Juglone in Combination with Temozolomide Shows a Promising Epigenetic Therapeutic Effect on the Glioblastoma Cell Line.

Glioblastoma (GBM) is the most common and aggressive primary brain tumor and one of the human malignancies with the highest mortality. Standard approaches for GBM, including gross total resection, radiotherapy, and chemotherapy, cannot destroy all the cancer cells, and despite advances in its treatment, the prognosis for GBM remains poor. The problem is that we still do not understand what triggers GBM. Until now, the most successful chemotherapy with temozolomide for brain gliomas is not effective, and therefore new therapeutic strategies for GBM are needed. We found that juglone (J), which exhibits cytotoxic, anti-proliferative, and anti-invasive effects on various cells, could be a promising agent for GBM therapy. In this paper, we present the effects of juglone alone and in combination with temozolomide on glioblastoma cells. In addition to the analysis of cell viability and the cell cycle, we looked at the epigenetics effects of these compounds on cancer cells. We showed that juglone induces strong oxidative stress, as identified by a high increase in the amount of 8-oxo-dG, and decreases m5C in the DNA of cancer cells. In combination with TMZ, juglone modulates the level of both marker compounds. Our results strongly suggest that a combination of juglone and temozolomide can be applied for better GBM treatment.

Cross-reactivity between histone demethylase inhibitor valproic acid and DNA methylation in glioblastoma cell lines.

Currently, valproic acid (VPA) is known as an inhibitor of histone deacetylase (epigenetic drug) and is used for the clinical treatment of epileptic events in the course of glioblastoma multiforme (GBM). Which improves the clinical outcome of those patients. We analyzed the level of 5-methylcytosine, a DNA epigenetic modulator, and 8-oxodeoxyguanosine, an cellular oxidative damage marker, affected with VPA administration, alone and in combination with temozolomide (TMZ), of glioma (T98G, U118, U138), other cancer (HeLa), and normal (HaCaT) cell lines. We observed the VPA dose-dependent changes in the total DNA methylation in neoplastic cell lines and the lack of such an effect in a normal cell line. VPA at high concentrations (250-500 µM) induced hypermethylation of DNA in a short time frame. However, the exposition of GBM cells to the combination of VPA and TMZ resulted in DNA hypomethylation. At the same time, we observed an increase of genomic 8-oxo-dG, which as a hydroxyl radical reaction product with guanosine residue in DNA suggests a red-ox imbalance in the cancer cells and radical damage of DNA. Our data show that VPA as an HDAC inhibitor does not induce changes only in histone acetylation, but also changes in the state of DNA modification. It shows cross-reactivity between chromatin remodeling due to histone acetylation and DNA methylation. Finally, total DNA cytosine methylation and guanosine oxidation changes in glioma cell lines under VPA treatment suggest a new epigenetic mechanism of that drug action.

ABCB1 Is Frequently Methylated in Higher-Grade Gliomas and May Serve as a Diagnostic Biomarker of More Aggressive Tumors.

ABCB1 belongs to a superfamily of membrane transporters that use ATP hydrolysis to efflux various endogenous compounds and drugs outside the cell. Cancer cells upregulate ABCB1 expression as an adaptive response to evade chemotherapy-mediated cell death. On the other hand, several reports highlight the role of the epigenetic regulation of ABCB1 expression. In fact, the promoter methylation of ABCB1 was found to be methylated in several tumor types, including gliomas, but its role as a biomarker is not fully established yet. Thus, the aim of this study was to analyze the methylation of the ABCB1 promoter in tumor tissues from 50 glioma patients to verify its incidence and to semi-quantitively detect ABCB1 methylation levels in order to establish its utility as a potential biomarker. The results of this study show a high interindividual variability in the ABCB1 methylation level of the samples derived from gliomas of different grades. Additionally, a positive correlation between ABCB1 methylation, the WHO tumor grade, and an IDH1 wild-type status has been observed. Thus, ABCB1 methylation can be regarded as a potential diagnostic or prognostic biomarker for glioma patients, indicating more aggressive tumors.

