Histone H3.3G34-Mutant Interneuron Progenitors Co-opt PDGFRA for Gliomagenesis.

Histone H3.3 glycine 34 to arginine/valine (G34R/V) mutations drive deadly gliomas and show exquisite regional and temporal specificity, suggesting a developmental context permissive to their effects. Here we show that 50% of G34R/V tumors (n = 95) bear activating PDGFRA mutations that display strong selection pressure at recurrence. Although considered gliomas, G34R/V tumors actually arise in GSX2/DLX-expressing interneuron progenitors, where G34R/V mutations impair neuronal differentiation. The lineage of origin may facilitate PDGFRA co-option through a chromatin loop connecting PDGFRA to GSX2 regulatory elements, promoting PDGFRA overexpression and mutation. At the single-cell level, G34R/V tumors harbor dual neuronal/astroglial identity and lack oligodendroglial programs, actively repressed by GSX2/DLX-mediated cell fate specification. G34R/V may become dispensable for tumor maintenance, whereas mutant-PDGFRA is potently oncogenic. Collectively, our results open novel research avenues in deadly tumors. G34R/V gliomas are neuronal malignancies where interneuron progenitors are stalled in differentiation by G34R/V mutations and malignant gliogenesis is promoted by co-option of a potentially targetable pathway, PDGFRA signaling.

Novel Concepts of Glioblastoma Therapy Concerning Its Heterogeneity.

Although treatment outcomes of glioblastoma, the most malignant central nervous system (CNS) tumor, has improved in the past decades, it is still incurable, and survival has only slightly improved. Advances in molecular biology and genetics have completely transformed our understanding of glioblastoma. Multiple classifications and different diagnostic methods were made according to novel molecular markers. Discovering tumor heterogeneity only partially explains the ineffectiveness of current anti-proliferative therapies. Dynamic heterogeneity secures resistance to combined oncotherapy. As tumor growth proceeds, new therapy-resistant sub clones emerge. Liquid biopsy is a new and promising diagnostic tool that can step up with the dynamic genetic change. Getting a 'real-time' picture of a specific tumor, anti-invasion and multi-target treatment can be designed. During invasion to the peri-tumoral brain tissue, glioma cells interact with the extracellular matrix components. The expressional levels of these matrix molecules give a characteristic pattern, the invasion spectrum, which possess vast diagnostical, predictive and prognostic information. It is a huge leap forward combating tumor heterogeneity and searching for novel therapies. Using the invasion spectrum of a tumor sample is a novel tool to distinguish between histological subtypes, specifying the tumor grades or different prognostic groups. Moreover, new therapeutic methods and their combinations are under trial. These are crucial steps towards personalized oncotherapy.

Analysis of Circulating miRNA Profile in Plasma Samples of Glioblastoma Patients.

(1) Background: Glioblastoma multiforme (GBM) is among the most aggressive cancers with a poor prognosis. Treatment options are limited, clinicians lack efficient prognostic and predictive markers. Circulating miRNAs-besides being important regulators of cancer development-may have potential as diagnostic biomarkers of GBM. (2) Methods: In this study, profiling of 798 human miRNAs was performed on blood plasma samples from 6 healthy individuals and 6 patients with GBM, using a NanoString nCounter Analysis System. To validate our results, five miRNAs (hsa-miR-433-3p, hsa-miR-362-3p, hsa-miR-195-5p, hsa-miR-133a-3p, and hsa-miR-29a-3p) were randomly chosen for RT-qPCR detection. (3) Results: In all, 53 miRNAs were significantly differentially expressed in plasma samples of GBM patients when data were filtered for FC 1 and FDR 0.1. Target genes of the top 39 differentially expressed miRNAs were identified, and we carried out functional annotation and pathway enrichment analysis of target genes via GO and KEGG-based tools. General and cortex-specific protein-protein interaction networks were constructed from the target genes of top miRNAs to assess their functional connections. (4) Conclusions: We demonstrated that plasma microRNA profiles are promising diagnostic and prognostic molecular biomarkers that may find an actual application in the clinical practice of GBM, although more studies are needed to validate our results.

Novel Molecular Markers in Glioblastoma-Benefits of Liquid Biopsy.

