Classification and microsurgical treatment of foramen magnum meningioma.

BACKGROUND: To investigate the classification and microsurgical treatment of foramen magnum meningioma (FMM). METHODS: We retrospectively analyzed 76 patients with FMM and classified them into two classifications, classification ABS according to the relationship between the FMM and the brainstem and classification SIM according to the relationship between the FMM and the vertebral artery (VA). All patients underwent either the far lateral approach (54 cases) or the suboccipital midline approach (22 cases). RESULTS: Of the 76 cases, 47 cases were located ahead of the brainstem (A), 16 cases at the back of the brainstem (B), and 13 cases were located laterally to the brainstem (S). There were 15 cases located superior to the VA (S), 49 cases were inferior (I), and 12 cases were mixed type (M). Among 76 cases, 71 cases were resected with Simpson grade 2 (93.42%), 3 with Simpson grade 3 (3.95%), and 2 with Simpson grade 4 (2.63%). We summarized four anatomical triangles: triangles SOT, VOT, JVV, and TVV. The mean postoperative Karnofsky performance score was improved in all patients (p < 0.05). However, several complications occurred, including hoarseness and CSF leak. CONCLUSION: ABS and SIM classifications are objective indices for choosing the surgical approach and predicting the difficulty of FMMs, and it is of great importance to master the content, position relationship with the tumor, and variable anatomical structures in the four "triangles" for the success of the operation.

Genomic Analysis of Glioblastoma Multiforme Reveals a Key Transcription Factor Signature Relevant to Prognosis and the Immune Processes.

INTRODUCTION: Glioblastoma multiforme (GBM) develops through the accumulation of both genetic and expression alterations. Although many gene signatures have been developed as prognostic and predictive biomarkers, their robustness and functional aspects are less well characterized. The expression of most genes is regulated by transcription factors (TFs); therefore, we aimed to investigate a TF signature relevant to GBM prognosis. METHODS: We used bioinformatic methods and data from public databases to establish four clusters of key TF genes, among which cluster 1, comprising 24 TFs, showed significant prognostic value. Further in silico functional analyses were applied to investigate the utility of the TF signature. RESULTS: Different mutation and copy number variation patterns were observed between different risk score groups (based on the TF signature). In silico analyses suggested that the cases with relative high risk scores were involved in immune and inflammatory processes or pathways. CONCLUSION: The TF signature has significant prognostic value in different cohorts or subgroups of patients with GBM and could lead to the development immunotherapy for GBM.

miR-504 suppresses mesenchymal phenotype of glioblastoma by directly targeting the FZD7-mediated Wnt-ß-catenin pathway.

BACKGROUND: MicroRNAs (miRNAs) play crucial roles in tumor initiation and development. Previously, we indicated that miR-504 is downregulated and suppresses tumor proliferation in glioblastoma (GBM). However, the regulation and relevant mechanism of miR-504 in GBM mesenchymal (ME) transition remain unclear. METHODS: Transcriptome and clinical data were obtained from The Cancer Genome Atlas (TCGA) database. The potential functions of miR-504 were predicted using gene ontology analysis. GBM cell migration and invasion were examined using wound healing and Transwell assays. Epithelial-mesenchymal transition (EMT) progression in GBM cell lines was detected with immunofluorescence and western blotting. The stemness activity of glioma stem-like cells (GSCs) was assessed by sphere formation assay and tumor xenograft model. miR-504 binding to the FZD7 (frizzled class receptor 7) 3' untranslated region (3'UTR) was validated using dual luciferase reporter assay. TOP/FOP Flash assays were conducted to determine the effects of miR-504 on Wnt/ß-catenin signaling. RESULTS: Analysis of TCGA transcriptomic data showed that low miR-504 expression correlated with ME subtype transition and poor survival in patients with GBM. Functional experiments showed that miR-504 overexpression suppressed malignant behaviors of GBM cells, such as migration, invasion, EMT, and stemness activity. Furthermore, miR-504 was a negative regulator of the Wnt-ß-catenin pathway by directly repressing FZD7 expression, and FZD7 overexpression reversed the EMT inhibition caused by miR-504. Moreover, the low miR-504/FZD7 expression ratio was a ME subtype marker and could serve as a significant prognostic indicator and predict the clinical outcome of chemotherapy and radiotherapy for patients with GBM in TCGA dataset. CONCLUSIONS: Our results suggest that miR-504 suppresses the aggressive biological processes associated with the ME phenotype of GBM and could be a potential candidate for therapeutic applications in these malignant brain tumors.