Holistic Approach to the Diagnosis and Treatment of Patients with Tumor Metastases to the Spine.

The treatment of neoplastic spine metastases requires multi-faceted assessment and an interdisciplinary approach to patients. The metastases do not show specific symptoms but are often the first confirmation of the presence of a primary tumor in a patient. The diagnostic process includes imaging and invasive procedures, e.g., biopsy. It is essential to qualify the patient for an appropriate treatment using dedicated scales. Decompression of the spinal cord is a critical issue to save or restore neurological function in a patient with spine metastases. Surgical treatment ought to meet three criteria: release spinal cord and nerve roots, restore the spine's anatomical relations, and ensure the internal stabilization of the spine. A good result from surgical treatment enables the continuation of radiotherapy, chemotherapy, hormone therapy, and targeted molecular therapy. Stereotactic radiosurgery and stereotactic body radiotherapy are more effective ways of treating spine metastases than conventional external beam radiotherapy. They allow higher doses of radiation, concentrated precisely at the tumor site. Our review summarizes the established and emerging concepts in the treatment of spine metastases. A holistic approach to the patient enables the selection of the appropriate therapy.

mTOR Signaling and Potential Therapeutic Targeting in Meningioma.

Meningiomas are the most frequent primary tumors arising in the central nervous system. They typically follow a benign course, with an excellent prognosis for grade I lesions through surgical intervention. Although radiotherapy is a good option for recurrent, progressive, or inoperable tumors, alternative treatments are very limited. mTOR is a protein complex with increasing therapeutical potential as a target in cancer. The current understanding of the mTOR pathway heavily involves it in the development of meningioma. Its activation is strongly dependent on PI3K/Akt signaling and the merlin protein. Both factors are commonly defective in meningioma cells, which indicates their likely function in tumor growth. Furthermore, regarding molecular tumorigenesis, the kinase activity of the mTORC1 complex inhibits many components of the autophagosome, such as the ULK1 or Beclin complexes. mTOR contributes to redox homeostasis, a vital component of neoplasia. Recent clinical trials have investigated novel chemotherapeutic agents for mTOR inhibition, showing promising results in resistant or recurrent meningiomas.

Epigenetic-Based Therapy-A Prospective Chance for Medulloblastoma Patients' Recovery.

Medulloblastoma (MB) is one of the most frequent and malignant brain tumors in children. The prognosis depends on the advancement of the disease and the patient's age. Current therapies, which include surgery, chemotherapy, and irradiation, despite being quite effective, cause significant side effects that influence the central nervous system's function and cause neurocognitive deficits. Therefore, they substantially lower the quality of life, which is especially severe in a developing organism. Thus, there is a need for new therapies that are less toxic and even more effective. Recently, knowledge about the epigenetic mechanisms that are responsible for medulloblastoma development has increased. Epigenetics is a phenomenon that influences gene expression but can be easily modified by external factors. The best known epigenetic mechanisms are histone modifications, DNA methylation, or noncoding RNAs actions. Epigenetic mechanisms comprehensively explain the complex phenomena of carcinogenesis. At the same time, they seem to be a potential key to treating medulloblastoma with fewer complications than past therapies. This review presents the currently known epigenetic mechanisms that are involved in medulloblastoma pathogenesis and the potential therapies that use epigenetic traits to cure medulloblastoma while maintaining a good quality of life and ensuring a higher median overall survival rate.

Elucidating of oxidative distress in COVID-19 and methods of its prevention.

