【作者】 史冬涛；

【导师】 陈卫昌；

【作者基本信息】 苏州大学 ， 内科， 2014， 博士

【摘要】 目的：利用已发表相关文献中的数据进行系统性Meta分析，以期明确RASSF1A基因启动子甲基化与胃癌发生的关系。方法：使用PubMed和Web of Science数据库搜索2013年7月以前所有相关文献。如果某研究属于病例-对照研究，且RASSF1A基因启动子甲基化的频率能在文中获取，那么该研究将被纳入我们的Meta分析。所有的数据由2位研究者独立检索并按照制定的数据收集标准进行收集。使用优势比(OR)及其95%可信区间(95%CI)来衡量RASSF1A基因启动子甲基化与胃癌风险之间的关系。使用基于卡方检验的Q检验和敏感性分析，评估不同研究间潜在的异质性，用漏斗图检验发表偏倚。结果：纳入文献11篇，共涉及研究病例1215例。将所有数据纳入Meta分析，结果显示RASSF1A基因启动子甲基化与胃癌风险有密切相关性（OR,12.67;95%CI,8.12-19.78;P<0.001），且纳入的文献之间不存在异质性。亚组分析进一步表明，RASSF1A基因甲基化的个体与未发生甲基化的个体相比，患胃癌的风险显著增加。整体和亚组分析均没有发现发表偏倚。结论：RASSF1A基因启动子甲基化显著增加胃癌的发病风险，RASSF1A基因启动子甲基化有希望成为潜在的胃癌风险预测因子。目的：研究3号染色体短臂(3p)抑癌基因启动子区CpG岛甲基化表型(CIMP)在胃癌及对照癌旁组织中表达状态，分析其与胃癌患者临床病理及预后的关系。方法：采用甲基化特异性PCR(MSP)方法检测100例胃癌组织及其对应癌旁组织中hOGG1、VHL、hMLH1、SEMA3B、RASSF1A、BLU、FHIT和RAR-B共8个抑癌基因启动子区甲基化表型状态。CIMP阳性定义为每份样本中同时有四个或多于四个基因同时甲基化。结果：100例胃癌组织样本中有99例(99%)表现出至少有一个基因的启动子区呈现甲基化，胃癌组织中hOGG1、VHL、hMLH1、SEMA3B、RASSF1A、BLU、 FHIT和RAR-B基因启动子区甲基化阳性率分别为7%、9%、58%、56%、43%、64%、67%和18%，对应癌旁组织中各基因甲基化阳性率分别为2%、2%、8%、35%、5%、55%、25%和13%。两组间VHL、hMLH1、SEMA3B、RASSF1A和FHIT基因的甲基化阳性率存在显著差异（P=0.030，P<0.001，P=0.003，P<0.001和P<0.001）。胃癌组织和对照癌旁组织中CIMP阳性率分别为44%和4%，两组间有显著差异（P<0.001）。胃癌组织CIMP阳性与肿瘤分化程度密切相关，分化程度越差其CIMP阳性率越高（P=0.004）；与淋巴结转移亦显著相关，伴淋巴结转移者其CIMP阳性率较无淋巴结转移者显著增高（P=0.005）；与其余病理特征包括性别、年龄、肿瘤直径、临床分期和TNM分期均无关（P>0.05）。CIMP阴性组和阳性组患者中位生存时间分别为31和15个月，生存率差异有统计学意义（P=0.009）。Cox回归多因素分析显示，CIMP是影响胃癌患者预后的独立因素（OR,4.3063;95%CI,1.7158-10.8084; P=0.002）。结论：3pCIMP阳性率在胃癌组织和正常胃黏膜中有显著差异，3pCIMP异常状态可能在胃癌形成的早期已经发生，可能影响肿瘤分化、导致淋巴结转移，可作为预测胃癌患者预后的重要指标。目的：研究3p CIMP在癌血样本和正常人外周血细胞样本中的阳性率差异，研究其与胃癌易感性的关系。方法：采用MSP方法检测100例胃癌外周血及70例正常人外周血白细胞中hOGG1、VHL、hMLH1、SEMA3B、RASSF1A、BLU、 FHIT和RAR-B共8个抑癌基因启动子区甲基化状态。结果：胃癌组和对照组hOGG1和VHL基因都未发现甲基化异常，故将这两个基因排除，胃癌组6个抑癌基因启动子区甲基化阳性率分别为：hMLH124.0%(24/100)，SEMA3B62.0%(62/100)，RASSF1A20.0%(20/100)，BLU48.0%(48/100)，FHIT50.0%(50/100)和RAR-B6.00%(6/100)；对照组各基因甲基化阳性率明显降低：hMLH17.1%(5/70)，SEMA3B28.6%(20/70)，RASSF1A2.9%(2/70)，BLU35.7%(25/70)，FHIT25.7%(18/70)和RAR-B4.3%(3/70)。两组间hMLH1、SEMA3B、FHIT和RASSF1A基因甲基化阳性率有显著差异（P=0.004，P=0.000，P=0.001，P=0.001）。胃癌组与对照组血样中的CIMP阳性率分别为30%(30/100)和4.3%(3/70)，两组间CIMP阳性率有显著差异（P<0.001）。3pCIMP阳性与肿瘤低分化及淋巴结转移密切相关（P=0.019，P=0.032）。Logistic回归分析显示， FHIT、hMLH1、SEMA3B、RASSF1A基因启动子区甲基化和3pCIMP阳性与胃癌风险有密切相关性（OR2.78,95%CI1.32-5.45; OR3.89,95%CI1.37-10.89;OR3.97,95%CI1.97-7.27; OR3.97,95%CI1.97-7.27; OR8.37,95%CI1.87-35.33; OR9.53,95%CI2.63-30.83），敏感性分别为50%、24%、62%、20%和30%，特异性分别为74.3%、92.9%、52.9%、97.1%和95.7%，阳性预测值分别为73.5%、82.8%、75.6%、90.9%和90.9%，准确度分别为60%、52.4%、65.9%、51.8%和57.1%。结论：胃癌患者和正常人对照的外周血细胞3pCIMP阳性率有显著差异，3pCIMP阳性可以显著增加胃癌的发病风险（OR9.53,95%CI2.63-30.83），将有可能成为胃癌有用的易感预测因子，3pCIMP阳性可能是胃癌低分化和淋巴结转移的预测指标。更多还原

