【作者】 徐雪；

【导师】 陆星华；

【作者基本信息】 北京协和医学院 ， 内科学， 2014， 博士

【摘要】 背景：胃早期癌和癌前病变多无明显的临床症状,胃癌及癌前病变相关的临床和生物学研究将有助于改善病人整体预后。目的：本研究从胃低级别上皮内瘤变、高级别上皮内瘤变和早期胃癌的表达谱特征入手,寻找它们的生物学联系和差异,分析胃癌变早期的分子功能变化、筛选胃早期癌变可能起关键作用的基因、并在组织蛋白水平探索其诊断标志物价值。将有助于揭示胃早期癌变的相关生物学事件,为分子诊断和标志物研究提供线索,为临床处理提供生物学依据。方法：本研究首先通过全基因表达谱芯片实验对19例胃低级别上皮内瘤变(LGIN)、20例胃高级别上皮内瘤变(HGIN)、19例早期胃癌(EGC)和19例慢性胃炎的组织mRNA表达特征进行分析,运用G0富集分析探索胃癌变早期的生物学规律,并筛选出重要的生物学功能及相关基因,GOS2基因和OSM基因；其次通过实时定量PCR实验,对GOS2基因和OSM基因在独立的26例LGIN、15例HGIN、14例EGC和20例慢性胃炎组织样本中的mRNA表达水平进行验证；同时,通过免疫组织化学染色实验,在65处慢性胃炎,45处肠上皮化生,24处低级别上皮内瘤变、46处高级别上皮内瘤变、33处早期胃癌和18处进展期胃癌组织中,检测GOS2基因和OSM基因的蛋白表达水平。结果：LGIN与HGIN、 LGIN与胃早期癌mRNA表达特征的差异显著,生物学功能主要为代谢、防御反应和NF-kB通路相关。HGIN和胃早期癌mRNA表达特征的差异并不显著,与免疫功能关系密切。GOS2和OSM基因的组织mRNA和蛋白表达水平,在HGIN和EGC中呈明显的高表达水平；而随着病变发展,进展期胃癌组织中的蛋白表达水平下降。结论：LGIN和HGIN基因表达特征的差异显著；相比于LGIN, HGIN和胃早期癌间的生物学联系更紧密。在胃癌变早期,起重要作用的基因随着LGIN→HGIN→EGC进展,表达水平不断升高。在肿瘤发生、发展中起重要作用的能量代谢、免疫反应、NF-kB信号通路,可能是胃癌变早期的重要生物学事件。筛选出的基因在胃癌变早期的表达改变显著,可能具一定分子诊断价值。更多还原

【Abstract】 Background:Unlike advanced-stage patients, patients with early-stage gastric adenocarcinoma(EGC) and precancerous lesions usually have no symptoms. It is important to understand more about EGC and precancerous lesions both clinically and biologically to improve the overall survival of patients with gastric carcinoma. Objectives:To explore the biological similarities and differences among high-and low-grade intraepithelial neoplasia(HGIN and LGIN, respectively), and EGC in detail, this study characterized their whole genome expression profiling to analyze the molecular and functional changes and discover related important genes in gastric early carcinogenesis. Together with the following evaluating of protein expression in tissues, this study would be a benefit for revealing of the early events in gastric carcinogenesis and provide some clue to related biomarker research. Methods:Gene expression profiling was performed on19LGIN,20HGIN,19EGC, and19gastritis tissue samples using microarrays. A GO(gene ontology) enrichment analysis was performed to explore the molecular distinction and functional correlation among these tissues. The differentially expressed genes, GO/G1switch2(GOS2) and Oncostatin M(OSM) were identified and their mRNA expression were validated using a real-time TaqMan(?) PCR assay with another group of independent tissue samples, including26LGIN,15HGIN,14EGC, and20gastritis. Furthermore, immunohistochemical(IHC) staining was used to detect GOS2and OSM expression in65cases chronic gastritis,45cases gastric intestinal metaplasia(IM),24cases LGIN,46cases HGIN,33cases EGC and18cases advanced-stage gastric adenocarcinoma(AGC). Results:The gene expression patterns of the LGIN and HGIN tissues and between LGIN and EGC were distinct. The related biological function were in the category of metabolism, defense response, and NF-kB cascade. The molecular differences between HGIN and EGC are not significant, which were mainly focused on the immune response. The mRNA expression and tissue expression after IHC staining of GOS2and OSM were relatively increased in HGIN and EGC. Conclusions:HGIN and LGIN are biologically distinct. Compared with LGIN, the biological similarities between HGIN and EGC were prominent. The overexpression of GOS2and OSM were validated as the neoplasia progressed from LGIN to HGIN, and then EGC. Alterations of metabolism and the immune response contribute to the malignant progression of gastric neoplasia, and maybe early events in gastric carcinogenesis.更多还原