade. Patients with glioma with low KIFC1 expression levels had a more favorable prognosis compared with patients with high KIFC1 expression levels. In vitro, KIFC1 knockdown not only inhibited the proliferation, migration and invasion of glioma cells, but also increased the autophagic flux and downregulated the expression levels of MMP2.

CONCLUSION

Upregulation of KIFC1 expression may promote glioma progression and KIFC1 may serve as a potential prognostic biomarker and possible therapeutic target for glioma.

Focus on current and emerging treatment options for glioma: A comprehensive review

This comprehensive review delves into the current updates and challenges associated with the management of low-grade gliomas (LGG), the predominant primary tumors in the central nervous system. With a general incidence rate of 5.81 per 100000, gliomas pose a significant global concern, necessitating advancements in treatment techniques to reduce mortality and morbidity. This review places a particular focus on immunotherapies, discussing promising agents such as Zotiraciclib and Lerapolturev. Zotiraciclib, a CDK9 inhibitor, has demonstrated efficacy in glioblastoma treatment in preclinical and clinical studies, showing its potential as a therapeutic breakthrough. Lerapolturev, a viral immunotherapy, induces inflammation in glioblastoma and displays positive outcomes in both adult and pediatric patients. Exploration of immunotherapy extends to Pembrolizumab, Nivolumab, and Entrectinib, revealing the challenges and variabilities in patient responses. Despite promising preclinical data, the monoclonal antibody Depatuxizumab has proven ineffective in glioblastoma treatment, emphasizing the critical need to understand resistance mechanisms. The review also covers the success of radiation therapy in pediatric LGG, with evolving techniques, such as proton therapy, showing potential improvements in patient quality of life. Surgical treatment is discussed in the context of achieving a balance between preserving the patient's quality of life and attaining gross total resection, with the extent of surgical resection significantly influencing the survival outcomes. In addition to advancements in cancer vaccine development, this review highlights the evolving landscape of LGG treatment, emphasizing a shift toward personalized and targeted therapies. Ongoing research is essential for refining strategies and enhancing outcomes in the management of LGG.

[11C]-methionine positron emission tomography in the evaluation of pediatric low-grade gliomas

Background

[11C]-Methionine positron emission tomography (PET; [11C]-MET-PET) is principally used for the evaluation of brain tumors in adults. Although amino acid PET tracers are more commonly used in the evaluation of pediatric brain tumors, data on [11C]-MET-PET imaging of pediatric low-grade gliomas (pLGG) is scarce. This study aimed to investigate the roles of [11C]-MET-PET in the evaluation of pLGGs.

Methods

Eighteen patients with newly diagnosed pLGG and 26 previously treated pLGG patients underwent [11C]-MET-PET met the inclusion and exclusion criteria. Tumor-to-brain uptake ratio (TBR) and metabolic tumor volumes were assessed for diagnostic performances (newly diagnosed, 15; previously treated 26), change with therapy (newly diagnosed, 9; previously treated 7), and variability among different histology (n = 12) and molecular markers (n = 7) of pLGGs.

Results

The sensitivity of [11C]-MET-PET for diagnosing pLGG, newly diagnosed, and previously treated combined was 93% for both TBRmax and TBRpeak, 76% for TBRmean, and 95% for qualitative evaluation. TBRmax showed a statistically significant reduction after treatment, while other PET parameters showed a tendency to decrease. Median TBRmax, TBRpeak, and TBRmean values were slightly higher in the BRAFV600E mutated tumors compared to the BRAF fused tumors. Median TBRmax, and TBRpeak in diffuse astrocytomas were higher compared to pilocytic astrocytomas, but median TBRmean, was slightly higher in pilocytic astrocytomas. However, formal statistical analysis was not done due to the small sample size.

Conclusions

Our study shows that [11C]-MET-PET reliably characterizes new and previously treated pLGGs. Our study also shows that quantitative parameters tend to decrease with treatment, and differences may exist between various pLGG types.

Dabrafenib plus Trametinib: A breakthrough in pediatric low-grade glioma therapy

Background and Aims

Pediatric-type low-grade gliomas (pLGGs) are the most common solid tumors in children, with v-raf murine sarcoma viral oncogene homolog B (BRAF) mutations playing a significant role in their development. Dabrafenib and trametinib are targeted therapies that are recently approved by Food and Drug Administration for pediatric patients with pLGG harboring a BRAF V600E mutation.

Body

This study emphasizes the role of Dabrafenib and Trametinib in pLGG. A multicenter Phase I/II trial demonstrated the superior efficacy of dabrafenib plus trametinib (D+T) compared to carboplatin plus vincristine (C+T), with higher overall response rates, clinical benefit rates, and longer progression-free survival. The safety profile of dabrafenib plus trametinib (D+T) was favorable, with fewer discontinuations and adverse events compared to the control group.

Conclusion

The introduction of D+T as a targeted therapy represents a significant advancement in the management of pLGG, necessitating further investigations to understand its long-term consequences and optimize patient care.

Comparative Analysis of Amino Acid Profiles in Patients with Glioblastoma and Meningioma Using Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry (LC-ESI-MS/MS)

Brain tumors account for 1% of all cancers diagnosed de novo. Due to the specificity of the anatomical area in which they grow, they can cause significant neurological disorders and lead to poor functional status and disability. Regardless of the results of biochemical markers of intracranial neoplasms, they are currently of no diagnostic significance. The aim of the study was to use LC-ESI-MS/MS in conjunction with multivariate statistical analyses to examine changes in amino acid metabolic profiles between patients with glioblastoma, meningioma, and a group of patients treated for osteoarthritis of the spine as a control group. Comparative analysis of amino acids between patients with glioblastoma, meningioma, and the control group allowed for the identification of statistically significant differences in the amino acid profile, including both exogenous and endogenous amino acids. The amino acids that showed statistically significant differences (lysine, histidine, α-aminoadipic acid, phenylalanine) were evaluated for diagnostic usefulness based on the ROC curve. The best results were obtained for phenylalanine. Classification trees were used to build a model allowing for the correct classification of patients into the study group (patients with glioblastoma multiforme) and the control group, in which cysteine turned out to be the most important amino acid in the decision-making algorithm. Our results indicate amino acids that may prove valuable, used alone or in combination, toward improving the diagnosis of patients with glioma and meningioma. To better assess the potential utility of these markers, their performance requires further validation in a larger cohort of samples.

Bridging the age gap: a review of molecularly informed treatments for glioma in adolescents and young adults

Gliomas are the most common primary central nervous system (CNS) tumors and a major cause of cancer-related mortality in children (age <15 years), adolescents and young adults (AYA, ages 15-39 years), and adults (age >39 years). Molecular pathology has helped enhance the characterization of these tumors, revealing a heterogeneous and ever more complex group of malignancies. Recent molecular analyses have led to an increased appreciation of common genomic alterations prevalent across all ages. The 2021 World Health Organization (WHO) CNS tumor classification, 5th edition (WHO CNS5) brings forward a nomenclature distinguishing "pediatric-type" and "adult-type" gliomas. The spectrum of gliomas in AYA comprises both "pediatric-like" and "adult-like" tumor entities but remains ill-defined. With fragmentation of clinical management between pediatric and adult centers, AYAs face challenges related to gaps in medical care, lower rates of enrollment in clinical trials and additional psychosocial and economic challenges. This calls for a rethinking of diagnostic and therapeutic approaches, to improve access to appropriate testing and potentially beneficial treatments to patients of all ages.

Current knowledges in pharmaconutrition: "Ketogenics" in pediatric gliomas

Brain tumors account for 20-25% of pediatric cancers. The most frequent type of brain tumor is Glioma from grade I to grade IV according to the rate of malignancy. Current treatments for gliomas use chemotherapy, radiotherapy, tyrosine kinase inhibitors, monoclonal antibodies and surgery, but each of the treatment strategies has several serious side effects. Therefore, to improve treatment efficacy, it is necessary to tailor therapies to patient and tumor characteristics, using appropriate molecular targets. An increasingly popular strategy is pharmaconutrition, which combines a tailored pharmacological treatment with a diet designed to synergize the effects of drugs. In this review we deal in the molecular mechanisms, the epigenetic effects and modulation of the oxidative stress pathway of ketogenic diets, that underlie its possible role, in the treatment of infantile gliomas, as a complementary approach to conventional cancer therapy.