: Glioblastoma is a primary Central Nervous System (CNS) malignancy with poor survival. Treatment options are scarce and despite the extremely heterogeneous nature of the disease, clinicians lack prognostic and predictive markers to characterize patients with different outcomes. Certain immunohistochemistry, FISH, or PCR-based molecular markers, including isocitrate dehydrogenase1/2 (IDH1/2) mutations, epidermal growth factor receptor variant III (EGFRvIII) mutation, vascular endothelial growth factor overexpression (VEGF) overexpression, or (O6-Methylguanine-DNA methyltransferase promoter) MGMT promoter methylation status, are well-described; however, their clinical usefulness and accuracy is limited, and tumor tissue samples are always necessary. Liquid biopsy is a developing field of diagnostics and patient follow up in multiple types of cancer. Fragments of circulating nucleic acids are collected in various forms from different bodily fluids, including serum, urine, or cerebrospinal fluid in order to measure the quality and quantity of these markers. Multiple types of nucleic acids can be analyzed using liquid biopsy. Circulating cell-free DNA, mitochondrial DNA, or the more stable long and small non-coding RNAs, circular RNAs, or microRNAs can be identified and measured by novel PCR and next-generation sequencing-based methods. These markers can be used to detect the previously described alterations in a minimally invasive method. These markers can be used to differentiate patients with poor or better prognosis, or to identify patients who do not respond to therapy. Liquid biopsy can be used to detect recurrent disease, often earlier than using imaging modalities. Liquid biopsy is a rapidly developing field, and similarly to other types of cancer, measuring circulating tumor-derived nucleic acids from biological fluid samples could be the future of differential diagnostics, patient stratification, and follow up in the future in glioblastoma as well.

[Prognostic significance of invasion in glioblastoma]. / Az inváziós spektrum prognosztikai jelentôsége glioblastomában.

BACKGROUND AND PURPOSE: Glioblastoma is the most common malignant CNS tumor, its surgical removal is hindered by the tumors invasive nature, while current anti-tumor therapies show limited effectiveness - mean overall survival is 16-24 months. Some patients show minimal response towards standard oncotherapy, however there are no routinely available prognostic and predictive markers in clinical practice to identify the background of mentioned differences in prognosis. This research aims to identify the prognostic significance of invasion-related extracellular (ECM) components. METHODS: Patient groups with different prognoses were created (OS: group A <16 months, group B > 16 months), and internationally recognized prognostic markers (IDH1 mutation and MGMT promoter hyper-methylation) were tested in the flash-frozen tumor samples. Furthermore, the mRNA levels of 46 invasion-related ECM molecules were measured. RESULTS: Clinical data of the patients who have been operated on at the University of Debrecen Clinical Center Department of Neurosurgery and treated at the Department of Clinical Oncology showed no significant differences except for survival data (OS and PFS), and reoperation rate. All samples were IDH wild type. MGMT promoter hypermethylation rate showed significant differences (28.6% vs 68.8%). The expressional pattern of the invasion-related ECM molecules, i.e. the invasion spectrum also showed major differences, integrin ß2, cadherin-12, FLT4/VEGFR-3 and versican molecules having signficantly different mRNA levels. The accuracy of the inivasion spectrum was tested by statistical classifier, 83.3% of the samples was sorted correctly, PPV was 0.93. CONCLUSION: The difference found in the reoperation rate when comparing different prognostic groups aligns with literature data. MGMG promoter region methylation data in Hungarian samples has not been published yet, and further confirming current knowledge urges the implementation of MGMT promoter analysis in clinical practice. Studying the invasion spectrum provides extra information on tumors, as a prognostic marker it helps recognizing more aggressive tumors, and calls attention to the necessity of using anti-invasive agents in GBM therapies in the future.

The Expressional Pattern of Invasion-Related Extracellular Matrix Molecules in CNS Tumors.

Aim of the study: Astrocytomas are primary CNS malignancies which infiltrate the peritumoral tissue, even when they are low-grade. Schwannomas are also primary CNS tumors, however, they do not show peritumoral infiltration similarly to brain metastases which almost never invade the neighboring parts of brain. Extracellular matrix is altered in composition in various cancer types and is proposed to play an important role in the development of invasiveness of astrocytic tumors. This study aims to identify differences in the ECM composition of CNS tumors with different invasiveness.Materials and methods: The mRNA and protein levels of ECM components were measured by QRT-PCR and mass-spectrometry, respectively, in grade II astrocytoma, NSCLC brain metastasis, schwannomas, and non-tumor brain control samples. Expressional data was analyzed statistically with ANOVA and nearest neighbor search.Results: There is a significant difference in the expressional pattern of invasion-related ECM components among various CNS tumors, especially among those of different embryonic origin. Non-invasive tumors show only slight differences in the expressional pattern of ECM molecules. Tumor samples can be separated based on their expressional pattern using statistical classifiers, therefore the ECM composition seems to be typical of various cancer types.Conclusions: Differences in the expressional pattern of the ECM could be responsible for the different invasiveness of various CNS tumors.