The pandemic of SARS-CoV-2 stimulates significant efforts and approaches to understand its global spread. Although the recent introduction of the vaccine is a crucial prophylactic step, the effective treatment for SARS-CoV-2 is still undiscovered. An in-depth analysis of symptoms and clinical parameters, as well as molecular changes, is necessary to comprehend COVID-19 and propose a remedy for affected people to fight that disease. The analysis of available clinical data and SARS-CoV-2 infection markers underlined the main pathogenic process in COVID-19 is cytokine storm and inflammation. That led us to suggest that the most important pathogenic feature of SARS-CoV-2 leading to COVID-19 is oxidative stress and cellular damage stimulated by iron, a source of Fenton reaction and its product hydroxyl radical (•OH), the most reactive ROS with t1/2-10-9s. Therefore we suggest some scavenging agents are a reasonable choice for overcoming its toxic effect and can be regarded as a treatment for the disease on the molecular level.

DNA methylation analysis with methylation-sensitive high-resolution melting (MS-HRM) reveals gene panel for glioma characteristics.

INTRODUCTION: Local DNA hypermethylation is a potential source of cancer biomarkers. While the evaluation of single gene methylation has limited value, their selected panel may provide better information. AIMS: This study aimed to analyze the promoter methylation level in a 7-gene panel in brain tumors and verifies the usefulness of methylation-sensitive high-resolution melting (MS-HRM) for this purpose. METHODS: Forty-six glioma samples and one non-neoplastic brain sample were analyzed by MS-HRM in terms of SFRP1, SFRP2, RUNX3, CBLN4, INA, MGMT, and RASSF1A promoter methylation. The results were correlated with patients' clinicopathological features. RESULTS: DNA methylation level of all analyzed genes was significantly higher in brain tumor samples as compared to non-neoplastic brain and commercial, unmethylated DNA control. RASSF1A was the most frequently methylated gene, with statistically significant differences depending on the tumor WHO grade. Higher MGMT methylation levels were observed in females, whereas the levels of SFRP1 and INA promoter methylation significantly increased with patients' age. A positive correlation of promoter methylation levels was observed between pairs of genes, for example, CBLN4 and INA or MGMT and RASSF1A. CONCLUSIONS: Our 7-gene panel of promoter methylation can be helpful in brain tumor diagnosis or characterization, and MS-HRM is a suitable method for its analysis.

Total DNA methylation as a biomarker of DNA damage and tumor malignancy in intracranial meningiomas.

BACKGROUND: Meningiomas are the most common primary intracranial tumors in adults. They are initially detected with neuroimaging techniques, but definite histological diagnosis requires tumor surgery to collect tumor tissue. Gross total resection is an optimal and final treatment for the majority of patients, followed by radiotherapy in malignant or refractory cases. However, there are a lot of uncertainties about i.a. the need for intervention in incidental cases, estimation of growth kinetics, risk of malignant transformation, or response to radiotherapy. Therefore a new diagnostic approach is needed. It has already been shown that epigenetics plays a crucial role in cancer biology, development, and progression. DNA methylation, the presence of 5-methylcytosine in DNA, is one of the main elements of a broad epigenetic program in a eukaryotic cell, with superior regulatory significance. Therefore, we decided to look at meningioma through changes of 5-methylcytosine. METHODS: We performed an analysis of the total amount of 5-methylcytosine in DNA isolated from intracranial meningioma tissues and peripheral blood samples of the same patients. The separation and identification of radioactively labeled nucleotides were performed using thin-layer chromatography. RESULTS: We found that the 5-methylcytosine level in DNA from intracranial meningiomas is inversely proportional to the malignancy grade. The higher the tumor WHO grade is, the lower the total DNA methylation. The amount of 5-methylcytosine in tumor tissue and peripheral blood is almost identical. CONCLUSIONS: We conclude that the total DNA methylation can be a useful marker for brain meningioma detection, differentiation, and monitoring. It correlates with tumor WHO grade, and the 5-methylcytosine level in peripheral blood reflects that in tumor tissue. Therefore it's applicable for liquid biopsy. Our study creates a scope for further research on epigenetic mechanisms in neurooncology and can lead to the development of new diagnostic methods in clinical practice.