Adolescents and Young Adults with Primary Brain Tumor: Description of the Care Pathway of Patients Diagnosed in Grenoble Between 2013 and 2019

Purpose: This study was undertaken to describe the Adolescents and Young Adults' (AYA-aged patients') neuro-oncology care pathways at Grenoble Alpes University Hospital according to the French health recommendations. Methods: A retrospective monocentric observational study was conducted between 2020 and 2021, on patients 13-29 years of age, diagnosed from January 2013 to 2019 in our institute with a primary brain tumor, excluding meningiomas, schwannomas, and neurinomas. The detailed analysis took into account the type of care unit (adult or pediatric), whether or not a dedicated AYA support team was involved, and various pretherapeutic actions. Results: Sixty patients were included in this study. Three of the 9 key stages of the care process were completed regardless of the type of management. Management in a pediatric oncology department seems to improve multidisciplinary discussions and access to the AYA team. Collaboration with an AYA team seems to improve the recourse to pediatric advice and supportive care. Conclusions: Increased vigilance at all key steps as defined in the recommendations of the Directorate General of Healthcare Services would significantly improve the overall quality of care for this specific population. In the absence of a dedicated AYA hospitalization unit, interdisciplinary cooperation between the different professionals of the adult and pediatric services is essential, and the involvement of the AYA mobile team is a factor that favors links and exchanges and ultimately an overall improvement in patient care and life. We propose our vision of an ideal AYA neuro-oncology care pathway.

Identification and validation of a novel HOX-related classifier signature for predicting prognosis and immune microenvironment in pediatric gliomas

Background: Pediatric gliomas (PGs) are highly aggressive and predominantly occur in young children. In pediatric gliomas, abnormal expression of Homeobox (HOX) family genes (HFGs) has been observed and is associated with the development and progression of the disease. Studies have found that overexpression or underexpression of certain HOX genes is linked to the occurrence and prognosis of gliomas. This aberrant expression may contribute to the dysregulation of important pathological processes such as cell proliferation, differentiation, and metastasis. This study aimed to propose a novel HOX-related signature to predict patients' prognosis and immune infiltrate characteristics in PGs. Methods: The data of PGs obtained from publicly available databases were utilized to reveal the relationship among abnormal expression of HOX family genes (HFGs), prognosis, tumor immune infiltration, clinical features, and genomic features in PGs. The HFGs were utilized to identify heterogeneous subtypes using consensus clustering. Then random forest-supervised classification algorithm and nearest shrunken centroid algorithm were performed to develop a prognostic signature in the training set. Finally, the signature was validated in an internal testing set and an external independent cohort. Results: Firstly, we identified HFGs significantly differentially expressed in PGs compared to normal tissues. The individuals with PGs were then divided into two heterogeneous subtypes (HOX-SI and HOX-SII) based on HFGs expression profiles. HOX-SII showed higher total mutation counts, lower immune infiltration, and worse prognosis than HOX-SI. Then, we constructed a HOX-related gene signature (including HOXA6, HOXC4, HOXC5, HOXC6, and HOXA-AS3) based on the cluster for subtype prediction utilizing random forest supervised classification and nearest shrunken centroid algorithm. The signature was revealed to be an independent prognostic factor for patients with PGs by multivariable Cox regression analysis. Conclusion: Our study provides a novel method for the prognosis classification of PGs. The findings also suggest that the HOX-related signature is a new biomarker for the diagnosis and prognosis of patients with PGs, allowing for more accurate survival prediction.

Personality Changes and Staring Spells in a 12-Year-Old Child: A Case Report Incorporating ChatGPT, a Natural Language Processing Tool Driven by Artificial Intelligence (AI)

Low grade gliomas (LGGs) are the most common type of brain tumors diagnosed in children. The presentation of intracranial tumors in pediatric patients is varied and diverse. The early identification and treatment of LGGs are important to achieve favorable outcomes. Although personality changes can be a symptom of intracranial tumors, they are rarely the only main presenting feature. In addition to central nervous system (CNS) tumors, personality changes can be associated with psychological and endocrine conditions, contributing to a broad differential diagnosis. Because symptoms such as personality changes have the potential to be missed, communication between family members and clinicians is imperative to identify these symptoms early. We report the case of a 12-year-old child who presented with personality changes as her main symptom and was found to have an intracranial neoplasm. This case report integrates original author writing with output from ChatGPT, a natural language processing tool driven by artificial intelligence (AI). In addition to the case itself, this report will explore the benefits and drawbacks of using natural language AI in this context.

Single-cell RNA sequencing reveals immunosuppressive myeloid cell diversity during malignant progression in a murine model of glioma

Recent studies have shown the importance of the dynamic tumor microenvironment (TME) in high-grade gliomas (HGGs). In particular, myeloid cells are known to mediate immunosuppression in glioma; however, it is still unclear if myeloid cells play a role in low-grade glioma (LGG) malignant progression. Here, we investigate the cellular heterogeneity of the TME using single-cell RNA sequencing in a murine glioma model that recapitulates the malignant progression of LGG to HGG. LGGs show increased infiltrating CD4⁺ and CD8⁺ T cells and natural killer (NK) cells in the TME, whereas HGGs abrogate this infiltration. Our study identifies distinct macrophage clusters in the TME that show an immune-activated phenotype in LGG but then evolve to an immunosuppressive state in HGG. We identify CD74 and macrophage migration inhibition factor (MIF) as potential targets for these distinct macrophage populations. Targeting these intra-tumoral macrophages in the LGG stage may attenuate their immunosuppressive properties and impair malignant progression.

Myeloid cell subpopulations compensate each other for Ccr2-deficiency in glioblastoma

AIMS

Glioblastomas are high-grade brain tumours that are characterised by the accumulation of brain-resident microglia and peripheral macrophages. Recruitment of these myeloid cells can be facilitated by CCR2/CCL2 signalling. Besides the well-known CCR2⁺ macrophages, we have identified microglia expressing CCR2 in glioma tissues. Thus, we investigated how Ccr2-deficiency of one of the myeloid cell populations affects the other population and tumour biology.

METHODS

We generated four chimeric groups to analyse single and combined Ccr2-deficiency of microglia and macrophages. On day 21 after tumour cell implantation (GL261), we conducted flow cytometry, immunofluorescence and real-time polymerase chain reaction analyses. Tumour volume and metabolism were determined by magnetic resonance imaging and magnetic resonance spectroscopy. Moreover, in vitro studies were performed with primary microglia and bone marrow-derived macrophages.

RESULTS

We demonstrated reduced infiltration of macrophages and microglia depending on the lack of Ccr2. However, the total number of myeloid cells remained constant except for the animals with dual Ccr2-knockout. Both microglia and macrophages with Ccr2-deficiency showed impaired expression of proinflammatory molecules and altered phagocytic activity. Despite the altered immunologic phenotype caused by Ccr2-deficiency, glioma progression and metabolism were hardly affected. Alterations were detected solely in apoptosis and proliferation of tumours from animals with specific Ccr2-deficient microglia, whereas vessel stability was increased in mice with Ccr2-knockout in both cell populations.

CONCLUSION

These results indicate that microglia and macrophages provide a homoeostatic balance within glioma tissue and compensate for the lack of the corresponding counterpart. Moreover, we identified that the CCR2/CCL2 axis is involved in the immunologic function of microglia and macrophages beyond its relevance for migration.

Integrative analyses reveal prognostic and immunogenic characteristics of m7G methylation regulators in patients with glioma

OBJECTIVES

The expression profiles, biological mechanisms, and clinical relevance of m7G regulators in glioma were studied in this research.

METHODS

Based on the Chinese Glioma Genome Atlas (CGGA) and The Cancer Genome Atlas (TCGA) datasets, glioma patients, can be categorized into three groups according to 29 m7G regulators, and different subtypes of glioma show different immune cell infiltration characteristics, function enrichment, and clinical prognosis. Three gene clusters were confirmed by utilizing the differentially expressed genes (DEGs) across the three m7G clusters.

RESULTS

A prognostic signature based on 12 m7G regulators was established and validated, producing an effective tool for predicting overall survival (OS) in glioma patients. High m7G scores indicated elevated tumor mutation burden and activation of immunity, suggesting an inflamed tumor microenvironment phenotype with poor overall survival. Low m7G scores characterized by a lack of immune infiltration and low mutation burden indicated a non-inflamed phenotype with a favorable clinical prognosis. It was also found that the m7G risk scores can affect chemotherapy sensitivity and prognosis of patients who received immunotherapy. The hub gene EIF4E1B of m7G regulators can inhibit the in vitro progression of glioma cells by regulating PD-L1 expression through p53 signaling pathway-related inactivation.

CONCLUSIONS

The m7G prognostic signature can be a biomarker of the overall survival of patients with glioma. An initial in-vitro experiment suggested the potential biological mechanisms of immune regulation, with m7G regulators affecting glioma progression by modulating immune responses. The present research provides a better understanding of how m7G regulators function in glioma progression as well as the impact on clinical outcomes, which can provide new insights that might be beneficial for precision therapy of glioma.

