Brain and CNS Tumors


Literature Analysis

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Tag cloud generated 29 August, 2019 using data from PubMed, MeSH and CancerIndex

Mutated Genes and Abnormal Protein Expression (32)

How to use this data tableClicking on the Gene or Topic will take you to a separate more detailed page. Sort this list by clicking on a column heading e.g. 'Gene' or 'Topic'.

PTEN 10q23.31 BZS, DEC, CWS1, GLM2, MHAM, TEP1, MMAC1, PTEN1, 10q23del -PTEN and Glioblastoma
DMBT1 10q26.13 SAG, GP340, SALSA, muclin -DMBT1 and Brain Tumours
-DMBT1 and Glioblastoma
-DMBT1 and Brain Stem Glioma
-DMBT1 and Brain, Astrocytoma
MMP2 16q12.2 CLG4, MONA, CLG4A, MMP-2, TBE-1, MMP-II -MMP2 and CNS Tumors
MGMT 10q26.3 -MGMT and Oligodendroglioma
KIAA1549 7q34 -KIAA1549 and Brain and CNS Tumours
KRIT1 7q21.2 CAM, CCM1 -KRIT1 and Brain and CNS Tumours
MIR21 17q23.1 MIRN21, miR-21, miRNA21, hsa-mir-21 -MicroRNA miR-21 and Brain Tumors
PDGFA 7p22.3 PDGF1, PDGF-A -PDGFA and Glioma
NOTCH2 1p12 hN2, AGS2, HJCYS -NOTCH2 and Brain Tumours
DONSON 21q22.11 B17, MIMIS, MISSLA, C21orf60 -DONSON and Brain and CNS Tumours
RTEL1 20q13.33 NHL, RTEL, DKCA4, DKCB5, PFBMFT3, C20orf41 -RTEL1 and Brain and CNS Tumours
GFAP 17q21.31 ALXDRD -GFAP and Oligodendroglioma
ATRX Xq21.1 JMS, XH2, XNP, MRX52, RAD54, RAD54L, ZNF-HX -ATRX and Oligodendroglioma
CCM2 7p13 OSM, C7orf22, PP10187 -CCM2 and Brain and CNS Tumours
PDCD10 3q26.1 CCM3, TFAR15 -PDCD10 and Brain and CNS Tumours
CIC 19q13.2 -CIC and Oligodendroglioma
OLIG2 21q22.11 BHLHB1, OLIGO2, RACK17, PRKCBP2, bHLHe19 -OLIG2 and Oligodendroglioma
S100A6 1q21.3 2A9, PRA, 5B10, CABP, CACY, S10A6 -S100A6 Expression in CNS Tumors
RAF1 3p25.2 NS5, CRAF, Raf-1, c-Raf, CMD1NN -RAF1 and Astrocytoma
ROS1 6q22.1 ROS, MCF3, c-ros-1 -ROS1 rearrangements in Glioblastoma
TGFB2 1q41 LDS4, G-TSF, TGF-beta2 -TGFB2 and Brain Tumours
FAT1 4q35.2 FAT, ME5, CDHF7, CDHR8, hFat1 -FAT1 and Glioblastoma
NKX2-2 20p11.22 NKX2B, NKX2.2 -NKX2-2 and Oligodendroglioma
LRP5 11q13.2 HBM, LR3, OPS, EVR1, EVR4, LRP7, OPPG, BMND1, LRP-5, OPTA1, VBCH2 -LRP5 and Brain and CNS Tumours
CCDC26 8q24.21 RAM -CCDC26 and Oligodendroglioma
IQGAP1 15q26.1 SAR1, p195, HUMORFA01 -IQGAP1 and Oligodendroglioma
PTPRK 6q22.33 R-PTP-kappa -PTPRK and Brain and CNS Tumours
CNTRL 9q33.2 FAN, CEP1, CEP110, bA165P4.1 -CNTRL and Oligodendroglioma
FTL 19q13.33 LFTD, NBIA3 -FTL and Oligodendroglioma
LRRN2 1q32.1 GAC1, LRRN5, LRANK1, FIGLER7 -LRRN2 and Oligodendroglioma
CLP1 11q12.1 HEAB, hClp1 -CLP1 and Brain and CNS Tumours
NOP53 19q13.33 PICT1, PICT-1, GLTSCR2 -GLTSCR2 and Oligodendroglioma

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications

Okuda T, Fujita M, Kato A
Significance of Elevated HMGB1 Expression in Pituitary Apoplexy.
Anticancer Res. 2019; 39(8):4491-4494 [PubMed] Related Publications
BACKGROUND/AIM: High-mobility group box 1 (HMGB1) is a nuclear DNA-binding protein that exerts a range of proinflammatory actions when it is secreted extracellularly. We hypothesized that HMGB1 released from damaged cells in pituitary apoplexy would exacerbate the neurological symptoms due to acute inflammation.
PATIENTS AND METHODS: All the patients included in this study suffered from non-functioning pituitary adenoma. Four patients with apoplexy and three patients without apoplexy were included in this study. They underwent endonasal transsphenoidal endoscopic surgery to resect the tumors. We conducted enzyme-linked immunosorbent assay (ELISA) to measure HMGB1 in the surgical specimens.
RESULTS: Patients with apoplexy expressed HMGB1 at significantly higher levels than those in the non-apoplexy group (p=0.0478).
CONCLUSION: HMGB1 may be involved in subacute inflammation of pituitary apoplexy. Further work is needed to elucidate the detailed biological significance of HMGB1 in this disease.

Benenemissi IH, Sifi K, Sahli LK, et al.
Angiotensin-converting enzyme insertion/deletion gene polymorphisms and the risk of glioma in an Algerian population.
Pan Afr Med J. 2019; 32:197 [PubMed] Free Access to Full Article Related Publications
Introduction: Just recently, it has been established that the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism is linked to the pathogenesis and to the evolution of human cancers. Therefore, the present study was concerned with the investigation of an eventual association between glioma and I/D polymorphism of the ACE gene.
Methods: The expression of ACE gene was detected by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis in 36 Algerian patients with glioma and 195 healthy controls.
Results: In glioma cases, allelic frequencies and genotypes distribution of the ACE I/D polymorphism were different from controls cases. ACE DD genotype were highly presented in glioma cases (63.9%) than controls (33.8%) and conferred 3.64-fold risk for predisposition in glioma cases (vs ID genotype, p<0.001). Recessive model (ACE II + ID genotypes vs DD) was associated with a 72% reduced risk of glioma (OR = 0.28, 95% CI: 0.13-0.60, p <0.001). Per copy D allele frequency was found higher in glioma cases (79.2%) than in controls (63.3 %), OR = 2.20, 95% CI: 1.20 - 4.03, p = 0.009.
Conclusion: The obtained data showed that the presence of the D allele might be a risk factor for the development of glioma. Further studies considering different ethnic groups with large samples are required to confirm this finding.

