Limited Role of Promoter Methylation of and in Triage of Low-Grade Squamous Intraepithelial Lesion / 中华医学杂志(英文版)

<p><b>Background</b>Promoter methylation of MGMT and C13ORF18 has been confirmed as a potential biomarker for early diagnosis of cervical cancer. The aim of this study was to evaluate the performance of MGMT and C13ORF18 promoter methylation for triage of cytology screening samples and explore the potential mechanism.</p><p><b>Methods</b>Methylation-sensitive high-resolution melting was used to detect promoter methylation of MGMT and C13ORF18 in 124 cervical samples. High-risk human papillomavirus (HR-HPV) was detected by the Digene Hybrid Capture 2. Gene methylation frequencies in relation to cervical intraepithelial neoplasia (CIN) were analyzed. Frequencies were compared by Chi-square tests. The expression of gene biomarkers and methylation regulators was analyzed by immunohistochemical staining, real-time fluorescence quantitative polymerase chain reaction, and Western blot.</p><p><b>Results</b>For triage of low-grade squamous intraepithelial lesion (LSIL), gene methylation increased specificity from 4.0% of HR-HPV detection to 30.8% of MGMT (χ = 9.873, P = 0.002) and to 50.0% of C13ORF18 (χ = 21.814, P = 0.001). For triage of atypical squamous cells of undetermined significance, HR-HPV detection had higher positive predictive value of 54.8%. Either MGMT or C13ORF18 methylation combined with HR-HPV increased the negative predictive value to 100.0% (χ = 9.757, P = 0.002). There was no relationship between MGMT and C13ORF18 expression and DNA methylation (χ = 0.776, P = 0.379 and χ = 1.411, P = 0.235, respectively). MBD2 protein level in cervical cancer was relatively lower than normal cervical tissue (t = 4.11, P = 0.006).</p><p><b>Conclusions</b>HR-HPV detection is the cornerstone for triage setting of CIN. Promoter methylation of MGMT and C13ORF18 plays a limited role in triage of LSIL. Promoter methylation of both genes may not be the causes of gene silence.</p>

Research Advances on Targeted Therapy for Acute Myeloid Leukemia--Review / 中国实验血液学杂志

Although the traditional chemotherapy has achieved a certain effect for patients with acute myeloid leukemia (AML), but there are still limitations in terms of improving the rate of complete remission and overcome relapse after remission. The further study found that many cytogenetic molecular and epigenetic abnormalities occurred during the progression of AML, such as abnormal expression of cell surface molecules, mutation, gene aberrant methylation and so on. The drugs targeted at these changes can improve the prognosis for patients, and provide a new way for treating patients with AML. At present, the mostly targeted drugs include monoclonal antibodies CD33-Ab, tyrosine kinase inhibitor, inhibitors of DNA methyltransferases inhibitors and so on. In this review, the progress of targeted therapy in AML treatment is summarized.

Aberrant DNA methylation and its targeted therapy in acute myeloid leukemia / 浙江大学学报·医学版

The occurrence and development of acute myeloid leukemia (AML) is not only related to gene mutations, but also influenced by abnormal epigenetic regulation, in which DNA methylation is one of the most important mechanisms. Abnormal DNA methylation may lead to the activation of oncogene and the inactivation of tumor suppressor gene, resulting in the occurrence of leukemia. The mutations of DNA methylation enzymes associated with AML may have certain characteristics. The AML with recurrent cytogenetic abnormalities is also related to abnormal methylation. Some fusion genes can alter DNA methylation status to participate in the pathogenesis of leukemia. In addition, chemotherapy drug resistance in patients with AML is associated with the change of gene methylation status. Considering the reversibility of the epigenetic modification, targeted methylation therapy has become a hotspot of AML research.

Relationship between promoter methylation & tissue expression of MGMT gene in ovarian cancer.

