Gene Summary

Gene:MGMT; O-6-methylguanine-DNA methyltransferase
Summary:Alkylating agents are potent carcinogens that can result in cell death, mutation and cancer. The protein encoded by this gene is a DNA repair protein that is involved in cellular defense against mutagenesis and toxicity from alkylating agents. The protein catalyzes transfer of methyl groups from O(6)-alkylguanine and other methylated moieties of the DNA to its own molecule, which repairs the toxic lesions. Methylation of the genes promoter has been associated with several cancer types, including colorectal cancer, lung cancer, lymphoma and glioblastoma. [provided by RefSeq, Sep 2015]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:methylated-DNA--protein-cysteine methyltransferase
Source:NCBIAccessed: 31 August, 2019


What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 31 August 2019 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 31 August, 2019 using data from PubMed, MeSH and CancerIndex

Latest Publications: MGMT (cancer-related)

Bouras E, Karakioulaki M, Bougioukas KI, et al.
Gene promoter methylation and cancer: An umbrella review.
Gene. 2019; 710:333-340 [PubMed] Related Publications
Gene promoter methylation is a common epigenetic event, taking place in the early phase of tumorigenesis, which has a great potential as a diagnostic and prognostic cancer biomarker. In this umbrella review, we provide an overview on the association between gene-promoter methylation of protein-coding genes and cancer risk based on currently available meta-analyses data on gene promoter methylation. We searched MEDLINE via PubMed and the Cochrane Database of Systematic Reviews for meta-analyses that examine the association between gene-promoter methylation and cancer, published until January 2019 in English. We used AMSTAR to assess the quality of the included studies and applied a set of pre-specified criteria to evaluate the magnitude of each association. We provide a comprehensive overview of 80 unique combinations between 22 different genes and 18 cancer outcomes, all of which indicated a positive association between promoter hypermethylation and cancer. In total, the 70 meta-analyses produced significant results under a random-effects model with odds ratios that ranged from 1.94 to 26.60, with the summary effect being in favor of the unmethylated group in all cases. Three of the strong evidence associations involve RASSF1 methylation on bladder cancer risk (OR = 18.46; 95% CI: 12.69-26.85; I

Wu P, Cai J, Chen Q, et al.
Lnc-TALC promotes O
Nat Commun. 2019; 10(1):2045 [PubMed] Free Access to Full Article Related Publications
Long noncoding RNAs (lncRNAs) have emerged as new regulatory molecules implicated in diverse biological processes, including therapeutic resistance. However, the mechanisms underlying lncRNA-mediated temozolomide (TMZ) resistance in glioblastoma (GBM) remain largely unknown. To illustrate the role of lncRNA in TMZ resistance, we induce TMZ-resistant GBM cells, perform a lncRNA microarray of the parental and TMZ-resistant cells, and find an unreported lncRNA in GBM, lnc-TALC (temozolomide-associated lncRNA in glioblastoma recurrence), correlated with TMZ resistance via competitively binding miR-20b-3p to facilitate c-Met expression. A phosphorylated AKT/FOXO3 axis regulated lnc-TALC expression in TMZ-resistant GBM cells. Furthermore, lnc-TALC increased MGMT expression by mediating the acetylation of H3K9, H3K27 and H3K36 in MGMT promoter regions through the c-Met/Stat3/p300 axis. In clinical patients, lnc-TALC is required for TMZ resistance and GBM recurrence. Our results reveal that lnc-TALC in GBM could serve as a therapeutic target to overcome TMZ resistance, enhancing the clinical benefits of TMZ chemotherapy.

Abolhassani M, Asadikaram G, Paydar P, et al.
Organochlorine and organophosphorous pesticides may induce colorectal cancer; A case-control study.
Ecotoxicol Environ Saf. 2019; 178:168-177 [PubMed] Related Publications
OBJECTIVES: Among the numerous agents, genetic factors and environmental elements such as pesticides have an important role in colorectal cancer (CRC) incidence. The present study aimed to investigate the probable-role of some organochlorine pesticides (OCPs) and organophosphorous pesticides (OPPs) in patients with CRC.
METHODS: In this case-control study, 42 patients with CRC and 30 healthy subjects were selected. The serum levels of some OCPs (α-HCH, β-HCH, γ-HCH, 2,4 DDE, 4,4 DDE, 2,4DDT and 4,4DDT) were measured by gas chromatography (GC) method. Serum levels of malondialdehyde (MDA), and total antioxidant capacity (TAC) as well as the enzyme activity of acetylcholinesterase (AChE) and arylesterase activity of Paraoxonase-1 (PON-1) were evaluated in all participants. The methylation specific PCR (MSP) assay was used for determining the methylation status of CpG island of p16 and MGMT genes in CRC patients.
RESULTS: The mean serum levels of each OCPs were significantly higher in the patient group compared to the control group (P < 0.001). The AChE and arylesterase activity of PON-1 in the patient group were significantly lower than the control group (P < 0.001). The mean serum levels of MDA and TAC in the serum of the patient group were significantly higher than the control group (P < 0.001 and P < 0.002, respectively). The current findings demonstrated significantly hypermethylation of p16 promoter in CRC patients.
CONCLUSION: Regarding the higher levels of OCPs in CRC patients, along with hypermethylation of the p16 promoter gene, diminishing in AChE and PON-1 activity and increasing in oxidative stress factors, the role of OCPs and OPPs in the CRC progression in the South-East of Iran may be assumed.

