Objective To evaluate the diagnostic accuracy of the aberrant methylation of genes in stool for colorectal tumor. Methods Databases including The Cochrane Library, PubMed, EMbase, CBM, Web of Science, CNKI and WanFang Data were searched to collect the diagnostic trials on the aberrant methylation of genes in stool for colorectal tumor published from January 1990 to February 2012. QUADAS items were used to evaluate the quality of the included studies, and the meta-analysis was conducted using Meta-Disc 1.4 software. Results A total of 32 studies involving 3 951 patients were included. The results of meta-analysis showed that, for detecting the colorectal tumor, the weighted sensitivity, specificity, diagnostic odds ratio (DOR), area under the summary receiver operating characteristic (SROC) curve and Q were 92% (95%CI 91% to 93%), 63% (95%CI 61% to 65%), 20.79 (95%CI 15.13 to 28.57), 0.861 9 (SE=0.020 4), and 0.792 6 (SE=0.019 8), respectively. For detecting the colorectal cancer, the weighted sensitivity, specificity and area under the curve (AUC) were 91% (95%CI 89% to 92%), 75% (95%CI 73% to 77%), and 0.900 7, respectively. For detecting the colorectal adenoma, the weighted sensitivity, specificity and AUC were 79% (95%CI 76% to 83%), 75% (95%CI 73% to 77%), and 0.845 7, respectively. Conclusion With high sensitivity (92%) and moderate specificity (63%), aberrant methylation of genes in stool can be used as an optional noninvasive method for the diagnosis of colorectal tumor.
Objective To investigate the expression level and methylation level of micro RNA-34b（miR-34b） gene in papillary thyroid carcinoma （PTC）， and to analyze the relationship between methylation and clinicopathological characters of PTC. Methods PTC tissues and tumor adjacent tissues were collected from 25 patients with PTC who underwent operation in Huai’an First People’s Hospital of Nanjing Medical University from Sep. 2008 to Oct. 2010. Expression of miR-34b gene and level of methylation in gene promoter were detected by real time PCR and methylation-specific PCR in the 2 kinds of tissues， respectively. Results The expression value of miR-34b mRNA in PTC tissues was 0.85±0.05， which was significantly lower than those of tumor adjacent tissues （1.62±0.09）， P=0.030. There were methylation in 18 （72%，18/25） PTC tissues， and 10 （40%，10/25） in tumor adjacent tissues， and the ratio of methylation was higher in PTC tissues （P=0.021）. In PTC tissues， methylation was not related to age， gender， tumor size， TNM stage， and invasion of the capsule （P＞0.05）， but was related to lymph node metastasis （P＜0.05）. Ratio of methylation in patients with lymph node metastasis was significantly higher than those of patients with no lymph node metastasis. Conclusion Methylation of miR-34b gene promoter is one of the reasons for inactivation of PTC， and it may be related to the development and metastasis of PTC， which needs to be further investigated.
Objective To evaluate the effect of methylation determination about the peripheral plasma DNA in diagnose of hepatocellular carcinoma （HCC） and select the highly sensitive and specific methylated cancer suppressor genes. Methods Methylation-specific PCR （MSP） was used to detect the degree of methylation about SLIT2 and DAPK genes in peripheral plasma and associated cancer tissues of 34 patients with HCC confirmed by pathology, then analyzed their relationship to clinicopathologic feature. Results The positive rate of the promoter methylation of SLIT2 and DAPK genes in cancer tissues in 34 cases were 70.6% （24/34） and 79.4% （27/34）, while the relevant promoter methylation rate in plasma were 44.1% （15/34） and 50.0% （17/34） correspondingly. The sensitivity of detection of DNA methylation about SLIT2 and DAPK genes in plasma was 62.5% and 63.0%, respectively；both of the specificity for them were 100%. The negative predicted value was 52.6% and 41.2%, respectively；while both of the positive predicted value were 100%. There were no significant correlation between the clinicopathologic features and the methylation rate in cancer tissues and plasma （P＞0.05）. In plasma of patients whose AFP＜400 μg/L, the positive rate of combined detection of DNA methylation of SLIT2 and DAPK was 61.1% （11/18）. Conclusions The detection rate of DNA methylation of SLIT2 and DAPK genes in plasma is higher, and there is a significant correlation between the DNA methylation in HCC tissue and plasma, based on MSP method. DNA methylation in plasma, as an non-invasive method, could be used to diagnose HCC, especially for the patients whose AFP is negative. HBV infection may be only associate with DNA methylation of part gene.
