Molecular pathology in adult gliomas: diagnostic, prognostic, and predictive markers

Reduction of Fluoroscopy Time and Radiation Dosage During Catheter Ablation for Atrial Fibrillation

Radiofrequency catheter ablation has become the treatment of choice for atrial fibrillation (AF) that does not respond to antiarrhythmic drug therapy. During the procedure, fluoroscopy imaging is still considered essential to visualise catheters in real-time. However, radiation is often ignored by physicians since it is invisible and the long-term risks are underestimated. In this respect, it must be emphasised that radiation exposure has various potentially harmful effects, such as acute skin injury, malignancies and genetic disease, both to patients and physicians. For this reason, every electrophysiologist should be aware of the problem and should learn how to decrease radiation exposure by both changing the setting of the system and using complementary imaging technologies. In this review, we aim to discuss the basics of X-ray exposure and suggest practical instructions for how to reduce radiation dosage during AF ablation procedures.

A clinical care pathway to improve the acute care of patients with glioma

BACKGROUND

Patients with glioma are at increased risk for tumor-related and treatment-related complications. Few guidelines exist to manage complications through supportive care. Our prior work suggests that a clinical care pathway can improve the care of patients with glioma.

METHODS

We designed a quality improvement (QI) project to address the acute care needs of patients with gliomas. We formed a multidisciplinary team and selected 20 best-practice measures from the literature. Using a plan-do-study-act framework, we brainstormed and implemented various improvement strategies starting in October 2013. Statistical process control charts were used to assess progress.

RESULTS

Retrospective data were available for 12 best practice measures. The baseline population consisted of 98 patients with glioma. Record review suggested wide variation in performance, with compliance ranging from 30% to 100%. The team hypothesized that lack of process standardization may contribute to less-than-ideal performance. After implementing improvement strategies, we reviewed the records of 63 consecutive patients with glioma. The proportion of patients meeting criteria for 12 practice measures modestly improved (65% pre-QI; 76% post-QI, P > .1). Unexpectedly, a higher proportion of patients were readmitted within 30 days of hospital discharge (pre-QI: 10%; post-QI: 17%, P > .1). Barriers to pathway development included difficulties with transforming manual measures into electronic data sets.

CONCLUSIONS

Creating evidence-based clinical care pathways for addressing the acute care needs of patients with glioma is feasible and important. There are many challenges, however, to developing sustainable systems for measuring and reporting performance outcomes overtime.

Frontal glioblastoma multiforme may be biologically distinct from non-frontal and multilobar tumors

Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults and carries a grim prognosis. Lobar GBM, notably those localized to the frontal lobe, are generally more amenable to complete surgical resection, and may carry a better prognosis. The biology of differently localized GBM has been reported scarcely in terms of prognostic markers, including isocitrate dehydrogenase 1 (IDH1) mutation and O(6)-methylguanine-methyltransferase (MGMT) methylation. To our knowledge, there has been no evaluation in the literature of different proliferation indexes in different GBM locations in the brain. We performed a retrospective evaluation of our prospectively collected database to assess the rate of IDH1 positivity, MGMT methylation and Ki67 index for GBM located in the frontal lobes alone, lobar GBM in other supra-tentorial lobes and multilobar GBM. IDH1 mutated tumors were localized in the frontal lobes in 50.0%, whereas only 20.3% of IDH1 wild-type tumors were localized in the frontal lobe (p=0.006); MGMT methylated tumors were localized in the frontal lobe in 32.0% of the cases. Only 13.75% of the MGMT unmethylated tumors were localized to the frontal lobe (p=0.005); Tumors with higher Ki67 proliferation index were more likely to be localized in the frontal lobe (40.6% vs. 19.5%, p=0.019). This is the largest cohort of GBM assessed for these purposes in the literature. Frontal lobe GBMs may be intrinsically biologically distinct from GBM in other lobes and from multilobar tumors.

Inhibition of DNA-repair genes Ercc1 and Mgmt enhances temozolomide efficacy in gliomas treatment: a pre-clinical study

Gliomas are the most common primary brain tumors. To date, therapies do not allow curing patients, and glioblastomas (GBMs) are associated with remarkably poor prognosis. This situation is at least partly due to intrinsic or acquired resistance to treatment, especially to chemotherapy. In 2005, temozolomide (TMZ) has become the first chemotherapeutic drug validated for GBM. Nevertheless TMZ efficacy depends on Mgmt status. While the methylation of Mgmt promoter was considered so far as a prognostic marker, its targeting is becoming an effective therapeutic opportunity. Thus, arrival of both TMZ and Mgmt illustrated that considerable progress can still be realized by optimizing adjuvant chemotherapy. A part of this progress could be accomplished in the future by overcoming residual resistance. The aim of the present study was to investigate the involvement of a set of other DNA-repair genes in glioma resistance to temozolomide. We focused on DNA-repair genes located in the commonly deleted chromosomal region in oligodendroglioma (1p/19q) highly correlated with patient response to chemotherapy. We measured effects of inhibition of ten DNA-repair genes expression using siRNAs on astrocytoma cell response to cisplatin (CDDP) and TMZ. SiRNAs targeting ercc1, ercc2, mutyh, and pnkp significantly sensitized cells to chemotherapy, increasing cell death by up to 25%. In vivo we observed a decrease of subcutaneous glioma tumor growth after injection of siRNA in conjunction with absorption of TMZ. We demonstrated in this pre-clinical study that targeting of DNA-repair genes such as Ercc1 could be used as an adjuvant chemosensitization treatment, similarly to Mgmt inhibition.

Upregulation of Long Noncoding RNA Small Nucleolar RNA Host Gene 18 Promotes Radioresistance of Glioma by Repressing Semaphorin 5A

PURPOSE

Although increasing evidence has shown that long noncoding RNAs play an important regulatory role in carcinogenesis and tumor progression, little is known about the role of small nucleolar RNA host gene 18 (SNHG18) in cancer. The goal of this study was to investigate the expression of SNHG18 and its clinical significance in glioma.

METHODS AND MATERIALS

Differences in the lncRNA expression profile between M059K and M059J cells were assessed by lncRNA expression microarray analysis. The expression and localization of SNHG18 in glioma cells or tissues was evaluated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH), respectively. the clinical associations of SNHG18 in glioma was evaluated by qRT-PCR, ISH and immunohistochemistry. The role of SNHG18 in glioma radiosensitivity was evaluated by colony formation assays, immunofluorescence, Western blot and tumor growth inhibition study.

RESULTS

The present study investigated the clinical associations of SNHG18 and its role in glioma. Our results showed that the expression of SNHG18 was remarkably upregulated in clinical glioma tissues compared with normal brain tissues. SNHG18 expression was associated with the clinical tumor grade and correlated negatively with isocitrate dehydrogenase 1 mutation. In addition, knockdown of SNHG18 with short hairpin RNA suppressed the radioresistance of glioma cells, and transgenic expression of SNHG18 had the opposite effect. Furthermore, xenograft tumors grown from cells with SNHG18 deletion were more radiosensitive than tumors grown from control cells. Further studies revealed that SNHG18 promotes radioresistance by inhibiting semaphorin 5A and that inhibition of semaphorin 5A expression abrogated the radiosensitizing effect caused by SNHG18 deletion.

CONCLUSIONS

Our findings provide new insights into the role of SNHG18 in glioma and suggest its potential as a target for glioma therapy.