BRAF-mediated brain tumors in adults and children: A review and the Australian and New Zealand experience

The mitogen-activated protein kinase (MAPK) pathway signaling pathway is one of the most commonly mutated pathways in human cancers. In particular, BRAF alterations result in constitutive activation of the rapidly accelerating fibrosarcoma-extracellular signal-regulated kinase-MAPK significant pathway, leading to cellular proliferation, survival, and dedifferentiation. The role of BRAF mutations in oncogenesis and tumorigenesis has spurred the development of targeted agents, which have been successful in treating many adult cancers. Despite advances in other cancer types, the morbidity and survival outcomes of patients with glioma have remained relatively stagnant. Recently, there has been recognition that MAPK dysregulation is almost universally present in paediatric and adult gliomas. These findings, accompanying broad molecular characterization of gliomas, has aided prognostication and offered opportunities for clinical trials testing targeted agents. The use of targeted therapies in this disease represents a paradigm shift, although the biochemical complexities has resulted in unexpected challenges in the development of effective BRAF inhibitors. Despite these challenges, there are promising data to support the use of BRAF inhibitors alone and in combination with MEK inhibitors for patients with both low-grade and high-grade glioma across age groups. Safety and efficacy data demonstrate that many of the toxicities of these targeted agents are tolerable while offering objective responses. Newer clinical trials will examine the use of these therapies in the upfront setting. Appropriate duration of therapy and durability of response remains unclear in the glioma patient cohort. Longitudinal efficacy and toxicity data are needed. Furthermore, access to these medications remains challenging outside of clinical trials in Australia and New Zealand. Compassionate access is limited, and advocacy for mechanism of action-based drug approval is ongoing.

Network pharmacological analysis of active components of Xiaoliu decoction in the treatment of glioblastoma multiforme

Background: Glioblastoma multiforme (GBM) is the most aggressive primary nervous system brain tumor. There is still a lack of effective methods to control its progression and recurrence in clinical treatment. It is clinically found that Xiaoliu Decoction (XLD) has the effect of treating brain tumors and preventing tumor recurrence. However, its mechanism is still unclear.

Methods: Search the Traditional Chinese Medicine System Pharmacology Database (TCSMP) for efficient substances for the treatment of XLD in the treatment of GBM, and target the targeted genes of the effective ingredients to construct a network. At the same time, download GBM-related gene expression data from the TCGA and GTEX databases, screen differential expression bases, and establish a drug target disease network. Through bioinformatics analysis, the target genes and shared genes of the selected Chinese medicines are analyzed. Finally, molecular docking was performed to further clarify the possibility of XLD in multiple GBMs.

Results: We screened 894 differentially expressed genes in GBM, 230 XLD active ingredients and 169 predicted targets of its active compounds, of which 19 target genes are related to the differential expression of GBM. Bioinformatics analysis shows that these targets are closely related to cell proliferation, cell cycle regulation, and DNA synthesis. Finally, through molecular docking, it was further confirmed that Tanshinone IIA, the active ingredient of XLD, was tightly bound to key proteins.

Conclusion: To sum up, the results of this study suggest that the mechanism of XLD in the treatment of GBM involves multiple targets and signal pathways related to tumorigenesis and development. This study not only provides a new theoretical basis for the treatment of glioblastoma multiforme with traditional Chinese medicine, but also provides a new idea for the research and development of targeted drugs for the treatment of glioblastoma multiforme.

Safety tumor treating fields (TTFields) therapy in pediatric patients with malignant brain tumors: Post-marketing surveillance data

There is an unmet need to develop effective and tolerable treatments for pediatric patients with malignant central nervous system tumors. This is especially essential for pediatric patients with aggressive brain tumors such as high-grade gliomas, which have a typical survival rate of under 2 years. Tumor Treating Fields (TTFields) are locoregional, noninvasive electric fields that produce an antimitotic effect on cancerous cells when applied to the skin via arrays. TTFields therapy (200 kHz) is currently approved in adult patients with newly diagnosed glioblastoma (GBM), with temozolomide, and recurrent GBM as monotherapy. Positive preclinical and clinical data have encouraged off-label use of TTFields therapy in pediatric patients with brain tumors, and this study aims to explore the safety of TTFields therapy in pediatric patients (0–18 years of age) based on data from an unsolicited post-marketing surveillance safety database. The real-world data reported here demonstrate that TTFields therapy has a favorable safety profile for pediatric patients with brain tumors, with no new safety signals observed. Findings from this study warrant further research into the efficacy of TTFields therapy, as well as its potential impact on the quality of life in pediatric patients.

Molecular Genetics and Targeted Therapies for Paediatric High-grade Glioma

Brain tumours are the leading cause of paediatric cancer-associated death worldwide. High-grade glioma (HGG) represents a main cause of paediatric brain tumours and is associated with poor prognosis despite surgical and chemoradiotherapeutic advances. The molecular genetics of paediatric HGG (pHGG) are distinct from those in adults, and therefore, adult clinical trial data cannot be extrapolated to children. Compared to adult HGG, pHGG is characterised by more frequent mutations in PDGFRA, TP53 and recurrent K27M and G34R/V mutations on histone H3. Ongoing trials are investigating novel targeted therapies in pHGG. Promising results have been achieved with BRAF/MEK and PI3K/mTOR inhibitors. Combination of PI3K/mTOR, EGFR, CDK4/6, and HDAC inhibitors are potentially viable options. Inhibitors targeting the UPS proteosome, ADAM10/17, IDO, and XPO1 are more novel and are being investigated in early-phase trials. Despite preclinical and clinical trials holding promise for the discovery of effective pHGG treatments, several issues persist. Inadequate blood-brain barrier penetration, unfavourable pharmacokinetics, dose-limiting toxicities, long-term adverse effects in the developing child, and short-lived duration of response due to relapse and resistance highlight the need for further improvement. Future pHGG management will largely depend on selecting combination therapies which work synergistically based on a sound knowledge of the underlying molecular target pathways. A systematic investigation of multimodal therapy with chemoradiotherapy, surgery, target agents and immunotherapy is paramount. This review provides a comprehensive overview of pHGG focusing on molecular genetics and novel targeted therapies. The diagnostics, genetic discrepancies with adults and their clinical implications, as well as conventional treatment approaches are discussed.

The Clinical Applications of Liquid Biopsies in Pediatric Brain Tumors: A Systematic Literature Review

Simple Summary

Brain tumors are the most common solid cancer in children and are traditionally diagnosed via a tissue biopsy or resection. Liquid biopsy offers the possibility to characterize brain tumors based on their circulating DNA in blood, cerebrospinal fluid or even urine. Moreover, disease progress can be monitored accurately and sometimes even detected before radiographic progression. More trials are needed to standardize the use of liquid biopsy in pediatric brain tumors.

Abstract

Background: Pediatric brain tumors are the most common solid tumor in children. Traditionally, tumor diagnosis and molecular analysis were carried out on tumor tissue harvested either via biopsy or resection. However, liquid biopsy allows analysis of circulating tumor DNA in corporeal fluids such as cerebrospinal fluid or blood. Methods: We performed a systematic review in Pubmed and Embase regarding the role of liquid biopsy in pediatric brain tumors. Results: Nine studies with a total of 570 patients were included. The preferred corporeal fluid for analysis with a relatively high yield of ct-DNA was cerebrospinal fluid (CSF). For high-grade glioma, liquid biopsy can successfully characterize H3K27mutations and predict tumor progression before it is radiographically detected. Moreover, liquid biopsy has the potential to distinguish between pseudo-progression and actual progression. In medulloblastoma, ct-DNA in the CSF can be used as a surrogate marker of measurable residual disease and correlates with response to therapy and progression of the tumor up to three months before radiographic detection. Conclusion: Liquid biopsy is primarily useful in high-grade pediatric brain tumors such as diffuse midline glioma or medulloblastoma. Disease detection and monitoring is feasible for both tumor entities. More trials to standardize its use for pediatric brain tumors are necessary.

The epigenetic-metabolic interplay in gliomagenesis

Although tumourigenesis occurs due to genetic mutations, the role of epigenetic dysregulations in cancer is also well established. Epigenetic dysregulations in cancer may occur as a result of mutations in genes encoding histone/DNA-modifying enzymes and chromatin remodellers or mutations in histone protein itself. It is also true that misregulated gene expression without genetic mutations in these factors could also support tumour initiation and progression. Interestingly, metabolic rewiring has emerged as a hallmark of cancer due to gene mutations in specific metabolic enzymes or dietary/environmental factors. Recent studies report an intricate cross-talk between epigenetic and metabolic reprogramming in cancer. This review discusses the role of epigenetic and metabolic dysregulations and their cross-talk in tumourigenesis with a special focus on gliomagenesis. We also discuss the role of recently developed human embryonic stem cells/induced pluripotent stem cells-derived organoid models of gliomas and how these models are proving instrumental in uncovering human-specific cellular and molecular complexities of gliomagenesis.