ObjectiveTo explore the clinical significance of promoter hypermethylation of O6-methylguanine-DNA methyltransferase (MGMT) in cholangiocarcinoma. MethodsPromoter methylation status of MGMT gene and expression of MGMT protein were detected in cholangiocarcinoma by methylationspecific PCR and immunohistochemical staining, respectively. ResultsAberrant methylation of MGMT gene was detected in 17 patients (47.2%). Twentyone cases showed negative immunoreactivities. Of 21 patients with negative MGMT expression, 14 patients had aberrant methylation of MGMT gene. In 15 patients with positive MGMT expression, aberrant methylation of MGMT gene was only found in three cases. There was a negative correlation between promoter methylation status of MGMT gene and the expression of MGMT protein (rs=-0.816, Plt;0.05). Promoter methylation status of MGMT gene was related to depth of invasion, degree of differentiation, and TNM stage (Plt;0.05), but not to age of patient, gender, pathological type, and lymph node metastasis (Pgt;0.05). ConclusionsHypermethylation of MGMT promoter is a frequency molecular event in cholangiocarcinoma and may be involved in carcinogenesis. Methylation status of MGMT gene may be used to evaluate malignant degree of cholangiocarcinoma.
Objective To review the research progress in relationship between hereditary diffuse gastric cancer (HDGC) and CDH1 gene. Methods Literatures on HDGC which were published in recent years were collected and analyzed. Results Aberrant CDH1 gene is significantly correlated with HDGC: mutations of CDH1 exons play the most important role in pathogenesis of HDGC. Screening CDH1 gene mutation is useful for diagnosis of HDGC as well as the treatments. Alterations of CDH1 other than exon mutation, such as intron mutation, gene promoter methylation and single nucleotide polymorphism may result in downregulation of the gene expression. Further study should be done to confirm the roles of these alterations. Conclusions Alterations of CDH1 gene are significantly associated with the pathogenesis of HDGC. Detecting alterations of CDH1 gene are important for diagnosis and management of HDGC as well as to get insights of the pathogenesis of the disease.
【Abstract】 Objective To investigate the relationship between methylation of tumor suppressor gene and gastric cancer. Methods The literatures in recent years about the concept of methylation, its biological significance and the relationship between DNA methylation/demethylation and gastric cancer were reviewed. The effects of methylation of different tumor suppressor genes on gastric cancer were also analyzed. Results The effect of aberrant methylation on the development and the progression of gastric cancer was still unclear but it was supposed that the inactivation of genes related with cell cycle regulation, mitotic checkpoint, apoptosis, DNA mismatch repair, metastasis suppression and so on might be attributable to the aberrant methylation in gastric cancer. Conclusion Aberrant methylation of tumor suppressor genes plays an important role in the development and progression of gastric cancer. The status of methylation of tumor suppressor genes may be used as a useful molecule marker for diagnosis, assessing metastasis and evaluating prognosis, and demethylation could possibly be a new therapy for gastric cancer.
ObjectiveTo determine the level of CDH1 gene promoter hypermethylation in human gastric carcinoma by establishing MS-PCR method, and analyze retrospectively the possible statistical relationship between CDH1 gene promoter hypermethylation in human gastric carcinoma and HP infection, tumor differentiation, invasion, lymph nodal and distant metastasis, respectively. MethodsThe bisulfite conversion MS-PCR method was adopted to examine the level of CDH1 gene promoter hypermethylation in 40 cases of human gastric carcinoma tissue collected between January 2008 and December 2009. The statistical relationship between CDH1 gene promoter hypermethylation in human gastric carcinoma and HP infection, tumor differentiation, invasion, lymph nodal and distant metastasis were examined respectively with SPSS statistical tools. ResultsThe positive rate of CDH1 gene promoter hypermethylation in gastric carcinomas (67.5%) was higher than that in paired normal gastric mucosae (12.5%), and the difference was significant (P<0.05). In gastric carcinomas, the positive rate of CDH1 gene promoter hypermethylation in well differentiated or moderately differentiated groups (22.2%) was lower than that in poorly differentiated groups (80.6%), and the difference was significant (P<0.05). The positive rate of CDH1 gene promoter hypermethylation in HP positive groups (78.1%) was higher than that in HP negative groups (25.0%), and the difference was significant (P<0.05). ConclusionCDH1 gene promoter hypermethylation may play an important role in the process of tumor carcinogenesis in gastric carcinomas. Meanwhile, the CDH1 gene promoter hypermethylation may lead to poor differentiation in gastric carcinomas. CDH1 gene promoter hypermethylation is related to HP infection in the original gastric carcinomas, which shows that HP may get involved in the process of tumor suppressor gene methylation/inactivation and tumor development process.