Oue N, Sentani K, Sakamoto N, et al.
Molecular carcinogenesis of gastric cancer: Lauren classification, mucin phenotype expression, and cancer stem cells.
Int J Clin Oncol. 2019; 24(7):771-778 [PubMed] Related Publications
Gastric cancer (GC), one of the most common human cancers, is a heterogeneous disease with different phenotypes, prognoses, and responses to treatment. Understanding the pathogenesis of GC at the molecular level is important for prognosis prediction and determining treatments. Microsatellite instability (MSI), silencing of MLH1, MGMT, and CDKN2A genes by DNA hypermethylation, KRAS mutation, APC mutation, and ERBB2 amplification are frequently found in intestinal type GC. Inactivation of CDH1 and RARB by DNA hypermethylation, and amplification of FGFR and MET, are frequently detected in diffuse type GC. In addition, BST2 and PCDHB9 genes are overexpressed in intestinal type GC. Both genes are associated with GC progression. GC can be divided into gastric/intestinal mucin phenotypes according to mucin expression. MSI, alterations of TP73, CDH1 mutation, and DNA methylation of MLH are detected frequently in the gastric mucin phenotype. TP53 mutation, deletion of APC, and DNA methylation of MGMT are detected frequently in the intestinal mucin phenotype. FKTN is overexpressed in the intestinal mucin phenotype, and IQGAP3 is overexpressed in the gastric mucin phenotype. These genes are involved in GC progression. To characterize cancer stem cells, a useful method is spheroid colony formation. KIFC1 and KIF11 genes show more than twofold higher expression in spheroid-forming cells than that in parental cells. Both KIF genes are overexpressed in GC, and knockdown of these genes inhibits spheroid formation. Alterations of these molecules may be useful to understand gastric carcinogenesis. Specific inhibitors of these molecules may also be promising anticancer drugs.

Rao S, Kanuri NN, Nimbalkar V, et al.
High frequency of H3K27M immunopositivity in adult thalamic glioblastoma.
Neuropathology. 2019; 39(2):78-84 [PubMed] Related Publications
Adult thalamic glioblastomas (GBM) are uncommon tumors with limited available molecular data. One of the reported molecular alterations in these tumors is the H3K27M mutation. It has been documented that H3K27M mutation is found in a high proportion of pediatric thalamic gliomas. In this study, we have analyzed the molecular alterations exclusive to adult thalamic GBM. This is a 6 years retrospective study of adult thalamic GBM patients who underwent surgical decompression of the tumor. Clinical data were obtained from the case records. Immunohistochemistry (IHC) was performed on the tumors using antibodies directed against the gene products of R132H mutant isocitrate dehydrogenase 1 (IDH1), alpha-thalassemia/mental retardation X-linked (ATRX), p53, H3K27M, H3K27me3, and V600E mutant BRAF. Molecular analyses were carried out to detect other IDH1 and IDH2 mutations, O

Aoki K, Natsume A
Overview of DNA methylation in adult diffuse gliomas.
Brain Tumor Pathol. 2019; 36(2):84-91 [PubMed] Related Publications
Adult diffuse gliomas form a heterogeneous group of tumors of the central nervous system that vary greatly in histology and prognosis. A significant advance during the last decade has been the identification of a set of genetic lesions that correlate well with histology and clinical outcome in diffuse gliomas. Most characteristic driver mutations consist of isocitrate dehydrogenase 1 (IDH1) and IDH2, and H3 histone family member 3A, which are strongly associated with DNA and histone methylation patterns. A well-characterized DNA methylation aberration is on the O6-methylguanine-DNA methyltransferase promoter. This aberration is associated with an improved response to the DNA alkylating agent, temozolomide. Methylation alterations are used for classification or treatment decisions of diffuse gliomas. This supports the importance of considering epigenomic aberrations in the pathogenesis of gliomas. Recent DNA methylation analyses revealed a small group of IDH mutant diffuse gliomas exhibiting decreased DNA hypermethylation resulting in substantial unfavorable prognosis comparable to glioblastoma. Thus, DNA methylation patterns may become a new standard that replaces the conventional grading system based on histological diagnosis. In this review, we summarize recent developments regarding the contributions of methylation patterns to the pathogenesis of adult diffuse glioma, the interactions between methylation patterns and driver mutations, and potential epigenomic targeted therapies.

Lombard DB, Cierpicki T, Grembecka J
Combined MAPK Pathway and HDAC Inhibition Breaks Melanoma.
Cancer Discov. 2019; 9(4):469-471 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
In this issue, Maertens and colleagues demonstrate that HDAC3 inhibition potentiates the effects of MAPK pathway inhibitors in melanoma, including difficult-to-treat

Makita K, Hara H, Sano E, et al.
Interferon-β sensitizes human malignant melanoma cells to temozolomide-induced apoptosis and autophagy.
Int J Oncol. 2019; 54(5):1864-1874 [PubMed] Related Publications
Malignant melanoma is a highly aggressive skin cancer that is highly resistant to chemotherapy. Adjuvant therapy is administered to patients with melanoma that possess no microscopic metastases or have a high risk of developing microscopic metastases. Methylating agents, including dacarbazine (DTIC) and temozolomide (TMZ), pegylated interferon (IFN)‑α2b and interleukin‑2 have been approved for adjuvant immuno‑chemotherapy; however, unsatisfactory results have been reported following the administration of methylating agents. IFN‑β has been considered to be a signaling molecule with an important therapeutic potential in cancer. The aim of the present study was to elucidate whether antitumor effects could be augmented by the combination of TMZ and IFN‑β in malignant melanoma. We evaluated the efficacy of TMZ and IFN‑β by comparing O6‑methylguanine‑DNA transferase (MGMT)‑proficient and ‑deficient cells, as MGMT has been reported to be associated with the resistance to methylating agents. Cell viability was determined by counting living cells with a Coulter counter, and apoptosis was analyzed by dual staining with Annexin V Alexa Fluor® 488 and propidium iodide. The expression of proteins involved in the cell cycle, apoptosis and autophagy was evaluated by western blot analysis. The combined treatment with TMZ and IFN‑β suppressed cell proliferation and induced cell cycle arrest. We also demonstrated that a combination of TMZ and IFN‑β enhanced apoptosis and autophagy more efficiently compared with TMZ treatment alone. These findings suggest that antitumor activity may be potentiated by IFN‑β in combination with TMZ.