Tong Y, Ye L, Li S, et al.
The association of 6 variants of 8q24 and the risk of glioma: A meta-analysis.
Medicine (Baltimore). 2019; 98(27):e16205 [PubMed] Free Access to Full Article Related Publications
With the advances in sequencing technologies and genome-wide association studies (GWAS), several inherited variants that increase glioma risk have been identified. Ten studies including 8818 cases and 17,551 controls were collected to conduct a meta-analysis to evaluate the associations between 6 variants in 8q24 and glioma risk. Of the 6 variants located in 8q24, 2 have strong significant associations with the risk of glioma, including rs4295627 (P = .003, odds ratio [OR] = 1.21), rs55705857 (P = 2.31 × 10, OR = 3.54). In particular, both homozygous GG (P = 1.91 × 10, OR1 = 2.01) and heterozygous GT (P = 7.75 × 10, OR2 = 1.35) genotypes of rs4295627 were associated with glioma risk. Further studies are needed to explore the role of the 8q24 variants involved in the etiology of glioma.

Ji YC, Zhan YB, Liu XZ, Zhang ZY
[IDH、TERT and 1p/19q predicting clinical outcomes in patients with anaplastic oligodendroglioma].
Zhonghua Yi Xue Za Zhi. 2019; 99(25):1959-1962 [PubMed] Related Publications

Liu Z, Liu H, Liu Z, Zhang J
Oligodendroglial tumours: subventricular zone involvement and seizure history are associated with CIC mutation status.
BMC Neurol. 2019; 19(1):134 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: CIC-mutant oligodendroglial tumours linked to better prognosis. We aim to investigate associations between CIC gene mutation status, MR characteristics and clinical features.
METHODS: Imaging and genomic data from the Cancer Genome Atlas and the Cancer Imaging Archive (TCGA/TCIA) for 59 patients with oligodendroglial tumours were used. Differences between CIC mutation and CIC wild-type were tested using Chi-square test and binary logistic regression analysis.
RESULTS: In univariate analysis, the clinical variables and MR features, which consisted 3 selected features (subventricular zone[SVZ] involvement, volume and seizure history) were associated with CIC mutation status (all p < 0.05). A multivariate logistic regression analysis identified that seizure history (no vs. yes odd ratio [OR]: 28.960, 95 confidence interval [CI]:2.625-319.49, p = 0.006) and SVZ involvement (SVZ- vs. SVZ+ OR: 77.092, p = 0.003; 95% CI: 4.578-1298.334) were associated with a higher incidence of CIC mutation status. The nomogram showed good discrimination, with a C-index of 0.906 (95% CI: 0.812-1.000) and was well calibrated. SVZ- group has increased (SVZ- vs. SVZ+, hazard ratio [HR]: 4.500, p = 0.04; 95% CI: 1.069-18.945) overall survival.
CONCLUSIONS: Absence of seizure history and SVZ involvement (-) was associated with a higher incidence of CIC mutation.

Yang Q, Wang R, Wei B, et al.
Gene and microRNA Signatures Are Associated with the Development and Survival of Glioblastoma Patients.
DNA Cell Biol. 2019; 38(7):688-699 [PubMed] Related Publications
This study was aimed to identify hub genes associated with the development of glioblastoma (GBM) by conducting a bioinformatic analysis. The raw gene expression data were downloaded from the Gene Expression Omnibus database and The Cancer Genome Atlas project. After the differentially expressed genes (DEGs) were identified, the functional enrichment analysis of DEGs was conducted. Subsequently, the protein-protein interaction (PPI) network, molecular complex detection clusters, and transcriptional factor (TF)-miRNA-target regulatory network were constructed, respectively. Furthermore, the survival analysis of prognostic outcomes and genes was analyzed. In addition, the expression of key genes was validated by quantitative real-time PCR (qRT-PCR) analysis. A total of 884 DEGs, including 418 upregulated and downregulated genes, were identified between GBM and normal samples. The PPI network comprised a set of 3418 pairs involving 751 nodes, and

Zuo J, Yu H, Xie P, et al.
miR-454-3p exerts tumor-suppressive functions by down-regulation of NFATc2 in glioblastoma.
Gene. 2019; 710:233-239 [PubMed] Related Publications
Glioblastoma (GBM) is the most prevalent and malignant primary brain tumor. Numerous studies have demonstrated that aberrant microRNAs (miRNAs) expression is involved in various pathogenesis events in GBM. miR-454-3p has been found to be downregulated in GBM, however, the role and underlying mechanism has not been fully investigated. The expression levels of miR-454-3p in GBM clinical tissues and cultured cell lines were measured by qRT-PCR. To evaluate the role of miR-454-3p in GBM, GBM cells were transfected with miR-454-3p inhibitor (anti-miR-454-3p)/control inhibitor (anti-miR-NC) or miR-454-3p mimic/control mimic (miR-NC). Online prediction algorithm Targetscan was used to predict the target genes of miR-454-3p. The dual luciferase reporter gene assay was performed to confirm whether nuclear factor of activated T cells c2 (NFATc2) was a direct biological target of miR-454-3p. We found that miR-454-3p expression was significantly decreased in both GBM tissues and cultured cell lines. Overexpression of miR-454-3p by transfection with miR-454-3p mimic suppressed cell proliferation and induced apoptosis of GBM cells. Nuclear factor of activated T cells c2 (NFATc2) was predicted as a target gene of miR-454-3p. We found that NFATc2 expression was significantly increased in both GBM tissues and cultured cell lines. Besides, expression levels of miR-454-3p were negatively associated with NFATc2 expression in GBM tissues. NFATc2 knockdown in GBM cells obviously inhibited cell proliferation and elevated apoptosis. Luciferase reporter assay revealed that NFATc2 was a target gene of miR-454-3p. miR-454-3p overexpression suppressed the NFATc2 expression, while inhibition of miR-454-3p induced the NFATc2 expression. Suppression of NFATc2 blocked the effects of miR-454-3p inhibitor on cell proliferation and apoptosis in GBM cells. The results indicated that miR-454-3p executed the tumor suppressive activity via downregulating NFATc2 in GBM.