Objective To investigate the tumor suppressor genes of phlegm DNA in smokers, and analyze the correlation between methylation level of tumor suppressor gene promoter and chronic mucus hypersecretion (CMH). Methods The study recruited the patients who were admitted in the respiratory department during 2013-2016 in this hospital, including 700 cases of urban smokers and 380 cases of rural smokers. Eleven genes commonly silenced by promoter methylation in lung cancer and associated with cancer risk were selected. Methylation specific PCR (MSP) was used in the sputum sample of 700 individuals in the urban smokers cohort. Replication was performed in 380 individuals from the rural smokers cohort. Results CMH was significantly associated with an overall increased number of methylated genes, with SULF2 methylation demonstrating the most consistent association. The association between SULF2 methylation and CMH was significantly increased in males but not in females both in the urban and rural groups (OR=2.73, 95%CI 1.53-4.93, P=0.001; OR=2.96, 95%CI 1.47-5.94, P=0.002, respectively). Furthermore, the association between methylation and CMH was more obvious among 139 male former smokers with persistent CMH compared with current smokers (SULF2, OR=3.64, 95%CI 1.57-8.35, P=0.002). Conclusion These findings demonstrate that especially male former smokers with persistent CMH have markedly increased promoter methylation of lung cancer risk genes and potentially could be at increased risk for lung cancer.
Recent advances in epigenetics indicate that several epigenetic modifications, including acetylation, methylatio, and microRNA (miRNA), play an important role in the pathogenesis of acute kidney injury (AKI). Our study reveales that enhancement of protein acetylation by pharmacological inhibition of class I histone deacetylases leads to more severe tubular injury, and delays the restoration of renal structure and function. The changes in promoter DNA methylation occurs in the kidney with ischemia/reperfusion. MiRNA expression is associated with the regulation of both renal injury and regeneration after AKI. Targeting the epigenetic process may provide a therapeutic treatment for patients with AKI. The purpose of this review is to summarize recent advances in epigenetic regulation of AKI and provide mechanistic insight into the role of acetylation, methylation, and miRNA expression in the pathological processes of AKI.
ObjectiveTo observe the expression and transcription of MART-1 in human uveal melanoma cell lines 92-1, 92-2, Ocm3, Me1285, as well as the possible effect of methylation on its expression.MethodsThe cell lines 92-1, 92-2, Ocm3 and Mel285 were cultured routinely and tested for MART-1 expression at protein and mRNA level by FACS analysis, Western blot and RT-PCR respectively. Methylation status of the MART-1 promoter region in all the cell lines were checked by Southern blots of DNA digested with methylation sensitive restriction enzymes.ResultsAs observed in FACS analysis and Western blot, 92-1, 92-2 and Ocm3 were MART-1 positive cell lines while Me1285 was negative cell line. Consistent with protein analysis, 92-1 and Ocm3 cell lines showed MART-1 specific PCR products and there was no product in Me1285 cell line in RT-PCR. The MART-1 positive cell lines, 92-1, 92-2, and Ocm3 show methylation at the MspI/HpaⅡ site, and the NruⅠ sites of all positive cell lines are not methylated. The MART-1 negative cell line Mel285 shows hypermethylation at the NruⅠsite and the MspⅠ/HpaⅡ site is not methylated.ConclusionsMART-1 could be expressed in human uveal melanoma cell lines 92-1, 92-2 and Ocm3. The change of methylation status of MART-1 promoter may correlate with the transcription of MART-1.