胃癌免疫基因组学分型及其特征研究

Study on immunogenome typing and characteristics of gastric cancer

目的通过基因组学分析建立胃癌免疫分型,并进一步探讨其免疫特征。方法从TCGA数据库下载443例胃癌患者的基因表达谱及生存数据,通过单样本基因集富集分析(ssGSEA)评分对患者进行分组;采用ESTIMATE及CIBERSORT分别评估各样本中免疫微环境及免疫细胞的组成;采用Kaplan-Meier法绘制生存曲线并对组间差异进行Log-rank检验。结果根据免疫评分将患者分为高、中、低免疫组,三组间预后具有统计学差异;高免疫组所包含的免疫细胞和基质细胞数量最多,肿瘤纯度最低;HLA基因及PD-L1、PD-L2、PIK3CA表达明显增高;高免疫组中CD8^+T细胞含量最高,而M0巨噬细胞和幼稚B细胞最少。结论胃癌免疫分型有助于判断患者的预后,高免疫组患者具有较高的免疫原性及抗肿瘤免疫活性。

Objective To establish a new classification of gastric cancer by genomic analysis and its immune charac-teristics was further explored.Methods The gene expression profile and survival information of 443 patients with gastric cancer were downloaded from the Cancer Genome Atlas Research Network(TCGA)database.On the basis of the single sam-ple Gene Set Enrichment Analysis(ssGSEA)scores,we hierarchically clustered patients into three groups.ESTIMATE and CIBERSORT were used to evaluate the immune microenvironment and the composition of immune cells in each sample.Kap-lan-Meier curves were plotted to estimate overall survival,and then evaluated with the log-rank test.Results Patients were divided into three subgroups by ssGSEA scores,the prognosis of the three groups was statistically different.Compared with the other two subgroups,immunity H group contained the highest number of immune cells and stromal cells and the lowest tumor purity;the expression levels of most HLA genes,pd-l1,pd-l2 and PIK3CA were significantly increased.Moreover,CD8^+T cells were the most abundant in this group,while M0 macrophages and naive B cells were the least.Conclusion Immune typing of gastric cancer is helpful to judge the prognosis of patients,Immunity H group have higher immunogenicity and more powerful anti-tumor immunoactivity.