Poor reliability and reproducibility of PCR-based testing of O6-methylguanine-DNA methyltransferase gene (MGMT) promoter methylation status in formalin-fixed and paraffin-embedded neurosurgical biopsy specimens

2008 ◽  
Vol 27 (11) ◽  
pp. 388-390 ◽  
Author(s):  
M. Preusser ◽  
L. Elezi ◽  
J.A. Hainfellner
Keyword(s):  
Promoter Methylation ◽  
Dna Methyltransferase ◽  
Methylation Status ◽  
Mgmt Promoter Methylation ◽  
Methylguanine Dna Methyltransferase ◽  
Biopsy Specimens ◽  
Mgmt Promoter ◽  
Methyltransferase Gene ◽  
Formalin Fixed ◽  
Mgmt Promoter Methylation Status

scholarly journals NCOG-29. O6-METHYLGUANINE DNA METHYLTRANSFERASE (MGMT) PROMOTER METHYLATION STATUS AND THE INCIDENCE OF TEMOZOLOMIDE-INDUCED HEMATOLOGIC TOXICITY: AN ASSOCIATION STUDY

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii135-ii135
Author(s):  
Alyssa Strohbusch ◽  
Heather Pound ◽  
Patrick Regis ◽  
Robert Cavaliere
Keyword(s):  
Promoter Methylation ◽  
Dna Methyltransferase ◽  
Statistical Difference ◽  
Methylation Status ◽  
Mgmt Promoter Methylation ◽  
Hematologic Toxicity ◽  
Methylguanine Dna Methyltransferase ◽  
Mgmt Promoter ◽  
Grade 3 ◽  
Mgmt Promoter Methylation Status

Abstract BACKGROUND Despite the growing body of evidence demonstrating an increased clinical benefit of alkylating agents in glioblastoma patients with O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation, little is known regarding the effect of MGMT status on toxicity. The purpose of this investigation is to provide insight into the potential association between MGMT promoter methylation and the development of Grade 3/4 hematologic toxicities in patients receiving temozolomide. METHODS A total of 63 patients with documented glioblastoma or anaplastic astrocytoma diagnoses were evaluated retrospectively. A chi-square test of independence was utilized to evaluate the incidence of hematologic toxicities and patient overall survival was determined by univariate analysis estimated through use of Kaplan-Meier curves. Relative frequencies of treatment discontinuation secondary to myelosuppression were also compared. RESULTS At the time of study completion, 71.4% of patients with MGMT promoter hypermethylation had survived compared with 50% of patients with hypomethylation (HR 0.86; 95% CI 0.71 to 1.05; P>0.05). The percentage of patients who experienced Grade 3/4 hematologic toxicities during concurrent treatment was 20% and 5.1% within the hypermethylated and hypomethylated groups, respectively, and 26.7% and 17.9% throughout standard therapy. While a statistical difference was not found between the cumulative incidences of Grade 3/4 hematologic toxicity events throughout both phases of treatment, a statistical difference was noted in the incidence of Grade 4 occurrences with ten events occurring in the hypermethylated group and zero in those with hypomethylated promoter regions (P< 0.01). Furthermore, use of temozolomide in hypermethylated patients resulted in fewer completed cycles of standard therapy and higher rates of treatment delays and drug discontinuation. CONCLUSIONS This study showed marked differences in the frequency of temozolomide-induced hematologic toxicities and treatment discontinuation based on tumor MGMT promoter methylation status. Further research is warranted in larger patient populations to both validate and determine the clinical significance of these findings.

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 <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 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.

Sign in / Sign up

Export Citation Format

Share Document