Stasenko M, Cybulska P, Feit N, et al.
Brain metastasis in epithelial ovarian cancer by BRCA1/2 mutation status.
Gynecol Oncol. 2019; 154(1):144-149 [PubMed] Article available free on PMC after 01/07/2020 Related Publications
OBJECTIVE: To evaluate clinical outcomes of patients with BRCA-associated ovarian cancer who developed brain metastases (BM).
METHODS: Patients with epithelial ovarian, fallopian tube, and primary peritoneal cancer (EOC) and BM, treated at a single institution from 1/1/2008-7/1/2018, were identified from two institutional databases. Charts and medical records were retrospectively reviewed for clinical characteristics and germline BRCA mutation status. Appropriate statistics were used.
RESULTS: Of 3649 patients with EOC, 91 had BM (2.5%). Germline mutation status was available for 63 (69%) cases; 21 (35%) of these harbored a BRCA1/2 mutation (15 BRCA1, 6 BRCA2). Clinical characteristics were similar between groups. BM were diagnosed at a median of 31 months (95% CI, 22.6-39.4) in BRCA-mutated (mBRCA) and 32 months (95% CI, 23.7-40.3) in wild-type BRCA (wtBRCA) (p = 0.78) patients. Brain metastases were the only evidence of disease at time of BM diagnoses in 48% (n = 10) mBRCA and 19% (n = 8) wtBRCA (p = 0.02) patients. There was no difference in treatment of BM by mutation status (p = 0.84). Survival from time of BM diagnosis was 29 months (95%CI, 15.5-42.5) in mBRCA and 9 months (95% CI, 5.5-12.5) in wtBRCA patients, with an adjusted hazard ratio (HR) of 0.53, p = 0.09; 95% CI, 0.25-1.11. HR was adjusted for presence of systemic disease at time of BM diagnosis.
CONCLUSION: This is the largest study to date comparing outcomes in patients with EOC and BM by mutation status. mBRCA patients were more likely to have isolated BM, which may be a factor in their long survival. This supports the pursuit of aggressive treatment for mBRCA EOC patients with BM. Additional studies examining the correlation of BRCA mutational status with BM are warranted.

Karlowee V, Amatya VJ, Takayasu T, et al.
Immunostaining of Increased Expression of Enhancer of Zeste Homolog 2 (EZH2) in Diffuse Midline Glioma H3K27M-Mutant Patients with Poor Survival.
Pathobiology. 2019; 86(2-3):152-161 [PubMed] Related Publications
INTRODUCTION: The interaction of K27M mutation in histone H3 (H3K27M mutation) with polycomb repressive complex 2 (PRC2) is facilitated by the enhancer of zeste homolog 2 (EZH2). Subsequently, this interaction leads to the global reduction level of H3K27me3. We analyzed the EZH2 expression level in H3K27M mutation-positive tumors and revealed the association of high EZH2 expression with poor survival.
METHODS: Our study included 12 patients, with an age range of 6-56 years and treated between 2007 and 2016. All patients underwent MRI study for nonenhanced T1, T2, diffusion, gadolinium-enhanced T1-weighted imaging, and fluid-attenuated inversion recovery (FLAIR). Immunohistochemical staining was performed against H3K27M, H3K27me3, EZH2, EED, mutant isocitrate dehydrogenase 1 (IDH1), α-thalassemia X-linked intellectual disability (ATRX), p53, O6-methylguanine-DNA methyltransferase (MGMT), and Ki-67 antibodies.
RESULTS: All patients were negative for IDH1R132H and H3K27me3, but H3K27M-positive. Staining against EZH2 was negative in all histological features of grade II cases (3/12) and positive in grade III and IV cases; EZH2 positivity is associated with poor prognosis (p = 0.0082). EZH2 positivity was not associated with EED positivity. Retained ATRX staining was found mostly in grade III and IV cases (6/12). P53 was predominantly positive in cases of astrocytoma and glioblastoma (8/12). The labeling index of Ki-67 was 1.2-31.4% for grade II and III histological features and 11.2-24.8% for grade IV.
CONCLUSION: We suggest that the expression of EZH2 is not associated with the PRC2 pathway and increases in patients with H3K27M-mutant diffuse midline glioma and a poor prognosis. Further studies are necessary to understand the mechanism involved.

Jain SU, Do TJ, Lund PJ, et al.
PFA ependymoma-associated protein EZHIP inhibits PRC2 activity through a H3 K27M-like mechanism.
Nat Commun. 2019; 10(1):2146 [PubMed] Article available free on PMC after 01/07/2020 Related Publications
Posterior fossa type A (PFA) ependymomas exhibit very low H3K27 methylation and express high levels of EZHIP (Enhancer of Zeste Homologs Inhibitory Protein, also termed CXORF67). Here we find that a conserved sequence in EZHIP is necessary and sufficient to inhibit PRC2 catalytic activity in vitro and in vivo. EZHIP directly contacts the active site of the EZH2 subunit in a mechanism similar to the H3 K27M oncohistone. Furthermore, expression of H3 K27M or EZHIP in cells promotes similar chromatin profiles: loss of broad H3K27me3 domains, but retention of H3K27me3 at CpG islands. We find that H3K27me3-mediated allosteric activation of PRC2 substantially increases the inhibition potential of EZHIP and H3 K27M, providing a mechanism to explain the observed loss of H3K27me3 spreading in tumors. Our data indicate that PFA ependymoma and DIPG are driven in part by the action of peptidyl PRC2 inhibitors, the K27M oncohistone and the EZHIP 'oncohistone-mimic', that dysregulate gene silencing to promote tumorigenesis.

Sidaraite A, Vilkeviciute A, Glebauskiene B, et al.
Association of ApoE haplotype with clinical evidence of pituitary adenoma.
Gene. 2019; 706:154-161 [PubMed] Related Publications
PURPOSE: To evaluate the association of the presence, invasiveness, hormonal activity and recurrence of pituitary adenoma (PA) with ApoE genotypes and alleles.
MATERIALS AND METHODS: Our study group included 142 patients with PA and the control group included 256 healthy individuals. The genotyping of ApoE (rs7412 and rs429358) was performed using a real-time PCR method.
RESULTS: After statistical analysis we found that ApoE genotype E2/E3 was associated with 2.6-fold increased odds of active PA (OR = 2.609; 95%CI: 1.380-4.932; p = 0.003), while the presence of ApoE E3/E3 decreased odds of active PA by 65% (OR = 0.343; 95%CI: 0.205-0.575; p < 0.001). The frequency of the allele ε3 was lesser in the PA group (74.3% vs. 83%, p = 0.003) when compared to controls but it was statistically significantly more frequent in the invasive PA than in the noninvasive PA subgroup (80.4% vs. 65.5%, p = 0.005). The ApoE E2/E4 genotype was more frequent in the noninvasive PA subgroup (10.3% vs. 0%, p = 0.003) than in the invasive PA subgroup. The ApoE E4/E4 genotype was more frequent in the recurrent than in the non-recurrent PA subgroup (6.6% vs. 0%, p = 0.006). No associations between ApoE polymorphisms and Ki-67 labelling index were found.
CONCLUSION: The ApoE E2/E3 genotype is associated with the presence of PA while the ApoE genotype E2/E4 is associated with noninvasive PA development. The allele ε3 could possibly have a protective effect against PA. The genotype E4/E4 is associated with the development of recurrent PA.