Liang X, Dong Z, Bin W, et al.
PAX3 Promotes Proliferation of Human Glioma Cells by WNT/β-Catenin Signaling Pathways.
J Mol Neurosci. 2019; 68(1):66-77 [PubMed] Related Publications
The PAX3 (paired box 3) gene plays an important role in embryonic development, diseases, and cancer formation. Our preliminary studies have shown that PAX3 gene is upregulated in glioma cells, which is associated with a worse prognosis. Moreover, PAX3, by facilitating cell proliferation and invasion and inhibiting cell apoptosis, plays an oncogenic role in glioma. However, the specific molecular mechanism of PAX3 acting as an oncogene in glioma remains unclarified. In the present study, we have found that PAX3 overexpression was observed in high grade glioma and predicted a worse prognosis. PAX3 overexpression did not correlate significantly to IDH1 mutation and MGMT methylation. Moreover, the expression of PAX3 was positively correlated with that of β-catenin. In U87 glioma cells, PAX3 interacted with β-catenin, as was confirmed by CO-IP. Besides, PAX3 overexpression promoted cell proliferation and cell cycle progression, while it inhibited cell apoptosis by altering the expressions of important molecules associated with the Wnt signaling pathway, including β-catenin, Myc, VEGF, cyclinD1, MMP7, and Wnt1. In the meantime, it was also proved that PAX3 correlated to β-catenin through a negative regulatory mechanism with respect to the promotion of U87 glioma cell proliferation and cell cycle progression and inhibition of the cell apoptosis. Our experiment demonstrated the role of PAX3 in promoting glioma growth and development, possibly by interacting directly with β-catenin and regulating the Wnt signaling pathway.

Eriksson M, Kahari J, Vestman A, et al.
Improved treatment of glioblastoma - changes in survival over two decades at a single regional Centre.
Acta Oncol. 2019; 58(3):334-341 [PubMed] Related Publications
BACKGROUND: Glioblastoma (GBM) is an aggressive brain tumor with a short overall survival (OS) in general. The treatment of GBM has evolved over the last decades and is today multimodal including surgical resection followed by radiochemotherapy and adjuvant chemotherapy for patients in good performance status. The aim of this study was to evaluate the development of treatment and the outcome for GBM patients at a single regional center.
PATIENTS AND METHODS: Survival was studied for 571 patients in our region diagnosed with GBM between 1995 and 2015. Samples from 244 patients out of those treated 2005-2015 have been included in a tissue/blood bank and a clinical database has been set up with basic patient characteristics and details on surgery and non-surgical treatment.
RESULTS: The median OS for all patients from 1995 to 2015 was 9.3 months. There was a stepwise improvement from 6.9 to 10.3 months for patients diagnosed 1995-1996 and 2010-2015, respectively (p < .05). The 2-year survival for the same time periods improved from 7% to 18% (p < .01). After introduction of postoperative radiochemotherapy for patients in good performance status in 2005 an increased OS was noted and following implementation of intraoperative 5-aminolevulinic acid the number of tumor resection ≥95% did increase from 33% to 54% (p < .001). Positive prognostic factors for survival were young age, good performance status, absence of inflammatory disease, absence of diabetes or metabolic disease, tumor resection ≥95%, and completion of postoperative radiochemotherapy.
DISCUSSION: The results of this study are consistent with earlier results regarding survival and prognostic factors and confirm results from randomized controlled trials in a clinical setting. Despite the improvements made, the prognosis is still dismal and the need for further research on GBM treatment is great.

Nguyen QN, Vuong LD, Truong VL, et al.
Genetic and epigenetic alterations of the EGFR and mutually independent association with BRCA1, MGMT, and RASSF1A methylations in Vietnamese lung adenocarcinomas.
Pathol Res Pract. 2019; 215(5):885-892 [PubMed] Related Publications
Genetic and epigenetic alterations importantly contribute to the pathogenesis of lung cancer. In the study, we measured the frequency and distribution of molecular abnormalities of EGFR as well as the aberrant promoter methylations of BRCA1, MGMT, MLH1, and RASSF1A in Vietnamese lung adenocarcinomas. We investigated the association between genetic and epigenetic alteration, and between each abnormality with clinicopathologic parameters. Somatic EGFR mutation that was found in 49/139 (35.3%) lung adenocarcinomas showed a significant association with young age, female gender, and non-smokers. EGFR overexpression was identified in 82 tumors (59.0%) and statistical relationships with EGFR or BRCA1 methylation but not EGFR mutation. In addition, EGFR, BRCA1, MGMT, MLH1, and RASSF1A methylations were found in 33 (23.7%), 41 (29.5%), 46 (33.1%), 28 (20.1%), and 41 (29.5%) cases of a total of 139 lung adenocarcinomas, respectively. The RASSF1A methylation was found to be linked to the smoking habit. Methylations in MGMT and RASSF1A were also found to correlate with metastasis status. Furthermore, the distribution of EGFR mutation and that of BRCA1, MGMT or RASSF1A methylation were significantly exclusive in lung adenocarcinomas. The main finding of our study demonstrate that epigenetic abnormalities might play a critical role for the lung tumorigenesis in patients with smoking history and metastasis, and partly affect the predictive value of EGFR mutations through blocking expression due to promoter EGFR hypermethylation. Mutually exclusive distribution of genetic and epigenetic alterations reflects differently biological characteristics in the etiology of lung adenocarcinomas.

