scholarly journals MGMT methylation alterations in brain cancer following organochlorine pesticides exposure

2021 ◽  
Vol 8 (1) ◽  
pp. 47-53
Author(s):  
Fatemeh Yousefi ◽  
Gholamreza Asadikaram ◽  
Saeid Karamouzian ◽  
Moslem Abolhassani ◽  
Vahid Moazed ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Organochlorine Pesticides ◽  
Promoter Methylation ◽  
Dna Methyltransferase ◽  
Methylation Status ◽  
Gene Promoter ◽  
Primary Brain Tumor ◽  
Mgmt Methylation ◽  
Specific Pcr ◽  
Mgmt Promoter

Background: Alterations in the methylation levels of tumor suppressor genes are considered as one of the essential aspects of malignancies. The present study explored the association of O6-methylguanine-DNA methyltransferase (MGMT) gene promoter methylation, as a tumor suppressor, with some organochlorine pesticides (OCPs) in primary brain tumor (PBT) patients. Methods: The present study was conducted on a total of 73 PBT patients. The patients’ serum was analyzed using gas chromatography for seven OCP derivatives. The methylation-specific PCR (MSP) method was also used to determine the methylation status of the MGMT promoter. Results: The current findings demonstrated that the methylation of MGMT promoter occurred in 22 out of 34 glioma cases (64%), but in only one out of 35 meningioma cases. No MGMT promoter methylation was observed in other PBT, hemangioma, and anaplastic medulloblastoma stages. Besides, there were significant associations between MGMT methylation and γ-HCH (odds ratio [OR]: 1.50; 95% CI: 1.03- 2.40, P=0.04), 4,4DDE (OR: 1.44; 95% CI: 1.01- 2.05, P=0.02), 2,4 DDT (OR: 1.23; CI: 1.04- 1.45, P=0.03), and 4,4DDT (OR: 1.46; CI: 1.23- 2.15, P=0.02) in glioma patients. Conclusion: The results of the study suggested that the hypermethylation of the MGMT promoter in glioma patients is associated with increased OCPs in their serum, especially γ- HCH, 4,4DDE, 2,4DDT, and 4,4DDT. Moreover, it may lead to the hypermethylation of the MGMT promoter gene. Hence, it can be concluded that exposure to OCPs may potentially induce glioma.

scholarly journals Favorable role of IDH1/2 mutations aided with MGMT promoter gene methylation in the outcome of patients with malignant glioma

2020 ◽  
pp. FSO663
Author(s):  
Arshad A Pandith ◽  
Iqbal Qasim ◽  
Shahid M Baba ◽  
Aabid Koul ◽  
Wani Zahoor ◽  
...  
Keyword(s):  
Promoter Methylation ◽  
Gene Promoter ◽  
Mgmt Promoter Methylation ◽  
Mgmt Methylation ◽  
Gene Methylation ◽  
Specific Pcr ◽  
Mgmt Promoter ◽  
Promoter Gene ◽  
Prognostic Outcome

Aim: The implications of molecular biomarkers IDH1/2 mutations and MGMT gene promoter methylation were evaluated for prognostic outcome of glioma patients. Materials & methods: Glioma cases were analyzed for IDH1/2 mutations and MGMT promoter methylation by DNA sequencing and methylation-specific PCR, respectively. Results: Mutations found in IDH1/2 genes totaled 63.4% (N = 40) wherein IDH1 mutations were significantly associated with oligidendrioglioma (p = 0.005) and astrocytoma (p = 0.0002). IDH1 mutants presented more, 60.5% in MGMT promoter-methylated cases (p = 0.03). IDH1 mutant cases had better survival for glioblastoma and oligodendrioglioma (log-rank p = 0.01). Multivariate analysis confirmed better survival in MGMT methylation carriers (hazard ratio [HR]: 0.59; p = 0.031). Combination of both biomarkers showed better prognosis on temozolomide (p < 0.05). Conclusion: IDH1/2 mutations proved independent prognostic factors in glioma and associated with MGMT methylation for better survival.

scholarly journals Tim-3 protein expression with MGMT methylation status in glioblastoma and association with survival

2020 ◽  
Author(s):  
ji zhang ◽  
Xiaoli Wang ◽  
Shengquan Ye ◽  
Lijiao Liang ◽  
Yi Zhou ◽  
...  
Keyword(s):  
Protein Expression ◽  
Promoter Methylation ◽  
Immune Checkpoint ◽  
Dna Methyltransferase ◽  
Methylation Status ◽  
Prognostic Significance ◽  
Mgmt Promoter Methylation ◽  
Mgmt Methylation ◽  
Methylguanine Dna Methyltransferase ◽  
Mgmt Promoter