Lupinacci FCS, Kuasne H, Roffé M, et al.
Polysome Profiling of a Human Glioblastoma Reveals Intratumoral Heterogeneity.
Int J Mol Sci. 2019; 20(9) [PubMed] Article available free on PMC after 01/07/2020 Related Publications
Glioblastoma (GBM) is one of the most aggressive cancers, with median survival of less than 2 years. Despite of considerable advance in molecular classification of GBMs, no improvements in therapy have been described. The scenario is further complicated by tumor heterogeneity and the relationship among genetic, transcriptional and functional findings. Classically, gene expression has been evaluated by steady-state mRNA, however, this does not take translational control into consideration, which contributes considerably to the composition of the proteome. In this study, we evaluated the transcriptomic and translatomic signature of a GBM obtained from a single patient focusing in tumor heterogeneity. In a sampling of eight fragments, we investigated the translation rates, mTORC1 and ERK1/2 pathways and identified both total and polysome associated mRNAs. An increased translation rate was observed in fragments with high-grade histological features. High-grade histology was also associated with the expression of genes related to extracellular matrix (ECM) and angiogenesis, in both transcriptomes and translatomes. However, genes associated with epithelial to mesenchymal transition and stress response, were observed only in translatomes from high-grade fragments. Overall, our results demonstrate that isolation of translated mRNA can be used to identify biomarkers and reveal previously unrecognized determinants of heterogeneity in GBMs.

Du N, Bao W, Zhang K, et al.
Cytogenetic characterization of the malignant primitive neuroectodermal SK-PN-DW tumor cell line.
BMC Cancer. 2019; 19(1):412 [PubMed] Article available free on PMC after 01/07/2020 Related Publications
BACKGROUND: The SK-PN-DW cell line was established in 1979 and is commercially available. Despite the use of this cell line as an in vitro model for functional and therapeutic studies of malignant primitive neuroectodermal tumor (PNET), there is a lack of complete information about the genetic alterations that are present at the cytogenetic level. Thus, the current study aimed to characterize the cytogenetic profile of this cell line.
METHODS: Routine G-banded chromosome analysis, fluorescence in situ hybridization, and oligonucleotide array comparative genomic hybridization assays were performed to characterize the chromosomal changes in this cell line.
RESULTS: The G-banded karyotype analysis showed that the number of chromosomes in this cell line ranged between 36 and 41. Importantly, all cells displayed a loss of chromosomes Y, 11, 13, and 18. However, some cells showed an additional loss of chromosome 10. Additionally, the observed structural changes indicated: a) unbalanced translocation between chromosomes 1 and 7; b) translocation between chromosomes 11 and 22 at breakpoints 11q24 and 22q12, which is a classical translocation that is associated with Ewing sarcoma; c) a derivative chromosome due to a whole arm translocation between chromosomes 16 and 17 at likely breakpoints 16p10 and 17q10; and d) possible rearrangement in the short arm of chromosome 18. Moreover, a variable number of double minutes were also observed in each metaphase cell. Furthermore, the microarray assay results not only demonstrated genomic-wide chromosomal imbalance in this cell line and precisely placed chromosomal breakpoints on unbalanced, rearranged chromosomes, but also revealed information about subtle chromosomal changes and the chromosomal origin of double minutes. Finally, the fluorescence in situ hybridization assay confirmed the findings of the routine cytogenetic analysis and microarrays.
CONCLUSION: The accurate determination of the cytogenetic profile of the SK-PN-DW cell line is helpful in enabling the research community to utilize this cell line for future identity and comparability studies, in addition to demonstrating the utility of the complete cytogenetic profile, as a public resource.

Khajehgoodari R, Khorvash F, Kheirollahi M, et al.
Correlations between the expression of hTERT and α and β splice variants in human brain tumors.
Adv Clin Exp Med. 2019; 28(4):507-513 [PubMed] Related Publications
BACKGROUND: Astrocytomas are diffusible infiltrative and aggressive brain tumors that are extensive and heterogeneous clusters of neoplastic growths in the central nervous system (CNS). Meningioma tumors are commonly benign but may demonstrate an invasive pattern with frequent recurrences. Human telomerase reverse transcriptase (hTERT) is an unfavorable prognostic factor for several types of cancers, and there are controversies about its role.
OBJECTIVES: In the present study, we investigated the relative expression of hTERT splice variants in 2 groups of brain tumors compared to non-tumor samples.
MATERIAL AND METHODS: The mRNA of 40 brain tumor samples and 4 control samples was extracted; mRNA expression of hTERT α-deletion and β-deletion variants, as well as the wild type isoform, was quantified using quantitative reverse transcription polymerase chain reaction (RT-qPCR).
RESULTS: The α-deletion variant was significantly expressed in primary benign meningeal tumors (p = 0.01). The results indicate a positive correlation between the relative expression of hTERT mRNA transcript and α-deletion and β-deletion variants in both groups of tumors (meningiomas and astrocytomas). A strong association between the expression of the full-length splice variant and the β-deletion variant was observed in astrocytoma tumors (p = 0.045). The most significant correlations were found between the hTERT full-length and β-deletion variants in high-grade meningiomas (p = 0.018, correlation coefficient (CC) = 0.964) and grade II astrocytomas (p = 0.015; CC = 0.580. In addition, in low grades of both types of tumors, the hTERT full-length variant and especially the α-deletion variant were the predominant isoforms. The overexpression of hTERT and β-deletion variants in high grades of these tumors was statistically significant. Our findings indicate that α-deletion and β-deletion isoforms are associated with high levels of full-length hTERT mRNA in both groups of brain tumor patients.
CONCLUSIONS: Changes in the splicing pattern of hTERT splice variants in brain tumors and their correlation with pathological alterations in cells could be applied as diagnostic or prognostic biomarkers, or possibly as targets for cancer therapy. However, the function and biological role of hTERT splice variants remain to be clarified.

Janik K, Och W, Popeda M, et al.
[Glioblastoma with BRAFV600E mutation and numerous metastatic foci: a case report].
Folia Neuropathol. 2019; 57(1):72-79 [PubMed] Related Publications
Glioblastoma, the most malignant astrocytic tumour, is associated with limited survival and thus rare metastases. We analysed a particularly interesting case - a 51-year-old male diagnosed within 2 years with primary and recurrent glioblastoma, isocitrate dehydrogenase (IDH)-wild type, as well as with numerous extra-central nervous system (CNS) metastatic foci. Genetic material obtained from primary and recurrent tumours, as well as from pulmonary metastasis was analysed and compared at a molecular level. Next generation sequencing (NGS) analysis revealed BRAFV600E mutation, detected only in 2-5% of glioblastomas, in both the primary tumour and pulmonary metastases. Importantly, this mutation provides a possible therapeutic option as it constitutes a target for clinically approved inhibitors. This case study not only demonstrates a molecular comparison of primary, recurrent and metastatic glioblastoma, but also emphasizes the need for precise molecular diagnostics, which may facilitate treatment choice, especially in tumours currently lacking efficient treatment.