Clinical presentation of Y189C mutation of the NOTCH3 gene in the Polish family with CADASIL.

INTRODUCTION: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary, progressive ischemic disease of small vessels of the brain characterized by migraine with aura (MA), recurrent subcortical ischemic episodes, cognitive decline and psychiatric disorders. CADASIL is caused by mutations in the NOTCH3 gene. We identified the NOTCH3 Y189C mutation as a genetic cause of CADASIL in a Polish family and provided its first clinical manifestation. MATERIAL AND METHODS: The study included twelve subjects from one family. The NOTCH3 mutation, APOE and MTHFR polymorphisms were determined by high-resolution melting analyses (HRMA) and Sanger sequencing. Neuroimaging included CT and MRI. Ultrastructural examination of skin-muscle biopsy material of the proband was performed. RESULTS: The NOTCH3 Y189C mutation was present in a 36-year-old woman and her two sisters (aged 40 and 27) from 6 siblings. The MA was found in all of them, and started or became more severe after childbirth. The numerous T2/FLAIR hyperintense lesions were shown in the brain MRI. The deposition of granular osmiophilic material in the wall of small vessels of the proband observed in histopathological analysis confirmed the high degree of CADASIL severity. CONCLUSIONS: Patients with the Y189C mutation of NOTCH3 from the same family display a similar phenotype of CADASIL.

Revealing the epigenetic effect of temozolomide on glioblastoma cell lines in therapeutic conditions.

Temozolomide (TMZ) is a drug of choice in glioblastoma treatment. Its therapeutic applications expand also beyond high grade gliomas. However, a significant number of recurrences and resistance to the drug is observed. The key factor in each chemotherapy is to achieve the therapeutic doses of a drug at the pathologic site. Nonetheless, the rate of temozolomide penetration from blood to cerebrospinal fluid is only 20-30%, and even smaller into brain intestinum. That makes a challenge for the therapeutic regimens to obtain effective drug concentrations with minimal toxicity and minor side effects. The aim of our research was to explore a novel epigenetic mechanism of temozolomide action in therapeutic conditions. We analyzed the epigenetic effects of TMZ influence on different glioblastoma cell lines in therapeutically achieved TMZ concentrations through total changes of the level of 5-methylcytosine in DNA, the main epigenetic marker. That was done with classical approach of radioactive nucleotide post-labelling and separation on thin-layer chromatography. In the range of therapeutically achieved temozolomide concentrations we observed total DNA hypomethylation. The significant hypermethylating effect was visible after reaching TMZ concentrations of 10-50 µM (depending on the cell line). Longer exposure time promoted DNA hypomethylation. The demethylated state of the glioblastoma cell lines was overcome by repeated TMZ applications, where dose-dependent increase in DNA 5-methylcytosine contents was observed. Those effects were not seen in non-cancerous cell line. The increase of DNA methylation resulting in global gene silencing and consecutive down regulation of gene expression after TMZ treatment may explain better glioblastoma patients' survival.

Analysis of pharmacotherapy regimen and costs in patients with drug-resistant epilepsy following vagus nerve stimulation therapy: a single-center study (Poland).

Approximately 30-40% of patients with drug-resistant epilepsy (DRE) who underwent vagus nerve stimulator (VNS) implantation achieve above 50% reduction in seizure frequency. VNS proves effective in reducing frequency of seizures in DRE patients, when combined with antiepileptic drugs (AEDs). This raises a question whether improvement of clinical parameters is achieved with VNS only or relies on combined therapy with AEDs. The aim of the study was the analysis of impact of VNS on clinical recovery of patients with DRE and the analysis of pharmacotherapy costs and drug regimen following VNS implantation in DRE patients. The study included all the patients who had VNS implanted at our department in the years 2014-2018. The patients would be followed up for 2 years after the VNS implantation date. The most commonly used drugs included levetiracetam, lacosamide, valproate, oxcarbazepine, and topiramate. Average cost of AEDs in year 1 following VNS implantation was between EUR 15.53 (CLB) and EUR 545.52 (TGB) and in year 2 between EUR 13.51 (NTZ) and EUR 779.44 (LAC). The greatest number of seizures affected the group of patients treated with three drugs. A statistically significant improvement in seizure frequency was observed in the group of patients treated with two and three drugs. With the rising costs of healthcare, the importance of economic efficiency is becoming increasingly relevant. VNS is a reasonable option for saving money in the healthcare system while ensuring measurable clinical and therapeutic outcomes over the long term.