Background & objectives: Epigenetic alterations, in addition to multiple gene abnormalities, are involved in the genesis and progression of human cancers. Aberrant methylation of CpG islands within promoter regions is associated with transcriptional inactivation of various tumour suppressor genes. O6-methyguanine-DNA methyltransferase (MGMT) is a DNA repair gene that removes mutagenic and cytotoxic adducts from the O6-position of guanine induced by alkylating agents. MGMT promoter hypermethylation and reduced expression has been found in some primary human carcinomas. We studied DNA methylation of CpG islands of the MGMT gene and its relation with MGMT protein expression in human epithelial ovarian carcinoma. Methods: A total of 88 epithelial ovarian cancer (EOC) tissue samples, 14 low malignant potential (LMP) tumours and 20 benign ovarian tissue samples were analysed for MGMT promoter methylation by nested methylation-specific polymerase chain reaction (MSP) after bisulphite modification of DNA. A subset of 64 EOC samples, 10 LMP and benign tumours and five normal ovarian tissue samples were analysed for protein expression by immunohistochemistry. Results: The methylation frequencies of the MGMT gene promoter were found to be 29.5, 28.6 and 20 per cent for EOC samples, LMP tumours and benign cases, respectively. Positive protein expression was observed in 93.8 per cent of EOC and 100 per cent in LMP, benign tumours and normal ovarian tissue samples. Promoter hypermethylation with loss of protein expression was seen only in one case of EOC. Interpretation & conclusions: Our results suggest that MGMT promoter hypermethylation does not always reflect gene expression.

IDH1 mutation and MGMT expression in astrocytoma and the relationship with prognosis after radiotherapy / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the correlation between IDH1 mutation, MGMT expression, clinicopathologic features and post-radiotherapy prognosis in patients with astrocytoma.</p><p><b>METHODS</b>Detection of IDH1 mutation and MGMT expression was carried out in 48 cases of astrocytoma (WHO grade II to III) by EnVision method with immunohistochemical staining. Follow-up data, including treatment response and overall survival time, were analyzed.</p><p><b>RESULTS</b>The rates of IDH1 mutation and MGMT expression in astrocytomas were 62.7% (30/48) and 47.9% (23/48), respectively. There was a negative correlation between IDH1 mutation and MGMT expression (r = -0.641, P < 0.01). The age of patients with IDH1 mutation was younger at disease onset. The IDH1 mutation rate in patients with WHO grade II astrocytoma was higher than that in patients with WHO grade III tumor (P < 0.05). The age at onset was an independent factor affecting the expression of mutant IDH1. After radiotherapy, patients with IDH1 mutation+/MGMT- tumor carried a longer overall survival time than patients with IDH1 mutation-/MGMT+ tumor (P < 0.05).</p><p><b>CONCLUSIONS</b>There is a correlation between IDH1 mutation and MGMT expression in WHO grade II to III astrocytoma. Age at onset is an independent factor affecting the expression of mutant IDH1. Tumors with IDH1+/MGMT- pattern show better response to radiotherapy than tumors with IDH1-/MGMT+ pattern. Detection of IDH1 mutation and MGMT protein expression can provide some guidance in choice of treatment modalities in patients with astrocytoma.</p>

Molecular biology of high-grade gliomas: what should the clinician know? / 癌症

The current World Health Organization classification system of primary brain tumors is solely based on morphologic criteria. However, there is accumulating evidence that tumors with similar histology have distinct molecular signatures that significantly impact treatment response and survival. Recent practice-changing clinical trials have defined a role for routine assessment of O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation in glioblastoma patients, especially in the elderly, and 1p and 19q codeletions in patients with anaplastic glial tumors. Recently discovered molecular alterations including mutations in IDH-1/2, epidermal growth factor receptor (EGFR), and BRAF also have the potential to become targets for future drug development. This article aims to summarize current knowledge on the molecular biology of high-grade gliomas relevant to daily practice.

Radiation and concomitant chemotherapy for patients with glioblastoma multiforme / 癌症

Postoperative external beam radiotherapy was considered the standard adjuvant treatment for patients with glioblastoma multiforme until the advent of using the drug temozolomide (TMZ) in addition to radiotherapy. High-dose volume should be focal, minimizing whole brain irradiation. Modern imaging, using several magnetic resonance sequences, has improved the planning target volume definition. The total dose delivered should be in the range of 60 Gy in fraction sizes of 1.8-2.0 Gy. Currently, TMZ concomitant and adjuvant to radiotherapy has become the standard of care for glioblastoma multiforme patients. Radiotherapy dose-intensification and radiosensitizer approaches have not improved the outcome. In spite of the lack of high quality evidence, stereotactic radiotherapy can be considered for a selected group of patients. For elderly patients, data suggest that the same survival benefit can be achieved with similar morbidity using a shorter course of radiotherapy (hypofractionation). Elderly patients with tumors that exhibit methylation of the O-6-methylguanine-DNA methyltransferase promoter can benefit from TMZ alone.

