早发型胃癌相关潜在驱动突变基因筛查研究

发布时间：2018-04-27 11:39

本文选题：早发型胃癌 + 全基因组测序　；参考：《浙江大学》2016年博士论文

【摘要】：背景和目的：胃癌是目前世界上发病率和死亡率均较高的恶性肿瘤之一,其治疗效果的局限性和预后不佳很重要的一方面原因即为胃癌本身的异质性,这种异质性可以体现在胃癌分子水平的差异。关于胃癌的具体发病机制目前仍不明确,但随着分子生物学、基因组学和信息生物学等的发展(尤其是高通量二代测序技术的展开),关于胃癌分子水平方面的研究正在逐渐深入。体细胞基因突变(尤其是驱动基因突变)造成的癌基因激活或者抑癌基因失活在恶性肿瘤的发生发展过程中扮演着至关重要的作用,因此找到胃癌相关的潜在驱动基因突变对了解胃癌发生发展机制、制定相应的后续治疗方案(尤其是近几年精准治疗模式的提出)等具有非常重要的意义。随着人类年龄的增长,外界环境对其的影响逐渐积累,其体内细胞内突变基因的数量也会逐渐增多,这些突变基因并非某种肿瘤形成的关键基因突变或驱动基因突变(而称之为旁路基因突变),在肿瘤基因研究过程中会产生一定的干扰；而相对于年龄较大的患者,年轻肿瘤患者其受外界环境和后天因素影响均较小,体内细胞内旁路基因突变数量也较少,其促进肿瘤形成的机制更依赖于本身存在的遗传背景或分子机制；因此,研究年轻肿瘤患者体内突变基因或分子水平特性一定程度上更能提示肿瘤发生发展的关键基因或分子变化。本研究旨在通过对早发型胃癌(发病年龄小于45岁)样本进行全基因组测序及分析,以筛查胃癌相关的潜在驱动突变基因,为后续胃癌分子研究提供一定的数据基础。方法：本研究中我们收集了5对早发型胃癌(发病年龄均小于45岁)组织及其相应的癌旁正常组织作为研究样本,通过Illumina Hiseq X平台进行全基因组测序并结合生物信息学对胃癌样本中体细胞突变情况等进行筛查分析,并进一步分析胃癌样本中的可能易感基因突变、融合基因、以及显著相关高频突变基因等,预测胃癌中的潜在驱动基因突变。结果：我们通过对5对早发型胃癌样本进行全基因组测序及生物信息学分析,共发现了162个胃癌相关的可能易感基因突变,以及70个由断点落在基因区的SV(结构变异)事件导致的不同基因融合事件。通过将检测到的体细胞突变与已知的癌症相关驱动基因数据库进行比对,共筛查出了49个已知的驱动突变基因,包括TP53、NOTCH1、ARID1A、PIK3CA和CDH1等常见突变基因。同时,我们还发现了8个目前尚未被报道的胃癌相关高频率突变基因,即CYP4F2、MIOX、 OCM2、OR11H1、MUC4、KLF2、GRM8和CBWD3,作为可能的潜在胃癌驱动突变基因；以及2个突变位点分布集中于突变簇(提示在肿瘤发生中可能存在关键作用因而经过正向选择过程)的胃癌可能驱动基因KLF2和SEMA5A。结论：本研究中发现的胃癌相关可能的驱动基因突变,一方面仍需要后续更大的样本量进行验证,另一方面为我们后续胃癌分子水平的深入研究提供了一定的数据基础和研究方向。
[Abstract]:Background and objective: gastric cancer is one of the malignant tumors with high morbidity and mortality in the world. The limitation of the treatment effect and the poor prognosis are the heterogeneity of gastric cancer itself. This heterogeneity can be reflected in the difference of the molecular level of gastric cancer. The specific pathogenesis of gastric cancer is still not available. It is clear, but with the development of molecular biology, genomics and information biology, especially the development of high throughput two generation sequencing technology, the research on the molecular level of gastric cancer is progressively deepening. The oncogene activation or the inactivation of tumor suppressor genes caused by the mutation of somatic gene (especially the mutation of the gene) in the malignant tumor It plays a vital role in the development of life, so it is of great significance to find the potential driving gene mutations related to gastric cancer to understand the mechanism of the development of gastric cancer, and to formulate a corresponding follow-up treatment scheme, especially in recent years. When the noise accumulates gradually, the number of mutated genes in the cells in the body increases gradually. These mutations are not a key gene mutation or a driving gene mutation (called the bypass gene mutation) of some kind of tumor. It is less affected by the external environment and acquired factors, and the number of mutations in the intracellular bypass gene is less. The mechanism for promoting the formation of tumor depends more on its own genetic background or molecular mechanism. Therefore, the study of the mutation gene or the water level specificity of the young tumor patients is more likely to indicate the occurrence of tumor. Key gene or molecular changes in development. The aim of this study was to complete genome sequencing and analysis of early onset gastric cancer (age less than 45 years old) to screen the potential driving mutation genes related to gastric cancer and provide a data basis for subsequent gastric cancer research. Methods: We collected 5 pairs of early gastric cancers in this study. Cancer (age less than 45 years old) and its corresponding normal tissue as a study sample, complete genome sequencing by Illumina Hiseq X platform and combined with bioinformatics to screen and analyze the mutation of somatic cell in gastric cancer samples, and further analyze the possible susceptible gene mutation and fusion gene in gastric cancer samples. The potential driving gene mutations in gastric cancer were predicted, as well as a significant correlation of high frequency mutation genes. Results: we have identified 162 possible susceptible gene mutations related to gastric cancer by genome sequencing and bioinformatics analysis of 5 samples of early onset gastric cancer, and 70 SV (structural variations) that fall in the gene area by the breakpoints. A total of 49 known mutation genes, including TP53, NOTCH1, ARID1A, PIK3CA and CDH1, were screened by comparing the detected somatic mutation with the known cancer related gene database. We also found 8 unreported gastric cancers. The related high frequency mutation genes, namely CYP4F2, MIOX, OCM2, OR11H1, MUC4, KLF2, GRM8 and CBWD3, are possible potential gastric cancer driven mutations, and the 2 mutation sites are concentrated in the mutation cluster (suggesting that the key role in the tumorigenesis may lead to a positive selection process) may drive the gene KLF2 and SEMA5A. junctions. On the one hand, it still needs a larger sample size to verify, and on the other hand, it provides a certain data basis and research direction for the further study of the molecular level of our follow-up gastric cancer.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R735.2

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