[The role of extracellular matrix components in the invasion of intracranial malignancies]. / Az extracelluláris mátrix komponensek tumorinvázióban betöltött szerepe intrakraniális daganatokban.

The usual local recurrence of primary brain tumors is mainly due to the infiltration of adjacent brain parenchyma by the glioma cells. This invasive feature of the tumors makes total surgical excision impossible and also decreases the efficacy of focal radiotherapy. Interestingly, intracerebral metastases originating from many anaplastic tumors of other organs perform very moderate peritumoral infiltration, therefore radical resection can be routinely achieved and focal irradiation, even stereotactic radiotherapy, provides good tumor control. Differences in the effectiveness of treatment between the two tumor types derive from the remarkably different extent of peritumoral infiltration. Thus significant molecular biological research has been dealing with the infiltrative activity of various brain tumors and many attempts were made to develop anti-invasive drugs for oncotherapy. This review summarizes the results of these studies, describing cellular and molecular events of brain tumor invasion and according potential oncotherapeutic possibilities.

[The role of low grade glioma prognostic factors in therapeutic choices - summary of international literature and recommendations with conclusions]. / Az alacsony grádusú gliómák prognosztikai faktorainak szerepe a terápia megválasztásában ­ a nemzetközi irodalom és ajánlások összefoglalása konklúziókkal.

Our knowledge on low grade gliomas has grown extensively recently. Both molecular alterations and clinical trials unraveling their clinical significance are difficult to get familiar with. Thus, efforts made to reach any consensus are of upmost importance, so that multidisciplinary teams involved in patient management can make up-to-date, individually-tailored therapeutic plans. Our aims were to synthesize all the molecular and clinical investigations, recommendations and guidelines related to low grade gliomas in Hungarian language, and to define low and high risk prognostic groups with different therapeutic strategies. The roles of 21 molecular pathological markers and their significance levels in low grade gliomas are summarized in this paper. Data from relevant literature, as well as recommendations of neuro-oncological organizations were included. This summary could help to integrate diverse therapeutic plans of the past decades in low grade gliomas. Moreover, this paper may serve as a source for future revisions when updating low and high risk groups in low grade gliomas.

Prognosis and Treatment Outcomes of Patients Undergoing Resection of Brain Metastases from Breast Cancer.

BACKGROUND: Brain metastases from breast cancer have poor prognosis and are a challenge to treat. Multiple treatment options are available. Descriptive and prognostic data on breast cancer brain metastases is limited. PATIENTS AND METHODS: This study analyzed clinical data of patients who underwent surgical resection of one or more brain metastases. Histological and clinical characteristics, as well as treatment modalities, were analyzed. RESULTS: Initial tumor stage or grade was found not to correlate with the median time to developing brain metastases or survival. Human epidermal growth factor receptor 2 (HER2)-positive status was not associated with shorter median time to developing brain metastases. No correlation was found between the number of brain metastases and patient outcome. Results confirm the survival benefit of surgical resection with or without irradiation. CONCLUSION: Data showed that patients with HER2-positive and those with triple-negative breast cancer develop brain metastases at lower stages but not earlier after diagnosis, and survival is mostly dependent on treatment modality rather than histological subtype.

Significance of liquid biopsy in glioblastoma - A review.

Glioblastoma (GBM) is the most common and most aggressive primary malignant brain tumor with a 16-24 -months overall survival time (OS). Effective management is hindered by intratumoral heterogeneity, a characteristic trait of GBM which results in subpopulations of cells with altered therapeutic responsiveness, different invasiveness and growth potential. Correct initial molecular profiling of the tumor, as well as following its molecular biological changes are further impeded by the intracranial location of the tumors, hence the risks of surgical interventions. Radiological examination, the sole non-invasive method of obtaining information about the tumors, also has limitations. This review article aims to summarize the currently available information about the promising applicability of liquid biopsy, extracellular vesicles (EVs), and circulating cell-free nucleic acids (cf-NAs) in GBM patients. Liquid biopsy is a quick and inexpensive way of obtaining exceptionally relevant information about tumors, and can be performed multiple times during the clinical course of the disease. Furthermore, integrating analyses of EVs and related cf-NAs in clinical practice might also help to establish diagnosis in a non-invasive manner, and complex oncotherapy could be indicated in the future without high-risk neurosurgical interventions.