Antagonism between gene therapy and epigenetic therapy on human laryngeal carcinoma tumor-bearing mice / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Gene therapy and epigenetic therapy have gained more attention in cancer treatment. However, the effect of a combined treatment of gene therapy and epigenetic therapy on head and neck squamous cell carcinoma have not been studied yet. To study the mechanism and clinical application, human laryngeal carcinoma cell (Hep-2) tumor-bearing mice were used.</p><p><b>METHODS</b>A xenograft tumor model was established by the subcutaneous inoculation of Hep-2 cells in the right armpit of BALB/c nu/nu mice. The mice with well-formed tumor were randomly divided into six groups. Multisite injections of rAd-p53 and/or 5-aza-dC were used to treat tumor. Tumor growth was monitored by measuring tumor volume and growth rate. p53 and E-cadherin protein levels in tumor tissues were detected by immunohistochemical staining. The mRNA levels were monitored with FQ-PCR.</p><p><b>RESULTS</b>Gene therapy was much more effective than single epigenetic therapy and combined therapy. The gene therapy group has the lowest tumor growth rate and the highest expression levels of p53 and E-cadherin.</p><p><b>CONCLUSIONS</b>The combined treatment of gene and epigenetic therapy is not suggested for treating head and neck carcinoma, because gene therapy shows an antagonistic effect to epigenetic therapy. However, the mechanisms of action are still unclear.</p>

Immunophenotypes and gene mutations in colorectal precancerous lesions and adenocarcinoma / 中华病理学杂志

<p><b>OBJECTIVE</b>To analyze immunophenotypes and gene mutations of colorectal precancerous lesions and adenocarcinoma, and to compare the difference of carcinogenetic mechanisms between the two precancerous lesions.</p><p><b>METHODS</b>Fifty-three cases of colorectal serrated lesions including 30 hyperplastic polyps, 20 sessile serrated adenomas (SSA) and 3 mixed polyps were collected from January 2006 to June 2012.Forty-five cases of traditional adenomas and 50 cases of colorectal adenocarcinomas were also recruited. Thirty hyperplastic polyps, 20 cases of SSA, 3 mixed polyps and 45 traditional adenomas were investigated by immunohistochemistry for the expression of DNA mismatch repair (MMR) proteins (MLH1, MSH2 and MSH6) and DNA methyltransferase MGMT. Mutations of KRAS, BRAF and PIK3CA genes in 10 cases of SSAs, 10 traditional adenomas, 1 mixed polyps and 50 colorectal adenocarcinomas were analyzed by PCR followed by direct Sanger sequencing.</p><p><b>RESULTS</b>(1) Only 3 cases of hyperplastic polyps lost MLH1 expression, and none of SSAs or traditional adenomas showed loss of MLH1. The negative expression rates of MSH2, MSH6 and MGMT in hyperplastic polyps and SSA were significantly higher than those of traditional adenomas. (2) KRAS mutation was found in 5/10 cases of SSAs, 5/10 traditional adenomas and 1/1 mixed polyps. (3) Colorectal adenocarcinomas harbored the mutations of KRAS (48%, 24/50), BRAF (6%, 3/50) and PIK3CA (4%, 2/50).</p><p><b>CONCLUSIONS</b>Immunophenotypic and gene mutation profiles are different between colorectal serrated lesion and traditional adenoma. Alterations of MMR and MGMT expression play important roles in the pathogenesis of "serrated neoplasm". KRAS mutation is a significant genetic change in the early phase of colorectal carcinogenesis.</p>

Avaliação da expressão do gene MGMT nos tecidos normal e neoplásico de doentes com câncer colorretal / Evaluation of the expression of the MGMT gene in normal and neoplastic tissue of patients with colorectal cancer