Zheng KB, Xie J, Li YT, et al.
Knockdown of CERB expression inhibits proliferation and migration of glioma cells line U251.
Bratisl Lek Listy. 2019; 120(4):309-315 [PubMed] Related Publications
BACKGROUND: Glioma is a type of tumor that occurs in the brain and accounts for almost 30 % of all brain and central nervous system tumors and 80 % of all malignant brain tumors. In this study, we investigate the role of cAMP response element-binding protein (CREB) in the progression of glioma.
METHODS: Tissue samples from glioma patients were collected and examined for expression of CREB and its correlation with tumor grades. CREB was then knocked down via siRNA to see if reduced expression of CREB affects cell proliferation and migration. Factors involved in cell cycles, adhesion and apoptosis were examined as well. Moreover, CRESP/CAS9 mediated knockout of CREB was conducted and athymic Nude mice model was used to investigate CREB's role in vivo.
RESULTS: The evaluated expression level of CREB in glioma patients was correlated with tumor grades. Knockdown of CREB via siRNA in glioma cell line U251 significantly inhibited the proliferation and migration of tumor cells. Moreover, CyclinD1 and Bcl-2 expression were reduced, as well as phosphorylation of IRK1/2 and AKT. Additionally, knockout of CREB via CRESP/CAS9 inhibited tumor formation of U251 cells in athymic Nude mice model.
CONCLUSIONS: In conclusion, our data suggest that over expression of CREB may contribute to progression of glioma and knockdown of CREB expression may serve as a novel target for therapy (Tab. 1, Fig. 6, Ref. 25).

Hu Q, Liu F, Yan T, et al.
MicroRNA‑576‑3p inhibits the migration and proangiogenic abilities of hypoxia‑treated glioma cells through hypoxia‑inducible factor‑1α.
Int J Mol Med. 2019; 43(6):2387-2397 [PubMed] Article available free on PMC after 01/07/2020 Related Publications
The most common and aggressive type of brain cancer in adults is glioblastoma multiforme (GBM), and hypoxia is a common feature of glioblastoma. As the histological features of glioma include capillary endothelial cell proliferation, they are highly prone to invading the surrounding normal brain tissue, which is often one of the reasons for the failure of treatment. However, the mechanisms involved in this process are not fully understood. MicroRNAs (miRs) are a class of non‑coding RNA that are able to inhibit the malignant progression of tumor cells through the regulation of downstream genes. In the present study, the low expression of miR‑576‑3p was detected in glioma samples and hypoxia‑treated glioma cells using a reverse transcription‑quantitative polymerase chain reaction. The present study focused on the effects of miR‑576‑3p on hypoxia‑induced glioma. The results of the functional experiments revealed that the overexpression of miR‑576‑3p significantly inhibited the migration and pro‑angiogenic abilities of the glioma cells under hypoxic conditions (P<0.05) compared with in the lentivirus‑miR‑negative control group. Furthermore, luciferase reporter gene assays were used to validate the hypothesis that miR‑576‑3p interacts with the 3'‑untranslated region of hypoxia‑inducible factor‑1α (HIF‑1α) and induces a reduction in the protein levels of matrix metalloproteinase‑2 and vascular endothelial growth factor. Rescue experiments demonstrated that the restoration of HIF‑1α expression attenuated the effect of miR‑576‑3p on the migration and proangiogenic abilities of glioma cells. In conclusion, the present study confirms that miR‑576‑3p is a novel GBM inhibitor and its inhibition of the migration and proangiogenic capacity of hypoxia‑induced glioma cells is mediated by HIF‑1α.

Ryzhova MV, Kadyrov SU, Kumirova EV, et al.
[Central nervous system atypical teratoid/rhabdoid tumor without loss of nuclear expression of INI1].
Arkh Patol. 2019; 81(2):36-42 [PubMed] Related Publications
The paper describes a clinical case of atypical teratoid/rhabdoid tumor with preserved INI1 expression and SMARCA4 gene mutations in an 8-month-old girl. Genome-wide DNA methylation, hierarchical clustering, and next-generation sequencing were used to make a tumor diagnosis. However, BRG1 immunohistochemical examination may be recommended in the routine practice of diagnosis and study of childhood CNS malignant tumors.

Chen H, Hu W, He H, et al.
Noninvasive assessment of H3 K27M mutational status in diffuse midline gliomas by using apparent diffusion coefficient measurements.
Eur J Radiol. 2019; 114:152-159 [PubMed] Related Publications
PURPOSE: H3 K27M-mutant diffuse midline gliomas are associated with worse prognosis than H3 K27M wild-type gliomas. In the present study, we sought to evaluate the conventional magnetic resonance imaging (cMRI) of H3 K27M-mutant glioma and examine whether diffusion-weighted imaging (DWI) derived apparent diffusion coefficient (ADC) could noninvasively predict H3 K27M mutational status in brain diffuse midline gliomas.
MATERIALS AND METHODS: The institutional review board approved this study and waived the requirement for informed consent. Thirty-eight patients with brain diffuse midline gliomas were retrospectively reviewed. The parameters of preoperative cMRI were evaluated. The minimal ADC, peritumoral ADC, ratio of minimal ADC, and ratio of peritumoral ADC were measured, and significant differences between the two groups were identified by logistic regression analysis adjusted for age and tumor location. Receiver operating characteristic curves and logistic regression analysis adjusted for age and tumor location were used to assess the diagnostic performances of the minimal ADC, peritumoral ADC, ratio of minimal ADC, and ratio of peritumoral ADC.
RESULTS: H3 K27M-mutant gliomas in different locations have diverse imaging characteristics. Minimal ADC, peritumoral ADC, ratio of minimal ADC, and ratio of peritumoral ADC values were significantly lower in the H3 K27M-mutant gliomas than in the wild-type gliomas (P < 0.05). The combination of ratio of minimal ADC and ratio of peritumoral ADC provided the largest area under the curve (AUC) of 0.872 in defining H3 K27M-mutational status.
CONCLUSIONS: The combination of ratio of minimal ADC and ratio of peritumoral ADC can noninvasively detect the H3 K27M mutational status in brain diffuse midline gliomas.