Total DNA Methylation Changes Reflect Random Oxidative DNA Damage in Gliomas.

DNA modifications can be used to monitor pathological processes. We have previously shown that estimating the amount of the main DNA epigenetic mark, 5-methylcytosine (m5C), is an efficient and reliable way to diagnose brain tumors, hypertension, and other diseases. Abnormal increases of reactive oxygen species (ROS) are a driving factor for mutations that lead to changes in m5C levels and cancer evolution. 8-oxo-deoxyguanosine (8-oxo-dG) is a specific marker of ROS-driven DNA-damage, and its accumulation makes m5C a hotspot for mutations. It is unknown how m5C and 8-oxo-dG correlate with the malignancy of gliomas. We analyzed the total contents of m5C and 8-oxo-dG in DNA from tumor tissue and peripheral blood samples from brain glioma patients. We found an opposite relationship in the amounts of m5C and 8-oxo-dG, which correlated with glioma grade in the way that low level of m5C and high level of 8-oxo-dG indicated increased glioma malignancy grade. Our results could be directly applied to patient monitoring and treatment protocols for gliomas, as well as bolster previous findings, suggesting that spontaneously generated ROS react with m5C. Because of the similar mechanisms of m5C and guanosine oxidation, we concluded that 8-oxo-dG could also predict glioma malignancy grade and global DNA demethylation in cancer cells.

Economic and clinical evaluation of vagus nerve stimulation therapy.

OBJECTIVES: The medical and social care of drug-resistant epilepsy (DRE) entails significant costs. Approximately 30 to 40 percent of patients with DRE who underwent vagus nerve stimulator (VNS) implantation achieve an above 50 percent reduction in seizure frequency. The study objective was to analyze the effect of VNS on clinical effects improvement and therapy cost reduction in patients with DRE over a 2-year follow-up period. The second purpose of the study was to compare average costs of VNS treatment of patients with DRE in selected countries, taking into account the purchasing power parity. MATERIALS AND METHODS: The study included all the patients who had VNS implanted at our department between 2014 and 2018. Data on clinical events and medical costs were collected prospectively and obtained from medical documentation. We also reviewed relevant literature on costs of VNS therapy in patients with DRE from the last 18 years. RESULTS: Resource utilization and epilepsy-related events were reduced during the follow-up period compared to the baseline. Average total cost was estimated at EUR 7703.59 in year 1 and at EUR 7108.38 in year 2 following VNS implantation. Average direct costs of VNS treatment of patients with DRE over the last 18 years varied between the countries and ranged from EUR 24 790.43 in the United States to EUR 64.84 in the United Kingdom. CONCLUSION: Vagus nerve stimulator is a cost-effective therapy yielding measurable clinical and therapeutic outcomes over the long term. Moreover, the analysis contained in this review highlights the poor consensus of methodological approaches.

Global DNA demethylation as an epigenetic marker of human brain metastases.