OBJETIVO: Avaliar a expressão tecidual do gene de reparo MGMT comparando a mucosa cólica normal e neoplásica em doentes com câncer colorretal. MÉTODOS: Foram estudados 44 portadores de adenocarcinoma colorretal confirmado por estudo histopatológico. Foram excluídos doentes suspeitos de pertencerem a famílias com câncer colorretal hereditário (HNPCC e PAF) e os portadores de câncer do reto médio e inferior submetidos a tratamento quimioradioterápico neoadjuvante. A expressão do gene MGMT foi avaliada pela técnica da reação de polimerase em cadeia em tempo real (RT-PCR). A comparação dos resultados encontrados para expressão do gene MGMT entre tecidos normais e neoplásicos foi feita pelo teste t de Student pareado, adotando-se nível de significância de 5% (p <0,05). RESULTADOS: A expressão tecidual do gene MGMT em todos os doentes foi menor no tecido neoplásico quando comparada a do tecido normal (p=0,002). CONCLUSÃO: O gene de reparo MGMT encontra-se menos expresso no tecido neoplásico quando comparados aos tecidos normais em portadores de CCR esporádico.

OBJECTIVE: To evaluate the expression of tissue repair gene MGMT by comparing normal and neoplastic colonic mucosa in patients with colorectal cancer (CRC). METHODS: We studied 44 patients with colorectal cancer confirmed by histopathology. We excluded patients suspected of belonging to families with hereditary colorectal cancer (HNPCC and FAP) and patients with cancer of the lower or medium rectum treated with neoadjuvant chemoradiotherapy. The MGMT gene expression was assessed by the technique of polymerase chain reaction in real time (RT-PCR). The comparison of results for MGMT gene expression between normal and neoplastic tissues was made by paired Student's t test, adopting a significance level of 5% (p <0.05). RESULTS: Tissue expression of the MGMT gene in all patients was lower in tumor tissue when compared to normal tissue (p = 0.002). CONCLUSION: The repair gene MGMT is less expressed in tumor tissue compared to normal tissues in patients with sporadic CRC.

Effect of DNA hypermethylation on NOR1 promoter activity and expression / 中南大学学报(医学版)

OBJECTIVE@#To analyze the effect of DNA hypermethylation on NOR1 promoter activity and expression.@*METHODS@#NOR1 promoter plasmids were treated with SssI methyltransferase. The plasmids were modified by sodium bisulfite and purified. Sodium bisulfite-modified plasmids were subjected to PCR with primers designed to analyze the methylation status of 26 CpG sites in a 311-bp region of the NOR1 promoter. Cells were transfected by methylated or mock-methylated promoter plasmids. The promoter activities were assessed by the luciferase levels of cell lysates or by directly observing GFP expression under fluorescence microscope. HL60 cells were treated with different concentrations of 5-aza-dC. Total RNA was isolated from harvested cells. Real-time RT-PCR was used to measure the expression level of NOR1 mRNA.@*RESULTS@#Bisulfite sequencing confirmed that SssI methyltransferase treatment successfully resulted in intensive hypermethylation of the NOR1 promoter plasmids. The promoter activity of NOR1 promoter plasmids was totally blocked by SssI methyltransferase treatment. NOR1 expression levels in HL60 cells were restored by 5-aza-dC treatment.@*CONCLUSION@#NOR1 promoter plasmids are intensively hypermethylated by SssI methyltransferase treatment. The promoter activity of NOR1 promoter plasmids are totally blocked by SssI methyltransferase treatment. The 5-aza-dC treatment may restore the endogenous NOR1 mRNA level in HL60 cells.