Olig2-Dependent Reciprocal Shift in PDGF and EGF Receptor Signaling Regulates Tumor Phenotype and Mitotic Growth in Malignant Glioma

Malignant gliomas exhibit extensive heterogeneity and poor prognosis. Here we identify mitotic Olig2-expressing cells as tumor-propagating cells in proneural gliomas, elimination of which blocks tumor initiation and progression. Intriguingly, deletion of Olig2 resulted in tumors that grow, albeit at a decelerated rate. Genome occupancy and expression profiling analyses reveal that Olig2 directly activates cell-proliferation machinery to promote tumorigenesis. Olig2 deletion causes a tumor phenotypic shift from an oligodendrocyte precursor-correlated proneural toward an astroglia-associated gene expression pattern, manifest in downregulation of platelet-derived growth factor receptor-α and reciprocal upregulation of epidermal growth factor receptor (EGFR). Olig2 deletion further sensitizes glioma cells to EGFR inhibitors and extends the lifespan of animals. Thus, Olig2-orchestrated receptor signaling drives mitotic growth and regulates glioma phenotypic plasticity. Targeting Olig2 may circumvent resistance to EGFR-targeted drugs.

CPEB1 restrains proliferation of Glioblastoma cells through the regulation of p27(Kip1) mRNA translation

The cytoplasmic element binding protein 1 (CPEB1) regulates many important biological processes ranging from cell cycle control to learning and memory formation, by controlling mRNA translation efficiency via 3' untranslated regions (3'UTR). In the present study, we show that CPEB1 is significantly downregulated in human Glioblastoma Multiforme (GBM) tissues and that the restoration of its expression impairs glioma cell lines growth. We demonstrate that CPEB1 promotes the expression of the cell cycle inhibitor p27(Kip1) by specifically targeting its 3'UTR, and competes with miR-221/222 binding at an overlapping site in the 3'UTR, thus impairing miR-221/222 inhibitory activity. Upon binding to p27(Kip1) 3'UTR, CPEB1 promotes elongation of poly-A tail and the subsequent translation of p27(Kip1) mRNA. This leads to higher levels of p27(Kip1) in the cell, in turn significantly inhibiting cell proliferation, and confers to CPEB1 a potential value as a tumor suppressor in Glioblastoma.

Reactivation of telomerase in cancer

Activation of telomerase is a critical step in the development of about 85 % of human cancers. Levels of Tert, which encodes the reverse transcriptase subunit of telomerase, are limiting in normal somatic cells. Tert is subjected to transcriptional, post-transcriptional and epigenetic regulation, but the precise mechanism of how telomerase is re-activated in cancer cells is poorly understood. Reactivation of the Tert promoter involves multiple changes which evolve during cancer progression including mutations and chromosomal re-arrangements. Newly described non-coding mutations in the Tert promoter region of many cancer cells (19 %) in two key positions, C250T and C228T, have added another layer of complexity to telomerase reactivation. These mutations create novel consensus sequences for transcription factors which can enhance Tert expression. In this review, we will discuss gene structure and function of Tert and provide insights into the mechanisms of Tert reactivation in cancers, highlighting the contribution of recently identified Tert promoter mutations.

Calycosin inhibits migration and invasion through modulation of transforming growth factor beta-mediated mesenchymal properties in U87 and U251 cells

In this study, we investigated the potential anticancer effects of calycosin against human glioblastoma cells, including the impacts on cell proliferation, apoptosis, and cell cycle distribution. We further studied its inhibitory activity on migration and invasion in U87 and U251 cells. Furthermore, transforming growth factor beta-mediated reductions of mesenchymal-associated genes/activators, matrix metalloproteinases-2, and -9 were detected in this process. Administration of calycosin in a glioblastoma xenograft model showed that calycosin could not only reduce tumor volume but also suppress transforming growth factor beta as well as its downstream molecules. These results revealed calycosin as a potential antitumor agent in human glioblastoma.

LncRNA TUG1 acts as a tumor suppressor in human glioma by promoting cell apoptosis

Previous studies have revealed multiple functional roles of long non-coding RNA taurine upregulated gene 1 in different types of malignant tumors, except for human glioma. Here, it was designed to study the potential function of taurine upregulated gene 1 in glioma pathogenesis focusing on its regulation on cell apoptosis. The expression of taurine upregulated gene 1 in glioma tissues was detected by quantitative RT-PCR and compared with that in adjacent normal tissues. Further correlation analysis was conducted to show the relationship between taurine upregulated gene 1 expression and different clinicopathologic parameters. Functional studies were performed to investigate the influence of taurine upregulated gene 1 on apoptosis and cell proliferation by using Annexin V/PI staining and cell counting kit-8 assays, respectively. And, caspase activation and Bcl-2 expression were analyzed to explore taurine upregulated gene 1-induced mechanism. taurine upregulated gene 1 expression was significantly inhibited in glioma and showed significant correlation with WHO Grade, tumor size and overall survival. Further experiments revealed that the dysregulation of taurine upregulated gene 1 affected the apoptosis and cell proliferation of glioma cells. Moreover, taurine upregulated gene 1 could induce the activation of caspase-3 and-9, with inhibited expression of Bcl-2, implying the mechanism in taurine upregulated gene 1-induced apoptosis. taurine upregulated gene 1 promoted cell apoptosis of glioma cells by activating caspase-3 and -9-mediated intrinsic pathways and inhibiting Bcl-2-mediated anti-apoptotic pathways, acting as a tumor suppressor in human glioma. This study provided new insights for the function of taurine upregulated gene 1 in cancer biology, and suggested a potent application of taurine upregulated gene 1 overexpression for glioma therapy.

Targeted superparamagnetic iron oxide nanoparticles for early detection of cancer: Possibilities and challenges

Nanomedicine, the integration of nanotechnological tools in medicine demonstrated promising potential to revolutionize the diagnosis and treatment of various human health conditions. Nanoparticles (NPs) have shown much promise in diagnostics of cancer, especially since they can accommodate targeting molecules on their surface, which search for specific tumor cell receptors upon injection into the blood stream. This concentrates the NPs in the desired tumor location. Furthermore, such receptor-specific targeting may be exploited for detection of potential metastases in an early stage. Some NPs, such as superparamagnetic iron oxide NPs (SPIONs), are also compatible with magnetic resonance imaging (MRI), which makes their clinical translation and application rather easy and accessible for tumor imaging purposes. Furthermore, multifunctional and/or theranostic NPs can be used for simultaneous imaging of cancer and drug delivery. In this review article, we will specifically focus on the application of SPIONs in early detection and imaging of major cancer types.

FROM THE CLINICAL EDITOR

Super-paramagnetic iron oxide nanoparticles (SPIONs) have been reported by many to be useful as an MRI contrast agent in the detection of tumors. To further enhance the tumor imaging, SPIONs can be coupled with tumor targeting motifs. In this article, the authors performed a comprehensive review on the current status of using targeted SPIONS in tumor detection and also the potential hurdles to overcome.