Abstract Background Understanding the molecular landscape of glioblastoma (GBM) is increasingly crucial for its therapy. Immune checkpoint molecules motivated the emergence of immune checkpoint-targeting therapeutic strategies. However, the prognostic significance of the immune checkpoint molecule T cell immunoglobulin mucin-3 (Tim-3) on tumor-infiltrating immune cells (TIICs) and O-6-Methylguanine-DNA methyltransferase (MGMT) methylation status remains to be fully elucidated. We aimed to develop an MGMT methylation status-associated immune prognostic signature for predicting prognosis in GBMs.Patients and Methods: A total of 84 patients with newly diagnosed GBM were involved. MGMT methylation status was retrospectively analyzed and the expression level of Tim-3 protein was investigated using immunohistochemistry (IHC). The correlation between Tim-3 protein expression and MGMT methylation status, and the prognosis was explored.Results The obtained data showed that Tim-3 protein was expressed at different levels in GBMs. Mesenchymal expression of Tim-3 protein in these tissues was 73.81% (62/84), including low 15.48% (13/84), moderate 7.14% (6/84) and strong expression 51.19% (43/84), respectively. Of the 48 patients whose tumors tested positive for MGMT methylation, the remaining 36 patients was negative.Conclusions We profiled the immune status in GBM with MGMT promoter methylation and established a local immune signature for GBM, which could independently identify patients with a favorable prognosis, indicating the relationship between prognosis and immune. MGMT promoter methylation with lower Tim-3 protein expression was statistically significantly associated with better survival.

scholarly journals XGBoost Improves Classification of MGMT Promoter Methylation Status in IDH1 Wildtype Glioblastoma

2020 ◽  
Vol 10 (3) ◽  
pp. 128 ◽  
Author(s):  
Nguyen Quoc Khanh Le ◽  
Duyen Thi Do ◽  
Fang-Ying Chiu ◽  
Edward Kien Yee Yapp ◽  
Hui-Yuan Yeh ◽  
...  
Keyword(s):  
Promoter Methylation ◽  
Dna Methyltransferase ◽  
Methylation Status ◽  
Mgmt Promoter Methylation ◽  
Gradient Boosting ◽  
Mgmt Methylation ◽  
Promoter Methylation Status ◽  
Extreme Gradient Boosting ◽  
Mgmt Promoter ◽  
Mgmt Promoter Methylation Status

Approximately 96% of patients with glioblastomas (GBM) have IDH1 wildtype GBMs, characterized by extremely poor prognosis, partly due to resistance to standard temozolomide treatment. O6-Methylguanine-DNA methyltransferase (MGMT) promoter methylation status is a crucial prognostic biomarker for alkylating chemotherapy resistance in patients with GBM. However, MGMT methylation status identification methods, where the tumor tissue is often undersampled, are time consuming and expensive. Currently, presurgical noninvasive imaging methods are used to identify biomarkers to predict MGMT methylation status. We evaluated a novel radiomics-based eXtreme Gradient Boosting (XGBoost) model to identify MGMT promoter methylation status in patients with IDH1 wildtype GBM. This retrospective study enrolled 53 patients with pathologically proven GBM and tested MGMT methylation and IDH1 status. Radiomics features were extracted from multimodality MRI and tested by F-score analysis to identify important features to improve our model. We identified nine radiomics features that reached an area under the curve of 0.896, which outperformed other classifiers reported previously. These features could be important biomarkers for identifying MGMT methylation status in IDH1 wildtype GBM. The combination of radiomics feature extraction and F-core feature selection significantly improved the performance of the XGBoost model, which may have implications for patient stratification and therapeutic strategy in GBM.

scholarly journals Methylation of MGMT promoter does not predict response to temozolomide in patients with glioblastoma in Donostia Hospital

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Larraitz Egaña ◽  
Jaione Auzmendi-Iriarte ◽  
Joaquin Andermatten ◽  
Jorge Villanua ◽  
Irune Ruiz ◽  
...  
Keyword(s):  
Promoter Methylation ◽  
Dna Methyltransferase ◽  
Methylation Status ◽  
Progression Free Survival ◽  
Mgmt Promoter Methylation ◽  
Mgmt Methylation ◽  
Free Survival ◽  
Methylguanine Dna Methyltransferase ◽  
Mgmt Promoter ◽  
Newly Diagnosed Glioblastoma

Abstract O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status has been considered a prognostic factor in newly diagnosed glioblastoma (GBM). In this study, we evaluated the prognostic and predictive value of MGMT promoter methylation in patients with glioblastoma in Donostia Hospital. Surprisingly, methylation of MGMT promoter did not predict response to temozolomide in patients with glioblastoma in Donostia Hospital. Specifically, overall survival (OS) and progression-free survival (PFS) did not differ significantly by MGMT methylation status in our cohort. In contrast, both were longer in patients who received treatment, received more TMZ cycles, had a better general status and perform at least a partial resection. No association was detected between methylation of MGMT promoter and molecular markers such as ATRX, IDH, p53 and Ki67. These results indicate that MGMT methylation did not influence in patient survival in our cohort.