Correlation between histone H3-K9 methylation, DNA methylation and expression of gene MGMT in Hep-2 cell line / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To explore the correlation between histone H3-K9 methylation, DNA methylation and expression of carcinoma suppressor gene MGMT in laryngeal carcinoma Hep-2 cell line.@*METHOD@#5-Aza-dC was used to deal with Hep-2 cell cultured in vitro. ChIP, MSP and Realtime-PCR were used to detect H3-K9 methylation, DNA methylation, of MGMT gene promoter region and MGMT gene expression before and after treatment with drugs.@*RESULT@#(1) In Hep-2 cell line, gene MGMT was characterized by DNA methylation and histone H3-K9 hypermethylation. (2) 5-Aza-dC was able to reduce H3-K9 methylation of MGMT gene histone in Hep-2 cell line, 5-Aza-dC was able to reverse DNA methylation of MGMT gene histone in Hep-2 cell line, 5-Aza-dC was able to upregulate the down-regulated gene expression of tumor suppressor genes MGMT.@*CONCLUSION@#Promoter methylation of cancer suppressor gene MGMT may induce the gene inactivity. DNA methylation may increase H3-K9 methylation. 5-Aza-dC can reduce H3-K9 methylation of tumor suppressor gene MGMT histone by reversing DNA methylation of tumor suppressor gene MGMT, and then the expression of tumor suppressor genes is increased and tumor development is inhibited.

Effect of methylation inhibitor on EphB4 gene expression, proliferation and apoptosis in CEM cells / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the regulation of methylation inhibitor 5-aza-2'-deoxycytidine on transcription of EphB4 gene and effects on the proliferation and apoptosis of human acute lymphocyte leukemia cell line CEM.</p><p><b>METHODS</b>Bisulfite sequencing PCR was used to detect CpG island methylation density in EphB4 promoter. The expression of EphB4 mRNA and protein was determined by Q-PCR and Western blot. MTS assay and flow cytometry were used to detect the apoptosis of CEM cells after treatment with different concentrations of 5-aza-2'-deoxycytidine (1.0, 2.5 and 5 μmol/L).</p><p><b>RESULTS</b>Methylation of EphB4 gene promoter was detected in CEM cells (31.4%). The methylation level of EphB4 gene was down-regulated after treatment with various concentrations of 5-aza-2'-deoxycytidine. The EphB4 mRNA and protein expression in CEM cells increased after 5-aza-2'-deoxycytidine treatment. 5-Aza-2'-deoxycytidine significantly inhibited the cell growth in dose and time dependent manners. Early apoptosis rates of CEM cells increased from 4.1% to 24.8% 96 hrs after 5-aza-2'-deoxycytidine treatment. CEM cells in G1 phase decreased from 62.4% to 46.8%, cells in G2 phase increased from 2.1% to 16.2%, and CEM cells were arrested in G2 phase after treatment with 5 μmol/L 5-aza-2'-deoxycytidine for 96 hrs.</p><p><b>CONCLUSIONS</b>5-Aza-2'-deoxycytidine, an inhibitor of specific methylation transferase, can induce expression of the silent EphB4 gene in CEM cells, inhibit the proliferation of leukemia cells and induce cell apoptosis.</p>

Effects of 5-Aza-2-deoxycytidine on DNA methylation of anti-oncogenes in non-small cell lung cancer cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To observe the expression of SFRP1 gene methylation in non-small cell lung cancer (NSCLC), and study the effect of 5-Aza-2-deoxycytidine (5-Aza-CdR) on DNA methylation and expression of SFRP1, p16 and MGMT genes in the human lung cancer cell line SPC-A-1 cells.</p><p><b>METHODS</b>SP immunohistochemistry and methylation-specific PCR were used to detect the SFRP1 methylation in 60 NSCLC cases, and 21 cases of benign lung diseases were used as control group. SPC-A-1 cells were cultured and treated with 5-Aza-CdR. The promoter methylation status of SFRP1, p16 and MGMT genes were detected by methylation-specific polymerase (MSP) chain reaction, and mRNAs were detected by real-time PCR.</p><p><b>RESULTS</b>The positive rate of SFRP1 gene methylation in NSCLC was significantly higher than that in normal lung tissue (58.3% vs. 14.3%; χ(2) = 12.118, P = 0.001). SFRP1 gene methylation was closely correlated with lymph node metastasis and degree of differentiation in NSCLC (P < 0.05). SFRP1 protein expression was correlated with clinical stage, degree of differentiation and lymph node metastasis in NSCLC (P < 0.05). The positive expression of SFRP1 protein in 30 cases of NSCLC tissue containing SFRP1 gene methylation was significantly higher than that in non-methylated NSCLC (68.6% vs. 24.0%; χ(2) = 9.613, P = 0.002). SFRP1 gene methylation was closely correlated with SFRP1 gene protein expression in NSCLC (P < 0.05). Negative expression of SFRP1 protein was correlated with the differentiation, clinical stage, and lymph node metastasis in NSCLC (all P < 0.05). Without 5-Aza-CdR treatment, the expressions of methylation of SFRP1, p16 and MGMT genes and their mRNA were low. After 5-Aza-CdR treatment at different concentrations, their expressions were significantly elevated (all P < 0.05).</p><p><b>CONCLUSIONS</b>SFRP1 gene methylation is closely associated with carcinogenesis and development of NSCLC. 5-Aza-CdR may reverse the methylation of SFRP1, p16 and MGMT genes, and facilitate the re-expression of the anti-oncogenes.</p>