The challenges and the promise of molecular targeted therapy in malignant gliomas

Malignant gliomas are the most common malignant primary brain tumors and one of the most challenging forms of cancers to treat. Despite advances in conventional treatment, the outcome for patients remains almost universally fatal. This poor prognosis is due to therapeutic resistance and tumor recurrence after surgical removal. However, over the past decade, molecular targeted therapy has held the promise of transforming the care of malignant glioma patients. Significant progress in understanding the molecular pathology of gliomagenesis and maintenance of the malignant phenotypes will open opportunities to rationally develop new molecular targeted therapy options. Recently, therapeutic strategies have focused on targeting pro-growth signaling mediated by receptor tyrosine kinase/RAS/phosphatidylinositol 3-kinase pathway, proangiogenic pathways, and several other vital intracellular signaling networks, such as proteasome and histone deacetylase. However, several factors such as cross-talk between the altered pathways, intratumoral molecular heterogeneity, and therapeutic resistance of glioma stem cells (GSCs) have limited the activity of single agents. Efforts are ongoing to study in depth the complex molecular biology of glioma, develop novel regimens targeting GSCs, and identify biomarkers to stratify patients with the individualized molecular targeted therapy. Here, we review the molecular alterations relevant to the pathology of malignant glioma, review current advances in clinical targeted trials, and discuss the challenges, controversies, and future directions of molecular targeted therapy.

HOXB1 Is a Tumor Suppressor Gene Regulated by miR-3175 in Glioma

The HOXB1 gene plays a critical role as an oncogene in diverse tumors. However, the functional role of HOXB1 and the mechanism regulating HOXB1 expression in glioma are not fully understood. A preliminary bioinformatics analysis showed that HOXB1 is ectopically expressed in glioma, and that HOXB1 is a possible target of miR-3175. In this study, we investigated the function of HOXB1 and the relationship between HOXB1 and miR-3175 in glioma. We show that HOXB1 expression is significantly downregulated in glioma tissues and cell lines, and that its expression may be closely associated with the degree of malignancy. Reduced HOXB1 expression promoted the proliferation and invasion of glioma cells, and inhibited their apoptosis in vitro, and the downregulation of HOXB1 was also associated with worse survival in glioma patients. More importantly, HOXB1 was shown experimentally to be a direct target of miR-3175 in this study. The downregulated expression of miR-3175 inhibited cell proliferation and invasion, and promoted apoptosis in glioma. The oncogenicity induced by low HOXB1 expression was prevented by an miR-3175 inhibitor in glioma cells. Our results suggest that HOXB1 functions as a tumor suppressor, regulated by miR-3175 in glioma. These results clarify the pathogenesis of glioma and offer a potential target for its treatment.

Wnt5a, Ryk and Ror2 expression in glioblastoma subgroups

BACKGROUND

Wnt5a, a non-canonical Wnt ligand, has been shown to play tumor-promoting or tumor-suppressive roles in different neoplasms. Increased Wnt5a expression and Wnt5a-dependent invasive activity that is mediated by one of its receptors, Ryk, have been reported in glioblastomas.

METHODS

We investigated the protein expression of Wnt5a, its receptors Ryk and Ror2, and the canonical Wnt pathway marker β-catenin in 186 cases of glioblastoma and its variants. Associations with clinicopathological and molecular variables and prognosis were analyzed.

RESULTS

All glioblastoma cases expressed Wnt5a, Ryk and Ror2 with a different grade. The expression of both Ryk and Ror2 correlated with that of Wnt5a in glioblastomas. The expression of β-catenin did not correlate with any of Wnt5a, Ryk or Ror2. Wnt5a expression was significantly different among subgroups of the glioblastoma. However, none of Wnt5a, Ryk or Ror2 had a prognostic impact on glioblastoma. For β-catenin, a shorter progression-free survival was noted in the glioblastoma with oligodendroglioma component (GBMO) subgroup.

CONCLUSIONS

Our results corroborated previous findings of Ryk-mediated Wnt5a effect, and suggested a role for Ror2 in the Wnt5a machinery in glioblastoma.

Second Surgery in Insular Low-Grade Gliomas

Background. Given the technical difficulties, a limited number of works have been published on insular gliomas surgery and risk factors for tumor recurrence (TR) are poorly documented. Objective. The aim of the study was to determine TR in adult patients with initial diagnosis of insular Low-Grade Gliomas (LGGs) that subsequently underwent second surgery. Methods. A consecutive series of 53 patients with insular LGGs was retrospectively reviewed; 23 patients had two operations for TR. Results. At the time of second surgery, almost half of the patients had experienced progression into high-grade gliomas (HGGs). Univariate analysis showed that TR is influenced by the following: extent of resection (EOR) (P < 0.002), ΔVT2T1 value (P < 0.001), histological diagnosis of oligodendroglioma (P = 0.017), and mutation of IDH1 (P = 0.022). The multivariate analysis showed that EOR at first surgery was the independent predictor for TR (P < 0.001). Conclusions. In patients with insular LGG the EOR at first surgery represents the major predictive factor for TR. At time of TR, more than 50% of cases had progressed in HGG, raising the question of the oncological management after the first surgery.

Trichosanthin suppresses the proliferation of glioma cells by inhibiting LGR5 expression and the Wnt/β-catenin signaling pathway

Studies have indicated that trichosanthin (TCS), a bioactive protein extracted and purified from the tuberous root of Trichosanthes kirilowii (a well-known traditional Chinese medicinal plant), produces antitumor effects on various types of cancer cells. However, the effects of TCS on glioma cells are poorly understood. The objective of this study was to investigate the antitumor effects of TCS on the U87 and U251 cell lines. The in vitro effects of TCS on these two cell lines were determined using a Cell Counting Kit-8 (CCK-8) assay, Annexin V-FITC staining, DAPI staining, Transwell assays, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assays, 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethyl-imidacar-bocyanine iodide (JC-1) staining and western blotting, which was utilized to assess the expression of leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) and key proteins in the Wnt/β-catenin signaling pathway. Our data indicated that TCS inhibited the proliferation of glioma cells in a dose- and time-dependent manner and played a role in inhibiting glioma cell invasion and migration. Additional investigation revealed that the expression levels of LGR5 and of key proteins in the Wnt/β-catenin signaling pathway were markedly decreased after TCS treatment. The results suggest that TCS may induce apoptosis in glioma cells by targeting LGR5 and repressing the Wnt/β-catenin signaling pathway. In the future, in vivo experiments should be conducted to examine the potential use of this compound as a novel therapeutic agent for gliomas.

Exogenous hydrogen sulfide promotes C6 glioma cell growth through activation of the p38 MAPK/ERK1/2-COX-2 pathways