Influence of Oncotherapy and Clinical Parameters on Survival of Glioblastoma Patients: A Single Center Experience.

BACKGROUND: Routine administration of temozolomide (TMZ) in the treatment protocol of glioblastoma in the last few years resulted in improving survival parameters of these patients but efficacy of supplementary bevacizumab (BVC) monotherapy has not been evidently proven. In this study, the effectiveness of different postoperative therapy for glioblastoma patients treated in our institute was evaluated. In addition, the prognostic value of clinical parameters on survival was also analyzed. METHODS: Accordance of clinical parameters (age, gender, tumor localization, size, side, Karnofsky performance score, and extension of tumor removal), postoperative treatment (radiotherapy [RT], RT + TMZ, RT + TMZ + BVC), and survival data were tested by 104 patients operated on glioblastoma in the Department of Neurosurgery, University of Debrecen between 2002 and 2012. RESULTS: Concurrent chemo-RT resulted in significant longer overall survival (OS) than RT alone (PRTvs.RT + TMZ = 0.0219) and BVC treatment after progression during TMZ also elongated survival significantly (PRT vs. RT + TMZ + BVC < 0.0001; PRT + TMZvs.RT + TMZ + BVC = 0.0022), respectively. Clinical parameters showed no significant influence on OS in comparison with different methods of postoperative oncotherapy. CONCLUSIONS: Both TMZ and BVC had a beneficial effect on glioblastoma patients' survival, but tested clinical parameters showed no evident accordance with final outcome. Although neurosurgery has an indispensable role in resecting space occupying tumors and providing good postoperative performance score patients for oncotherapy, the survival of glioblastoma patients depends rather on radio- and chemo-sensitivity than tested clinical parameters.

Extracellular matrix differences in glioblastoma patients with different prognoses.

Glioblastoma is the most common malignant central nervous system tumor. Patient outcome remains poor despite the development of therapy and increased understanding of the disease in the past decades. Glioma cells invade the peritumoral brain, which results in inevitable tumor recurrence. Previous studies have demonstrated that the extracellular matrix (ECM) is altered in gliomas and serves a major role in glioma invasion. The present study focuses on differences in the ECM composition of tumors in patients with poor and improved prognosis. The mRNA and protein expression of 16 invasion-associated ECM molecules was determined using reverse trascription-quantitiative polymerase chain reaction and immunohistochemistry, respectively. Clinical factors of patients with different prognoses was also analyzed. It was determined that age and postoperative Karnofsky performance score were associated with patient survival. Furthermore, Fms-related tyrosine kinase 4/vascular endothelial growth factor receptor 3 (FLT4/VEGFR3), murine double minute 2 (MDM2) and matrix metallopeptidase 2 (MMP2) mRNA levels were significantly different between the two prognostic groups. Additionally, brevican, cluster of differentiation 44, hyaluronan mediated motility receptor, integrin-αV and -ß1, and MDM2 protein expression were indicated to be significantly different in immunohistochemistry slides. Using the expression profile, including the invasion spectrum of the samples, it was possible to identify the prognostic group of the sample with high efficacy, particularly in cases with poor prognosis. In conclusion, it was determined that ECM components exhibit different expression levels in tumors with different prognoses and thus the invasion spectrum can be used as a prognostic factor in glioblastoma.

Tumor Grade versus Expression of Invasion-Related Molecules in Astrocytoma.

Peritumoral infiltration is characteristic of astrocytomas even in low-grade tumors. Tumor cells migrate to neighbouring tissue and cause recurrence. The extracellular matrix (ECM) plays a role in tumor invasion; expression levels of its components' have been linked to tumor invasion. This study determines the mRNA and protein expression of 20 invasion-related ECM components by examining non-tumor brain; grade I-II-III astrocytoma and glioblastoma samples. Expression levels were measured by QRT-PCR and mass-spectroscopy. The connection between the expression pattern and tumor grade is statistically analyzed. During the analysis of data, key molecules (brevican, cadherin-12, fibronectin and integrin-ß1) correlating the most with tumor grade were selected. While the mRNA level of brevican, ErbB2, fibronectin, integrin-ß1 and versican discriminates low-grade from high-grade gliomas, of proteins RHAMM, integrin-α1 and MMP2 seems important. The expression pattern was found to be distinctive for tumor grade, as statistical classifiers are capable of identifying an unknown sample's grade using them. Furthermore, normal brain and glioma expression patterns, along with low-grade astrocytoma and glioblastoma samples, differ the most. Determining the invasion-related molecules' expression profile provides extra information regarding the tumor's clinical behavior. Additionally, identifying molecules playing a key role in glioma invasion could uncover potential therapeutic targets in the future.