Wu X, Luo Q, Zhao P, et al.
MGMT-activated DUB3 stabilizes MCL1 and drives chemoresistance in ovarian cancer.
Proc Natl Acad Sci U S A. 2019; 116(8):2961-2966 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
Chemoresistance is a severe outcome among patients with ovarian cancer that leads to a poor prognosis. MCL1 is an antiapoptotic member of the BCL-2 family that has been found to play an essential role in advancing chemoresistance and could be a promising target for the treatment of ovarian cancer. Here, we found that deubiquitinating enzyme 3 (DUB3) interacts with and deubiquitinates MCL1 in the cytoplasm of ovarian cancer cells, which protects MCL1 from degradation. Furthermore, we identified that O

Jovanović N, Mitrović T, Cvetković VJ, et al.
The Impact of
Medicina (Kaunas). 2019; 55(2) [PubMed] Article available free on PMC after 01/04/2020 Related Publications

Na K, Kim HS, Shim HS, et al.
Targeted next-generation sequencing panel (TruSight Tumor 170) in diffuse glioma: a single institutional experience of 135 cases.
J Neurooncol. 2019; 142(3):445-454 [PubMed] Related Publications
PURPOSE: The TruSight Tumor 170 (TST-170) panel consists of a DNA workflow for the identification of single-nucleotide variants, small insertions and deletions, and copy number variation, as well as a panel of 55 genes for a RNA workflow for the identification of splice variants and gene fusions. To date, the application of TST-170 in diffuse gliomas (DGs) has not been described.
METHODS: We analyzed 135 samples of DG, which were diagnosed by WHO criteria based on histological features and conventional molecular tests including immunostaining, 1p/19q FISH, and analysis of MGMT methylation and TERT promoter mutation.
RESULTS: A total of 135 cases consisted of 38 IDH-mutant [17 astrocytoma (AC), 13 oligodendroglioma (OD) and eight glioblastoma (GBM)], 87 IDH-wildtype (six AC, three OD and 78 GBM), and 10 diffuse midline glioma, H3K27M-mutant. DNA analysis enabled the detection of all mutations identified in these samples by conventional techniques, and the results were highly comparable to the known mutations in each subtype. RNA analysis detected four fusion genes including PTPRZ1-MET, FGFR3-TACC3, FAM131B-BRAF, and RET-CCDC6 and one splicing variant (EGFR vIII mutant). Clustered copy number loss in 1p and 19q loci genes were detected in 1p/19q-codeleted OD.
CONCLUSIONS: The application of TST-170 panel based NGS in clinical and laboratory setting is expected to improve diagnostic accuracy and prognostication. Most benefits are expected in IDH-wildtype DG, a group of genetically heterogenous tumors harboring DNA sequence changes, copy number alterations, and fusions in a large number of oncogenes and tumor suppressor genes.

Kamarádová K, Vošmiková H, Rozkošová K, et al.
Morphological, immunohistochemical and molecular features of inflammatory bowel disease associated colorectal carcinoma and associated mucosal lesions - Single institution experience.
Pathol Res Pract. 2019; 215(4):730-737 [PubMed] Related Publications
BACKGROUND: Patients with inflammatory bowel disease (IBD) - ulcerative colitis (UC) and Crohn's disease (CD) have an elevated risk of developing colorectal carcinoma (CRC). Major risk factor in IBD patients is the continuous chronic inflammation leading to development of dysplasia and carcinoma. Nevertheless, other types of non-conventional but suspicious mucosal changes serrated change/dysplasia, NOS and villous hypermucinous change, have also been reported in IBD patients. Preneoplastic potential of these lesions is still not well elucidated.
AIMS: The aim of this study was identification of IBD-associated CRCs focusing on finding related precursor lesions in the surgical specimen or in archival biopsy samples followed by a detailed morphological, immunohistochemical and molecular evaluation. For the purpose of the study the mucosal lesions were divided into conventional IBD-associated dysplasia and non-conventional lesions that were merged under a provisory term of putative preneoplastic lesions (PPL).
METHODS: A total of 309 consecutive IBD colectomy specimens diagnosed during a 10-year period were reviewed. Detailed morphological evaluation, immunohistochemical analysis of mismatch repair (MMR) proteins, p53 and O
RESULTS: We identified 11 cases of morphologically heterogenous IBD-associated CRCs, occurring in 5 males and 6 females, aged 26-79 years (mean 44 years). A total of 22 mucosal lesions were revealed in 8 CRC patients comprising conventional IBD-associated dysplasia (4 lesions), PPLs as serrated change/dysplasia NOS (11 lesions), villous hypermucinous change (5 lesions), and two true serrated lesions (one sessile serrated adenoma and one traditional serrated adenoma). More than one type of lesion was found in 6 patients. Seven CRC cases harbored mutation of KRAS/NRAS and one case of BRAF. Two patients with KRAS-mutated CRC showed the same mutation in PPL in the same specimen (one serrated change NOS and one TSA with high-grade dysplasia). Similarly, one BRAF-mutated carcinoma case presented the same mutation in serrated change/dysplasia, NOS in the same specimen. Of the CRCs, two showed deficient MMR system profile, six presented with loss of MGMT expression, and six showed aberrant p53 expression. PPLs showed deficient MGMT expression (14 cases) and aberrant p53 (10 cases) as well.
CONCLUSION: IBD-associated CRCs are very heterogeneous entities. Besides conventional IBD-related dysplasia, other types of mucosal lesions may be associated with long lasting IBD and CRC e.g. villous hypermucinous change and serrated change/dysplasia, NOS. Since these lesions share certain genetic or immunohistochemical changes with the related CRC, a suspicion is raised that these lesions may also have preneoplastic potential. Awareness of these changes is necessary to prevent their missing and under-reporting, and further studies of these lesions should be carried out.