Hydrogen sulfide (H2S) participates in multifarious physiological and pathophysiologic progresses of cancer both in vitro and in vivo. We have previously demonstrated that exogenous H2S promoted liver cancer cells proliferation/anti‑apoptosis/angiogenesis/migration effects via amplifying the activation of NF-κB pathway. However, the effects of H2S on cancer cell proliferation and apoptosis are controversial and remain unclear in C6 glioma cells. The present study investigated the effects of exogenous H2S on cancer cells growth via activating p38 MAPK/ERK1/2-COX-2 pathways in C6 glioma cells. C6 glioma cells were treated with 400 µmol/l NaHS (a donor of H2S) for 24 h. The expression levels of phosphorylated (p)-p38 MAPK, total (t)-p38 MAPK, p-ERK1/2, t-ERK1/2, cyclooxygenase-2 (COX-2) and caspase-3 were measured by western blotting assay. Cell viability was detected by Cell Counting Kit-8 (CCK-8). Apoptotic cells were observed by Hoechst 33258 staining assay. Cell proliferation was directly detected under fully automatic inverted microscope. Exposure of C6 glioma cells to NaHS resulted in cell proliferation, as evidenced by an increase in cell viability. In addition, NaHS treatment reduced apoptosis, as indicated by the decreased apoptotic percentage and the cleaved caspase-3 expression. Importantly, exposure of the cells to NaHS increased the expression levels of p-p38 MAPK, p-ERK1/2 and COX-2. Notably, co-treatment of C6 glioma cells with 400 µmol/l NaHS and AOAA (an inhibitor of CBS) largely suppressed the above NaHS-induced effects. Combined treatment with NaHS and SB203580 (an inhibitor of p38 MAPK) or PD-98059 (an inhibitor of ERK1/2) resulted in the synergistic reduction of COX-2 expression and increase of caspase-3 expression, a decreased number of apoptotic cells, along with decreased cell viability. Combined treatment with NS-398 (an inhibitor of COX-2) and NaHS also resulted in the synergistic increase of caspase-3, a decreased in the number of apoptotic cells and the decrease in cell viability. The findings of the present study provide novel evidence that p38 MAPK/ERK1/2-COX-2 pathways are involved in NaHS-induced cancer cell proliferation and anti-apoptosis in C6 glioma cells.

MiR-323-5p acts as a tumor suppressor by targeting the insulin-like growth factor 1 receptor in human glioma cells

BACKGROUND

MicroRNAs, small noncoding RNA molecules, can regulate mammalian cell growth, apoptosis and differentiation by controlling the expression of target genes. The aim of this study was to investigate the function of miR-323-5p in the glioma cell line, U251.

MATERIALS AND METHODS

After over-expression of miR-323- 5p using miR-323-5p mimics, cell growth, apoptosis and migration were tested by MTT, flow cytometry and cell wound healing assay, respectively. We also assessed the influence of miR-323-5p on the mRNA expression of IGF- 1R by quantitative real-time reverse transcriptase PCR (qRT-PCR), and on the protein levels by Western blot analysi. In addition, dual-luciferase reporter assays were performed to determine the target site of miR-323-5p to IGF-1R 3'UTR.

RESULTS

Our findings showed that over-expression of miR-323-5p could promote apoptosis of U251 and inhibit the proliferation and migration of the glioma cells.

CONCLUSIONS

This study demonstrated that increased expression of miR-323-5p might be related to glioma progression, which indicates a potential role of miR-323-5p for clinical therapy.

Association of Telomerase Reverse Transcriptase Promoter Mutations with the Prognosis of Glioma Patients: a Meta-Analysis

Previous studies have found that telomerase reverse transcriptase (TERT) has vital roles in the development of malignant diseases including glioma. The occurrence of TERT promoter mutations in gliomas is frequent. So far, several studies on the association between TERT promoter mutations and prognosis of gliomas had been published, but the conclusion was still not uncertain. The aim of the present meta-analysis was to assess the association between TERT promoter mutations and survival of glioma patients by pooling data from published studies. PubMed, Embase, and Web of Science were searched for articles on the association between TERT promoter mutations and survival of glioma patients until June 30, 2015. Hazard ratios (HR) and the 95% confidence intervals (CIs) were utilized to analyze the prognosis of glioma patients with TERT promoter mutations. Heterogeneity of included studies was assessed using Cochrane's Q test and I (2) method. Eleven studies with a total of 3,444 glioma patients were finally included into the meta-analysis. Nine studies reported the HRs adjusting for other confounding factors. Meta-analysis of total 11 studies suggested that TERT promoter mutations were significantly associated with worse prognosis of patients with gliomas (HR = 2.07, 95% CI = 1.58-2.71, P < 0.00001). Meta-analysis of nine studies with adjusted outcomes suggested that TERT promoter mutations were independently associated with worse prognosis of patients with gliomas (HR = 2.28, 95% CI = 1.72-3.01, P < 0.00001). In conclusion, TERT promoter mutation is a promising biomarker for predicting worse prognosis for patients with gliomas. More prospective well-designed cohort studies are needed to further validate its prognostic role in gliomas.

Knockdown of PFTK1 Inhibits the Migration of Glioma Cells

The prognosis of glioma patients is generally poor, so it is urgent to find out the underlying molecular mechanisms. PFTK1 is a member of cyclin-dependent kinases (Cdks) family and has been reported to contribute to tumor migration and invasion. In this study, we aimed to explore the expression and function in human glioma. Western blot and immunohistochemistry were used to evaluate the expression of PFTK1. PFTK1 expression was higher in glioma tissues compared with normal brain tissues, and its level was associated with the WHO grade in Western blot analysis. The suppression of PFTK1 expression by RNA interference was shown to inhibit the migration of glioma cells. Knockdown of PFTK1 increases E-cadherin expression and decreases vimentin expression. These data show that PFTK1 may participate in the pathogenic process of glioma, suggesting that PFTK1 can become a potential therapeutic strategy for gastric cancer.

A new anti-glioma therapy, AG119: pre-clinical assessment in a mouse GL261 glioma model

BACKGROUND

High grade gliomas (HGGs; grades III and IV) are the most common primary brain tumors in adults, and their malignant nature ranks them fourth in incidence of cancer death. Standard treatment for glioblastomas (GBM), involving surgical resection followed by radiation and chemotherapy with temozolomide (TMZ) and the anti-angiogenic therapy bevacizumab, have not substantially improved overall survival. New therapeutic agents are desperately needed for this devastating disease. Here we study the potential therapeutic agent AG119 in a pre-clinical model for gliomas. AG119 possesses both anti-angiogenic (RTK inhibition) and antimicrotubule cytotoxic activity in a single molecule.

METHODS

GL261 glioma-bearing mice were either treated with AG119, anti-VEGF (vascular endothelial growth factor) antibody, anti c-Met antibody or TMZ, and compared to untreated tumor-bearing mice. Animal survival was assessed, and tumor volumes and vascular alterations were monitored with morphological magnetic resonance imaging (MRI) and perfusion-weighted imaging, respectively.

RESULTS

Percent survival of GL261 HGG-bearing mice treated with AG119 was significantly higher (p < 0.001) compared to untreated tumors. Tumor volumes (21-31 days following intracerebral implantation of GL261 cells) were found to be significantly lower for AG119 (p < 0.001), anti-VEGF (p < 0.05) and anti-c-Met (p < 0.001) antibody treatments, and TMZ-treated (p < 0.05) mice, compared to untreated controls. Perfusion data indicated that both AG119 and TMZ were able to reduce the effect of decreasing perfusion rates significantly (p < 0.05 for both), when compared to untreated tumors. It was also found that IC50 values for AG119 were much lower than those for TMZ in T98G and U251 cells.

CONCLUSIONS

These data support further exploration of the anticancer activity AG119 in HGG, as this compound was able to increase animal survival and decrease tumor volumes in a mouse GL261 glioma model, and that AG119 is also not subject to methyl guanine transferase (MGMT) mediated resistance, as is the case with TMZ, indicating that AG119 may be potentially useful in treating resistant gliomas.