Astrocytoma progression scoring system based on the WHO 2016 criteria.

Diffuse astrocytoma (including glioblastoma) is morbid with a worse prognosis than other types of glioma. Therefore, we sought to build a progression-associated score to improve malignancy and prognostic predictions for astrocytoma. The astrocytoma progression (AP) score was constructed through bioinformatics analyses of the training cohort (TCGA RNA-seq) and included 18 genes representing distinct aspects of regulation during astrocytoma progression. This classifier could successfully discriminate patients with distinct prognoses in the training and validation (REMBRANDT, GSE16011 and TCGA-GBM Microarray) cohorts (P < 0.05 in all cohorts) and in different clinicopathological subgroups. Distinct patterns of somatic mutations and copy number variation were also observed. The bioinformatics analyses suggested that genes associated with a higher AP score were significantly involved in cancer progression-related biological processes, such as the cell cycle and immune/inflammatory responses, whereas genes associated with a lower AP score were associated with relatively normal nervous system biological processes. The analyses indicated that the AP score was a robust predictor of patient survival, and its ability to predict astrocytoma malignancy was well elucidated. Therefore, this bioinformatics-based scoring system suggested that astrocytoma progression could distinguish patients with different underlying biological processes and clinical outcomes, facilitate more precise tumour grading and possibly shed light on future classification strategies and therapeutics for astrocytoma patients.

Is the relationship between social support and depressive symptoms mediated by hope among Chinese central nervous system tumor patients?

BACKGROUND: It is common for central nervous system (CNS) tumor patients to suffer from depressive symptoms. If unrecognized or untreated, CNS tumors may lead to many serious problems in these patients. This study examines the association of social support with depressive symptoms in CNS tumor patients and explores the extent to which hope mediates this relationship. METHODS: A total of 269 CNS tumor patients in China were included in this study. We assessed depressive symptoms using the Epidemiologic Studies Depression Scale (CES-D), social support using the Perceived Social Support Scale (PSSS), and hope using the Herth Hope Index (HHI). Questionnaires were distributed to collect these data. Hierarchical linear regression analyses explored the interrelationship between social support, hope, and depressive symptoms. RESULTS: After adjustment for demographic characteristics, patients with less social support exhibited more depressive symptoms (ß = - 0.452, P < 0.01). Social support explained 19.1% of the variance in depressive symptoms. After adding hope to the regression model, the effect size for social support was reduced by over half but remained significant (from ß = - 0.452 to ß = - 0.218, P < 0.01). In addition, a lower level of hope (ß = - 0.386, P < 0.01) was associated with more depressive symptoms, and this measure explained an additional 9.3% of the variance in depressive symptoms. CONCLUSIONS: Much of the relationship between social support and depressive symptoms is explained by hope. Thus, interventions boosting both social support and hope help to reduce depressive symptoms in patients with CNS tumors.

Temozolomide increases MHC-I expression via NF-κB signaling in glioma stem cells.

Gliomas are the most common and primary tumors of the central nervous system in adults. Temozolomide (TMZ) is the main drug used to treat glioma; however, prognosis remains poor for most patients. Glioma stem cells (GSCs) are thought to enable glioma initiation and evasion from immune surveillance; their immunogenicity can be determined by expression of major histocompatibility complex (MHC)-I. The present study investigated the effect of TMZ on MHC-I expression in GSCs. Glioma spheres were cultured in serum-free medium containing epidermal growth factor, basic fibroblast growth factor, and B27; MHC-I expression was detected by immunocytochemistry, quantitative real-time PCR, and flow cytometry. Nuclear factor (NF)-κB expression in glioma stem cells was detected by Western blot. TMZ enhanced MHC-I expression in GSCs, and NF-κB was activated. TMZ treatment increased MHC-I expression via modulation of NF-κB signaling in GSCs. In addition to being a chemotherapeutic agent, TMZ may also serve as an immunomodulatory agent in the treatment of glioma patients.

Prevalence and associated positive psychological variables of anxiety and depression among patients with central nervous system tumors in China: a cross-sectional study.