Prawdzic Seńkowska A, Kiczmer P, Strzelczyk JK, et al.
Impact of HPV infection on gene expression and methylation in oral cancer patients.
J Med Microbiol. 2019; 68(3):440-445 [PubMed] Related Publications
PURPOSE: The current study aimed to examine the association between head and neck squamous cell carcinoma (HNSCC) and infection with different human papillomavirus virus (HPV) subtypes, including analysis of promoter methylation of several genes (APC, CDKN2A, MGMT, CDH1 and TIMP3) and the correlation with their mRNA expression in tumours and surgical margins.
METHODOLOGY: In 47 patients with a primary tumour of the oral cavity, HPV detection and identification of 33 subtypes was performed after previous DNA isolation using a GenoFlow HPV Array Test Kit.
RESULTS: Fifteen patients (31.92 %) were HPV [+] and the following HPV types were detected: 16 (46.67 %), 18 (6.67 %) and 43/44 (40 %). This study is the first to describe HPV 43/44 subtypes in HNSCC in a Polish population. We noted no clinical significance of HPV [+] HNSCC compared to HPV [-], however, this differed among HPV subtypes. CDKN2A promoter methylation was more frequent in HPV-16/18 patients compared to HPV43/44 patients, but there was no difference in gene expression level between HPV [+] and [-] patients.
CONCLUSION: We detected HPV infection in 31.92 % of oral cancer cases. HPV 16, along with HPV 43/44, were the most frequent subtypes. Knowledge of HPV [+] HNSCC biology may be useful in establishing the prognosis and developing novel therapies in future.

Ricci R, Martini M, Ravegnini G, et al.
Preferential MGMT methylation could predispose a subset of KIT/PDGFRA-WT GISTs, including SDH-deficient ones, to respond to alkylating agents.
Clin Epigenetics. 2019; 11(1):2 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
BACKGROUND: Succinate dehydrogenase (SDH)-deficient gastrointestinal stromal tumors (GISTs) constitute a small KIT/PDGFRA-WT GIST subgroup featuring DNA methylation which, although pervasive, appears nevertheless not randomly distributed. Although often indolent, these tumors are mostly chemorefractory in aggressive cases. Promoter methylation-induced O
RESULTS: Nine GISTs of our series were SDH-deficient, revealing significantly enriched in MGMT-methylated cases (6/9-67%-, vs. 6/39-15%- of SDH-proficient GISTs; p = 0.004). The pathogenetically heterogeneous KIT/PDGFRA-WT GISTs were also significantly MGMT-methylated (11/24-46%-, vs. 1/24-4%- of KIT/PDGFRA-mutant cases, p = 0.002).
CONCLUSIONS: A subset of KIT/PDGFRA-WT GISTs, including their largest pathogenetically characterized subgroup (i.e., SDH-deficient ones), is preferentially MGMT-methylated. This finding could foster a reappraisal of alkylating agents for treating malignant cases occurring among these overall chemorefractory tumors.

Gao WZ, Guo LM, Xu TQ, et al.
Identification of a multidimensional transcriptome signature for survival prediction of postoperative glioblastoma multiforme patients.
J Transl Med. 2018; 16(1):368 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
BACKGROUND: Glioblastoma multiform (GBM) is a devastating brain tumor with maximum surgical resection, radiotherapy plus concomitant and adjuvant temozolomide (TMZ) as the standard treatment. Diverse clinicopathological and molecular features are major obstacles to accurate predict survival and evaluate the efficacy of chemotherapy or radiotherapy. Reliable prognostic biomarkers are urgently needed for postoperative GBM patients.
METHODS: The protein coding genes (PCGs) and long non-coding RNA (lncRNA) gene expression profiles of 233 GBM postoperative patients were obtained from The Cancer Genome Atlas (TCGA), TANRIC and Gene Expression Omnibus (GEO) database. We randomly divided the TCGA set into a training (n = 76) and a test set (n = 77) and used GSE7696 (n = 80) as an independent validation set. Survival analysis and the random survival forest algorithm were performed to screen survival associated signature.
RESULTS: Six PCGs (EIF2AK3, EPRS, GALE, GUCY2C, MTHFD2, RNF212) and five lncRNAs (CTD-2140B24.6, LINC02015, AC068888.1, CERNA1, LINC00618) were screened out by a risk score model and formed a PCG-lncRNA signature for its predictive power was strongest (AUC = 0.78 in the training dataset). The PCG-lncRNA signature could divide patients into high- risk or low-risk group with significantly different survival (median 7.47 vs. 18.27 months, log-rank test P < 0.001) in the training dataset. Similar result was observed in the test dataset (median 11.40 vs. 16.80 months, log-rank test P = 0.001) and the independent set (median 8.93 vs. 16.22 months, log-rank test P = 0.007). Multivariable Cox regression analysis verified that it was an independent prognostic factor for the postsurgical patients with GBM. Compared with IDH mutation status, O-(6)-methylguanine DNA methyltransferase promoter methylation status and age, the signature was proved to have a superior predictive power. And stratified analysis found that the signature could further separated postoperative GBM patients who received TMZ-chemoradiation into high- and low-risk groups in TCGA and GEO dataset.
CONCLUSIONS: The PCG-lncRNA signature was a novel prognostic marker to predict survival and TMZ-chemoradiation response in GBM patients after surgery.