Fluorescent diagnostics with chlorin e6 in surgery of low-grade glioma

Intraoperative fluorescence diagnostics of high-grade gliomas is widely used in neurosurgical practice. This work analyzes the possibilities of fluorescence diagnostics for low-grade gliomas (LGG) using chlorin e6 photosensitizer. The study included patients with newly diagnosed LGG, for whom chlorin e6 was used for intraoperative fluorescence control at a dose of 1 mg/kg. During the operation, the fluorescence intensity of various areas of the putative tumor tissue was analyzed using the RSS Cam – Endo 1.4.313 software. Tissue samples with various degrees of fluorescence intensity were compared with the results of their histopathological analysis (WHO tumor diagnosis, Ki-67 index, P53, VEGF). Fluorescence was detected in more than half of the cases, but in most cases had a focal character and low fluorescence intensity. The fluorescence intensity directly correlated with the data of histopathological examination of tumor tissues (Ki-67 index (p=0.002), expression of P53 (p=0.0015) and VEGF (p=0.001)). The sensitivity of the method for LGG surgery was 72%, the specificity was 56,7%. Intraoperative fluorescence diagnostics with chlorin e6 can be used in LGG surgery, especially to visualize intratumoral areas with a higher degree of anaplasia.

Nimotuzumab as Additional Therapy for GLIOMA in Pediatric and Adolescent: A Systematic Review

INTRODUCTION

Pediatric gliomas represent the most common brain tumor in children and its higher grades are associated with higher recurrence and low survival rate. All therapeutic modalities are reported to be insufficient to achieve satisfactory result, with follow-up treatment such as adjuvant radiotherapy and chemotherapy recommended to increase survival and hinder tumor progression. Nimotuzumab is a monoclonal antibody that acts as an inhibitor of epidermal growth factor receptor found on the surface of glioma cells and had been studied for its usage in pediatric gliomas in recent years.

METHODS

A systematic review is performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. A through literature search was conducted on PubMed, Scopus, Cochrane, and clinicaltrials.gov database. Articles were selected systematically based on the PRISMA protocol and reviewed completely. The relevant data were summarized and discussed. We measured overall survival, progression-free survival, and adverse Events (AE) for nimotuzumab usage as an adjunct therapy in pediatric glioma population.

RESULT

From 5 studies included for qualitative analysis, 151 patients are included with overall survival (OS) that vary from 3.2-22.8 mo, progression-free survival (PFS) from 1.7-21.6 mo, and relatively low serious adverse events (0-21) are recorded. Follow-up ranged from 2.4-66 mo with four studies reporting diffuse intrinsic pontine glioma (DIPG) patients and only one study reporting nimotuzumab usage in pediatric high-grade glioma (HGG) patients with better outcome in HGG patients than DIPG.

CONCLUSION

There are no significant differences in the PFS and OS of nimotuzumab as adjunct therapy for pediatric compared to result of standard therapy in majority of previous studies. There were also no differences in the AE of nimotuzumab for pediatric glioma between studies, and low event of serious adverse events indicating its safety. But still there is an evidence of possible benefit of nimotuzumab as adjuvant therapy in pediatric glioma. We recommend further studies with larger number of patients that may lead to possibly different results. There should also be more studies with better level of evidence to further validate the effect of nimozutumab on pediatric glioma.

MIR17HG: A Cancerogenic Long-Noncoding RNA in Different Cancers

LncRNA MIR17HG, located at chromosome 13q31, plays an inevitable role in promoting tumor progressions, such as tumorigenesis, proliferation, and metastasis. Besides, lncRNA MIR17HG is rare due to its open reading frame (ORF), which can be translated to produce protein. By systematically retrieval, we summarized that MIR17HG is an emerging lncRNA that exhibits carcinogenically in osteosarcoma (OS), glioma, cervical squamous cell carcinoma (CSCC), colorectal cancer (CRC), gastric cancer (GC), atypical teratoid rhabdoid tumors (ATRT). Furthermore, a high expression level of MIR17HG protein is also linked with meningioma. Additionally, MIR17HG polymorphisms in glioma, CRC, liver cancer (LC), breast cancer (BC), head and neck squamous cell carcinoma (HNSCC), and multiple myeloma (MM) also have a large influence on cancer susceptibility, prognosis, and so on. Collectively, long non-coding RNA MIR17HG's tumor-stimulative role could be a promising therapeutic target. Besides, by investigating patients' MIR17HG single-nucleotide polymorphisms (SNPs), clinicians could also personalize the productive interventions in gene therapy or predict the diagnosis/prognosis precisely.

Adolescent and young adult glioma: systematic review of demographic, disease, and treatment influences on survival

BACKGROUND

Prognostic factors in adolescent and young adult (AYA) glioma are not well understood. Though clinical and molecular differences between pediatric and adult glioma have been characterized, their application to AYA populations is less clear. There is a major need to develop more robust evidence-based practices for managing AYA glioma patients.

METHODS

A systematic review using PRISMA methodology was conducted using multiple databases with the objective of identifying demographic, clinical, molecular and treatment factors influencing AYA glioma outcomes.

RESULTS

40 Studies met inclusion criteria. Overall survival was highly variable across studies depending on glioma grade, anatomic compartment and cohort characteristics. Thirty-five studies suffered from high risk of bias in at least one domain. Several studies included older adults within their cohorts; few captured purely AYA groups. Despite study heterogeneity, identified favorable prognosticators included younger age, higher functional status at diagnosis, low-grade pathology, oligodendroglioma histology and increased extent of surgical resection. Though isocitrate dehydrogenase (IDH) mutant status was associated with favorable prognosis, validity of this finding within AYA was compromised though may studies including older adults. The prognostic influence of chemotherapy and radiotherapy on overall survival varied across studies with conflicting evidence.

CONCLUSION

Existing literature is heterogenous, at high risk of bias, and rarely focused solely on AYA patients. Many included studies did not reflect updated pathological and molecular AYA glioma classification. The optimal role of chemotherapy, radiotherapy, and targeted agents cannot be determined from existing literature and should be the focus of future studies.

Pediatric and Adult Low-Grade Gliomas: Where Do the Differences Lie?

Two thirds of pediatric gliomas are classified as low-grade (LGG), while in adults only around 20% of gliomas are low-grade. However, these tumors do not only differ in their incidence but also in their location, behavior and, subsequently, treatment. Pediatric LGG constitute 65% of pilocytic astrocytomas, while in adults the most commonly found histology is diffuse low-grade glioma (WHO II), which mostly occurs in eloquent regions of the brain, while its pediatric counterpart is frequently found in the infratentorial compartment. The different tumor locations require different skillsets from neurosurgeons. In adult LGG, a common practice is awake surgery, which is rarely performed on children. On the other hand, pediatric neurosurgeons are more commonly confronted with infratentorial tumors causing hydrocephalus, which more often require endoscopic or shunt procedures to restore the cerebrospinal fluid flow. In adult and pediatric LGG surgery, gross total excision is the primary treatment strategy. Only tumor recurrences or progression warrant adjuvant therapy with either chemo- or radiotherapy. In pediatric LGG, MEK inhibitors have shown promising initial results in treating recurrent LGG and several ongoing trials are investigating their role and safety. Moreover, predisposition syndromes, such as neurofibromatosis or tuberous sclerosis complex, can increase the risk of developing LGG in children, while in adults, usually no tumor growth in these syndromes is observed. In this review, we discuss and compare the differences between pediatric and adult LGG, emphasizing that pediatric LGG should not be approached and managed in the same way as adult LCG.