Brain metastases are the most common intracranial tumors in adults. They usually originate from: lung, breast, renal cell and gastrointestinal cancers, as well as melanoma. Prognosis for brain metastases is still poor and classical treatment combining surgery and radiation therapy should be strongly supported with molecular approaches. However, their successful application depends on a deep understanding of not only genetic, but also epigenetic background of the disease. That will result in an earlier and more precise diagnosis, successful treatment, as well as individualized estimation of clinical outcomes and prognosis. It has already been shown that the epigenetic machinery plays a crucial role in cancer biology, development, and progression. Therefore, we decided to look for metastasis through changes in the most studied epigenetic mark, 5-methylcytosine (m5C) in DNA. We performed global analysis of the m5C contents in DNA isolated from the brain metastatic tumor tissue and peripheral blood samples of the same patients, using thin layer chromatography separation of radioactively labeled nucleotides. We found that the m5C level in DNA from brain metastases: changes in the broad range, overlaps with that of blood, and negatively correlates with the increasing tumor grade. Because the amount of m5C in tumor tissue and blood is almost identical, the genomic DNA methylation can be a useful marker for brain metastases detection and differentiation. Our research creates a scope for future studies on epigenetic mechanisms in neuro-oncology and can lead to development of new diagnostic methods in clinical practice.

MicroRNAs as efficient biomarkers in high-grade gliomas.

High-grade gliomas are the most aggressive and devastating brain neoplasms. Therefore much effort is put on understanding their background as well as development of new effective diagnostic and therapeutic methods. However, until now the genetic only approach has not provided a satisfactory answer. Recently, it has been shown that the epigenetic issue is important for high-grade gliomas' development and progression. Out of many epigenetic mechanisms, as DNA methylation, histone methylation and acetylation, especially microRNAs showed to be deeply involved in the carcinogenesis process. MicroRNAs are short non-coding RNAs. They are new candidates for human disease biomarkers due to their simple identification. MicroRNAs are stable in tissue and body fluids, what makes them very prospective non-invasive, blood-based biomarkers. There is a lot of data showing that various profiles of serum microRNAs are linked to numerous neoplastic processes, indicating that microRNAs can be really a new class of biomarkers for human diseases.

Wnt pathway antagonists, SFRP1, SFRP2, SOX17, and PPP2R2B, are methylated in gliomas and SFRP1 methylation predicts shorter survival.

The deregulation of Wnt signaling is observed in various cancers, including gliomas, and might be related to the methylation of the genes encoding antagonists of this signaling pathway. The aim of the study was to assess the methylation status of the promoter regions of six Wnt negative regulators and to determine their prognostic value in clinical samples of gliomas of different grades. The methylation of SFRP1, SFRP2, PPP2R2B, DKK1, SOX17, and DACH1 was analyzed in 64 glioma samples using methylation-specific polymerase chain reaction (MSP). The results were analyzed in correlation with clinicopathological data. Promoter methylation in at least one of the analyzed genes was found in 81.3 % of the tumors. All benign tumors [grade I according to the World Health Organization (WHO) classification] lacked the methylation of the studied genes, whereas grade II, III, and IV tumors were, in most cases, methylation-positive. The methylation index correlated with the patient's age. The most frequently methylated genes were SFRP1 and SFRP2 (73.4 % and 46.9 %, respectively), followed by SOX17 (20.3 %) and PPP2R2B (10.9 %); DKK1 and DACH1 were basically unmethylated (1.6 %). SFRP1 methylation negatively correlated with patients' survival time, and was significantly more frequent in older patients and those with higher grade tumors. Overall, the results of this study indicate that aberrant promoter methylation of Wnt pathway antagonists is common in gliomas, which may be the possible cause of up-regulation of this signaling pathway often observed in these tumors. Moreover, SFRP1 promoter methylation can be regarded as a potential indicator of glioma patients' survival.

A New Epigenetic Mechanism of Temozolomide Action in Glioma Cells.