Hyare H, Rice L, Thust S, et al.
Modelling MR and clinical features in grade II/III astrocytomas to predict IDH mutation status.
Eur J Radiol. 2019; 114:120-127 [PubMed] Related Publications
BACKGROUND AND PURPOSE: There is increasing evidence that many IDH wildtype (IDHwt) astrocytomas have a poor prognosis and although MR features have been identified, there remains diagnostic uncertainty in the clinic. We have therefore conducted a comprehensive analysis of conventional MR features of IDHwt astrocytomas and performed a Bayesian logistic regression model to identify critical radiological and basic clinical features that can predict IDH mutation status.
MATERIALS AND METHODS: 146 patients comprising 52 IDHwt astrocytomas (19 WHO Grade II diffuse astrocytomas (A II) and 33 WHO Grade III anaplastic astrocytomas (A III)), 68 IDHmut astrocytomas (53 A II and 15 A III) and 26 GBM were studied. Age, sex, presenting symptoms and Overall Survival were recorded. Two neuroradiologists assessed 23 VASARI imaging descriptors of MRI features and the relation between IDH mutation status and MR and basic clinical features was modelled by Bayesian logistic regression, and survival by Kaplan-Meier plots.
RESULTS: The features of greatest predictive power for IDH mutation status were, age at presentation (OR = 0.94 +/-0.03), tumour location within the thalamus (OR = 0.15 +/-0.25), involvement of speech receptive areas (OR = 0.21 +/-0.26), deep white matter invasion of the brainstem (OR = 0.10 +/-0.32), and T1/FLAIR signal ratio (OR = 1.63 +/-0.64). A logistic regression model based on these five features demonstrated excellent out-of-sample predictive performance (AUC = 0.92 +/-0.07; balanced accuracy 0.81 +/-0.09). Stepwise addition of further VASARI variables did not improve performance.
CONCLUSION: Five demographic and VASARI features enable excellent individual prediction ofIDH mutation status, opening the way to identifying patients with IDHwt astrocytomas for earlier tissue diagnosis and more aggressive management.

Dirkse A, Golebiewska A, Buder T, et al.
Stem cell-associated heterogeneity in Glioblastoma results from intrinsic tumor plasticity shaped by the microenvironment.
Nat Commun. 2019; 10(1):1787 [PubMed] Article available free on PMC after 01/07/2020 Related Publications
The identity and unique capacity of cancer stem cells (CSC) to drive tumor growth and resistance have been challenged in brain tumors. Here we report that cells expressing CSC-associated cell membrane markers in Glioblastoma (GBM) do not represent a clonal entity defined by distinct functional properties and transcriptomic profiles, but rather a plastic state that most cancer cells can adopt. We show that phenotypic heterogeneity arises from non-hierarchical, reversible state transitions, instructed by the microenvironment and is predictable by mathematical modeling. Although functional stem cell properties were similar in vitro, accelerated reconstitution of heterogeneity provides a growth advantage in vivo, suggesting that tumorigenic potential is linked to intrinsic plasticity rather than CSC multipotency. The capacity of any given cancer cell to reconstitute tumor heterogeneity cautions against therapies targeting CSC-associated membrane epitopes. Instead inherent cancer cell plasticity emerges as a novel relevant target for treatment.

Su H, Zou D, Sun Y, Dai Y
Hypoxia-associated circDENND2A promotes glioma aggressiveness by sponging miR-625-5p.
Cell Mol Biol Lett. 2019; 24:24 [PubMed] Article available free on PMC after 01/07/2020 Related Publications
Background: As a newfound type of non-coding RNA, circular RNAs (circRNAs) are involved in various physiological and pathological processes via regulation of gene expression. Increasing evidence shows that aberrantly expressed circRNAs play a crucial role in the initiation and progression of many tumors. However, the functions of different circRNAs in gliomas remain elusive.
Methods: The levels of circRNAs, miRNAs, and mRNAs were quantified by qPCR. The interaction between circDENND2A and miR-625-5p was determined by luciferase reporter and pull-down assays. The migratory and invasive capabilities of glioma cells were examined by wound healing and Transwell assays. Immunohistochemistry was performed to analyze the HIF1α level in glioma tissues.
Results: We predicted circDENND2A (has_circ_0002142) to be a hypoxia-responsive circRNA in glioma via a bioinformatic analysis. We found that hypoxia induced the expression of circDENND2A, which promoted migration and invasion of glioma cells. To understand the behaviors of circDENND2A in glioma, we studied the putative miRNAs targeted by circDENND2A and identified circDENND2A as an efficient sponge of miR-625-5p in glioma cells. Phenotype experiments verified that circDENND2A was required for the hypoxia-induced migration and invasion of glioma cells and that this occurred by sponging of miR-625-5p. Notably, glioma tissues overexpressing HIF1α exhibited a high expression of circDENND2A as well as a low expression of miR-625-5p. circDENND2A was negatively correlated with miR-625-5p.
Conclusion: circDENND2A is required for the hypoxia-induced malignancy of glioma cells and functions by sponging miR-625-5p.

Hu A, Zhang Y, Zhao X, et al.
CBX1 is a direct target of miR-205-5p and contributes to the progression of pituitary tumor.
Pharmazie. 2019; 74(3):154-156 [PubMed] Related Publications
MicroRNAs (miRs) are crucial regulators for tumorigenesis through negatively regulating their target genes expression in the manner of 3'-untranslated region (3'-UTR) binding. MiR-205-5p has been reported to function as a tumor suppressor in several cancer types. The aim of this study was to investigate the role of miR-205-5p/chromobox homolog 1 (CBX1) axis in human pituitary tumors. The expression of miR-205-5p was firstly examined by quantitative real-time PCR and the results revealed that miR-205-5p expression was declined in pituitary cell lines compared with normal cell line. Overexpression of miR-205-5p effectively decreased cell proliferation and cell migration. Based on the results of bioinformatic analysis, luciferase reporter assay, and western blot, we identified CBX1 as a direct target of miR-205-5p. Notably, overexpression of CBX1 promoted cell proliferation and migration. The effects of miR-205-5p overexpression on cell proliferation and migration can be reversed by CBX1 overexpression. Based on these findings, we deducted that miR-205-5p inhibits the cell proliferation and migration through directly targeting CBX1.

Savci-Heijink CD, Halfwerk H, Koster J, et al.
A specific gene expression signature for visceral organ metastasis in breast cancer.
BMC Cancer. 2019; 19(1):333 [PubMed] Article available free on PMC after 01/07/2020 Related Publications
BACKGROUND: Visceral organ metastasis is associated with poor survival outcomes in terms of metastasis free- and overall survival in breast carcinomas. Identification of a gene expression profile in tumours that selects a subpopulation of patients that is more likely to develop visceral organ metastases will help elucidate mechanisms for the development of distant metastases and could be of clinical value. With this study we aimed to determine genomic predictors that would help to distinguish breast cancer patients with more likelihood to develop visceral metastasis.
METHODS: Gene expression profiling data of 157 primary tumours from breast cancer patients who developed distant metastases were analyzed and differentially expressed genes between the group of tumours with visceral metastasis and the those without visceral metastases were identified. Published data were used to validate our findings. Multivariate logistic regression tests were applied to further investigate the association between the gene-expression-signature and clinical variables. Survival analyses were performed by the Kaplan-Meier method.
RESULTS: Fourteen differentially expressed genes (WDR6, CDYL, ATP6V0A4, CHAD, IDUA, MYL5, PREP, RTN4IP1, BTG2, TPRG1, ABHD14A, KIF18A, S100PBP and BEND3) were identified between the group of tumours with and without visceral metastatic disease. Five of these genes (CDYL, ATP6V0A4, PREP, RTN4IP1 and KIF18A) were up-regulated and the other genes were down-regulated. This gene expression signature was validated in the training and in the independent data set (p 2.13e- 08 and p 9.68e- 06, respectively). Multivariate analyses revealed that the 14-gene-expression-signature was associated with visceral metastatic disease (p 0.001, 95% CI 1.43-4.27), independent of other clinicopathologic features. This signature has been also found to be associated with survival status of the patients (p < .001).
CONCLUSION: We have identified an unique gene expression signature which is specific to visceral metastasis. This 14-gene-expression-signature may play a role in identifying the subgroup of patients with potential to develop visceral metastasis.

