胃癌组织中MGMT基因的高甲基化以及DNMT1的表达

发布时间：2018-02-10 18:30

本文关键词： 胃癌 MGMT 甲基化 DNMT1　出处：《青岛大学》2017年硕士论文　论文类型：学位论文

【摘要】：目的:本实验检测胃癌组织以及癌旁组织中6-氧-甲基鸟嘌呤-DNA甲基转移酶(MGMT)基因的甲基化以及MGMT蛋白的表达情况,分析MGMT基因甲基化的状态与胃癌发生以及发展的关系。探究胃癌组织以及癌旁组织中DNA甲基转移酶1(DNA methyltransferase 1,DNMT1)蛋白表达情况,分析其与胃癌的关系及临床意义。另外还对胃癌组织中MGMT甲基化与DNMT1蛋白表达的关系进行初步的探究。方法:1.收集青岛市市立医院普外科于2015年1月至2016年7月切除的60例胃癌患者的新鲜胃癌组织及其相应的癌旁组织标本,胃癌组织取自癌灶中央非坏死区域,癌旁组织取自距离癌组织5cm以上,且术前未行放疗、化疗、靶向治疗等抗肿瘤治疗。提取组织DNA,采用甲基化特异性PCR(MSP)技术检测上述组织标本中MGMT基因甲基化状态。分析MGMT基因甲基化与胃癌的关系。2.提取胃癌组织及相应癌旁组织中的RNA,应用逆转录-多聚合酶链反应(RT-PCR)检测MGMT及DNMT1的mRNA的表达情况。3.用免疫组化SP法(IHC)检测胃癌组织以及相应的癌旁组织中MGMT和DNMT1的蛋白表达情况,综合分析MGMT及DNMT1表达与胃癌的关系,并对胃癌中MGMT基因甲基化及DNMT1蛋白表达的关系进行初步探讨。结果:1.胃癌组织中MGMT基因甲基化率为45.00%(27/60),明显高于癌旁组织(13.33%,8/60),差异有意义(χ2=14.56,P0.001)。2.胃癌组织中MGMT mRNA阳性表达率低于癌旁组织(41.67%vs93.33%,χ2=36.51,P0.001);而胃癌组织中DNMT1 mRNA阳性率明显高于癌旁组织(76.67%vs18.33%,χ2=40.94,P0.001)。3.MGMT mRNA阴性表达的胃癌组织中其基因的甲基化率较阳性表达者升高(57.14%vs28.00%,χ2=11.96,P0.05)。4.胃癌组织以及癌旁组织中MGMT以及DNMT1蛋白表达情况与mRNA表达基本一致,MGMT蛋白在胃癌组织中的表达阳性率(40%,24/60)明显低于癌旁组织(93.33%,56/60),差异有统计学意义(χ2=38.4,P0.001)。而DNMT1在胃癌组织中的表达阳性率(76.67%,46/60)却明显高于癌旁组织(6.67%,4/60),差异有意义(χ2=60.48,P0.001)。5.胃癌组织中MGMT与DNMT1蛋白表达呈负相关(r=-0.795,P0.01)。结论:1.MGMT基因高甲基化与胃癌的发生以及发展有关。2.MGMT的低表达以及DNMT1的高表达在胃癌的发生过程中起重要作用。3.在胃癌中MGMT高甲基化改变可能是导致MGMT低表达的原因之一。4.DNMT1可能调控MGMT基因的甲基化过程。意义:胃癌是一种死亡率很高的恶性肿瘤,大部分胃癌患者确诊时已处于晚期阶段,其早期诊断十分重要。胃癌产生与演变过程极为复杂,涉及环境、遗传等各个方面,其中DNA甲基化在胃癌发生过程中起到一定作用。本实验在表观遗传学水平,研究MGMT基因高甲基化及DNMT1蛋白表达与胃癌的关系,为胃癌的诊断、肿瘤分期以及预后等方面提供思路。
[Abstract]:Objective: to detect the methylation of 6-oxy-methylguanine-DNA methyltransferase (MGMT) gene and the expression of MGMT protein in gastric cancer tissues and adjacent tissues. To analyze the relationship between the status of methylation of MGMT gene and the occurrence and development of gastric cancer, and to investigate the expression of DNA methyltransferase 1 methyltransferase 1 methyltransferase 1 DNMT1 protein in gastric cancer tissues and adjacent tissues. In addition, the relationship between MGMT methylation and DNMT1 protein expression in gastric cancer tissues was studied. Methods: 1. Collecting general surgery department of Qingdao Municipal Hospital from January 2015 to July 2016. Fresh gastric cancer tissues and their corresponding paracancerous tissues from 60 patients with gastric cancer resected, The tissues of gastric cancer were taken from the non-necrotic area in the center of the cancer focus, and the adjacent tissues were taken from the tissues more than 5 cm from the cancerous tissue, and they were not treated with radiotherapy and chemotherapy before operation. The methylation status of MGMT gene was detected by methylation specific PCR technique. The relationship between methylation of MGMT gene and gastric cancer was analyzed. 2. The tissues of gastric cancer and corresponding cancer were extracted. The expression of mRNA in MGMT and DNMT1 was detected by reverse transcription-polymerase chain reaction (RT-PCR). The expression of MGMT and DNMT1 in gastric carcinoma and adjacent tissues was detected by immunohistochemical SP method. The relationship between the expression of MGMT and DNMT1 and gastric cancer was analyzed. The relationship between the methylation of MGMT gene and the expression of DNMT1 protein in gastric cancer was studied. Results: 1. The methylation rate of MGMT gene in gastric cancer was 45.000.27 / 60%, which was significantly higher than that in paracancerous tissue (13.33 / 60 / 60). The difference was significant (蠂 ~ 2 ~ (14. 