Karlsson I, Veevnik D, Fedulov A, et al.
Local delivery of temozolomide via a biologically inert carrier (Temodex) prolongs survival in glioma patients, irrespectively of the methylation status of MGMT.
Neoplasma. 2019; 66(2):288-293 [PubMed] Related Publications
Glioma is the most common brain malignancy. Standard first-line therapy for glioma includes surgery, radiotherapy and systemic administration of temozolomide. However, temozolomide does not reach the brain in sufficient doses when administered orally and has poor efficiency in more than half of the patients. Strategies to improve the treatment of glial malignancies are therefore needed. We have recently developed a system (Temodex) for local administration of temozolomide by encapsulating the drug in a biologically inert matrix. Here, we assessed the effect of Temodex in combination with standard therapy in a small-scale clinical study. Since the efficacy of temozolomide therapy is known to depend on the methylation status of the O6-methylguanine-DNA methyltransferase gene (MGMT) promoter, we also analyzed whether the effect of Temodex was influenced by the methylation status of MGMT. Our data show that the combination of standard therapy and Temodex was more efficient than standard therapy alone, promoting the overall patient survival by up to 33 weeks. Moreover, the efficacy of Temodex was not dependent on the methylation status of MGMT. Local Temodex administration in combination with standard therapy thereby emerges as a novel therapeutic option, with applicability that is independent on the methylation status of the MGMT promoter.

Keskin DB, Anandappa AJ, Sun J, et al.
Neoantigen vaccine generates intratumoral T cell responses in phase Ib glioblastoma trial.
Nature. 2019; 565(7738):234-239 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
Neoantigens, which are derived from tumour-specific protein-coding mutations, are exempt from central tolerance, can generate robust immune responses

Cui T, Bell EH, McElroy J, et al.
miR-4516 predicts poor prognosis and functions as a novel oncogene via targeting PTPN14 in human glioblastoma.
Oncogene. 2019; 38(16):2923-2936 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
Glioblastomas (GBMs) are the most aggressive primary brain tumors, with an average survival of less than 15 months. Therefore, there is a critical need to develop novel therapeutic strategies for GBM. This study aimed to assess the prognostic value of miR-4516 and investigate its oncogenic functions and the underlying cellular and molecular mechanisms in GBM. To determine the correlation between miR-4516 expression and overall survival of patients with GBM, total RNAs were isolated from 268 FFPE tumor samples, miR expression was assayed (simultaneously) using the nCounter human miRNA v3a assay followed by univariable and multivariable survival analyses. Further, in vitro and in vivo studies were conducted to define the role of miR-4516 in GBM tumorigenesis and the underlying molecular mechanisms. Upon multivariable analysis, miR-4516 was correlated with poor prognosis in GBM patients (HR = 1.49, 95%CI: 1.12-1.99, P = 0.01). Interestingly, the significance of miR-4516 was retained including MGMT methylation status. Overexpression of miR-4516 significantly enhanced cell proliferation and invasion of GBM cells both in vitro and in vivo. While conducting downstream targeting studies, we found that the tumor-promoting function of miR-4516, in part, was mediated by direct targeting of PTPN14 (protein tyrosine phosphatase, non-receptor type 14) which, in turn, regulated the Hippo pathway in GBM. Taken together, our data suggest that miR-4516 represents an independent negative prognostic factor in GBM patients and acts as a novel oncogene in GBM, which regulates the PTPN14/Hippo pathway. Thus, this newly identified miR-4516 may serve as a new potential therapeutic target for GBM treatment.

Nie E, Miao F, Jin X, et al.
Fstl1/DIP2A/MGMT signaling pathway plays important roles in temozolomide resistance in glioblastoma.
Oncogene. 2019; 38(15):2706-2721 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
Temozolomide was recognized as the first-line therapy for glioblastoma to prolong the survival of patients noticeably, while recent clinical studies found that some patients were not sensitive to temozolomide treatment. The possible mechanisms seemed to be methylguanine-DNA-methyltransferase (MGMT), mismatch repair, PARP, etc. And the abnormal expression of MGMT might be the most direct factor. In this study, we provide evidence that Fstl1 plays a vital role in temozolomide resistance by sequentially regulating DIP2A protein distribution, H3K9 acetylation (H3K9Ac), and MGMT transcription. As a multifunctional protein widely distributed in cells, DIP2A cooperates with the HDAC2-DMAP1 complex to enhance H3K9Ac deacetylation, prevent MGMT transcription, and increase temozolomide sensitivity. Fstl1, a glycoprotein highly expressed in glioblastoma, competitively binds DIP2A to block DIP2A nuclear translocation, so as to hinder DIP2A from binding the HDAC2-DMAP1 complex. The overexpression of Fstl1 promoted the expression of MGMT in association with increased promoter H3K9Ac. Upregulation of Fstl1 enhanced temozolomide resistance, whereas Fstl1 silencing obviously sensitized GBM cells to temozolomide both in vivo and in vitro. Moreover, DIP2A depletion abolished the effects of Fstl1 on MGMT expression and temozolomide resistance. These findings highlight an important role of Fstl1 in the regulation of temozolomide resistance by modulation of DIP2A/MGMT signaling.