Differences in Extracellular Matrix Composition and its Role in Invasion in Primary and Secondary Intracerebral Malignancies.

BACKGROUND/AIM: The most common malignant primary brain tumor is glioblastoma which infiltrates the peritumoral brain, while secondary brain metastases are well demarcated malignancies. Previous research has proved the pivotal role of the changes in the extracellular matrix (ECM) in cancer cell invasion. MATERIALS AND METHODS: The mRNA expression of 40 ECM molecules was determined using qRT-PCR in 54 fresh-frozen glioblastoma and brain metastasis samples. Seventy-two samples were used to determine the levels of 20 ECM proteins. RESULTS: The mRNA and protein expression pattern of the studied tumors differs greatly. Linear discriminant analysis of mRNA expression identified samples based on their mRNA expression profile with 92.3% probability and highlighted the role of some molecules as their level greatly influenced sample identification. CONCLUSION: Different tumor types with different invasiveness differ in the composition of their ECM and this can be used to identify samples. Furthermore, some ECM molecules greatly contribute to tumor invasiveness and could be targets of anti-invasive oncotherapy.

Prognostic Role of the Expression of Invasion-Related Molecules in Glioblastoma.

Background Glioblastoma multiforme (GBM) is the most common malignant disease of the central nervous system. Its prognosis is unfavorable, and the median overall survival of patients is 16 to 24 months. The main cause of the poor survival data are the extensive invasion of cancer cells to the neighboring parenchyma, thus leading to inevitable local recurrence. The extracellular matrix (ECM) is a known factor in tumor invasion, and differences in the ECM of nontumor brain and glioblastoma has been proven. Methods In this research, 20 invasion-related expressions of ECM components were determined in 26 GBM flash-frozen samples using quantitative reverse transcription-polymerase chain reaction and proteomic measurements. Expression data were then set against the survival data of the patients. Results Significant alterations between groups with different survival rates could not be established in the individual evaluation of the expression level of the selected molecules. However, statistical analysis of the expression pattern of invasion-related molecules revealed a correlation with prognosis. The positive predictive values of the messenger RNA (mRNA) and the proteomic expression studies were 0.85 and 0.89, respectively. The receiver operation characteristic value was 0.775 for the mRNA expression data and 0.875 for the protein expression data. Furthermore, a group of molecules, including brevican, cadherin-12, integrin ß1, integrin α3, laminin α4, and laminin ß1, that play a prominent role in invasion were identified. Conclusions Joint assessment of the expression of invasion-related molecules provides a specific invasion spectrum of the tumor that correlates with the survival of glioblastoma patients. Using statistical classifiers enables the adoption of an invasion spectrum as a considerably accurate prognostic factor while gaining predictive information on potential molecular oncotherapeutic targets at the same time.

Expression pattern of invasion-related molecules in the peritumoral brain.

OBJECTIVE: The effectiveness of therapy of intracerebral neoplasms is mainly influenced by the invasive behaviour of the tumour. The peritumoral invasion depends on the interaction between the tumour cells and the extracellular matrix (ECM) of the surrounding brain. The invading tumour cells induce change in the activity of proteases, synthases and expression of ECM-components. These alterations in the peritumoral ECM are in connection to the highly different invasiveness of gliomas and metastatic brain tumours. To understand the fairly modified invasive potential of anaplastic intracerebral tumours of different origin, the effect of tumour on the peritumoral ECM and alterations of invasion related ECM components in the peritumoral brain were evaluated. METHODS: For this reason the mRNA expression of 19 invasion-related molecules by quantitative reverse transcriptase polymerase chain reaction was determined in normal brain tissue (Norm), in the peritumoral brain tissue of glioblastoma (peri-GBM) and of intracerebral adenocarcinoma metastasis (peri-Met). To evaluate the translational expression of the investigated molecules protein levels were determined by targeted proteomic methods. RESULTS: Establishing the invasion pattern of the investigated tissue samples 8 molecules showed concordant difference at mRNA and protein levels in the peri-GBM and peri-Met, 11 molecules in the peri-Met and normal brain and 12 in the peri-GBM and normal brain comparison. CONCLUSION: Our results bring some ECM molecules into focus that probably play key role in arresting tumour cell invasion around the metastatic tumour, and also in the lack of impeding tumour cell migration in case of glioblastoma.