CpG岛甲基化表型结直肠癌新标记物及临床病理特征研究

发布时间：2018-06-24 21:08

本文选题：CpG岛甲基化表型 + 结直肠癌　；参考：《第二军医大学》2015年硕士论文

【摘要】：研究目的：CpG岛甲基化表型(CIMP)是一种特殊的结直肠癌亚型,其特征在于基因启动子中的CpG岛大量甲基化,导致一些肿瘤抑制基因或肿瘤相关的基因失活。CIMP被发现与多种不同的临床和分子特征有关,比如对5-FU和西妥昔单敏感性低,患者预后更差等。然而,迄今CIMP结直肠癌的临床和分子特征之间仍然存在争议。造成这种争议的原因包括：研究人群的种族差异、病例对照选择标准,用于定义CIMP甲基化表型的基因marker不同,和DNA甲基化检测的方法不同。寻找新的CIMP marker和更为灵敏的检测方法是研究和评估CIMP肿瘤的主要挑战。本研究选择了5个新的基因SHISA3, STC2,TMEM200B,CTSL1和LRIF1,从散发性结直肠癌中筛选和鉴定CpG岛甲基化表型。研究方法：我们前期利用MBP沉淀测序的方法,比较了3对普通结直肠癌和正常对照,3对CIMP(利用经典的CIMP marker)的DNA甲基化谱,最终选择了5个仅在CIMP肿瘤中甲基化的基因作为标记分子,SHISA3,STC2, TMEM200B, C TSL1 LRIF1。分别收集216对结直肠癌和正常对照组织,抽提DNA后进行重亚硫酸盐处理,分别检测新的5对分子marker SHISA3, STC2, TMEM200B, CTSL1 LRIF1和经典的分子marker CACNAIG, IGF2, NEUROG1, RUNX3,S0CS1的甲基化情况。为了更准确地量化甲基化,我们使用数字PCR(ddPCR)新技术来检测甲基化情况。结果：在我们分析的216个肿瘤,我们选择新的基因SHISA3, STC2, TMEM200B, CTSL1 LRIF1敏感性,特异性,PPV和NPV分别是80%,95.3%,85.7%和93.2%,比之前验证5个经典的基因CACNA1G,IGF2, NEUROG1, RUNX3,SOCS1有更高的敏感性和特异性：CIMP肿瘤中BRAF突变更为常见,但K-RAS突变低于非CIMP肿瘤。CIMP生存率显著低于非CIMP肿瘤。结论：新CIMP基因组合比经典5个基因组合具有更高的敏感性和特异性。
[Abstract]:Objective: CpG island methylation phenotype (CIMP) is a special subtype of colorectal cancer characterized by CpG island methylation in gene promoter. Inactivation of some tumor suppressor genes or tumor-related genes. CIMP has been found to be associated with a variety of clinical and molecular characteristics such as low sensitivity to 5-FU and cetuximab and worse prognosis in patients. However, the clinical and molecular characteristics of CIMP colorectal cancer are still controversial. The reasons for this controversy include ethnic differences in the study population, case-control selection criteria, different genes used to define the methylation phenotype of CIMP, and different methods for methylation detection. Finding new CIMP marker and more sensitive detection methods are the main challenges in the study and evaluation of CIMP tumors. In this study, five new genes, SHISA3, STC2TMEM200BnCTSL1 and LRIF1, were selected to screen and identify CpG island methylation phenotypes from sporadic colorectal cancer. Methods: we compared the methylation spectra of 3 pairs of normal colorectal cancer and 3 pairs of normal controls (using the classical CIMP marker) by MBP precipitation sequencing. Finally, five methylated genes were selected as marker molecules such as SHISA3, TMEM200B, C TSL1 LRIF1. Two hundred and sixteen pairs of colorectal cancer and normal control group were collected and treated with heavy sulfite. The methylation of five new molecules, marker SHISA3, STC2, TMEM200B, CTSL1 LRIF1 and classical molecules marker CACNAIGI, IGF2, neurogl, RUNX3S0CS1, were detected. In order to quantify methylation more accurately, we use digital PCR (ddPCR) to detect methylation. Results: in our analysis of 216 tumors, we selected new genes SHISA3, STC2, TMEM200B, CTSL1 LRIF1 sensitivity. The specificity of PPV and NPV were 85.7% and 93.2%, respectively. The BRAF mutation was more sensitive and specific in the tumor than that in the non-CIMP tumor, but the survival rate of the K-RAS mutation was significantly lower than that of the non-CIMP tumor .CIMP survival rate was significantly lower than that of the non-CIMP tumor. The sensitivity and specificity of BRAF mutation were higher than those of the five classical genes CACNA1GfIGF2, NEUROG1 and RUNX3nSOCS1, but the K-RAS mutation was significantly lower than that of the non-CIMP tumor. Conclusion: the new CIMP gene combination has higher sensitivity and specificity than the classical five gene combinations.
【学位授予单位】：第二军医大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R735.34

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