BACKGROUND: Anxiety and depression have been identified as common psychological distresses faced by the majority of patients with cancer. However, no studies have investigated the relationship between positive psychological variables (hope, optimism and general self-efficacy) and anxiety and depression among patients with central nervous system (CNS) tumors in China. Our hypothesis is that the patients with higher levels of hope, optimism or general self-efficacy have lower levels of anxiety and depression when encountered by stressful life events such as CNS tumors. METHODS: Questionnaires, including the Hospital Anxiety and Depression Scale, the Herth Hope Index, the Life Orientation Scale-Revised and the General Self-Efficacy Scale, and demographic and clinical records were used to collect information about patients with CNS tumors in Liaoning Province, China. The study included 222 patients (effective response rate: 66.1%). Hierarchical linear regression analyses were performed to explore the associations among hope, optimism, general self-efficacy and anxiety/depression. RESULTS: Prevalence of anxiety and depression were 42.8 and 32.4%, respectively, among patients with CNS tumors. Hope and optimism both were negatively associated with anxiety and together accounted for 21.4% of variance in anxiety. Similarly, hope and optimism both were negatively associated with depression and accounted for 32.4% of variance in depression. CONCLUSIONS: The high prevalence of anxiety and depression among patients with CNS tumors should receive more attention in Chinese medical settings. To help reduce anxiety and depression, health care professionals should develop interventions to promote hope and optimism based on patients' specific needs.

The Association Between Genetic Polymorphism rs703842 in CYP27B1 and Multiple Sclerosis: A Meta-Analysis.

Multiple sclerosis (MS) is the most frequent nontraumatic disabling neurological disease among young adults. Previous studies have examined the association of rs703842 in CYP27B1 with MS susceptibility, with inconsistent results reported.The objective of this study is to conduct a systematic literature search and perform meta-analyses to examine whether rs703842 is associated with MS risk.We searched potential literature in PubMed, Cochrane Library, Embase, Google Scholar, Web of Science, and HuGE by using the following inclusion criteria: studies were on human subjects; the studies were case-control studies; studies included subjects who had MS and those who did not have MS; and the studies provided genotype data for rs703842 for subjects who had and did not have MS, or provided odds ratios (ORs) and the 95% confidence intervals (CIs) for assessing the association of rs703842 with MS, or provided sufficient data for the calculation of OR and the 95% CI. We used random-effects models to calculate the OR as a measure of association. We used I to assess between-study heterogeneity, and a funnel plot and Egger test to assess publication bias.Seven studies published since 2008 met the eligibility criteria and were included in the meta-analyses. We found that the C allele was significantly associated with reduced MS susceptibility (OR = 0.88, 95% CI: 0.80-0.89; P < 0.0001). We also found significant association of rs703842 with MS risk using a dominant and a recessive model (both P < 0.0002). Our results remain unchanged if our meta-analysis was limited to studies that included only Caucasian participants (OR = 0.85, 95% CI: 0.80-0.90; P < 0.0001).Our study has several limitations: The sample size is limited; We were unable to control for some important confounding factors as data for individual participant were not available; and Most of the included studies focus on MS risk in Caucasian. As a result, we could not perform meta-analysis for assessing the relationship in other ethnic groups.In summary, we found that the genetic variant rs703842 in CYP27B1 is associated with MS risk in Caucasians. More studies with larger sample size that control for important confounding factors are needed to validate the findings from this study.

The Association Between Genetic Variants in the Dopaminergic System and Posttraumatic Stress Disorder: A Meta-Analysis.

Posttraumatic stress disorder (PTSD) is a complex mental disorder and can severely interfere with the normal life of the affected people. Previous studies have examined the association of PTSD with genetic variants in multiple dopaminergic genes with inconsistent results. To perform a systematic literature search and conduct meta-analysis to examine whether genetic variants in the dopaminergic system is associated with PTSD. Data Sources: PubMed, Cochrane Library, Embase, Google Scholar, and HuGE. Study eligibility criteria and participants: The studies included subjects who had been screened for the presence of PTSD; the studies provided data for genetic variants of genes involved in the dopaminergic system; the outcomes of interest included diagnosis status of PTSD; and the studies were case-control studies. Study appraisal and synthesis methods: Odds ratio was used as a measure of association. We used random-effects model in all the meta-analyses. Between-study heterogeneity was assessed using I², and publication bias was evaluated using Egger test. Findings from meta-analyses were confirmed using random-effects meta-analyses under the framework of generalized linear model (GLM). A total of 19 studies met the eligibility criteria and were included in our analyses. We found that rs1800497 in DRD2 was significantly associated with PTSD (OR = 1.96, 95% CI: 1.15-3.33; P = 0.014). The 3'-UTR variable number tandem repeat (VNTR) in SLC6A3 also showed significant association with PTSD (OR = 1.62, 95% CI: 1.12-2.35; P = 0.010), but there was no association of rs4680 in COMT with PTSD (P = 0.595). Sample size is limited for some studies; type and severity of traumatic events varied across studies; we could not control for potential confounding factors, such as age at traumatic events and gender; and we could not examine gene-environment interaction due to lack of data. We found that rs1800497 in DRD2 and the VNTR in SLC6A3 showed significant association with PTSD. Future studies controlling for confounding factors, with large sample sizes and more homogeneous traumatic exposure, are needed to validate the findings from this study.