5) P ~ (0.001) P ~ (0.001) 路2.The positive expression of MGMT mRNA in gastric cancer tissue was higher than that in paracancerous tissue (P ~ (0.001 / 60)). The positive rate of DNMT1 mRNA in gastric cancer tissues was significantly higher than that in paracancerous tissues (76.67 vs 18.33). The methylation rate of genes in gastric cancer tissues with negative expression of mRNA was higher than that in those with positive expression of 57.14 vs 28.00, 蠂 211.96U P 0.05p 0.05. 4. The methylation rate of MGMT in gastric cancer tissues and adjacent tissues was significantly higher than that in cancer tissues with negative expression of VS93.331.The positive rate of methylation in gastric cancer tissues was significantly higher than that in those with negative expression of VS93.330.The positive rate of DNMT1 mRNA in gastric cancer tissues and adjacent tissues was significantly higher than that in gastric cancer tissues and adjacent tissues. The methylation rate of MGMT in gastric cancer tissues and adjacent tissues was significantly higher than that in those with positive expression. The positive rate of DNMT1 protein expression in gastric cancer tissues was significantly lower than that in adjacent tissues 93.33 / 56 / 60 (蠂 ~ 2 / 38.4N / P 0.001), while the positive rate of DNMT1 expression in gastric cancer tissues was 76.6746 / 60), which was significantly higher than that in cancer tissues (76.67 / 46 / 60), and the positive rate of DNMT1 expression in gastric cancer tissues was significantly higher than that in paracancerous tissues (蠂 ~ 2 / 38.4N ~ (56 / 60)) (蠂 ~ (2 / 2) ~ (38.4) P 0.001). The difference was significant (蠂 ~ 2 / 60.48 / P 0.001 ~ 1.5.The expression of MGMT and DNMT1 protein was negatively correlated with the expression of DNMT1 protein. Conclusion: 1. The hypermethylation of MGMT gene is related to the occurrence and development of gastric cancer. 2. The low expression of MGMT and the high expression of DNMT1 may play an important role in the pathogenesis of gastric cancer. The change of MGMT hypermethylation in gastric cancer may be one of the causes of low expression of MGMT. 4. DNMT1 may regulate the methylation process of MGMT gene. Most patients with gastric cancer are in the late stage of diagnosis, and their early diagnosis is very important. The process of gastric cancer production and evolution is extremely complex, involving various aspects, such as environment, heredity and so on. DNA methylation plays an important role in the carcinogenesis of gastric cancer. In this study, the relationship between the hypermethylation of MGMT gene and the expression of DNMT1 protein in gastric cancer was studied to be the diagnosis of gastric cancer. Tumor staging and prognosis provide ideas.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R735.2

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