【Abstract】 Objective: To assess the association of RASSF1A promoter methylation with gastric cancer risk by acomprehensive meta-analysis. Methods: Relevant studies were identified by searches of PubMed andWeb of Science databases with no restrictions. Combined odds ratio (OR) and95%confidence interval(CI) were used to assess the strength of the association between RASSF1A promoter methylation andgastric cancer risk. A chi-square-based Q-test and sensitivity analyses were performed to test thebetween-study heterogeneity and the contributions of single studies to the final results, respectively.Funnel plots were carried out to evaluate publication bias. Results: Overall, a significant associationwas observed between RASSF1A promoter methylation and gastric cancer risk (OR,12.67;95%CI,8.12-19.78; P <0.001) with no between-study heterogeneity. Subgroup analyses further revealed thatgastric cancer risk was increased for individuals carrying the methylated RASSF1A compared withthose with unmethylated RASSF1A. In addition, no publication bias was detected in the overall andsubgroup analyses. Conclusion: This sudy identified a strong association between RASSF1A promotermethylation and risk of gastric cancer, and highlighted a promising potential for RASSF1A promotermethylation in gastric cancer risk prediction. Objective: To study whether CpG island methylation phenotype (CIMP) status involving tumorsuppressor gene lacated on chromosome3p could correlate with gastric cancer. Methods: Methylationspecific PCR (MSP) was used to examine methylation profiles for eight TSGs harbored in chromosome3p in100gastric cancer tissues and100paired normal tissues. CIMP positive is referred to having fouror more than four synchronously methylated genes per sample. The correlation of CIMP and the overallsurvival time were evaluated by Kaplan-Meier chart and Log-rank test．Cox model was used formultivariate analysis．Results:99of100(99%) gastric cancer tissue samples presented promotermethylation of at least one gene. The frequency of promoter methylation for eight genes explored ranged from7%for hOGG1to67%for FHIT. CIMP+increased in44of100gastric cancer tissues(44.0%) as compared to the paired normal tissues (4.0%), respectively (P<0.001). CIMP positive isclosely related to the low degree of tumor differentiation (P=0.004) and lymph node metastasis(P=0.005). The median survival time of patients with negative and positive CIMP was31and15months，respectively (P=0.009). Cox regression analysis suggested that CIMP was independent factorsaffecting the prognosis of gastric cancer patients (OR,4.3063;95%CI,1.7158-10.8084; P=0.002).Conclusion: Normal and malignant gastric tissues are found to have its own unique CIMP patterns.CIMP+may play a role in poor differentiation and lymph node metastasis of gastric cancer and could beused as an important survival predictor in human gastric cancer. Objective: To assess the association of CpG island methylator phenotype status involving tumorsuppressor genes located on chromosome3p with gastric cancer risk by a case-control study. Methods:Using MSP method, we examined methylation profiles for eight TSGs harbored in chromosome3p in100gastric cancer blood samples as well as70normal blood samples. Odds ratio (OR) and95%confidence interval (CI) were used to assess the strength of the association between CIMP and gastriccancer risk. Results:99/100(99%) gastric cancer blood samples presented promoter methylation of atleast one gene. Given that VHL and hOGG1showed no methylation of any sample, we didn‘t considerthe contribution of the two gene to CIMP+. CIMP+was found in30.0%(30/100) of blood samples fromgastric cancer patients and4.3%(3/70) of normal blood samples, respectively (P<0.001). CIMP+isclosely related to the low degree of tumor differentiation (P=0.019) and lymph node metastasis(P=0.032). A significant association was observed between CIMP and gastric cancer risk (OR,9.53;95%CI,2.63-30.83; P<0.001). Conclusion: CIMP in peripheral blood cells could provide usefulbiomarkers of susceptibility to gastric cancer.更多还原