Decreased Expression of MiRNA-204-5p Contributes to Glioma Progression and Promotes Glioma Cell Growth, Migration and Invasion

Gliomas are the most common malignant primary brain tumors in adults and exhibit a spectrum of aberrantly aggressive phenotype. Although increasing evidence indicated that the deregulation of microRNAs (miRNAs) contributes to tumorigenesis and invasion, little is known about the roles of miR-204-5p in human gliomas. In the present study, the expression of miR-204-5p in clinical glioma tissues was measured by qRT-PCR. The effects of miR-204-5p on glioma cell growth and metastasis were examined by overexpressing or inhibiting miR-204-5p. We found that the expression level of miR-204-5p was significantly reduced in clinical glioma tissues compared with normal brain tissues. Moreover, we revealed that the introduction of miR-204-5p dramatically suppressed glioma cell growth, migration and invasion. Furthermore, mechanistic investigations revealed that RAB22A, a member of the RAS oncogene family, is a direct functional target of miR-204-5p in gliomas. In vivo, restoring miR-204-5p expression in glioma cells suppressed tumorigenesis and increased overall host survival. Our findings suggest that miR-204-5p is a cancer suppressor miRNA and overexpression of miR-204-5p is a novel glioma treatment strategy.

Molecular Markers in Low-Grade Glioma-Toward Tumor Reclassification

Low-grade diffuse gliomas are a heterogeneous group of primary glial brain tumors with highly variable survival. Currently, patients with low-grade diffuse gliomas are stratified into risk subgroups by subjective histopathologic criteria with significant interobserver variability. Several key molecular signatures have emerged as diagnostic, prognostic, and predictor biomarkers for tumor classification and patient risk stratification. In this review, we discuss the effect of the most critical molecular alterations described in diffuse (IDH1/2, 1p/19q codeletion, ATRX, TERT, CIC, and FUBP1) and circumscribed (BRAF-KIAA1549, BRAF(V600E), and C11orf95-RELA fusion) gliomas. These molecular features reflect tumor heterogeneity and have specific associations with patient outcome that determine appropriate patient management. This has led to an important, fundamental shift toward developing a molecular classification of World Health Organization grade II-III diffuse glioma.

Applicable advances in the molecular pathology of glioblastoma

Comprising more than 80% of malignant brain tumors, glioma has proven to be a daunting cause of mortality in a vast majority of the human population. Progressive and extensive research on malignant glioma has substantially enhanced our understanding of glioma cell biology and molecular pathology. Subtypes of glioma such as astrocytoma and oligodendroglioma are currently grouped together into one pathological class, where they show many differences in histology and molecular etiology. This indicates that it may be beneficial to consider a new and radical subclassification. Thus, we summarize recent developments in glioblastoma multiforme (GBM) subtypes, immunohistochemical analyses useful for diagnoses and the biological evaluation and therapeutic implications of gliomas in this review.

EGFR promoter exhibits dynamic histone modifications and binding of ASH2L and P300 in human germinal matrix and gliomas

Several signaling pathways important for the proliferation and growth of brain cells are pathologically dysregulated in gliomas, including the epidermal growth factor receptor (EGFR). Expression of EGFR is high in neural progenitors during development and in gliomas but decreases significantly in most adult brain regions. Here we show that EGFR expression is maintained in the astrocyte ribbon of the adult human subventricular zone. The transcriptional regulation of EGFR expression is poorly understood. To investigate the role of epigenetics on EGFR regulation in the contexts of neural development and gliomagenesis, we measured levels of DNA methylation and histone H3 modifications at the EGFR promoter in human brain tissues, glioma specimens, and EGFR-expressing neural cells, acutely isolated from their native niche. While DNA was constitutively hypomethylated in non-neoplastic and glioma samples, regardless of their EGFR-expression status, the activating histone modifications H3K27ac and H3K4me3 were enriched only when EGFR is highly expressed (developing germinal matrix and gliomas). Conversely, repressive H3K27me3 marks predominated in adult white matter where EGFR is repressed. Furthermore, the histone methyltransferase core enzyme ASH2L was bound at EGFR in the germinal matrix and in gliomas where levels of H3K4me3 are high, and the histone acetyltransferase P300 was bound in samples with H3K27ac enrichment. Our studies use human cells and tissues undisturbed by cell-culture artifact, and point to an important, locus-specific role for chromatin remodeling in EGFR expression in human neural development that may be dysregulated during gliomagenesis, unraveling potential novel targets for future drug therapy.

High CD133 Expression Is Associated with Worse Prognosis in Patients with Glioblastoma

The CD133 antigen has been identified as a putative stem cell marker in gliomas. However, the prognostic significance of CD133 expression in glioblastoma patients remained controversial. A meta-analysis of published data was performed to comprehensively assess the prognostic role of CD133 expression in glioblastoma patients. Publications assessing the prognostic significance of CD133 expression in glioblastoma patients were identified in PubMed, Embase, and Web of Science up to November 2014. The pooled hazard ratio (HR) with 95% confidence interval (95% CI) was calculated using meta-analysis to evaluate the prognostic significance of CD133 expression in glioblastoma. Ten studies with a total of 715 glioblastoma patients were included into the meta-analysis. Overall, high CD133 expression was associated with poorer overall survival in patients with glioblastoma (HR = 1.96, 95% CI 1.46-2.64, P < 0.001). In addition, high CD133 expression was also associated with poorer progression-free survival in patients with glioblastoma (HR = 2.03, 95% CI 1.43-2.88, P < 0.001). Meta-analyses of studies with high quality showed that high CD133 expression was associated with both poorer overall survival (HR = 2.39, 95% CI 1.77-3.23, P < 0.001) and poorer progression-free survival (HR = 2.17, 95% CI 1.60-2.94, P < 0.001) in patients with glioblastoma. Meta-analysis of studies with adjusted estimates further showed that high CD133 expression was an independent prognostic factor of glioblastoma. High CD133 expression is associated with worse prognosis in patients with glioblastoma. More prospective studies with well-design are needed to confirm this finding.

Molecular and genetic pathways in gliomas: the future of personalized therapeutics

In the last few decades, we have seen significant advances in brain imaging, which have resulted in more detailed anatomic and functional localization of gliomas in relation to the eloquent cortex, as well as improvements in microsurgical techniques and enhanced delivery of adjuvant stereotactic radiation. While these advancements have led to a relatively modest improvement in clinical outcomes for patients with malignant gliomas, much more work remains to be done. As with other types of cancer, we are now rapidly moving past the era of histopathology dictating treatment for brain tumors and into the realm of molecular diagnostics and associated targeted therapies, specifically based on the genomic architecture of individual gliomas. In this review, we discuss the current era of molecular glioma characterization and how these profiles will allow for individualized, patient-specific targeted treatments.

Impact on prognosis of the regional distribution of MGMT methylation with respect to the CpG island methylator phenotype and age in glioma patients

Clinical and molecular prognostic factors in gliomas include age, IDH mutation, the glioma CpG island methylator phenotype (G-CIMP+) and promoter methylation of the O(6)-methylguanine DNA-methyltransferase (MGMT) gene. Among these markers, a predictive value was reported in glioblastomas (GBM) for MGMT promoter methylation, in particular in elderly GBM patients. In this study, methylation data from 46 glioma samples with the Illumina 450K platform were obtained and extended using external data to include a total of 247 glioma samples. Methylation analysis of the whole MGMT gene with this platform revealed two strongly survival-associated CpG regions within the promoter and the gene body, which were confirmed in a reported dataset of high grade-gliomas. Methylation at the promoter (CpG 25, cg12981137 and the prognostic model MGMT-STP27) and at the gene body CpG 165 (cg07933035), were significantly associated with better overall survival, and strongly correlated with G-CIMP+ status. In this series, the prognostic value of MGMT methylation at the promoter was not observed in G-CIMP- cases, although around 50 % of them were MGMT-methylated. These results were also obtained in an homogeneously-treated series of chemoradiated G-CIMP- GBMs analyzed by MSP and qMSP, and confirmed in a reported pyrosequencing-analyzed series of gliomas. Interestingly, in contrast to the MGMT promoter, gene body methylation was of prognostic value in G-CIMP-patients older than 65 years. Our study highlights the relevance of the prognostic value of the different regions of methylation throughout the MGMT gene that could be affected by specific G-CIMP profiles and age groups.