Zhang Y, Zhu J
Ten genes associated with MGMT promoter methylation predict the prognosis of patients with glioma.
Oncol Rep. 2019; 41(2):908-916 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
Glioma originates from the glial cells of the spine or brain, and promoter methylation of O6‑methylguanine‑DNA methyltransferase (MGMT) can promote the chemosensitivity of glioma. The present study aimed to reveal the key genes implicated in MGMT promoter methylation in patients with glioma. RNA‑sequencing data and methylation data for glioma were extracted from The Cancer Genome Atlas database. Following expression characteristic analysis and differential expression analysis using unsupervised hierarchical clustering and a rank sum test, the feature genes were identified between high and low methylation groups. Furthermore, multivariate survival analysis for the feature genes was performed using the survival package in R. Additionally, the independent glioma RNA expression datasets GSE7696 and GSE42669 were used to validate the prognostic efficiency of the gene combination. The results indicated that the prognosis of the low methylation group was significantly worse than that of the high methylation group. The ten genes corresponding to the cut‑off value of 0.56 (Rho GTPase‑activating protein 21, CECR2, histone acetyl‑lysine reader, endosulfine α, G‑patch domain‑containing 8, KIAA1109, MGMT, protocadherin β 13, selenoprotein M, sperm‑associated antigen 9 and WD repeat domain 6) were able to significantly predict prognosis and were differentially expressed between the two groups. Multivariate survival analysis suggested that the ten genes were effective for sample classification and prognostic prediction. Furthermore, the validation datasets confirmed the correlation of the ten genes with prognosis. In conclusion, these 10 genes may be mediated by MGMT promoter methylation in glioma. In addition, the ten‑gene combination may be associated with the prognosis of patients with glioma.

Seliger C, Schaertl J, Gerken M, et al.
Use of statins or NSAIDs and survival of patients with high-grade glioma.
PLoS One. 2018; 13(12):e0207858 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
BACKGROUND: High-grade glioma (HGG) is associated with a limited prognosis. Drug repurposing has become of increasing interest to improve standard therapy. Statins and NSAIDs inhibit glioma cell growth in vitro and in vivo, but data on statin and NSAID treatment in relation to survival of patients with HGG are sparse.
METHODS: We performed multivariable adjusted Cox-regression analyses among 1,093 patients with HGG from a regional cancer registry to obtain Hazard Ratios (HRs) with 95% Confidence Intervals (CIs) for overall survival (OS) and progression-free survival (PFS) according to treatment with statins or NSAIDs. Data on dose and duration of treatment was mostly lacking in our analysis, therefore we were not able to perform dose-response analyses.
RESULTS: Use of statins was unrelated to OS or PFS of glioma patients. Use of aspirin was associated with prolonged OS and PFS in patients with WHO grade III, but not WHO grade IV glioma. Use of other NSAIDs (diclofenac, ibuprofen) or non-NSAID analgesics (paracetamol) was mostly unrelated to survival of glioma patients. Use of selective COX-2 inhibitors and metamizol was related to inferior patient survival in parts of the analyses.
CONCLUSIONS: Use of statins or NSAIDS, including aspirin, was not associated with prolonged OS or PFS of patients with WHO grade IV glioma in our selected cohort. There was an indication for improved survival in patients with WHO grade III glioma using aspirin, but further studies are needed to confirm our first observation.

Chen Z, Wei X, Shen L, et al.
20(S)-ginsenoside-Rg3 reverses temozolomide resistance and restrains epithelial-mesenchymal transition progression in glioblastoma.
Cancer Sci. 2019; 110(1):389-400 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
Glioblastoma multiforme (GBM) is one of the most malignant human intracranial tumors. Temozolomide (TMZ) is the primary alkylating agent for GBM patients. However, many GBM patients are resistant to TMZ. Therefore, patients with GBM urgently need more effective therapeutic options. 20(S)-ginsenoside-Rg3 (20(S)-Rg3) is a natural chemical with anti-tumor effects, but at present there is little understanding of its functional mechanism. Several research reports have demonstrated that O

Cornel KMC, Wouters K, Van de Vijver KK, et al.
Gene Promoter Methylation in Endometrial Carcinogenesis.
Pathol Oncol Res. 2019; 25(2):659-667 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
Up to 60% of untreated atypical hyperplastic endometrium will develop into endometrial carcinoma (EC), and for those who underwent a hysterectomy a coexisting EC is found in up to 50%. Gene promoter methylation might be related to the EC development. The aim of this study is to determine changes in gene promoter profiles in normal endometrium, atypical hyperplasia (AH) and EC in relation to K-Ras mutations. A retrospective study was conducted in patients diagnosed with endometrial hyperplasia with and without subsequent EC. Promoter methylation of APC, hMLh1, O6-MGMT, P14, P16, RASSF1, RUNX3 was analysed on pre-operative biopsies, and correlated to the final histological diagnosis, and related to the presence of K-Ras mutations. In the study cohort (n=98), differences in promoter methylation were observed for hMLH1, O6-MGMT, and P16. Promoter methylation of hMLH1 and O6-MGMT gradually increased from histologically normal endometrium to AH to EC; 27.3, 36.4% and 38.0% for hMLH1 and 8.3%, 18.2% and 31.4% for O6-MGMT, respectively. P16 promoter methylation was significantly different in AH (7.7%) compared to EC (38%). K-Ras mutations were observed in 12.1% of AH, and in 19.6% of EC cases. No association of K-Ras mutation with promoter methylation of any of the tested genes was found. In conclusion, hMLH1 and O6-MGMT promoter methylation are frequently present in AH, and thus considered to be early events in the carcinogenesis of EC, whereas P16 promoter methylation was mainly present in EC, and not in precursor lesions supporting a late event in the carcinogenesis.