A tumor-suppressive microRNA, miR-504, inhibits cell proliferation and promotes apoptosis by targeting FOXP1 in human glioma.

MicroRNAs (miRNAs) have been proposed as useful prognostic cancer biomarkers and as potential molecular targets for treating various cancers. Previous findings have indicated that miR-504 is dysregulated and involved in tumorigenesis of several types of cancer. However, the biological role of miR-504 in glioma remains unclear. In this study, we showed that miR-504 expression was markedly decreased in both glioma tissues and cell lines and that miR-504 downregulation significantly correlated with aggressive clinicopathological features and poor prognosis for glioma patients. In addition, miR-504 overexpression inhibited cell proliferation, induced cell cycle arrest, and promoted apoptosis in glioma cell lines. Furthermore, we identified forkhead box protein P1 (FOXP1) as a direct target of miR-504 using microarray analysis and a luciferase assay. Moreover, we demonstrated that miR-504 regulated glioma tumorigenesis by downregulating FOXP1 expression. Our results suggest that miR-504 might function as an important suppressor of glioma tumorigenesis and could serve as a promising candidate for therapeutic applications in glioma treatment.

The Association Between Apolipoprotein E and Functional Outcome After Traumatic Brain Injury: A Meta-Analysis.

Traumatic brain injury (TBI) is a leading cause of death and disability. Previous studies have investigated the association of apolipoprotein E (APOE) ε4 with functional outcome after TBI and reported inconsistent results.The purpose of this study was to perform a systematic literature search and conduct meta-analyses to examine whether APOE ε4 is associated with poorer functional outcome in patients with TBI.We performed a systematic literature search in PubMed, Cochrane Library, Embase, Google Scholar, and HuGE.The eligibility criteria of this study included the following: Patients had TBI; the studies reported APOE genotype data or provided odds ratios (ORs) and the corresponding 95% confidence intervals (CIs); the functional outcome was assessed using the Glasgow Outcome Scale (GOS) or the Glasgow Outcome Scale Extended (GOSE); and patients were followed for at least 3 months after TBI.In all meta-analyses, we used random-effects models to calculate the odds ratio as a measure of association. We examined the association of APOE ε4 with functional outcome at different time points after TBI.A total of 12 studies met the eligibility criteria and were included in the meta-analyses. We did not find a significant association between APOE ε4 and functional outcome at 6 (P = 0.23), 12 (P = 0.44), and 24 months (P = 0.85) after TBI. However, APOE ε4 was associated with an increased risk of unfavorable long-term (≥6 months) functional outcome after TBI (OR = 1.36, 95% CI: 1.07-1.74, P = 0.01).Limitations of this study include The sample size was limited; the initial severity of TBI varied within and across studies; we could not control for potential confounding factors, such as age at injury and sex; a meta-analysis of the genotype dosage effect was not feasible; and we could not examine the association with specific factors such as neurobehavioral or specific cognitive functions.Our meta-analysis indicates APOE ε4 is associated with the long-term functional outcome of patients with TBI. Future studies that control for confounding factors, with large sample sizes and more homogeneous initial TBI severity levels, are needed to validate the findings from this study.

Identification of low miR-105 expression as a novel poor prognostic predictor for human glioma.