Decreased miRNA-637 is an unfavorable prognosis marker and promotes glioma cell growth, migration and invasion via direct targeting Akt1

Although increasing evidence indicated that the deregulation of microRNAs (miRNAs) contributes to tumorigenesis and invasion, little is known about the role of miR-637 in human gliomas. In the present study, we found that the expression level of miR-637 was significantly reduced in clinical glioma tissues compared with normal brain tissues. Moreover, we revealed that the introduction of miR-637 dramatically suppressed glioma cell growth, migration and invasion in vitro and in vivo. Further studies revealed that Akt1 is a direct target gene of miR-637. Silencing of Akt1 inhibited the growth and invasion of glioma cells by decreasing phosphorylated Akt, β-catenin, phosphorylated Foxo1 and Cyclin D1 and inducing the expression of Foxo1, which was consistent with the effect of miR-637 overexpression. Suppressed expression of miR-637 and increased Akt1 protein levels were correlated with unfavorable progression and poor prognosis, respectively, and a negative relationship between the miR-637 expression and Akt1 protein levels was observed in gliomas. Our findings provide new insights into the role of miR-637 in the development of gliomas, and implicate the potential application of miR-637 in cancer therapy.

Matrine inhibits the invasive properties of human glioma cells by regulating epithelial‑to‑mesenchymal transition

Matrine is reported to be effective in tumor therapies; however, the anti‑metastatic effect and molecular mechanism(s) of matrine on glioma remain poorly understood. Therefore, the purpose of this study was to assess the effects of matrine on glioma and the associated mechanism(s). In the study, we demonstrated that matrine inhibited the proliferation of glioma cells. We also observed that matrine inhibited the migration and invasion of glioma cells at non‑toxic concentrations. Matrine also decreased the expression of E‑cadherin and increased the expression of N‑cadherin. These results suggest that the anti‑metastatic effect of matrine may be correlated with epithelial‑to‑mesenchymal transition (EMT). Moreover, matrine could reduce the phosphorylation levels of p38 and AKT proteins. In conclusion, these results suggest matrine may be a potential alternative against invasive glioma cells via the p38 MAPK and AKT signaling‑dependent inhibition of EMT.

Contributions to drug resistance in glioblastoma derived from malignant cells in the sub-ependymal zone

Glioblastoma, the most common and aggressive adult brain tumor, is characterized by extreme phenotypic diversity and treatment failure. Through fluorescence-guided resection, we identified fluorescent tissue in the sub-ependymal zone (SEZ) of patients with glioblastoma. Histologic analysis and genomic characterization revealed that the SEZ harbors malignant cells with tumor-initiating capacity, analogous to cells isolated from the fluorescent tumor mass (T). We observed resistance to supramaximal chemotherapy doses along with differential patterns of drug response between T and SEZ in the same tumor. Our results reveal novel insights into glioblastoma growth dynamics, with implications for understanding and limiting treatment resistance.

Anatomical localization of isocitrate dehydrogenase 1 mutation: a voxel-based radiographic study of 146 low-grade gliomas

BACKGROUND AND PURPOSE

A brain tumor's location is associated with the genetic profile of its tumor precursor cells. Mutations in isocitrate dehydrogenase 1 (IDH1) are an early event in tumor development and play a critical role in gliomagenesis. This study was conducted to specify the anatomical characteristics of IDH1 mutation in low-grade gliomas and to further explore the origin of gliomas with IDH1 mutation. The impact of IDH1 mutation on disease prognosis was also evaluated.

METHODS

The pre-operative magnetic resonance images obtained from 146 patients with histologically confirmed low-grade glioma were analyzed retrospectively. All tumors were manually marked and registered to the standard location. Voxel-based lesion-symptom mapping analysis was used to identify brain regions associated with a high occurrence of IDH1 mutation. Progression-free survival and overall survival were estimated using the Kaplan-Meier method, and potential prognostic factors were evaluated using the multivariate proportional hazards model.

RESULTS

Isocitrate dehydrogenase 1 mutated low-grade gliomas occurred most frequently in the frontal lobe, and specifically in the area surrounding the rostral extension of the lateral ventricles. Additionally, it was demonstrated that IDH1 mutation was an independent predictor for longer progression-free survival and overall survival.

CONCLUSIONS

Low-grade gliomas with IDH1 mutation are region-specific and preferentially located surrounding the rostral extension of the lateral ventricles. Furthermore, such mutations are associated with a favorable clinical outcome.

Downregulation of STAT3 and activation of MAPK are involved in the induction of apoptosis by HNK in glioblastoma cell line U87

Honokiol [3,5-di-(2-propenyl)-1,1-biphenyl-2,2-diol; HNK], a natural bioactive molecular compound isolated from the Magnolia officinalis, exhibits potent antitumor activity against a variety of human cancer cell lines. However, few studies have reported the antineoplastic effects of HNK on glioblastoma cells. It remains unknown how apoptosis is induced by HNK in glioblastoma cells and through which associated pathway this compound acts. The present study confirmed that HNK inhibited proliferation of glioblastoma cells by inducing a slight G0/G1 phase cell cycle arrest and apoptosis. We demonstrated for the first time that HNK triggered apoptosis of glioblastoma cells through both caspase-independent and caspase-dependent pathways, the latter including the extrinsic pathway and intrinsic pathway. Moreover, the inhibition of STAT3 signaling, ERK1/2 as well as activation of the p38 MAPK signaling pathway may be involved in apoptosis induced by HNK in U87 cells. Our findings suggest that HNK treatment could be a promising therapeutic strategy in human glioblastoma.

Polysomy of chromosomes 1 and 19: an underestimated prognostic factor in oligodendroglial tumors

The clinical significance of chromosomes 1 and 19 deletion was well established in oligodendroglial tumors (ODGs). This study was designed to evaluate the prognostic implication of chromosomes 1 and 19 polysomy in gliomas. 584 patients with histological diagnosis of primary gliomas enrolled in the study. Chromosomes 1 and 19 status was detected with fluorescence in situ hybridization (FISH). Of the 584 cases, the frequency of 1q and 19p polysomy in mixed gliomas was significantly higher than ODGs or astrocytic tumors (1q P = 0.032 and P = 0.044; 19p P = 0.024 and P = 0.027); the frequency of 1q and 19p polysomy in low-grade gliomas (WHO II) was relatively lower compared with WHO III or WHO IV (1q P = 0.097 and P = 0.026; 19p P = 0.04 and P = 0.002). 1q, 19p and co-polysomy were confirmed as risk factors conveyed unfavorable outcomes, which has been further validated in both anaplastic oligodendroglial tumors (AOGs) (P = 0.07, P = 0.028 and P = 0.054 for PFS; P = 0.007, P = 0.001 and P = 0.002 for OS, respectively) and glioblastomas with oligodendroglioma component (GBMOs) (P = 0.005, P < 0.001 and P < 0.001 for PFS; P = 0.136, P = 0.006 and P = 0.051 for OS, respectively). Based on chromosomes 1/19 co-deletion and co-polysomy, AOGs and GBMOs could be divided into three subgroups which harbored distinct prognosis (AOGs P < 0.001 for PFS and P < 0.001 for OS; GBMOs P < 0.001 for PFS and P = 0.012 for OS). Chromosomes 1/19 polysomy are potential prognostic factors which confer unfavorable outcomes. The molecular prognostic grouping model based on chromosomes 1/19 co-polysomy and co-deletion better predicts prognosis and provides a more reliable information for treatment decision-making.