Temozolomide (TMZ) is an oral alkylating chemotherapeutic agent that prolongs the survival of patients with glioblastoma (GBM). Despite that high TMZ potential, progression of disease and recurrence are still observed. Therefore a better understanding of the mechanism of action of this drug is necessary and may allow more durable benefit from its anti-glioma properties. Using nucleotide post-labelling method and separation on thin-layer chromatography we measured of global changes of 5-methylcytosine (m5C) in DNA of glioma cells treated with TMZ. Although m5C is not a product of TMZ methylation reaction of DNA, we analysed the effects of the drug action on different glioma cell lines through global changes at the level of the DNA main epigenetic mark. The first effect of TMZ action we observed is DNA hypermethylation followed by global demethylation. Therefore an increase of DNA methylation and down regulation of some genes expression can be ascribed to activation of DNA methyltransferases (DNMTs). On the other hand hypomethylation is induced by oxidative stress and causes uncontrolled expression of pathologic protein genes. The results of brain tumours treatment with TMZ suggest the new mechanism of modulation epigenetic marker in cancer cells. A high TMZ concentration induced a significant increase of m5C content in DNA in the short time, but a low TMZ concentration at longer time hypomethylation is observed for whole range of TMZ concentrations. Therefore TMZ administration with low doses of the drug and short time should be considered as optimal therapy.

Comprehensive analysis of microRNA expression profile in malignant glioma tissues.

Malignant gliomas represent the most devastating group of brain tumors in adults, among which glioblastoma multiforme (GBM) exhibits the highest malignancy rate. Despite combined modality treatment, GBM recurs and is invariably fatal. A further insight into the molecular background of gliomagenesis is required to improve patient outcomes. The primary aim of this study was to gain broad information on the miRNA expression pattern in malignant gliomas, mainly GBM. We investigated the global miRNA profile of malignant glioma tissues with miRNA microarrays, deep sequencing and meta-analysis. We selected miRNAs that were most frequently deregulated in glioblastoma tissues, as well as in peritumoral areas, in comparison with normal human brain. We identified candidate miRNAs associated with the progression from glioma grade III to glioma grade IV. The meta-analysis of miRNA profiling studies in GBM tissues summarizes the past and recent advances in the investigation of the miRNA signature in GBM versus noncancerous human brain and provides a comprehensive overview. We propose a list of 35 miRNAs whose expression is most frequently deregulated in GBM patients and of 30 miRNA candidates recognized as novel GBM biomarkers.

DNA methylation analysis of benign and atypical meningiomas: correlation between RUNX3 methylation and WHO grade.

PURPOSE: Although meningiomas are common central nervous system tumors, the biomarkers allowing early diagnosis and progression are still needed. The aim of this study was to evaluate the methylation status of 12 cancer-related genes, namely ERCC1, hMLH1, ATM, CDKN2B (p15INK4B), p14ARF, CDKN2A (p16INK4A), RASSF1A, RUNX3, GATA6, NDRG2, PTEN, and RARß, in 44 meningioma samples of WHO grade I and II. METHODS: All genes were analyzed using methylation-specific polymerase chain reaction, while pyrosequencing (PSQ) was used to study NDRG2 promoter methylation. RESULTS: The most frequently methylated genes in both types of meningiomas were p14ARF, RASSF1A, and p15INK4B. RUNX3, GATA6, and p16INK4A were methylated to a lesser extent, whereas ATM and RARß were found to be methylated in a marginal number of patients. The ERCC1, hMLH1, NDRG2, and PTEN genes were unmethylated in all cases. Although tumors of the same grade according to WHO criteria had different genes methylated, the number of methylated genes for each individual patient was low. RUNX3 methylation significantly correlated with meningioma WHO grade, therefore, can be considered as a potential indicator of tumor aggressiveness. The sequence of NDRG2 chosen for PSQ analysis was found methylated in the majority of meningiomas; however, the methylation level was only slightly elevated as compared to non-cancerous brain. CONCLUSIONS: Overall, the results of this study confirm that DNA methylation plays an important role in the pathogenesis of meningiomas. Further investigations, particularly concerning RUNX3 methylation, are necessary in order to assess the clinical usefulness of the methylation analysis of the studied genes.