Malignant Tumor Purity Reveals the Driven and Prognostic Role of CD3E in Low-Grade Glioma Microenvironment

The tumor microenvironment (TME) contributes to the initiation and progression of many neoplasms. However, the impact of low-grade glioma (LGG) purity on carcinogenesis remains to be elucidated. We selected 509 LGG patients with available genomic and clinical information from the TCGA database. The percentage of tumor infiltrating immune cells and the tumor purity of LGG were evaluated using the ESTIMATE and CIBERSORT algorithms. Stromal-related genes were screened through Cox regression, and protein-protein interaction analyses and survival-related genes were selected in 487 LGG patients from GEO database. Hub genes involved in LGG purity were then identified and functionally annotated using bioinformatics analyses. Prognostic implications were validated in 100 patients from an Asian real-world cohort. Elevated tumor purity burden, immune scores, and stromal scores were significantly associated with poor outcomes and increased grade in LGG patients from the TCGA cohort. In addition, CD3E was selected with the most significant prognostic value (Hazard Ratio=1.552, P<0.001). Differentially expressed genes screened according to CD3E expression were mainly involved in stromal related activities. Additionally, significantly increased CD3E expression was found in 100 LGG samples from the validation cohort compared with adjacent normal brain tissues. High CD3E expression could serve as an independent prognostic indicator for survival of LGG patients and promotes malignant cellular biological behaviors of LGG. In conclusion, tumor purity has a considerable impact on the clinical, genomic, and biological status of LGG. CD3E, the gene for novel membrane immune biomarker deeply affecting tumor purity, may help to evaluate the prognosis and develop individual immunotherapy strategies for LGG patients. Evaluating the ratio of differential tumor purity and CD3E expression levels may provide novel insights into the complex structure of the LGG microenvironment and targeted drug development.

Dysregulated Alanine as a Potential Predictive Marker of Glioma-An Insight from Untargeted HRMAS-NMR and Machine Learning Data

Metabolic alterations play a crucial role in glioma development and progression and can be detected even before the appearance of the fatal phenotype. We have compared the circulating metabolic fingerprints of glioma patients versus healthy controls, for the first time, in a quest to identify a panel of small, dysregulated metabolites with potential to serve as a predictive and/or diagnostic marker in the clinical settings. High-resolution magic angle spinning nuclear magnetic resonance spectroscopy (HRMAS-NMR) was used for untargeted metabolomics and data acquisition followed by a machine learning (ML) approach for the analyses of large metabolic datasets. Cross-validation of ML predicted NMR spectral features was done by statistical methods (Wilcoxon-test) using JMP-pro16 software. Alanine was identified as the most critical metabolite with potential to detect glioma with precision of 1.0, recall of 0.96, and F1 measure of 0.98. The top 10 metabolites identified for glioma detection included alanine, glutamine, valine, methionine, N-acetylaspartate (NAA), γ-aminobutyric acid (GABA), serine, α-glucose, lactate, and arginine. We achieved 100% accuracy for the detection of glioma using ML algorithms, extra tree classifier, and random forest, and 98% accuracy with logistic regression. Classification of glioma in low and high grades was done with 86% accuracy using logistic regression model, and with 83% and 79% accuracy using extra tree classifier and random forest, respectively. The predictive accuracy of our ML model is superior to any of the previously reported algorithms, used in tissue- or liquid biopsy-based metabolic studies. The identified top metabolites can be targeted to develop early diagnostic methods as well as to plan personalized treatment strategies.

5-ALA in Suspected Low-Grade Gliomas: Current Role, Limitations, and New Approaches

Radiologically suspected low-grade gliomas (LGG) represent a special challenge for the neurosurgeon during surgery due to their histopathological heterogeneity and indefinite tumor margin. Therefore, new techniques are required to overcome these current surgical drawbacks. Intraoperative visualization of brain tumors with assistance of 5-aminolevulinic acid (5-ALA) induced protoporphyrin IX (PpIX) fluorescence is one of the major advancements in the neurosurgical field in the last decades. Initially, this technique was exclusively applied for fluorescence-guided surgery of high-grade glioma (HGG). In the last years, the use of 5-ALA was also extended to other indications such as radiologically suspected LGG. Here, we discuss the current role of 5-ALA for intraoperative visualization of focal malignant transformation within suspected LGG. Furthermore, we discuss the current limitations of the 5-ALA technology in pure LGG which usually cannot be visualized by visible fluorescence. Finally, we introduce new approaches based on fluorescence technology for improved detection of pure LGG tissue such as spectroscopic PpIX quantification fluorescence lifetime imaging of PpIX and confocal microscopy to optimize surgery.

Correlation between Stage and Histopathological Features and Clinical Outcomes in Patients with Glioma Tumors

BACKGROUND: Brain tumor incidence continues to increase during the last decade in several countries. Determining the response of intracranial tumors to treatment remains a major challenge in the field of neuro-oncology. Karnofsky Performance Status Scale (KPS) is a widely used method for assessing the functional status of a patient. AIM: This study aims to determine the relationship between stadium and histopathological features with clinical outcomes in patients with glioma tumors. METHODS: This was an observational analytic study with a retrospective approach at the H. Adam Malik General Hospital in Medan from September 2019 to September 2020. The study population was glioma patients. The research sample was 36 subjects taken consecutively. The independent variables of the study were stage and histopathological features, while the dependent variable of the study was KPS. Statistical analysis with Gamma test. RESULTS: Mean age was 38.11 ± 13.86 years. Most subjects were male, amounting to 20 subjects (55.6%). The most common type of glioma tumor was anaplastic astrocytoma, amounting to 8 subjects (22.2%). The highest tumor stage was a high-grade glioma, amounting to 19 subjects (52.8%), and the most histopathological features based on WHO criteria were WHO grade 3, totaling 13 subjects (36.1%). Most KPS is 80–100 with 19 subjects (52.8%). There is a significant correlation between the stage and histopathological features with KPS with a moderate correlation strength (p = 0.036; r = 0.598) (p = 0.024; r = 0.508) CONCLUSION: There is a significant correlation between stage and histopathological features with KPS with moderate correlation strength

LncRNA GAS8-AS1 downregulates lncRNA NEAT1 to inhibit glioblastoma cell proliferation

BACKGROUND

LncRNA GAS8-AS1 has been reported to participate in several types of cancer, while its role in glioblastoma (GBM) is unknown. In the present study, we aimed to investigate the function of GAS8-AS1 in GBM and the underlying mechanisms.

METHODS

The expression levels of GAS8-AS1 and NEAT1 in GBM patients and the healthy controls were measured by performing RT-qPCR. Diagnostic values of plasma GAS8-AS1 and NEAT1 for GBM were analyzed by performing ROC curve analysis with GBM patients as true positive cases and the healthy controls as true negative cases. Linear regression analysis was performed to study the correlation between the expression levels of GAS8-AS1 and NEAT1. The expression levels of GAS8-AS1 and NEAT1 in GBM cells were also determined by RT-qPCR. CCK-8 and transwell invasion assays were performed to detect the proliferation and invasion of GBM cells. Western blot assay was performed to detect the expression levels of β-catenin, Axin2, c-myc, cyclin D1, and GAPDH in GBM cells.

RESULTS

GAS8-AS1 was downregulated, while lncRNA NEAT1 was upregulated in the plasma of GBM patients. Altered expression levels of GAS8-AS1 and NEAT1 distinguished GBM patients from the healthy controls. The expression of GAS8-AS1 and NEAT1 was inversely correlated only in GBM patients. Overexpression of GAS8-AS1 reduced the expression levels of NEAT1 in GBM cells, while knock-down of GAS8-AS1 increased the expression levels of NEAT1. However, overexpression of NEAT1 showed no significant effects on the expression of GAS8-AS1. Knock-down of GAS8-AS1 promoted GBM cell proliferation and invasion and enhanced the activation of the Wnt/β-catenin pathway. However, the effects of knock-down of GAS8-AS1 were alleviated by the knock-down of NEAT1.

CONCLUSION

Overexpression of GAS8-AS1 inhibits GBM cell proliferation and invasion by downregulating NEAT1.

Molecular biomarkers and integrated pathological diagnosis in the reclassification of gliomas

The present study aimed to evaluate the impact caused by the 2016 World Health Organization (WHO) diagnostic classification of gliomas in 139 patients studied in Argentina. Formalin-fixed paraffin-embedded tissues were used for histological and immunohistochemical analysis [glial fibrillary acidic protein, KI67, synaptophysin and isocitrate dehydrogenase (IDH)1-R132H]. DNA from formalin-fixed paraffin-embedded tissues was used for molecular analysis: 1p/19q co-deletion and mutation status of the IDH gene. These experiments were performed by direct Sanger sequencing and multiplex ligation-dependent probe amplification. According to the new classification, diagnoses included oligodendroglioma IDH-mutant and 1p/19q co-deletion (4.20%), anaplastic oligodendroglioma IDH-mutant and 1p/19q co-deletion (2.52%), diffuse astrocytoma IDH-mutant (6.72%), diffuse astrocytoma IDH-wild type (1.68%), anaplastic astrocytoma IDH-mutant (5.04%), anaplastic astrocytoma IDH-wild type (8.40%), glioblastoma IDH-mutant (5.88%) and glioblastoma IDH-wild type (65.56%). Regarding tumor histology, 60% of oligodendrogliomas, 35% of astrocytoma and 100% of unclassified gliomas were re-classified, while glioblastomas maintained their initial classification. Additionally, the present study evaluated the prognostic value of the histological grade for the 2007 and 2016 WHO classifications of gliomas. The histological subgroup associated with longer overall survival (OS) was grade II glioma (OS-2007WHO, 35.6 months; and OS-2016WHO, 47.7 months). Glioblastoma was the subgroup associated with a poor outcome (OS-2007WHO, 10.4 months; and OS-2016WHO, 11.1 months). The present study evaluated the OS of tumor grade subgroups with respect to their IDH status. For all subgroups, IDH-mutant tumors were associated with an improved prognosis compared with IDH-wild type tumors. The results suggested that the incorporation of molecular biomarkers in the new WHO classification improves tumor characterization and prognostic value of the subgroups.