Costa AL, Moreira-Barbosa C, Lobo J, et al.
DNA methylation profiling as a tool for testicular germ cell tumors subtyping.
Epigenomics. 2018; 10(12):1511-1523 [PubMed] Related Publications
AIM: Assess differential patterns of selected five genes' promoter methylation among testicular germ cell tumors (TGCT) subtypes.
MATERIALS & METHODS:  CRIPTO, HOXA9, MGMT, RASSF1A and SCGB3A1 promoter methylation levels were evaluated by quantitative methylation-specific PCR in 161 TGCT and 16 controls. Associations between clinicopathological parameters and promoter methylation levels were assessed, and receiver operating characteristics curve analysis was performed.
RESULTS: Promoter methylation of CRIPTO/HOXA9/SCGB3A1 panel and RASSF1A best discriminated between controls and nonseminomatous tumors or seminomas, respectively, whereas HOXA9/RASSF1A panel displayed the best discriminative performance between nonseminomatous tumor and seminomas. Significant differences in CRIPTO, MGMT and RASSF1A methylation levels were depicted between pure forms and matched mixed components of seminomas and embryonal carcinoma. HOXA9, RASSF1A and SCGB3A1 promoter methylation significantly associated with tumor stage.
CONCLUSION: Different combinations of five genes' promoter methylation levels discriminate among TGCT subtypes. Methylation patterns may also assist in identification of more clinically aggressive tumors.

Wani HA, Majid S, Bhat AA, et al.
Impact of catechol-O-methyltransferase gene variants on methylation status of P16 and MGMT genes and their downregulation in colorectal cancer.
Eur J Cancer Prev. 2019; 28(2):68-75 [PubMed] Related Publications
Globally, colorectal cancer (CRC) is the third most commonly diagnosed cancer in males and the second most commonly diagnosed cancer in females, with 1.4 million new cases and almost 694 000 deaths estimated to have occurred in 2012. The development and progression of CRC is dictated by a series of alterations in diverse genes mostly proto-oncogenes and tumor suppressor genes. In this dreadful disease disturbances different from mutations called as epigenetic regulations are also taken into consideration and are thoroughly investigated. The present study was designed to analyze the promoter hypermethylation of CpG (cytosine, followed by guanine nucleotide) islands of cyclin-dependent kinase inhibitor 2A (P16) and O-methylguanine-DNA methyltransferase (MGMT) genes and its subsequent effect on the protein expression in CRC. The impact of the common functional polymorphism of the catechol-O-methyltransferase (COMT) gene, Val158Met, on promoter hypermethylation of P16 and MGMT genes in CRC was also investigated. The study included 200 CRC cases and equal numbers of normal samples. DNA was extracted using the kit method and methylation specific-PCR was performed for analysis of the promoter hypermethylation status. Total protein was isolated form all CRC cases and western blotting was performed for P16 and MGMT proteins. The COMT Val158Met polymorphism was analyzed by a PCR-restriction fragment length polymorphism assay. Epigenetic analysis showed that unlike other high-risk regions, the Kashmiri population has a different promoter hypermethylation profile of both P16 and MGMT genes, with frequent and significant promoter hypermethylation of both in CRC. The frequency of promoter hypermethylation of both genes was significantly higher in males and was insignificantly found to be higher in stage III/IV. The degree of P16 and MGMT promoter hypermethylation increased significantly with increasing severity of the lesion. We also found a significant correlation between P16 and MGMT promoter hypermethylation and loss of protein expression in CRC. A significant association was found between COMT polymorphism (homozygous variant) and P16 methylation status. Similar results were also found for MGMT hypermethylated cases.

Lønning PE, Knappskog S
BRCA1 methylation in newborns: genetic disposition, maternal transfer, environmental influence, or by chance only?
Clin Epigenetics. 2018; 10(1):128 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
In this letter, we respond to and discuss the recent publication by Al-Moghrabi et al.: Methylation of BRCA1 and MGMT genes in white blood cells are transmitted from mothers to daughters. We discuss their findings with emphasis on two other recently published papers and argue that their data allows no conclusion regarding the transmission of BRCA1 methylation from parent to child.

Johannessen LE, Brandal P, Myklebust TÅ, et al.
Cancer Genomics Proteomics. 2018 Nov-Dec; 15(6):437-446 [PubMed] Article available free on PMC after 01/10/2019 Related Publications
BACKGROUND: Although methylation of the O
MATERIALS AND METHODS: Methylation of MGMT promoter was examined by methylation-specific polymerase chain reaction (MSP), quantitative real-time MSP, methylation-sensitive high-resolution melting analysis, and two commercial pyrosequencing (PSQ) kits. Survival was compared among 48 patients with glioblastoma according to assay results.
RESULTS: Only PSQ and MSP significantly separated patients who benefited from temozolomide, with PSQ being the superior method. For PSQ analysis, the cut-off value that best correlated with prognostic outcome was 7% methylation of MGMT. Median survival in patients with MGMT promoter methylation above this cut-off value was 7.8 months longer compared to those with less than 7% methylation. Two-year overall survival for the two groups was 42% and 7.4%, respectively.
CONCLUSION: PSQ is the method of choice for MGMT promoter methylation analysis in routine clinical practice.

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