【作者】 程昭栋；

【导师】 胡世莲；

【作者基本信息】 安徽医科大学 ， 老年医学， 2010， 硕士

【摘要】 目的本研究通过检测胃癌组织、癌旁5cm组织与和正常对照组织以及相对应的术前、术后血清中CHFR基因和RUNX3基因启动子区的甲基化水平,探讨它们在胃癌发生发展中的作用以及与临床资料参数之间的联系;另外比较甲基化特异性PCR（Methylation-specific PCR,MSP）方法与结合重亚硫酸盐限制性内切酶法（combined bisulfite restriction analysis,COBRA）在检测胃癌抑癌基因甲基化水平上的差异性。方法选择经病理确诊的原发性胃癌患者,胃癌患者术前均未行放疗和化疗,收集胃癌根治术后肿瘤组织和配对的癌旁5cm组织各123例,正常对照组织30例,同时收集78例术前、术后血清。采用目前常用的MSP法、COBRA法检测上述标本中的CHFR与RUNX3基因启动之区甲基化的状态。结果1. CHFR基因启动子区CpG岛的异常甲基化胃癌组织中CHFR基因甲基化阳性率为41.5%（51/123）,癌旁组织为11.4%（14/123）,正常组织为0%（0/30）,前组与后两组比较差异具有统计学意义（P<0.05）。CHFR基因在分化程度为G3/G4的胃癌组织中的甲基化阳性率显著高于G1/G2的甲基化阳性率,差异具有统计学意义（P<0.05）。在肿瘤直径≥5cm的胃癌组织中的甲基化阳性率显著高于其在<5cm的胃癌组织的甲基化阳性率（P<0.05）,而其异常甲基化在患者年龄、性别、肿瘤浸润深度、病理分期以及淋巴结转移等临床资料参数中的差异不具有统计学意义（P>0.05）。CHFR基因在术前血清中的甲基化阳性率为20.5%（16/78）,显著高于术后血清中的甲基化阳性率2.6%（2/78）,差异具有统计学意义（P<0.05）,而且,外周血清中基因甲基化水平与相应的癌组织中相同基因的甲基化水平存在一致性（P<0.05,Kappa值为0.521）。2. RUNX3基因启动子区CpG岛的异常甲基化胃癌组织中RUNX3基因甲基化阳性率为55.3%（68/123）,癌旁组织为9.8%（12/123）,而正常组织为0%（0/30）,前组与后两组比较差异有统计学意义（P<0.05）。RUNX3基因在浸润深度为T3/T4的胃癌组织中的甲基化阳性率显著高于其在T₁/T₂的胃癌组织的甲基化阳性率（P<0.05）,在肿瘤直径≥5cm的胃癌组织中的甲基化阳性率显著高于其在<5cm的胃癌组织的甲基化阳性率（P<0.05）,而其异常甲基化在患者年龄、性别、组织分化程度、病理分期以及淋巴结转移等临床资料参数中的差异均无统计学意义（P>0.05）。RUNX3基因在术前血清中的甲基化阳性率为28.2%（22/78）,显著高于术后血清中的甲基化阳性率2.6%（2/78）,差异具有统计学意义（P<0.05）,而且,外周血清中基因甲基化水平与相应的癌组织中相同基因的甲基化水平存在一致性（P<0.05,Kappa值为0.377）。3. MSP、COBRA两种方法在检测胃癌组织中CHFR基因启动子区甲基化阳性率的比较。在检测64例胃癌组织CHFR基因启动子区甲基化阳性率中,MSP方法测定的甲基化阳性率为51.6%（33/64）,与COBRA方法检测的结果42.2%（27/64）相比较,差异不具有统计学意义（P>0.05）。结论1.胃癌组织和血清中存在CHFR和RUNX3基因启动子区的异常甲基化,且具有一致性,参与了胃癌的发生发展,联合检测多个基因启动子区的甲基化状态可能为胃癌的诊断提供一种新的方法,有助于胃癌的临床筛选。2. CHFR基因启动子区CpG岛的异常甲基化与胃癌组织的分化程度密切相关,可作为评估胃癌组织分化程度的参考指标。3. RUNX3基因启动子区的异常甲基化与胃癌的浸润深度密切相关,可以作为评价肿瘤浸润深度的检测指标。4. RUNX3和CHFR基因启动子区CpG岛的异常甲基化与肿瘤大小显著相关,可作为评估胃癌生长的参考指标。5. MSP方法与COBRA方法在检测胃癌抑癌基因启动子区甲基化阳性率上无差异,采用上述两种检测方法报道的抑癌基因甲基化水平可以相互比较。更多还原