Identification of collagen genes related to immune infiltration and epithelial-mesenchymal transition in glioma

Background

Gliomas account for the majority of fatal primary brain tumors, and there is much room for research in the underlying pathogenesis, the multistep progression of glioma, and how to improve survival. In our study, we aimed to identify potential biomarkers or therapeutic targets of glioma and study the mechanism underlying the tumor progression.

Methods

We downloaded the microarray datasets (GSE43378 and GSE7696) from the Gene Expression Omnibus (GEO) database. Then, we used weighted gene co-expression network analysis (WGCNA) to screen potential biomarkers or therapeutic targets related to the tumor progression. ESTIMATE (Estimation of STromal and Immune cells in MAlignant Tumors using Expression data) algorithm and TIMER (Tumor Immune Estimation Resource) database were used to analyze the correlation between the selected genes and the tumor microenvironment. Real-time reverse transcription polymerase chain reaction was used to measure the selected gene. Transwell and wound healing assays were used to measure the cell migration and invasion capacity. Western blotting was used to test the expression of epithelial-mesenchymal transition (EMT) related markers.

Results

We identified specific module genes that were positively correlated with the WHO grade but negatively correlated with OS of glioma. Importantly, we identified that 6 collagen genes (COL1A1, COL1A2, COL3A1, COL4A1, COL4A2, and COL5A2) could regulate the immunosuppressive microenvironment of glioma. Moreover, we found that these collagen genes were significantly involved in the EMT process of glioma. Finally, taking COL3A1 as a further research object, the results showed that knockdown of COL3A1 significantly inhibited the migration, invasion, and EMT process of SHG44 and A172 cells.

Conclusions

In summary, our study demonstrated that collagen genes play an important role in regulating the immunosuppressive microenvironment and EMT process of glioma and could serve as potential therapeutic targets for glioma management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-01982-0.

High-grade gliomas in adolescents and young adults highlight histomolecular differences from their adult and pediatric counterparts

BACKGROUND

Considering that pediatric high-grade gliomas (HGGs) are biologically distinct from their adult counterparts, the objective of this study was to define the landscape of HGGs in adolescents and young adults (AYAs).

METHODS

We performed a multicentric retrospective study of 112 AYAs from adult and pediatric Ile-de-France neurosurgical units, treated between 1998 and 2013 to analyze their clinicoradiological and histomolecular profiles. The inclusion criteria were age between 15 and 25 years, histopathological HGG diagnosis, available clinical data, and preoperative and follow-up MRI. MRI and tumoral samples were centrally reviewed. Immunohistochemistry and complementary molecular techniques such as targeted/next-generation sequencing, whole exome sequencing, and DNA-methylation analyses were performed to achieve an integrated diagnosis according to the 2016 World Health Organization (WHO) classification.

RESULTS

Based on 80 documented AYA patients, HGGs constitute heterogeneous clinicopathological and molecular groups, with a predominant representation of pediatric subtypes (histone H3-mutants, 40%) but also adult subtypes (isocitrate dehydrogenase [IDH] mutants, 28%) characterized by the rarity of oligodendrogliomas, IDH mutants, and 1p/19q codeletion and the relative high frequency of "rare adult IDH mutations" (20%). H3G34-mutants (14%) represent the most specific subgroup in AYAs. In the H3K27-mutant subgroup, non-brainstem diffuse midline gliomas are more frequent (66.7%) than diffuse intrinsic pontine gliomas (23.8%), contrary to what is observed in children. We found that WHO grade has no prognostic value, but molecular subgrouping has major prognostic importance.

CONCLUSIONS

HGGs in AYAs could benefit from a specific classification, driven by molecular subtyping rather than age group. Collaborative efforts are needed from pediatric and adult neuro-oncology teams to improve the management of HGGs in AYAs.

Roles of glia-derived extracellular vesicles in central nervous system diseases: an update

Extracellular vesicles (EVs) are a heterogeneous group of cell-derived membranous vesicles secreted by various cells in the extracellular space. Accumulating evidence shows that EVs regulate cell-to-cell communication and signaling in the pathological processes of various diseases by carrying proteins, lipids, and nucleic acids to recipient cells. Glia-derived EVs act as a double-edged sword in the pathogenesis of central nervous system (CNS) diseases. They may be vectors for the spread of diseases or act as effective clearance systems to protect tissues. In this review, we summarize recent studies on glia-derived EVs with a focus on their relationships with CNS diseases.

Natural polymeric nanocarriers in malignant glioma drug delivery and targeting

Among all central nervous diseases, malignant glioma is a crucial part that deserves more attention since high fatality and disability rate. There are several therapeutic strategies applied to the treatment of malignant glioma, especially certain chemotherapy-related treatments. However, the existence of the blood-brain barrier (BBB) seriously hinders the strategy's progress, so how to escape from the barriers is a fascinating question. Herein, we comprehensively discussed the details of malignant glioma and the BBB's functional morphology and summarized several routes bypassing the BBB. Additionally, since possessing excellent properties for drug delivery, we provided an insight into various promising natural polymeric materials and highlighted their applications in the treatment of malignant glioma.

A functional MRI study of presurgical cognitive deficits in glioma patients

Background

The main goal of this functional MRI (fMRI) study was to examine whether cognitive deficits in glioma patients prior to treatment are associated with abnormal brain activity in either the central executive network (CEN) or default mode network (DMN).

Methods

Forty-six glioma patients, and 23 group-matched healthy controls (HCs) participated in this fMRI experiment, performing an N-back task. Additionally, cognitive profiles of patients were evaluated outside the scanner. A region of interest–based analysis was used to compare brain activity in CEN and DMN between groups. Post hoc analyses were performed to evaluate differences between low-grade glioma (LGG) and high-grade glioma (HGG) patients.

Results

In-scanner performance was lower in glioma patients compared to HCs. Neuropsychological testing indicated cognitive impairment in LGG as well as HGG patients. fMRI results revealed normal CEN activation in glioma patients, whereas patients showed reduced DMN deactivation compared to HCs. Brain activity levels did not differ between LGG and HGG patients.

Conclusions

Our study suggests that cognitive deficits in glioma patients prior to treatment are associated with reduced responsiveness of the DMN, but not with abnormal CEN activation. These results suggest that cognitive deficits in glioma patients reflect a reduced capacity to achieve a brain state necessary for normal cognitive performance, rather than abnormal functioning of executive brain regions. Solely focusing on increases in brain activity may well be insufficient if we want to understand the underlying brain mechanism of cognitive impairments in patients, as our results indicate the importance of assessing deactivation.

Challenges and Perspectives of Standard Therapy and Drug Development in High-Grade Gliomas

Despite their low incidence rate globally, high-grade gliomas (HGG) remain a fatal primary brain tumor. The recommended therapy often is incapable of resecting the tumor entirely and exclusively targeting the tumor leads to tumor recurrence and dismal prognosis. Additionally, many HGG patients are not well suited for standard therapy and instead, subjected to a palliative approach. HGG tumors are highly infiltrative and the complex tumor microenvironment as well as high tumor heterogeneity often poses the main challenges towards the standard treatment. Therefore, a one-fit-approach may not be suitable for HGG management. Thus, a multimodal approach of standard therapy with immunotherapy, nanomedicine, repurposing of older drugs, use of phytochemicals, and precision medicine may be more advantageous than a single treatment model. This multimodal approach considers the environmental and genetic factors which could affect the patient's response to therapy, thus improving their outcome. This review discusses the current views and advances in potential HGG therapeutic approaches and, aims to bridge the existing knowledge gap that will assist in overcoming challenges in HGG.

No Association Between FTO Gene Polymorphisms and Central Nervous System Tumor Susceptibility in Chinese Children

Background

Central nervous system (CNS) tumor is a malignancy commonly seen occurring in childhood, worldwide. Fat mass and obesity-associated (FTO) enzyme, initially identified as an obesity-related protein, also functions as a susceptibility gene for cancers. However, predisposing effect of FTO gene single nucleotide polymorphisms (SNPs) on CNS tumor risk remains unknown.