Effects of dujieqing oral liquid on the promoter methylation of the MGMT gene in middle-and-late stage tumor patients receiving chemotherapy / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe the effects of Dujieqing Oral Liquid (DJQ) on the promoter methylation of the O6-methylguanine-DNA methyltransferase (MGMT) gene in the plasma DNA samples from middle-and-late stage tumor patients receiving chemotherapy.</p><p><b>METHODS</b>Recruited 60 patients were randomly assigned to the treatment group (treated by conventional chemotherapy combined DJQ, 20 mL each time, three times daily) and the control group (treated by chemotherapy alone), 30 in each group. The therapeutic course was 8 weeks. The promoter methylation of the MGMT gene in the plasma DNA samples form middle-and-late stage tumor patients receiving chemotherapy was detected before and after treatment using nested methylation-specific polymerase chain reaction (MSP). Meanwhile, the peripheral hemogram was detected. The clinical efficacy and toxic/adverse reactions were assessed using Karnofsky performance scale (KPS).</p><p><b>RESULTS</b>Results of the promoter methylation of MGMT genes showed that methylation rate was 20.00% in the treatment group and 46.67% in the control group (P<0.05). Compared with before treatment, the KPS was significantly improved in the treatment group after treatment, while it significantly decreased in the control group after treatment (both P<0.05). There was statistical difference in the KPS between the two groups after treatment (P<0.01). The toxic/adverse reactions were milder in the treatment group than in the control group (P<0.01).</p><p><b>CONCLUSIONS</b>DJQ showed efficiency synergism and toxicity reducing effects, but with no effect on the hematopoietic function of the bone marrow. MGMT gene was indicated as DJQ's target point for efficiency synergism and toxicity reducing. The efficiency synergism and toxicity reducing effects were achieved by regulating the activities of MGMT gene.</p>

Decitabine for treatment of myelodysplastic syndrome in an elderly patient and review of literature / 南方医科大学学报

Findings in epigenetic changes in meylodysplastic syndromes (MDS) and the development of demethylating drugs provide a new approach to the treatment of MDS. We used standard-dose decitabine for treatment of MDS in an elderly patient with an International Prostate Symptom Score (IPSS) of moderate risk group 2, and achieved a complete response in the first course. We report our experience with this case and review the relevant literatures.

Correlation of MGMT promoter methylation status with gene and protein expression levels in glioblastoma

OBJECTIVES: 1) To correlate the methylation status of the O6-methylguanine-DNA-methyltransferase (MGMT) promoter to its gene and protein expression levels in glioblastoma and 2) to determine the most reliable method for using MGMT to predict the response to adjuvant therapy in patients with glioblastoma. BACKGROUND: The MGMT gene is epigenetically silenced by promoter hypermethylation in gliomas, and this modification has emerged as a relevant predictor of therapeutic response. METHODS: Fifty-one cases of glioblastoma were analyzed for MGMT promoter methylation by methylation-specific PCR and pyrosequencing, gene expression by real time polymerase chain reaction, and protein expression by immunohistochemistry. RESULTS: MGMT promoter methylation was found in 43.1 percent of glioblastoma by methylation-specific PCR and 38.8 percent by pyrosequencing. A low level of MGMT gene expression was correlated with positive MGMT promoter methylation (p = 0.001). However, no correlation was found between promoter methylation and MGMT protein expression (p = 0.297). The mean survival time of glioblastoma patients submitted to adjuvant therapy was significantly higher among patients with MGMT promoter methylation (log rank = 0.025 by methylation-specific PCR and 0.004 by pyrosequencing), and methylation was an independent predictive factor that was associated with improved prognosis by multivariate analysis. DISCUSSION AND CONCLUSION: MGMT promoter methylation status was a more reliable predictor of susceptibility to adjuvant therapy and prognosis of glioblastoma than were MGMT protein or gene expression levels. Methylation-specific polymerase chain reaction and pyrosequencing methods were both sensitive methods for determining MGMT promoter methylation status using DNA extracted from frozen tissue.

