ObjectiveTo explore the relationship between aberrant promoter CpG islands methylation status of E-cadherin gene and hepatocarcinogenesis, and to assess its significance in clinical early diagnosis of hepatocellular carcinoma (HCC). MethodsSurgically resected specimens, among which cancerous and corresponding noncancerous liver tissues from 34 HCC patients, 10 liver cirrhosis from patients without HCC and normal liver tissues from 4 accidental deaths, were collected in West China Hospital. Breast cancer cell line MDA-MB-435 with promoter CpG islands hypermethylation of E-cadherin as positive control was gained from the Cell Bank of Chinese Academy of Sciences in Shanghai. The methylation status of promoter CpG island of E-cadherin gene was detected by nested methylationspecific polymerase chain reaction (nested-MSP). ResultsE-cadherin gene promoter CpG islands hypermethylation was found in 61.76% (21/34) of cancerous tissues, in 29.41% (10/34) of noncancereous tissues from the 34 HCC patients and in 50.00% (5/10) liver cirrhosis from patients without HCC. None of the 4 normal liver samples were detected E-cadherin mehylation positive. Moreover, the methylation of E-cadherin gene was significantly more frequent in 34 cancerous than that in corresponding noncancerous liver tissues (Plt;0.05), which had no significant difference between the 10 cirrhotic samples and cancerous or non-cancerous liver tissues (Pgt;0.05). In 34 cancerous samples, with the combination of both biomarkers of E-cadherin methylation and AFP400 (serum AFP level at a cutoff of 400 μg/L), the diagnostic sensitivity of HCC increased to 82.35%. ConclusionsThe aberrant promoter methylation of E-cadherin gene may play a vital role in the development and progression of HCC. Moreover, it might be an early event in hepatocarcinogensis. It is of high value to make further study to confirm the significance of E-cadherin gene methylation in clinical diagnosis and therapy.
【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 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.
Lung cancer is the most common malignant tumor in the world and the leading cause of cancer-related death. Due to the lack of effective early diagnosis methods, the prognosis of lung cancer is poor, but compared with advanced lung cancer, the survival rate of early lung cancer is greatly improved. Therefore, early diagnosis of lung cancer is crucial. As a major epigenetic modification, DNA methylation plays an important role in the development of lung cancer. A large number of studies have shown that detection of tumor suppressor gene methylation is an ideal early diagnosis method for lung cancer. With the continuous improvement of detection technology, methylation detection of multiple genes can be achieved. And it is found that multi-gene methylation combined detection of tissue samples obtained by minimally invasive operation such as puncture of diseased tissue and puncture of lymph node tissue, as well as the noninvasive samples such as peripheral blood, bronchoalveolar lavage fluid and sputum have higher detection rate and higher sensitivity and specificity than single gene methylation. It is an ideal method for early diagnosis of lung cancer.
Objective To review the advance of gene diagnosis and gene therapy on gastric cancer. Methods Literatures about the advance of gene diagnosis and therapy on gastric cancer were reviewed. Results Detection of tumor marker by gene technique is important for early diagnosis, follow-up and therapy evaluation of gastric cancer in clinic. But there are still many problems in gene therapy of gastric cancer. Conclusion Gene detection and gene therapy will become important supplementary means for diagnosis and treatment of gastric cancer.
Objective To investigate the role of DNA methylation on regulation of cell apoptosis and proliferation in ischemia-reperfusion of small intestine. Methods Thirty-five male Wistar rats were randomly divided into normal group， sham operation group， and ischemia-reperfusion group. The apoptotic cell was assessed by TUNEL and electron microscopy and the expression of Ki-67 was examined by immunohistochemistry in the small intestinal parts （villi epithe-lium， crypt epithelium， and lamina propria mucosa of small intestine）. The DNA methylation was detected by DNA histo-endonuclease-linked detection of methylated DNA sites. Results ①The apoptotic positive cells increased at 3 h， 6 h，and 12 h after ischemia-reperfusion in the villi epithelium， crypt epithelium， and lamina propria mucosa of small intestine as compared with the normal group and sham operation group （P＜0.01）；Moreover， the apoptotic cells in the lamina propria mucosa of small intestine were identified as T cells by electron microscopy. ②The expressions of Ki-67 markedly increased at 3 h， 6 h， 12 h， and 24 h after ischemia-reperfusion in the villi epithelium cells as compared with the normal group and sham operation group （P＜0.01）. ③The weak expression of DNA methylation was found in the villi epith-elium and crypt epithelium in the normal group and sham operation group， the b expression was examined in the crypt epithelium cells nearby stem cell site in the ischemia-reperfusion of small intestine， the change of expression was gradually weak from crypt epithelium to villi epithelium. Conclusion This initial results indicate that the DNA methyl-ation in the ischemia-reperfusion of small intestine might regulate cell apoptosis and proliferation.
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 role of DNA methylation in the pathogenesis of cholangiocarcinoma and its progress as a therapeutic target for cholangiocarcinoma.MethodThe relevant literatures at home and abroad in recent years about the DNA methylation and cholangiocarcinoma were reviewed.ResultsMethylation is a frequent event in cholangiocarcinoma and effect the occurrence and development of cholangiocarcinogenesis. DNA methylation inhibitors reactivate tumor suppressor genes.ConclusionsDNA methylation is closely related to the cholangiocarcinogenesis. Despite there is no effective clinical therapeutics and diagnosis at present, with further study, DNA methylation is expected to be one of the new target to treatment and diagnosis this disease.
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.