Glioma is the most common and aggressive brain tumor with poor clinical outcome. Identification and development of new biomarkers could be beneficial for diagnosis and prognosis of glioma patients. Recent studies have showed evidences that dysregulation of microRNAs (miRNAs) is involved in glioma tumorigenesis. Therefore, we attempted to identify specific miRNAs as prognostic and predictive markers for glioma. We statistically compared expression profile of 365 miRNAs between WHO grade IV and grade III gliomas, by qRT-PCR. MiR-105 was identified as a remarkably decreased miRNA in grade IV gliomas compared with grade III gliomas (P=0.012, fold change =0.04). We subsequently examined its expression levels in an independent series of gliomas, and statistically analyzed the associations between miR-105 expression and clinicopathological characteristics and survivals of these glioma patients. MiR-105 showed remarkably decreased expression in gliomas as compared to non-neoplastic brains. And grade IV gliomas had significantly lower miR-105 expression compared with grade III and II gliomas (both P<0.001). Additionally, low miR-105 expression was statistically associated with advanced tumor grade, advanced patient's age and low pre-operative Karnofsky performance score (all P<0.001). Furthermore, patients with low miR-105 expression had significantly poorer survival by Kaplan-Meier method (P<0.001). Multivariate analysis indicated miR-105 as an independent prognostic indicator for glioma patients (P=0.018, risk ratio =4.2). Our results suggested that low expression of miR-105 may correlate with unfavorable clinical outcome and be involved in tumorigenesis and aggressive progression of glioma. And miR-105 may be a novel biomarker in prognostic prediction for glioma.

High miR-196a and low miR-367 cooperatively correlate with unfavorable prognosis of high-grade glioma.

Identification of microRNAs (miRNAs) could be beneficial for the diagnosis and prognosis of glioma. Therefore, we attempted to identify and develop specific miRNAs as prognostic and predictive markers for glioma patients. We compared the expression profiles of 365 miRNAs between 4 glioblastomas (GBMs, WHO grade IV) and 4 anaplastic astrocytomas (AAs, WHO grade III) using miRNA qPCR Array. MiR-196a (P = 0.004, fold change = 289.86) and miR-367 (P = 0.044, fold change = 0.03) were identified as the most up-regulated and down-regulated miRNAs in GBMs compared with AAs, respectively. We subsequently examined miR-196a and miR-367 expression levels in an independent series of 63 gliomas including 50 GBMs and 13 AAs, as well as 10 non-neoplastic brain tissues, and statistically analyzed the associations between miRNA expression and clinicopathological characteristics and survivals of these glioma patients. MiR-196a and miR-367 showed significant increased and decreased expression in high-grade gliomas relative to non-neoplastic brains, as well as in GBMs versus AAs, respectively. Additionally, high-miR-196a and low-miR-367 expression, alone or in combination, statistically correlated with aggressive clinicopathological features of gliomas. Furthermore, overall survivals of glioma patients with high-miR-196a, low-miR-367 and high-miR-196a/low-miR-367 expression tended to be shorter than the corresponding control groups (all P ≤ 0.001). Moreover, multivariate analysis indicated high-miR-196a/low-miR-367 as an independent prognostic indicator for glioma patients (P = 0.005, risk ratio = 1.8). Our results suggested that both high-miR-196a and low-miR-367 expression may be associated with aggressive progression and unfavorable clinical outcome in glioma patients. And combination of high-miR-196a and low-miR-367 expression may be a novel biomarker in identifying a poor prognosis group of high-grade glioma.

Up-regulation of microRNA-15b correlates with unfavorable prognosis and malignant progression of human glioma.

Recent studies have demonstrated that microRNA-15b (miR-15b) regulates cell cycle progression, proliferationnd apoptosis in glioma cells by targeting Cyclins. However, the clinical significance of miR-15b in human glioma remains unclear. Therefore, the aim of this study was to investigate the significance of miR-15b expression in diagnosis, prognosis and malignant progression of glioma. Quantitative real-time reverse transcriptive-PCR (qRT-PCR) was performed to examine miR-15b expression levels in 76 glioma tissues (13 grade II, 13 grade III and 50 grade IV gliomas) and seven glioma cell lines, as well as 10 non-neoplastic brain tissues and human astrocyte as control. MiR-15b showed significant increased expression in high-grade gliomas (P≤0.001) and glioma cells (fold change 2.8-7.6) relative to non-neoplastic brains and astrocyte, respectively. Additionally, high miR-15b expression was significantly associated with advanced WHO grade (P≤0.001), advanced patient age (P≤0.001) and low Karnofsky performance score (KPS, P≤0.001). Furthermore, Kaplan-Meier survival analysis and Cox regression analysis showed that patients with high miR-15b expression had significantly poor overall survival rate (P≤0.001) and miR-15b expression was an independent prognosis-predicting factor for glioma patients (P≤0.001; risk ratio=5.6), respectively. Moreover, miR-15b expression was examined in seven independent patients with primary grade II or III gliomas that spontaneously progressed to grade III or IV gliomas. Statistically significant higher expression (P=0.01) in the recurrent tumor compared with the corresponding primary tumor was observed in all of the seven patients. Our results suggest that miR-15b may be a prognostic predictor and be involved in malignant progression of glioma.