scholarly journals Recycling drug screen repurposes hydroxyurea as a sensitizer of glioblastomas to temozolomide targeting de novo DNA synthesis, irrespective of molecular subtype

2017 ◽  
Vol 20 (5) ◽  
pp. 642-654 ◽  
Author(s):  
Jian Teng ◽  
Seyedali Hejazi ◽  
Lotte Hiddingh ◽  
Litia Carvalho ◽  
Mark C de Gooijer ◽  
...  
Keyword(s):  
Promoter Methylation ◽  
Dna Methyltransferase ◽  
Methylation Status ◽  
Primary Cultures ◽  
Mgmt Promoter Methylation ◽  
In Vivo Models ◽  
Promoter Methylation Status ◽  
Mgmt Promoter ◽  
Mgmt Promoter Methylation Status

Abstract Background Glioblastoma (GBM) is the most common and most aggressive primary malignant brain tumor. Standard-of-care treatment involves maximal surgical resection of the tumor followed by radiation and chemotherapy (temozolomide [TMZ]). The 5-year survival rate of patients with GBM is &lt;10%, a colossal failure that has been partially attributed to intrinsic and/or acquired resistance to TMZ through O6-methylguanine DNA methyltransferase (MGMT) promoter methylation status in the tumor. Methods A drug screening aimed at evaluating the potential recycling and repurposing of known drugs was conducted in TMZ-resistant GBM cell lines and primary cultures of newly diagnosed GBM with different MGMT promoter methylation status, phenotypic/genotypic background and subtype, and validated with sphere formation, cell migration assays, and quantitative invasive orthotopic in vivo models. Results We identified hydroxyurea (HU) to synergize with TMZ in GBM cells in culture and in vivo, irrespective of MGMT promoter methylation status, subtype, and/or stemness. HU acts specifically on the S-phase of the cell cycle by inhibiting the M2 unit of enzyme ribonucleotide reductase. Knockdown of this enzyme using RNA interference and other known chemical inhibitors exerted a similar effect to HU in combination with TMZ both in culture and in vivo. Conclusions We demonstrate preclinical efficacy of repurposing hydroxyurea in combination with TMZ for adjuvant GBM therapy. This combination benefit is of direct clinical interest given the extensive use of TMZ and the associated problems with TMZ-related resistance and treatment failure.

scholarly journals Evaluation of MGMT gene methylation in neuroendocrine neoplasms

2021 ◽  
Author(s):  
Rosa Della Monica ◽  
Mariella Cuomo ◽  
Roberta Visconti ◽  
Annabella di Mauro ◽  
Michela Buonaiuto ◽  
...  
Keyword(s):  
Dna Methyltransferase ◽  
Alkylating Agents ◽  
Methylation Status ◽  
Neuroendocrine Neoplasms ◽  
Mgmt Methylation ◽  
Gene Methylation ◽  
Mgmt Gene ◽  
Methylguanine Dna Methyltransferase ◽  
Specific Pcr ◽  
Well Differentiated

Unresectable neuroendocrine neoplasms (NENs) often poorly respond to standard therapeutic approaches. Alkylating agents, in particular temozolomide, commonly used to treat high-grade brain tumors including glioblastomas, have recently been tested in advanced or metastatic NENs, where they showed promising response rates. In glioblastomas, prediction of response to temozolomide is based on the assessment of the methylation status of the MGMT gene, as its product, O-6-methylguanine-DNA methyltransferase, may counteract the damaging effects of the alkylating agent. However, in NENs, such a biomarker has not been validated yet. Thus, we have investigated MGMT methylation in 42 NENs of different grades and from various sites of origin by two different approaches: in contrast to methylation-specific PCR (MSP), which is commonly used in glioblastoma management, amplicon bisulfite sequencing (ABS) is based on high resolution next-generation sequencing and interrogates several additional CpG sites compared to those covered by MSP. Overall, we found MGMT methylation in 74% (31/42) of the NENs investigated. A higher methylation degree was observed in well-differentiated tumors and in tumors originating in the gastrointestinal tract. Comparing MSP and ABS results, we demonstrate that the region analyzed by the MSP test is sufficiently informative of the MGMT methylation status in NENs, suggesting that this predictive parameter could routinely be interrogated also in NENs

Correlation of the quantitative level of MGMT promoter methylation and overall survival in primary diagnosed glioblastomas using the quantitative MethyQESD method