Advances in genetic and epigenetic analyses of gliomas: a neuropathological perspective

Gliomas, the most common malignant primary brain tumors, are universally fatal once they progress from low-grade into high-grade neoplasms. In recent years, we have accumulated unprecedented data about the genetic and epigenetic abnormalities in gliomas; yet, our appreciation of how these deadly tumors arise is still rudimentary. One of the major deterrents in understanding gliomagenesis is the remarkably complex and heterogeneous molecular composition of gliomas, as well as their ability to change phenotypically as they progress and recur. In the past decade, several monumental studies have begun to define better glioma heterogeneity. Four distinct molecular subgroups have emerged: proneural, classical, mesenchymal, and neural; which have unique gene expression signatures and prognostic significance. Of these, gliomas of the proneural subtype, which encompass most grade II/III diffuse gliomas and secondary glioblastomas and often carry isocitrate dehydrogenase (IDH) mutations, have emerged as a distinct tumor subclass with a notably superior prognosis. Important molecular markers with prognostic relevance, such as mutant IDH1/2, have already been incorporated into clinical neuropathological practice. The recent molecular discoveries in gliomas have also emphasized the intimate link between epigenetics and genetics in gliomagenesis. Several of the novel genetic mutations described are responsible for distinct epigenetic remodeling in gliomas, the mechanisms of which are currently being elucidated. Importantly, these epigenetic and genomic alterations represent new and exciting drug targets for future therapeutic interventions in our continuous fight with this fatal malignancy.

A vaccine targeting mutant IDH1 induces antitumour immunity

Monoallelic point mutations of isocitrate dehydrogenase type 1 (IDH1) are an early and defining event in the development of a subgroup of gliomas and other types of tumour. They almost uniformly occur in the critical arginine residue (Arg 132) in the catalytic pocket, resulting in a neomorphic enzymatic function, production of the oncometabolite 2-hydroxyglutarate (2-HG), genomic hypermethylation, genetic instability and malignant transformation. More than 70% of diffuse grade II and grade III gliomas carry the most frequent mutation, IDH1(R132H) (ref. 3). From an immunological perspective, IDH1(R132H) represents a potential target for immunotherapy as it is a tumour-specific potential neoantigen with high uniformity and penetrance expressed in all tumour cells. Here we demonstrate that IDH1(R132H) contains an immunogenic epitope suitable for mutation-specific vaccination. Peptides encompassing the mutated region are presented on major histocompatibility complexes (MHC) class II and induce mutation-specific CD4(+) T-helper-1 (TH1) responses. CD4(+) TH1 cells and antibodies spontaneously occurring in patients with IDH1(R132H)-mutated gliomas specifically recognize IDH1(R132H). Peptide vaccination of mice devoid of mouse MHC and transgenic for human MHC class I and II with IDH1(R132H) p123-142 results in an effective MHC class II-restricted mutation-specific antitumour immune response and control of pre-established syngeneic IDH1(R132H)-expressing tumours in a CD4(+) T-cell-dependent manner. As IDH1(R132H) is present in all tumour cells of these slow-growing gliomas, a mutation-specific anti-IDH1(R132H) vaccine may represent a viable novel therapeutic strategy for IDH1(R132H)-mutated tumours.

Long non-coding RNAs in glioma: functional roles and clinical perspectives

Long non-coding RNAs (lncRNAs) are a new class of non-coding gene regulators. But unlike their smaller counterparts, microRNAs, relatively less is known about the roles and functions of lncRNAs. Current evidence suggests that lncRNAs may play important roles in a wide range of biological processes in human cancers, including glioma. By acting as oncogenes or tumor suppressors, lncRNAs may contribute to glioma initiation, progression and other malignant phenotypes. Their expression profiles may also have important clinical implications in glioma subclassification and patients' prognostication. Here, we review current evidence related to the functional roles of lncRNAs in glioma. We will discuss the aberrant lncRNA expression signatures associated with glioma initiation and progression, as well as the potential mechanisms underlying lncRNA dysregulation. We also discuss the functional roles of lncRNAs in glioma biological behavior. Finally, the potentials and prospects of employing lncRNAs as novel biomarkers and therapeutic targets for glioma clinical practice will also be addressed.

A prognostic model based on preoperative MRI predicts overall survival in patients with diffuse gliomas

BACKGROUND AND PURPOSE

Diffuse gliomas are classified as grades II-IV on the basis of histologic features, with prognosis determined mainly by clinical factors and histologic grade supported by molecular markers. Our aim was to evaluate, in patients with diffuse gliomas, the relationship of relative CBV and ADC values to overall survival. In addition, we also propose a prognostic model based on preoperative MR imaging findings that predicts survival independent of histopathology.

MATERIALS AND METHODS

We conducted a retrospective analysis of the preoperative diffusion and perfusion MR imaging in 126 histologically confirmed diffuse gliomas. Median relative CBV and ADC values were selected for quantitative analysis. Survival univariate analysis was made by constructing survival curves by using the Kaplan-Meier method and comparing subgroups by log-rank probability tests. A Cox regression model was made for multivariate analysis.

RESULTS

The study included 126 diffuse gliomas (median follow-up of 14.5 months). ADC and relative CBV values had a significant influence on overall survival. Median overall survival for patients with ADC < 0.799 × 10(-3) mm(2)/s was <1 year. Multivariate analysis revealed that patient age, relative CBV, and ADC values were associated with survival independent of pathology. The preoperative model provides greater ability to predict survival than that obtained by histologic grade alone.

CONCLUSIONS

ADC values had a better correlation with overall survival than relative CBV values. A preoperative prognostic model based on patient age, relative CBV, and ADC values predicted overall survival of patients with diffuse gliomas independent of pathology. This preoperative model provides a more accurate predictor of survival than histologic grade alone.