Downregulation of microRNA-504 is associated with poor prognosis in high-grade glioma.

Several previous reports indicated that microRNA-504 (miR-504) has an oncogenic function through negatively regulating p53. On the other hand, a recent study revealed that miR-504 inhibits cancer cell proliferation through targeting CDK6 in hypopharyngeal squamous cell carcinoma (HSCC), suggesting the tumor suppressive role of this miRNA. However, the role of miR-504 in human malignant glioma remains unclear. Therefore, the aim of this study was to investigate the clinical significance of miR-504 expression in high pathological grade glioma. Quantitative real-time reverse transcriptive-PCR (qRT-PCR) was performed to examine miR-504 expression levels in 63 glioma tissues including 13 anaplastic astrocytomas (AA, WHO grade III) and 50 glioblastomas (GBM, WHO grade IV), as well as 10 non-neoplastic brain tissues. Associations between miR-504 expression and clinicopathological factors and prognosis of glioma patients were statistically analyzed. MiR-504 showed significant decreased expression levels both in AAs and GBMs relative to non-neoplastic brains (P ≤ 0.001, respectively). Additionally, low expression level of miR-504 was significantly associated with advanced WHO grade (P = 0.01). Moreover, Kaplan-Meier survival analysis showed that patients with low expression of miR-504 had significantly poor survival rate (P = 0.002). Cox regression analysis showed that miR-504 expression was independent prognosis-predicting factor for malignant glioma patients (P = 0.038; risk ration = 2.5). Our results suggest that miR-504 may be a prognostic predictor and be involved in tumorigencity as a tumor suppressor of malignant glioma.

Clinical implications of microRNAs in human glioblastoma.

Glioblastoma (GBM) is one of the most common and dismal brain tumors in adults. Further elucidation of the molecular pathogenesis of GBM is mandatory to improve the overall survival of patients. A novel small non-coding RNA molecule, microRNA (miRNA), appears to represent one of the most attractive target molecules contributing to the pathogenesis of various types of tumors. Recent global analyses have revealed that several miRNAs are clinically implicated in GBM, with some reports indicating the association of miRNA dysregulation with acquired temozolomide (TMZ) resistance. More recent studies have revealed that miRNAs could play a role in cancer stem cell (CSC) properties, contributing to treatment resistance. In addition, greater impact might be expected from miRNA-targeted therapies based on tumor-derived exosomes that contain numerous functional miRNAs, which could be transferred between tumor cells and surrounding structures. Tumor-derived miRNAs are now considered to be a novel molecular mechanism promoting the progression of GBM. Establishment of miRNA-targeted therapies based on miRNA dysregulation of CSCs could provide effective therapeutic strategies for TMZ-resistant GBM. Recent progress has revealed that miRNAs are not only putative biological markers for diagnosis, but also one of the most promising targets for GBM treatment. Here in, we summarize the translational aspects of miRNAs in the diagnosis and treatment of GBM.

MicroRNAs in Human Malignant Gliomas.

MicroRNA (miRNA) is a new class of small noncoding RNA molecules that regulate a wide spectrum of gene expression in a posttranscriptional manner. MiRNAs play crucial roles in tumorigenesis, angiogenesis, invasion, and apoptosis for various types of tumor. Recent studies have identified dysregulation of specific miRNAs in malignant gliomas. Global expression profiling of miRNAs has revealed several miRNAs clinically implicated in human glioblastomas. Some miRNAs are clearly associated with clinical outcome and chemo- and radio-therapy resistance in these tumors. Furthermore, miRNAs also regulate specific signaling pathways, including the critical core pathways in glioblastoma. As a result, miRNAs have the potential to affect the responses to molecular-targeted therapies. More recent studies have revealed that miRNAs might be associated with cancer stem cell properties, affecting tumor maintenance and progression. Recent investigation have revealed that miRNAs are not only biological markers with diagnostic implications, but also one of the most promising treatment targets in human glioblastoma. Herein, we summarized the novel insights of miRNAs into human malignant gliomas.