The clinical research of the MGMT expression levels in glioma pations / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the correlation between the expression of tumor O (6)-methylquanine DNA methyl-tranferase(MGMT) and pathological grade,and the influence of racial factors on tumor MGMT expression levels for glioma patients.</p><p><b>METHODS</b>Compare and analysis the correlation between the pathological grade and MGMT levels and the racial factors on MGMT expression levels by the immunohistochemical staining on the tumor specimens of 33 Uygur and 61 Han.</p><p><b>RESULTS</b>The positive rate of 61 Han gliomas pations with MGMT is 45.90% and 33 cases of the Uygur is 30.30% , there's no clear correlation between the racial factors and the tumor MGMT levels. (P >0.05). Comparative the 94 patients with pathological level and tumor MGMT level, there is no clear correlation between pathologic level and MGMT pression in tumor tissues (P >0.05).</p><p><b>CONCLUSION</b>There's no clear correlation of tumor MGMT expression and pathological levels; and there's no significant effect between racial factors and expression of glioma MGMT.</p>

A Consideration of MGMT Gene Promotor Methylation Analysis for Glioblastoma Using Methylation-Specific Polymerase Chain Reaction and Pyrosequencing

BACKGROUND: O6-methylguanine-DNA methyltransferase (MGMT) gene promoter methylation is currently the most promising predictive marker for the outcome and benefit from temozolomide treatment in patients with glioblastoma, but there is no consensus on the analysis method for assessing the methylation status in the molecular diagnostic field. The objective of this study was to evaluate methylation-specific polymerase chain reaction (MSP) and pyrosequencing methods for assessing MGMT gene promotor methylation of glioblastoma as well as assessing the MGMT protein expression by immunohistochemistry. METHODS: Twenty-seven cases of glioblastoma from the archives at the Department of Pathology Konkuk University Hospital were selected. MGMT promoter methylation was evaluated by MSP and the pyrosequencing methods. The MGMT expression was also measured at the protein level by immunohistochemistry. RESULTS: Overall, MGMT hypermethylation was observed in 44.4% (12/27 cases) of the case of glioblastoma using either MSP or pyrosequencing. The concordant rate was 70.3% (19/27 cases) between MSP and pyrosequencing for MGMT methylation. There was no correlation between MGMT methylation and the protein expression. No significant differences in progression free survival and overall survival were seen between the methylated group and the unmethylated group by using either MSP or pyrosequencing. The status of the MGMT protein expression was correlated with progression free survival (p=0.026). CONCLUSIONS: In this study the concordance rate between MSP and the pyrosequencing methods for assessing MGMT gene promotor methylation was relatively low for the cases of glioblastoma. This suggests that more reliable techniques for routine MGMT methylation study of glioblastoma remain to be developed because of quality control and assurance issues.

DNA Methylation Changes Following 5-azacitidine Treatment in Patients with Myelodysplastic Syndrome

DNA methyltransferase inhibitor, 5-azacitidine (AC) is effective in myelodysplastic syndromes (MDS) and can induce re-expression in cancer. We analyzed the methylation of 25 tumor suppressor genes in AC-treated MDS. Hypermethylation of CDKN2B, FHIT, ESR1, and IGSF4 gene was detected in 9/44 patients. In concordance with the clinical response, a lack of or decreased methylation in 4 patients with hematologic improvements and persistent methylation in 4 others with no response was observed. The mRNA expression of CDKN2B, IGSF4, and ESR1 was significantly reduced in MDS. Our results suggest that methylation changes contribute to disease pathogenesis and may serve as marker to monitor the efficacy of treatments.