Diagnostic discrepancies in malignant astrocytoma due to limited small pathological tumor sample can be overcome by IDH1 testing

The accurate grading of malignant astrocytomas has significant prognostic and therapeutic implications. Traditional histopathological grading can be challenging due to regional tumor heterogeneity, especially in scenarios where small amounts of tissue are available for pathologic review. Here, we hypothesized that a critical tumor resection volume is needed for correct grading of astrocytomas by histopathology. For insufficient tissue sampling, IDH1 molecular testing can act as a complementary marker to improve diagnostic accuracy. Volumetric analyses were obtained using preoperative and postoperative MRI images. Histological specimens were gathered from 403 patients with malignant astrocytoma who underwent craniotomy. IDH1 status was assessed by immunohistochemistry and sequencing. Patients with >20 cubic centimeters (cc) of the total tumor volume resected on MRI have higher rate of GBM diagnosis compared to <20 cc [odds ratio (OR) 2.57, 95% confidence interval (CI) 1.6-4.06, P < 0.0001]. The rate of IDH1 status remained constant regardless of the tumor volume resected (OR 0.81, 95% CI 0.48-1.36, P < 0.43). The rate of GBM diagnosis is twofold greater for individual surgical specimen >10 cc than those of lower volume (OR 2.48, 95% CI 1.88-3.28, P < 0.0001). Overall survival for AA patients with >20 cc tumor resection on MRI is significantly better than those with <20 cc tumor resected (P < 0.05). No volume-dependent differences were observed in patients with GBM (P < 0.4), IDH1 wild type (P < 0.1) or IDH1 mutation (P < 0.88). IDH1 status should be considered when total resection volume is <20 cc based on MRI analysis and for surgical specimen <10 cc to complement histopathologic diagnosis of malignant astrocytomas. In these specimens, under-diagnosis of GBM may occur when analysis is restricted to histopathology alone.

Anaplastic astrocytomas: survival and prognostic factors in a surgical series

BACKGROUND

To study patient characteristics, prognostic factors and overall survival (OS) in a consecutive, surgical series of WHO grade III anaplastic astrocytomas (AA).

METHODS

Patients were identified from a prospective tumor database at Oslo University Hospital, Norway, and patients undergoing surgery for an AA from 2005-2012 were included. Patients' medical charts were retrospectively reviewed for data collection.

RESULTS

A total of 99 adult patients with histologically verified AA were included. Median age was 52 years (20-81). Biopsy was conducted in 33 % and resection in 67 %. Adjuvant treatment with radiation therapy + temozolomide or radiation therapy only was given in 63 % and 26 %, respectively. The thirty-day mortality rate was 3 %. Median OS was 19 months (95 % CI 11-27 months). Age ≥ 65 years, KPS < 70, biopsy as opposed to resection, and no adjuvant treatment were confirmed negative prognostic factors in multivariate analysis. For patients undergoing resection, presence of postoperative contrast-enhanced tumor, not volume of residual tumor, had significant impact on OS in adjusted analysis.

CONCLUSIONS

Median OS following surgery was 19 months, though much variable outcome was observed among subgroups of AA (95 % CI 11-27 months). Age ≥65 years, KPS < 70, biopsy as opposed to resection, and no adjuvant treatment were confirmed negative prognostic factors for OS.

The proteomic response in glioblastoma in young patients

Increasing age is an important prognostic variable in glioblastoma (GBM). We have defined the proteomic response in GBM samples from 7 young patients (mean age 36 years) compared to peritumoural-control samples from 10 young patients (mean age 32 years). 2-Dimensional-gel-electrophoresis, image analysis, and protein identification (LC/MS) were performed. 68 proteins were significantly altered in young GBM samples with 29 proteins upregulated and 39 proteins downregulated. Over 50 proteins are described as altered in GBM for the first time. In a parallel analysis in old GBM (mean age 67 years), an excellent correlation could be demonstrated between the proteomic profile in young GBM and that in old GBM patients (r² = 0.95) with only 5 proteins altered significantly (p < 0.01). The proteomic response in young GBM patients highlighted alterations in protein–protein interactions in the immunoproteosome, NFkB signalling, and mitochondrial function and the same systems participated in the responses in old GBM patients.

Reconstructing and reprogramming the tumor-propagating potential of glioblastoma stem-like cells

Developmental fate decisions are dictated by master transcription factors (TFs) that interact with cis-regulatory elements to direct transcriptional programs. Certain malignant tumors may also depend on cellular hierarchies reminiscent of normal development but superimposed on underlying genetic aberrations. In glioblastoma (GBM), a subset of stem-like tumor-propagating cells (TPCs) appears to drive tumor progression and underlie therapeutic resistance yet remain poorly understood. Here, we identify a core set of neurodevelopmental TFs (POU3F2, SOX2, SALL2, and OLIG2) essential for GBM propagation. These TFs coordinately bind and activate TPC-specific regulatory elements and are sufficient to fully reprogram differentiated GBM cells to "induced" TPCs, recapitulating the epigenetic landscape and phenotype of native TPCs. We reconstruct a network model that highlights critical interactions and identifies candidate therapeutic targets for eliminating TPCs. Our study establishes the epigenetic basis of a developmental hierarchy in GBM, provides detailed insight into underlying gene regulatory programs, and suggests attendant therapeutic strategies. PAPERCLIP:

Extracts from glioma tissues following cryoablation have proapoptosis, antiproliferation, and anti-invasion effects on glioma cells

OBJECTIVE

This study is to investigate the in vivo apoptotic processes in glioma tissues following cryoablation and the effects of glioma tissue extracts on GL261 glioma cells in vitro.

METHODS

TUNEL and flow cytometry analysis were performed to detect the apoptotic processes in the glioma tissues following cryoablation and in the GL261 cells treated with cryoablated tumor extracts. The scratch assay, the transwell assay, and Western blot analysis were carried out to evaluate the effects of cryoablated tumor extracts on the migration, invasion, and proliferation of tumor cells.

RESULTS

Our in vivo results indicated that the rapid-onset apoptosis was induced via the intrinsic pathway and the delayed apoptosis was triggered through the extrinsic pathway. The in vitro results showed that extracts from glioma tissues following cryoablation induced apoptosis via extrinsic pathways in GL261 glioma cells. Furthermore, cryoablated tumor extracts significantly inhibited the migration and proliferation of these cells, which would be related to the inhibition of ERK1/2 pathway and the activation of P38 pathway.

CONCLUSION

Glioma cells surviving in cryoablation undergo intrinsic or extrinsic apoptosis. Augmenting the induction of apoptosis or enhancing the cryosensitization of tumor cells by coupling cryoablation with specific chemotherapy effectively increases the efficiency of this therapeutic treatment.

Relationships between PTEN gene mutations and prognosis in glioma: a meta-analysis

We conducted a meta-analysis in order to investigate the relationships between PTEN gene mutations and the prognosis in glioma. The following electronic databases were searched for relevant articles without any language restrictions: Web of Science (1945 ~ 2013), the Cochrane Library Database (Issue 12, 2013), PubMed (1966 ~ 2013), EMBASE (1980 ~ 2013), CINAHL (1982 ~ 2013), and the Chinese Biomedical Database (CBM) (1982 ~ 2013). Meta-analyses were conducted using the STATA software (Version 12.0, Stata Corporation, College Station, Texas USA). Hazard ratio (HR) with its corresponding 95 % confidence interval (95%CI) was calculated. Six independent cohort studies with a total of 357 glioma patients met our inclusion criteria. Our meta-analysis results indicated that glioma patients with PTEN gene mutations exhibited a significantly shorter overall survival (OS) than those without PTEN gene mutations (HR = 3.66, 95%CI = 2.02 ~ 5.30, P < 0.001). Ethnicity-stratified subgroup analysis demonstrated that PTEN gene mutations were closely linked to poor prognosis in glioma among Americans (HR = 3.72, 95%CI = 1.72 ~ 5.73, P < 0.001), while similar correlations were not observed among populations in Sweden, Italy, and Malaysia (all P > 0.05). Our meta-analysis provides direct and strong evidences for the speculation of PTEN gene mutations' correlation with poor prognosis of glioma patients.