Methods

Herein, we genotyped 314 CNS tumor patients and 380 healthy controls samples from three hospitals to explore whether FTO gene SNPs impact CNS tumor risk. TaqMan SNP genotyping assay was applied for the genotyping. Odds ratios (ORs) and 95% confidence intervals (CIs), generated from multinomial logistic regression, were applied to determine the associations of SNPs (rs1477196 G>A, rs9939609 T>A, rs7206790 C>G, and rs8047395 A>G) in FTO gene with risk of CNS tumor.

Results

We failed to detect significant associations between FTO gene SNPs and CNS tumor risk, either in single-locus or combined analysis. A significantly increased ependymoma risk was found for carriers with 3-4 risk genotypes in comparison to 0-2 risk genotypes (adjusted OR=1.94, 95% CI=1.11-3.37, P=0.020).

Conclusion

Our data indicated that FTO gene SNPs are unlikely to have large effects on CNS tumor risk but may have weaker effects.

Current Developments in Targeted Drug Delivery Systems for Glioma

BACKGROUND

Glioma is one of the most commonly observed tumours, representing about 75% of brain tumours in the adult population. Generally, glioma treatment includes surgical resection followed by radiotherapy and chemotherapy. The current chemotherapy for glioma involves the use of temozolomide, doxorubicin, monoclonal antibodies, etc. however, the clinical outcomes in patients are not satisfactory. Primarily, the blood-brain barrier hinders these drugs from reaching the target leading to the recurrence of glioma post-surgery. In addition, these drugs are not target-specific and affect the healthy cells of the body. Therefore, glioma-targeted drug delivery is essential to reduce the rate of recurrence and treat the condition with more reliable alternatives.

METHODS

A literature search was conducted to understand glioma pathophysiology, its current therapeutic approaches for targeted delivery using databases like Pub Med, Web of Science, Scopus, and Google Scholar, etc. Results: This review gives an insight to challenges associated with current treatments, factors influencing drug delivery in glioma, and recent advancements in targeted drug delivery.

CONCLUSION

The promising results could be seen with nanotechnology-based approaches, like polymeric, lipidbased, and hybrid nanoparticles in the treatment of glioma. Biotechnological developments, such as carrier peptides and gene therapy, are future prospects in glioma therapy. Therefore, these targeted delivery systems will be beneficial in clinical practices for glioma treatment.

LncRNA RP11-84E24.3 drives tumorigenesis and epithelial-to-mesenchymal transition of glioma cells by promoting TFAP2C-mediated activation of SNAI1

PURPOSE

Long noncoding RNAs (LncRNAs) are essential epigenetic regulators with critical roles in tumor initiation and malignant progression; however, the mechanism by which aberrantly expressed lncRNA RP11-84E24.3 regulates the pathogenesis of glioma is not fully understood. Here, we investigate the function of lncRNA RP11-84E24.3 in glioma onset and progression as well as identify a molecular pathway regulated by this lncRNA.

METHODS

Differentially expressed lncRNAs related to glioma were identified. The aberrant expression of lncRNA RP11-84E24.3 was verified in samples from patients with glioma as well as glioma cell lines. The role of lncRNA RP11-8424.3 in proliferation, apoptosis, migration, and invasion was assessed using gain- and loss-of function approaches, EdU incorporation, flow cytometry, wound healing and Transwell invasion assays. Western blot analysis was utilized to examine the expression of proteins associated with epithelial-to-mesenchymal transition (EMT). The interaction between lncRNA RP11-84E24.3, TFAP2C and SNAI1 was confirmed using RNA pull-down, ChIP and luciferase reporter assays.

RESULTS

LncRNA RP11-84E24.3 was up-regulated in both glioma tissues and cell lines. LncRNA RP11-84E24.3 overexpression enhanced the proliferation, migration and invasion of glioma cells while reducing apoptosis. This was associated with a decrease in E-cadherin expression and an increase in N-cadherin and Vimentin expression. LncRNA RP11-84E24.3 directly targeted TFAP2C protein, resulting in increased SNAI1 expression. Knockdown of TFAP2C or SNAI1 reversed the effects of lncRNA RP11-84E24.3 overexpression, while silencing lncRNA RP11-84E24.3 inhibited tumor formation of glioma cells in vivo.

CONCLUSIONS

LncRNA RP11-84E24.3 increased SNAI1 expression by forming a complex with TFAP2C protein, promoting EMT in glioma cells and tumor formation.

Inhibition of purinergic P2X receptor 7 (P2X7R) decreases granulocyte-macrophage colony-stimulating factor (GM-CSF) expression in U251 glioblastoma cells

Glioblastoma is the most aggressive form of primary brain cancer, with a median survival of 12-15 months. The P2X receptor 7 (P2X7R) is upregulated in glioblastoma and is associated with increased tumor cell proliferation. The cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) is also upregulated in glioblastoma and has been shown to have both pro- and anti-tumor functions. This study investigates the potential mechanism linking P2X7R and GM-CSF in the U251 glioblastoma cell line and the therapeutic potential of P2X7R antagonism in this setting. P2X7R protein and mRNA was demonstrated to be expressed in the U251 cell line as assessed by immunocytochemistry and qPCR. Its channel function was intact as demonstrated by live cell confocal imaging using a calcium indicator Fluo-4 AM. Inhibition of P2X7R using antagonist AZ10606120, decreased both GM-CSF mRNA (P < 0.05) and protein (P < 0.01) measured by qPCR and ELISA respectively. Neutralization of GM-CSF with an anti-GM-CSF antibody did not alter U251 cell proliferation, however, P2X7R antagonism with AZ10606120 significantly reduced U251 glioblastoma cell numbers (P < 0.01). This study describes a novel link between P2X7R activity and GM-CSF expression in a human glioblastoma cell line and highlights the potential therapeutic benefit of P2X7R inhibition with AZ10606120 in glioblastoma.

Frequency of mismatch repair protein deficiency and PD-L1 in high-grade gliomas in adolescents and young adults (AYA)

Central nervous system tumors in adolescents and young adults (AYA) are rarely reported in the literature. The association with cancer predisposition syndrome is not established. Programmed death ligand 1 (PD-L1) can predict the potential response of patients to immunotherapy. A link between mismatch repair protein deficiency (MMRP-D) and response to immunotherapy is established. P53 is reported to be positive in MMRD-D cases. We aim to investigate the frequency of MMRP-D in AYA with high-grade glioma and any potential association with PD-L1. A total of 96 cases were tested including 49 (51.0%) cases of glioblastoma. Six cases (6.25%) were MMRP-D, 17 (17.7%) were PD-L1 positive, mostly in grade IV tumors (8.7% in grade III compared to 26% in grade IV, p value = 0.027), and 69 (71.9%) were P3 positive. None of the MMRP-D cases expressed PD-L1. P53-positive cases were mostly MMRP proficient (n = 67; 74.4%, p value 0.051). Fourteen cases (28.7%) were positive for both PD-L1 and P53, while p53-positive grade IV tumors were mostly associated with negative PD-L1 (n = 29, 58%, p value = 0.043). MMRP deficiency does not appear to be prevalent in high-grade glioma in AYA. Expression of PD-L1 in a quarter of cases might suggest a role for immunotherapy in high-grade glioma.

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.

The Ethical Dilemma in the Surgical Management of Low Grade Gliomas According to the Variable Availability of Resources and Surgeon Experience

Low grade gliomas (LGGs) affect young individuals in the prime of life. Management may alternatively include biopsy and observation or surgical resection. Recent evidence strongly favors maximal and supramaximal resection of LGGs in optimizing survival metrics. Awake craniotomy with cortical mapping and electrical stimulation along with other preoperative and intraoperative surgical adjuncts, including intraoperative magnetic resonance and diffusion tensor imaging, facilitates maximization of resection and eschews precipitating neurological deficits. Intraoperative imaging permits additional resection of identified residual to be completed within the same surgical session, improving extent of resection and consequently progression free and overall survival. These resources are available in only a few centers throughout the United States, raising an ethical dilemma as to where patients harboring LGGs should most appropriately be treated.

SYT16 is a prognostic biomarker and correlated with immune infiltrates in glioma: A study based on TCGA data

BACKGROUND

Glioma is the most lethal primary brain tumor. Lower-grade glioma (LGG) is the crucial pathological type of Glioma. Immune-infiltration of the tumor microenvironment positively associated with overall survival in LGG. SYT16 is a gene has not been reported in cancer. We assess the role of SYT16 in LGG, via the publicly available TCGA database.