2019 ◽  
Vol 73 (2) ◽  
pp. 112-115 ◽  
Author(s):  
Charlotte von Rosenstiel ◽  
Benedikt Wiestler ◽  
Bernhard Haller ◽  
Friederike Schmidt-Graf ◽  
Jens Gempt ◽  
...  
Keyword(s):  
Overall Survival ◽  
Promoter Methylation ◽  
Promoter Region ◽  
Dna Methyltransferase ◽  
Methylation Status ◽  
Mgmt Promoter Methylation ◽  
Newly Diagnosed ◽  
Quantitative Level ◽  
Mgmt Promoter ◽  
The Impact

AimsO(6)-methylguanine-DNA-methyltransferase (MGMT) promoter methylation is a high predictive factor for therapy results of temozolomide in patients with glioma. The objective of this work was to analyse the impact of MGMT promoter methylation in patients with primary diagnosed glioblastoma (GBM) relating to survival using a quantitative method (methylation quantification of endonuclease-resistant DNA, MethyQESD) by verifying a cut-off point for MGMT methylation provided by the literature (</≥10%) and calculating an optimal cut-off.Methods67 patients aged 70 years or younger, operated between January 2013 and December 2015, with newly diagnosed IDH wild-type GBM and clinical follow-up were retrospectively investigated in this study. A known MGMT promoter methylation status was the inclusion criteria.ResultsMedian overall survival (OS) was 16.9 months. Patients who had a methylated MGMT promoter region of ≥10% had an improved OS compared with patients with a methylated promoter region of <10% (p=0.002). Optimal cut-off point for MGMT promoter methylation was 11.7% (p=0.012).ConclusionThe results confirm that the quantitative level of MGMT promoter methylation is a positive prognostic factor in newly diagnosed patients with GBM. The cut-off provided by the literature (</≥10%) and the calculated optimal cut-off value of 11.7% give a statistically significant separation. Hence, MethyQESD is a reliable method to calculate MGMT promoter methylation in GBM.

O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation and relation to 1p/19q loss in low grade gliomas: A GICNO study

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 20064-20064 ◽  
Author(s):  
L. Nicolardi ◽  
R. Bertorelle ◽  
L. Bonaldi ◽  
A. Compostella ◽  
A. Roma ◽  
...  
Keyword(s):  
Promoter Methylation ◽  
Dna Methyltransferase ◽  
Alkylating Agents ◽  
Methylation Status ◽  
Mgmt Promoter Methylation ◽  
Low Grade ◽  
Tumor Localization ◽  
Response To Chemotherapy ◽  
Mgmt Promoter ◽  
The Impact

20064 Background: 1p and 19q deletions have been associated with a favorable response to chemotherapy and a good prognosis in patients (pts) with oligodendroglioma. MGMT promoter methylation has been associated with a longer survival in pts with glioblastoma who receive alkylating agents. As yet, there are no data on the expression of MGMT, and on the relationship between 1p/19q deletions and MGMT promoter methylation in low grade glioma (LGG). Methods: Pts that received a first line chemotherapy regimen with temozolomide for progressive LGG were enrolled in the study, designed to investigate the correlation between MGMT methylation status and 1p/19q deletions in this setting. 1p/19q deletions were analysed by FISH, and MGMT promoter methylation by methylation specific PCR (MSP). Results: Seventy-five pts (26 females, 49 males; median age 42 years: range 22–68 years) were accrued. Of these, 48 (64%) had oligodendrogliomas (O), 19 (25.3%) astrocytomas (A), and 8 (10.6%) oligoastrocytomas (OA); 44 (58.7%) had a history of epilepsy, 41 (54.7%) had a frontal tumor localization, 27 (36%) had MRI contrast enhancing lesions, and 35 (46.7%) had been pre-treated with radiotherapy. 1p/19q deletions, evaluable in 58 pts (77.3%), were both present in 36 pts (62%), (3 being A and 2 OA); 18 pts (31%) had no loss; 1 pt (1.7%) had 1p loss; 3 pts (5.2%) 19q loss. Combined 1p and 19q loss was not correlated with a frontal localization (p = 0.12), median age (0.47) and/or gender (0.62). MGMT promoter methylation, present in 17 (56.6%) of 30 assessable cases, was significantly associated with combined 1p/19q deletions (p = 0.03). MGMT promoter methylation was not significantly associated with age (p = 0.46), gender (p = 0.2), tumor localization (p = 0.12) and/or histology (0.37). Conclusions: 1p/19q deletions are strictly correlated to histology and to MGMT promoter methylation; further prospective trials are required to clarify the impact of these molecular signatures on clinical outcome. No significant financial relationships to disclose.

Sign in / Sign up

Export Citation Format

Share Document