Molecular characteristics of glioblastoma with 1p/19q co-deletion.

Recent developments in molecular analysis have revealed genetic alterations in human gliomas. Loss of heterozygosity (LOH) is a critical molecular marker for classification of human glioma, and is useful for predicting outcome. Our previous LOH study identified a small subgroup of glioblastoma (GBM), with 1p/19q co-deletion, with a favorable clinical outcome. In this study, we investigated molecular pathological features of eight GBM with 1p/19q co-deletion compared with "classic" GBM and anaplastic oligodendroglioma (AO). We estimated EGFR gene amplification, EGFRvIII expression, CDKN2A (p16) homozygous deletion, and isocitrate dehydrogenase 1/2 (IDH1/2) gene mutations. We also conducted an analysis of the expression of proneural genes (DLL3, OLIG2, SOX2). On histopathological review, only one GBM was diagnosed as glioblastoma with oligodendroglioma component (GBMO). Loss of chromosomes 10 and 17p is common, and neither IDH1/2 mutations nor EGFRvIII expression were detected in GBM with 1p/19q co-deletion. The expression profile revealed high expression of the OLIG2 gene in this subgroup. High expression of proneural gene OLIG2 without EGFRvIII expression may be associated with a favorable clinical outcome; however, IDH1/2 gene status and the extent of LOH regions may indicate that this small subgroup of GBM is a distinct genetic subgroup from oligodendroglial tumors.

Loss of heterozygosity analysis in malignant gliomas.

Despite recent advances in the diagnosis and treatment of glioblastomas, patient outcomes for these highly malignant tumors remain poor. Research into the molecular pathology of glioblastoma has uncovered various genetic changes that contribute to malignancy. Some of the identified molecular markers--such as loss of heterozygosity (LOH) on chromosome 1p/19q and chromosome 10, O6-methylguanine methyltransferase promoter hypermethylation, and mutation of isocitrate dehydrogenase-1--may help to predict patient outcomes. Indeed, LOH analysis is an effective approach to classify malignant gliomas. Genome-wide analyses have revealed that the extent and pattern of LOH regions may have important implications for the clinical course of the disease. As the genetic underpinnings of malignant gliomas are complex and varied, careful selection of the methods for genetic analysis in the clinic is important. The fundamental principles of each assay need to be understood to allow careful selection of practically useful methods. This review summarizes recent developments in the molecular analysis of malignant glioma.

MiRNA-196 is upregulated in glioblastoma but not in anaplastic astrocytoma and has prognostic significance.

PURPOSE: MicroRNAs (miRNA) are short noncoding RNAs that can play critical roles in diverse biological processes. They are implicated in tumorigenesis and function both as tumor suppressors and as oncogenes. The clinical significance of miRNA expression profiles in malignant gliomas remains unclear. EXPERIMENTAL DESIGN: In this study, we examined the expression levels of 365 mature human miRNAs in 12 malignant gliomas, including 8 glioblastomas and 4 anaplastic astrocytomas, using TaqMan real-time quantitative PCR arrays. A validation study was done to corroborate a subset of the results, including expression levels of miR-196a, -196b, -21, and -15b, by analyzing 92 malignant gliomas by conventional real-time PCR. We modeled the relationship between the expression levels of these miRNAs and the survival rate of 39 glioblastoma patients by Kaplan-Meier method and multivariate analysis. RESULTS: Expression profiles in glioblastomas and anaplastic astrocytomas suggested that 16 miRNAs were candidate markers associated with the malignant progression of gliomas. Among them, miR-196a showed the most significant difference (P = 0.0038), with miR-196b also having a high significance (P = 0.0371). Both miRNAs showed increased expression levels in glioblastomas relative to both anaplastic astrocytomas and normal brains in the validation study. Furthermore, patients with high miR-196 expression levels showed significantly poorer survival by the Kaplan-Meier method (P = 0.0073). Multivariate analysis showed that miR-196 expression levels were an independent predictor of overall survival in all 39 glioblastoma patients (P = 0.021; hazard ratio, 2.81). CONCLUSIONS: Our results suggest that miR-196 may play a role in the malignant progression of gliomas and may be a prognostic predictor in glioblastomas.