METHODS

Gene Expression Profiling Interactive Analysis (GEPIA) was used to analyze the expression of SYT16 in LGG. We evaluated the influence of SYT16 on survival of LGG patients by survival module. Then, datasets of LGG were downloaded from TCGA. The correlations between the clinical information and SYT16 expression were analyzed using logistic regression. Univariable survival and Multivariate Cox analysis was used to compare several clinical characteristics with survival. we also explore the correlation between SYT16 and cancer immune infiltrates using CIBERSORT and correlation module of GEPIA. Gene set enrichment analysis (GSEA) was performed using the TCGA dataset. In addition, we use TIMER to explore the collection of SYT16 Expression and Immune Infiltration Level in LGG and to explore cumulative survival in LGG.

RESULTS

The univariate analysis using logistic regression, indicated that increased SYT16 expression significantly correlated with the tumor grade. Moreover, multivariate analysis revealed that the up-regulated SYT16 expression is an independent prognostic factor for good prognosis. Specifically, SYT16 expression level has significant negative correlations with infiltrating levels of B cell, CD4+ T cells, Macrophages, Neutrophils and DCs in LGG. In addition, GSEA identified ingle organism behavior, gated channel activity, cognition, transporter complex and ligand gated channel activity  in Gene Ontology (GO) were differentially enriched in the high SYT16 expression phenotype pathway. Neuroactive ligand receptor interaction, calcium signaling pathway, long term potentiation, type II diabetes mellitus and long term depression were identified as differentially enriched  pathway in Kyoto Encyclopedia of Genes and Genomes (KEGG).

CONCLUSION

SYT16 is a Prognostic Biomarker and Correlated with Immune Infiltrates in LGG.

Incidence of high grade gliomas presenting as radiographically non-enhancing lesions: experience in 111 surgically treated non-enhancing gliomas with tissue diagnosis

PURPOSE

Although non-enhancing lesions suspicious for glioma are usually assumed to be low grade glioma (LGG), some high grade glioma (HGG) do not enhance, which may lead to a delay in biopsy and/or resection, diagnosis, and treatment initiation. Thus, there is a clear need for a large-sample study that quantifies the rate of malignant, non-enhancing gliomas.

METHODS

We retrospectively reviewed our series of 561 consecutive surgically treated gliomas with tissue diagnosis, 111 of which were non-enhancing, to determine the prevalence of high-grade histology in radiographically presumed LGG. Relative expression of tumor markers were also reported for non-enhancing lesions to investigate genetic correlates.

RESULTS

We identified 561 surgically treated gliomas with tissue diagnosis from August 2012 to July 2018 and found that 111 patients (19.8%) demonstrated non-enhancing lesions suspicious for glioma on preoperative MRI. Thirty-one (27.9%) of the non-enhancing lesions were classified as HGGs (WHO Grade III or IV). Non-enhancing lesions were four times more likely to be HGG in patients older than 60 years than patients younger than 35 years (41.2% vs. 11.4%, Pearson Chi² p < 0.001). Binomial logistic regression showed a significant inverse effect of age on the presence of IDH mutation in non-enhancing HGGs (p = 0.007).

CONCLUSION

A clinically significant proportion (27.9%) of non-enhancing lesions were found to be HGG on final pathologic diagnosis. Thus, in patients with good functional and health status, especially those older than 60 years, we recommend obtaining tissue diagnosis of all lesions suspected to be glioma, even those that are non-enhancing, to guide diagnosis as well as early initiation of chemotherapy and radiation therapy.

Pediatric low-grade glioma in the era of molecular diagnostics

Low grade gliomas are the most frequent brain tumors in children and encompass a spectrum of histologic entities which are currently assigned World Health Organisation grades I and II. They differ substantially from their adult counterparts in both their underlying genetic alterations and in the infrequency with which they transform to higher grade tumors. Nonetheless, children with low grade glioma are a therapeutic challenge due to the heterogeneity in their clinical behavior – in particular, those with incomplete surgical resection often suffer repeat progressions with resultant morbidity and, in some cases, mortality. The identification of up-regulation of the RAS–mitogen-activated protein kinase (RAS/MAPK) pathway as a near universal feature of these tumors has led to the development of targeted therapeutics aimed at improving responses while mitigating patient morbidity. Here, we review how molecular information can help to further define the entities which fall under the umbrella of pediatric-type low-grade glioma. In doing so we discuss the specific molecular drivers of pediatric low grade glioma and how to effectively test for them, review the newest therapeutic agents and their utility in treating this disease, and propose a risk-based stratification system that considers both clinical and molecular parameters to aid clinicians in making treatment decisions.

Somatic Mosaicism of IDH1 R132H Predisposes to Anaplastic Astrocytoma: A Case of Two Siblings

Anaplastic astrocytomas are aggressive glial cancers that present poor prognosis and high recurrence. Heterozygous IDH1 R132H mutations are common in adolescent and young adult anaplastic astrocytomas. In a majority of cases, the IDH1 R132H mutation is unique to the tumor, although rare cases of anaplastic astrocytoma have been described in patients with mosaic IDH1 mutations (Ollier disease or Maffucci syndrome). Here, we present two siblings with IDH1 R132H mutant high grade astrocytomas diagnosed at 14 and 26 years of age. Analysis of IDH^R132H mutations in the siblings' tumors and non-neoplastic tissues, including healthy regions of the brain, cheek cells, and primary teeth indicate mosaicism of IDH^R132H. Whole exome sequencing of the tumor tissue did not reveal any other common mutations between the two siblings. This study demonstrates the first example of IDH1 R132H mosaicism, acquired during early development, that provides an alternative mechanism of cancer predisposition.

A Multi-Institutional Analysis of Factors Influencing Surgical Outcomes for Patients with Newly Diagnosed Grade I Gliomas

OBJECTIVE

To assess the impact of intraoperative magnetic resonance imaging (iMRI), extent of resection (EOR), and other factors on overall survival (OS) and progression-free survival (PFS) for patients with newly diagnosed grade I gliomas.

METHODS

A multicenter database was queried to identify patients with grade I gliomas. Retrospective analyses assessed the impact of patient, treatment, and tumor characteristics on OS and PFS.

RESULTS

A total of 284 patients underwent treatment for grade I gliomas, including 248 resections (205 with iMRI, 43 without), 23 biopsies, and 13 laser interstitial thermal therapy treatments. Log-rank analyses of Kaplan-Meier plots showed improved 5-year OS (P = 0.0107) and PFS (P = 0.0009) with increasing EOR, and a trend toward improved 5-year OS for patients with lower American Society of Anesthesiologists score (P = 0.0528). Greater EOR was associated with significantly increased 5-year PFS for pilocytic astrocytoma (P < 0.0001), but not for ganglioglioma (P = 0.10) or dysembryoplastic neuroepithelial tumor (P = 0.57). Temporal tumors (P = 0.04) and location of "other" (P = 0.04) were associated with improved PFS, and occipital/parietal tumors (P = 0.02) were associated with decreased PFS compared with all other locations. Additional tumor resection was performed after iMRI in 49.7% of cases using iMRI, which produced gross total resection in 64% of these additional resection cases.

CONCLUSIONS

Patients with grade I gliomas have extended OS and PFS, which correlates positively with increasing EOR, especially for patients with pilocytic astrocytoma. iMRI may increase EOR, indicated by the rate of gross total resection after iMRI use but was not independently associated with increased OS or PFS.

Coronarin D Induces Apoptotic Cell Death and Cell Cycle Arrest in Human Glioblastoma Cell Line

Glioblastoma (GBM) is the most frequent and highest-grade brain tumor in adults. The prognosis is still poor despite the use of combined therapy involving maximal surgical resection, radiotherapy, and chemotherapy. The development of more efficient drugs without noticeable side effects is urgent. Coronarin D is a diterpene obtained from the rhizome extract of Hedychium coronarium, classified as a labdane with several biological activities, principally anticancer potential. The aim of the present study was to determine the anti-cancer properties of Coronarin D in the glioblastoma cell line and further elucidate the underlying molecular mechanisms. Coronarin D potently suppressed cell viability in glioblastoma U-251 cell line, and also induced G1 arrest by reducing p21 protein and histone H2AX phosphorylation, leading to DNA damage and apoptosis. Further studies showed that Coronarin D increased the production of reactive oxygen species, lead to mitochondrial membrane potential depolarization, and subsequently activated caspases and ERK phosphorylation, major mechanisms involved in apoptosis. To our knowledge, this is the first analysis referring to this compound on the glioma cell line. These findings highlight the antiproliferative activity of Coronarin D against glioblastoma cell line U-251 and provide a basis for further investigation on its antineoplastic activity on brain cancer.