【Abstract】 Objective In this study, the methylation level of CHFR and RUNX3 genes promoter in gastric carcinoma tissues, 5cm adjacent nonmalignant gastric mucosa tissues and normal gastric mucosa, pre-operative and post-operative serum, were detected by combination of methylation-specific polymerase chain reaction (MSP) and combined bisulfite restriction analysis (COBRA), and to explore the relationship between the aberrant methylation of these two genes and the clinical parameters of the gastric cancer. Then, we compare the difference of MSP and COBRA on the methylation detecting of tumor suppressor gene in gastic cancer.Methods Patients diagnosed as primary gastric cancer without receiving any radiotherapy or chemotherapy before operation were collected. A total of 123 carcinoma specimens, the matched neighboring tissues during their surgical resection, and thirty normal gastric mucosa were collected as control group.78 pre-operative and corresponding post-operative sera were taken from the patients. The techniques of MSP and COBRA was adopted to investigate the promoter methylation of CHFR gene in 64 carcinoma specimens .Results1. The aberrant methylation of CpG islands of CHFR gene promoterThe positive rate of methylation of CHFR gene was found to be 41.5% (51/123) in gastric cancer tissues,11.4% (14/123) in the matched neighboring tissues and 0% (0/30) in normal gastric mucosa.The positive rate of methylation of CHFR gene in the former group was significantly higher than that in the latter two groups (P<0.05).The positive rate of methylation of CHFR gene from degree of histological differentiation G3/G4 carcinoma tissues was significantly higher than that from the tissues samller than G1/G2 (P<0.05). And the positive rate of methylation of CHFR gene from diameter lager than 5cm was significantly higher than that from the tissues samller than 5cm (P<0.05). While no significant difference was found in other clinical parameters including the age, gender, invasion depth, stage of pathology and the involvement of lymph node from the carcinoma specimens group (P>0.05).The positive rate of methylation of CHFR gene was found to be 20.5% (16/78) in pre-operative serum of gastric cancer, 2.6% (2/78) in the matched post-operative serum. The positive rate of methylation of CHFR gene in the former group was significantly higher than that in the latter two groups (P<0.05). And the positive rate of methylation of CHFR gene in serum had significant consistency with carcinoma specimens(P<0.05, Kappa value is 0.521).2. The aberrant methylation of CpG islands of RUNX3 gene promoterThe positive rate of methylation of RUNX3 gene was found to be 55.3% (68/123) in gastric cancer tissues, 9.8% (12/123) in the matched neighboring tissues and 0% (0/30) in normal gastric mucosa. The positive rate of methylation of RUNX3 gene in the former group was significantly higher than that in the latter two groups (P<0.05).The positive rate of methylation of RUNX3 gene from invasion depth T3/T4 carcinoma tissues was significantly higher than that from the tissues samller than T1/T2 (P<0.05). And the positive rate of methylation of RUNX3 gene from diameter lager than 5cm was significantly higher than that from the tissues samller than 5cm (P<0.05). While no significant difference was found in other clinical parameters including the age, gender, degree of histological differentiation, stage of pathology and the involvement of lymph node from the carcinoma specimens group (P>0.05). The positive rate of methylation of RUNX3 gene was found to be 28.2% (22/78) in pre-operative serum of gastric cancer, 2.6% (2/78) in the matched post-operative serum. The positive rate of methylation of RUNX3 gene in the former group was significantly higher than that in the latter two groups (P<0.05). And the positive rate of methylation of RUNX3 gene in serum had significant consistency with carcinoma specimens(P<0.05, Kappa value is 0.377).3.Comparison of the results of promoter methylation of CHFR gene between MSP and COBRA.There was no significant difference was found on the result of promoter methylation of CHFR gene between MSP and COBRA in 64 gastric cancer tissue specimens(P>0.05).Conclusions1. The aberrant CpG islands methylation of CHFR and RUNX3 gene promoter were existed both in carcinoma specimens and matched serum.. It indicated that the aberrant CpG islands methylation of CHFR and RUNX3 involved during the occurrence and development of gastric cancer. Combined detection of multi-TSG would contribute the diagnosis of gastric cancer on the clinic.2. Methylation of the promoter CpG islands of CHFR genes is significant associated with the degree of histological differentiation, indicating that aberrant methylation of this gene can used as a sensitive referred parameter on the evaluation of degree of histological differentiation in gastric cancer.3. Aberrant promoter CpG islands methylation of RUNX3 gene is significant associated with the invasion depth of gastric cancer. It can be a good parameter to evaluate the invasion depth of gastric cancer. 4. Aberrant promoter CpG islands methylation of RUNX3 and CHFR gene of gastric cancer specimens was significantly correlated with the tumor size. It can be used to evaluate the growth of gastric cancer in gastric cancer.5. There was no significant difference was found on the result of promoter methylation of TSG between MSP and COBRA.It is feasible to compare the results of promoter methylation of TSG of different experiment using different methods.更多还原