Wang Y, Hou Y, Zhang W, et al.
Lipolytic inhibitor G0S2 modulates glioma stem-like cell radiation response.
J Exp Clin Cancer Res. 2019; 38(1):147 [PubMed] Article available free on PMC after 01/07/2020 Related Publications
BACKGROUND: Ionizing radiation (IR) therapy is the standard first-line treatment for newly diagnosed patients with glioblastoma (GBM), the most common and malignant primary brain tumor. However, the effects of IR are limited due to the aberrant radioresistance of GBM.
METHODS: Transcriptome analysis was performed using RNA-seq in radioresistant patient-derived glioma stem-like cells (GSCs). Survival of glioma patient and mice bearing-brain tumors was analyzed by Kaplan-Meier survival analysis. Lipid droplet and γ-H2AX foci-positive cells were evaluated using immunofluorescence staining.
RESULTS: Lipolytic inhibitor G0/G1 switch gene 2 (G0S2) is upregulated in radioresistant GSCs and elevated in clinical GBM. GBM patients with high G0S2 expression had significantly shorter overall survival compared with those with low expression of G0S2. Using genetic approaches targeting G0S2 in glioma cells and GSCs, we found that knockdown of G0S2 promoted lipid droplet turnover, inhibited GSC radioresistance, and extended survival of xenograft tumor mice with or without IR. In contrast, overexpression of G0S2 promoted glioma cell radiation resistance. Mechanistically, high expression of G0S2 reduced lipid droplet turnover and thereby attenuated E3 ligase RNF168-mediated 53BP1 ubiquitination through activated the mechanistic target of rapamycin (mTOR)-ribosomal S6 kinase (S6K) signaling and increased 53BP1 protein stability in response to IR, leading to enhanced DNA repair and glioma radioresistance.
CONCLUSIONS: Our findings uncover a new function for lipolytic inhibitor G0S2 as an important regulator for GSC radioresistance, suggesting G0S2 as a potential therapeutic target for treating gliomas.

Tejero R, Huang Y, Katsyv I, et al.
Gene signatures of quiescent glioblastoma cells reveal mesenchymal shift and interactions with niche microenvironment.
EBioMedicine. 2019; 42:252-269 [PubMed] Article available free on PMC after 01/07/2020 Related Publications
BACKGROUND: Glioblastoma (GBM), a highly malignant brain tumor, invariably recurs after therapy. Quiescent GBM cells represent a potential source of tumor recurrence, but little is known about their molecular underpinnings.
METHODS: Patient-derived GBM cells were engineered by CRISPR/Cas9-assisted knock-in of an inducible histone2B-GFP (iH2B-GFP) reporter to track cell division history. We utilized an in vitro 3D GBM organoid approach to isolate live quiescent GBM (qGBM) cells and their proliferative counterparts (pGBM) to compare stem cell properties and therapy resistance. Gene expression programs of qGBM and pGBM cells were analyzed by RNA-Seq and NanoString platforms.
FINDINGS: H2B-GFP-retaining qGBM cells exhibited comparable self-renewal capacity but higher therapy resistance relative to pGBM. Quiescent GBM cells expressed distinct gene programs that affect cell cycle control, metabolic adaptation, and extracellular matrix (ECM) interactions. Transcriptome analysis also revealed a mesenchymal shift in qGBM cells of both proneural and mesenchymal GBM subtypes. Bioinformatic analyses and functional assays in GBM organoids established hypoxia and TGFβ signaling as potential niche factors that promote quiescence in GBM. Finally, network co-expression analysis of TCGA glioma patient data identified gene modules that are enriched for qGBM signatures and also associated with survival rate.
INTERPRETATION: Our in vitro study in 3D GBM organoids supports the presence of a quiescent cell population that displays self-renewal capacity, high therapy resistance, and mesenchymal gene signatures. It also sheds light on how GBM cells may acquire and maintain quiescence through ECM organization and interaction with niche factors such as TGFβ and hypoxia. Our findings provide a starting point for developing strategies to tackle the quiescent population of GBM. FUND: National Institutes of Health (NIH) and Deutsche Forschungsgemeinschaft (DFG).

Cowman S, Fan YN, Pizer B, Sée V
Decrease of Nibrin expression in chronic hypoxia is associated with hypoxia-induced chemoresistance in some brain tumour cells.
BMC Cancer. 2019; 19(1):300 [PubMed] Article available free on PMC after 01/07/2020 Related Publications
BACKGROUND: Solid tumours are less oxygenated than normal tissues. This is called tumour hypoxia and leads to resistance to radiotherapy and chemotherapy. The molecular mechanisms underlying such resistance have been investigated in a range of tumour types, including the adult brain tumours glioblastoma, yet little is known for paediatric brain tumours. Medulloblastoma (MB) is the most common malignant brain tumour in children. We aimed to elucidate the impact of hypoxia on the sensitivity of MB cells to chemo- and radiotherapy.
METHODS: We used two MB cell line (D283-MED and MEB-Med8A) and a widely used glioblastoma cell line (U87MG) for comparison. We applied a range of molecular and cellular techniques to measure cell survival, cell cycle progression, protein expression and DNA damage combined with a transcriptomic micro-array approach in D283-MED cells, for global gene expression analysis in acute and chronic hypoxic conditions.
RESULTS: In D283-MED and U87MG, chronic hypoxia (5 days), but not acute hypoxia (24 h) induced resistance to chemotherapy and X-ray irradiation. This acquired resistance upon chronic hypoxia was present but less pronounced in MEB-Med8A cells. Using transcriptomic analysis in D283-MED cells, we found a large transcriptional remodelling upon long term hypoxia, in particular the expression of a number of genes involved in detection and repair of double strand breaks (DSB) was altered. The levels of Nibrin (NBN) and MRE11, members of the MRN complex (MRE11/Rad50/NBN) responsible for DSB recognition, were significantly down-regulated. This was associated with a reduction of Ataxia Telangiectasia Mutated (ATM) activation by etoposide, indicating a profound dampening of the DNA damage signalling in hypoxic conditions. As a consequence, p53 activation by etoposide was reduced, and cell survival enhanced. Whilst U87MG shared the same dampened p53 activity, upon chemotherapeutic drug treatment in chronic hypoxic conditions, these cells used a different mechanism, independent of the DNA damage pathway.
CONCLUSION: Together our results demonstrate a new mechanism explaining hypoxia-induced resistance involving the alteration of the response to DSB in D283-MED cells, but also highlight the cell type to cell type diversity and the necessity to take into account the differing tumour genetic make-up when considering re-sensitisation therapeutic protocols.

