Identification of rare and penetrant germline mutations for gastric cancer

与其他常见癌症一样，胃癌的起源是多因素或单基因的。然而，迄今发现的唯一单基因形式的胃癌是遗传性弥漫性胃癌(HDGC)，它是由基因CDH1(E-钙粘蛋白)的高度穿透性突变引起的，根据Lauren分类，仅限于组织病理学弥漫型胃癌患者。近年来，通过全外显子测序(WES)方法发现了更多单基因形式的胃癌候选基因。然而，在所有这些研究中，只分析了CDH1阴性的HDGC患者和/或下一代测序仅限于已知的肿瘤学相关的预定基因组。通过过去几年的工作，申请者已经为拟议的研究建立了先决条件，并建立了国际研究网络STAR(http://star-project.md/).STAR的目的是阐明胃癌的遗传和细胞生物学原因。STAR生物库包含来自5,100名欧洲胃癌患者的生物材料，是鉴定胃癌背后常见和罕见基因变异和突变全谱的最佳资源。申请者现在假设，罕见的、尚未确定的致病基因突变以单基因方式导致胃癌。这些突变的鉴定具有重要的临床意义。由于它们的高外显性，这种单基因形式将对受影响的患者和健康携带者的临床管理产生影响。为了识别罕见和穿透性的胚系突变，300名极早发病(45岁)的胃癌患者的样本将接受WES检查。这一队列的选择是基于力量分析和这样一个事实，即起病早期病例在单基因癌症类型中高度丰富。在所有患者中，CDH1突变的存在都已被排除。WES将在西德基因组中心进行，使用最现代的NGS技术。然后，申请者将使用最先进的方法进行生物信息学研究，包括。现代负荷测试，以便为后续分析确定基因和突变的优先顺序。最后，申请者将使用桑格测序确认所有已识别的突变。生成的数据将在后续项目中进一步分析。已确定的癌症基因将在整个明星胃癌队列中进行研究，这是详细的临床特征。这些分析将有助于确定已识别的癌症基因对胃癌的详细贡献，以及这是否取决于疾病开始的年龄。此外，将对新的单基因疾病基因进行第一次功能研究，以确定各自的细胞功能障碍。

As with other common cancers gastric cancer is multifactorial or monogenic in origin. However, the only monogenic form of gastric cancer identified to date is Hereditary Diffuse Gastric Cancer (HDGC), which is caused by highly penetrant mutations in the gene CDH1 (E-cadherin) and restricted to patients with a histopathologically diffuse type of gastric cancer according to the Lauren classification. In recent years, further candidate genes for monogenic forms of gastric cancer have been identified via Whole-Exome Sequencing (WES) approaches. However, in all these studies only CDH1-negative HDGC patients were analyzed and/or the Next Generation Sequencing (NGS) was limited to predefined groups of genes of known oncological relevance.Through work conducted over the past years, the applicants have established the prerequisites for the proposed research and have established the international research network STAR (http://star-project.md/). The aim of STAR is to elucidate the genetic and cell-biological causes of gastric cancer. The STAR Biobank contains biomaterials from > 5,100 European gastric cancer patients, and is an optimal resource for the identification of the entire spectrum of common and rare gene variants and mutations underlying gastric cancer. The applicants now hypothesize that rare, and as yet unidentified, pathogenic gene mutations contribute to gastric cancer in a monogenic manner. The identification of those mutations is of major clinical relevance. Due to their high penetrance, such monogenic forms would have implications for the clinical management of both affected patients and healthy carriers. In order to identify rare and penetrant germline mutations, samples of 300 gastric cancer patients with an extreme early onset (< 45 years) will be subjected to WES. The selection of this cohort was based on a power analysis and the fact, that early age at onset cases are highly enriched among monogenic cancer types. In all patients the presence of CDH1 mutations has been excluded. The WES will be carried out at the West German Genome Center using most modern NGS technology. The applicants will then conduct the bioinformatics work-up using state-of-the-art methods, incl. modern Burden tests in order to prioritize genes and mutations for subsequent analysis. Finally, the applicants will confirm all identified mutations using Sanger sequencing. The generated data will be further analyzed in follow-up projects. The identified cancer genes will be investigated in the entire STAR gastric cancer cohort, which is detailed clinically characterized. These analyses will help to determine the contribution of the identified cancer genes to gastric cancer in detail, and whether this is dependent on the age of disease onset. In addition, first functional studies of new monogenic disease genes will be carried out in order to characterize the respective cellular dysfunction.