Perrech M, Dreher L, Röhn G, et al.
Qualitative and Quantitative Analysis of IDH1 Mutation in Progressive Gliomas by Allele-Specific qPCR and Western Blot Analysis.
Technol Cancer Res Treat. 2019; 18:1533033819828396 [PubMed] Article available free on PMC after 01/07/2020 Related Publications
To date, diagnosis of IDH1 mutation is based on DNA sequencing and immunohistochemistry, methods limited in terms of sensitivity and ease of use. Recently, the diagnosis of IDH1 mutation by real-time polymerase chain reaction was introduced as an alternative method. In this study, real-time polymerase chain reaction was validated as a tool for detection of IDH1 mutation, and expression levels were analyzed for correlation with course of the disease. A total of 113 tumor samples were obtained intraoperatively from 84 patients with glioma having a diagnosis of diffuse glioma (World Health Organization II), anaplastic glioma (World Health Organization III), secondary glioblastoma ± chemotherapy, primary glioblastoma ± chemotherapy (World Health Organization IV). Tumor samples were snap frozen and processed for sectioning and RNA and protein isolation. Presence of IDH1 mutation was determined by DNA sequencing. Hereafter, quantitative expression of IDH1 messenger RNA was assessed using real-time polymerase chain reaction with specific primers for IDH1 mutation and -wt; protein expression was verified by Western Blot analysis and immunohistochemistry. Additionally, 19 samples of low-grade glioma and their consecutive high-grade glioma were analyzed at different time points of the disease. IDH1 mutation was identified in 63% of samples by DNA sequencing. In correlation with the real-time polymerase chain reaction results, a cutoff value was determined. Above this threshold, sensitivity and specificity of real-time polymerase chain reaction in detecting IDH1 mutation were 98% and 94%, respectively. Quantitative analysis revealed that IDH1 mutation expression is upregulated in secondary glioblastoma (mean ± standard error of mean: 3.52 ± 0.55) compared to lower grade glioma (II = 1.54 ± 0.22; III = 1.67 ± 0.23). In contrast, IDH1 wt expression is upregulated in all glioma grades (concentration >0.1) compared to control brain tissue (0.007 ± 0.0016). Western Blot analysis showed a high concordance to both sequencing and real-time polymerase chain reaction results in qualitative analysis of IDH1 mutation status (specificity 100% and sensitivity 100%). Moreover, semiquantitative protein expression analysis also showed higher expression levels of mutated IDH1 in secondary glioblastoma. In our study, real-time polymerase chain reaction and Western Blot analysis were found to be highly efficient methods in detecting IDH1 mutation in glioma samples. As cost-effective and time-saving methods, real-time polymerase chain reaction and Western Blot analysis may therefore play an important role in IDH1 mutation analysis in the future. IDH1 mutation expression level was found to correlate with the course of disease to a certain extent. Yet, clinical factors as recurrent disease or prior radiochemotherapy did not alter IDH1 mutation expression level.

Chai Y, Liu W, Wang C, et al.
Prognostic Role of Chicken Ovalbumin Upstream Promoter Transcription Factor II in Isocitrate Dehydrogenase-Mutant Glioma with 1p19q Co-Deletion.
J Mol Neurosci. 2019; 68(2):234-242 [PubMed] Related Publications
BACKGROUND: Chicken ovalbumin upstream promoter transcription factor II is known to play a crucial role in the tumor microenvironment. However, the role of NR2F2 in gliomas is unknown.
METHODS: The genomic and clinical data of 530 cases of lower grade gliomas (LGGs) patients and 167 cases of glioblastoma (GBM) patients in The Cancer Genome Atlas (TCGA) were extracted for analysis. R2 and UCSC Xena browser were used for Kaplan-Meier survival in the GSE16011 dataset and TCGA dataset, respectively. GraphPad Prism 7 was used to compare the differences in NR2F2 expression between various groups and subtypes.
RESULTS: LGG patients with low NR2F2 expression had a significantly favorable outcome compared with those with high NR2F2 expression (p < 0.05). By matching histological subtypes and gene expression profiles of LGG patients, grade II glioma group showed lowest levels of NR2F2 expression compared with grade III gliomas and GBM. Patients diagnosed with astrocytoma have highest expression of NR2F2 but lowest OS (p < 0.05). In LGGs, NR2F2 expression was significantly downregulated in patient group with IDH mutation and 1p19q co-deletion (p < 0.05).
CONCLUSION: Our study suggests that NR2F2 can be used as a prognostic marker in LGG patients with IDH mutation and 1p19 co-deletion.

Yin J, Zeng A, Zhang Z, et al.
Exosomal transfer of miR-1238 contributes to temozolomide-resistance in glioblastoma.
EBioMedicine. 2019; 42:238-251 [PubMed] Article available free on PMC after 01/07/2020 Related Publications
BACKGROUND: Although temozolomide (TMZ) resistance is a significant clinical problem in glioblastoma (GBM), its underlying molecular mechanisms are poorly understood. In this study, we identified the role of exosomal microRNAs (miRNAs) from TMZ-resistant cells as important mediators of chemoresistance in GBM cells.
METHODS: Exosomes were isolated from TMZ-resistant GBM cells and characterized via scanning electron microscopy (SEM). Expression levels of miR-1238 in GBM cell lines and their exosomes, clinical tissues, and sera were evaluated by RT-qPCR. In vitro and in vivo experiments were performed to elucidate the function of exosomal miR-1238 in TMZ resistance in GBM cells. Co-immunoprecipitation assays and western blot analysis were used to investigate the potential mechanisms of miR-1238/CAV1 that contribute to TMZ resistance.
FINDINGS: MiR-1238 levels were higher in TMZ-resistant GBM cells and their exosomes than in sensitive cells. Higher levels of miR-1238 were found in the sera of GBM patients than in healthy people. The loss of miR-1238 may sensitize resistant GBM cells by directly targeting the CAV1/EGFR pathway. Furthermore, bioactive miR-1238 may be incorporated into the exosomes shed by TMZ-resistant cells and taken up by TMZ-sensitive cells, thus disseminating TMZ resistance.
INTERPRETATION: Our findings establish that miR-1238 plays an important role in mediating the acquired chemoresistance of GBM and that exosomal miR-1238 may confer chemoresistance in the tumour microenvironment. These results suggest that circulating miR-1238 serves as a clinical biomarker and a promising therapeutic target for TMZ resistance in GBM. FUND: This study was supported by the National Natural Science Foundation of China (No·81402056, 81472362, and 81772951) and the National High Technology Research and Development Program of China (863) (No·2012AA02A508).

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