作者：周星宇，叶锦宁，房得梁，赵绍基，孙开宇，徐建波

单位：中山大学附属第一医院 胃肠外科中心， 广东 广州 510080

Authors:  Zhou Xingyu, Ye Jinning, Fang Deliang, Zhao Shaoji, Sun Kaiyu, Xu Jianbo

Unit:  Department of Gastrointestinal Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, Guangdong, China

摘要：

目的 筛选与胃癌免疫相关基因(immune-related genes, IRGs)及其预后分析。方法 首先通过R软件,分析TCGA数据库胃癌基因表达数据集获得差异表达IRGs,并进一步筛选出与预后相关的IRGs。分析胃癌组织转录组测序数据获得差异表达IRGs,与前者取交集获得关键IRGs。接着,对关键IRGs进行差异分析、生存分析及临床病理特征相关性分析。然后,使用CIBERSORT方法计算胃癌免疫浸润情况,分析关键IRGs与免疫浸润的相关性,使用TIMER数据库分析免疫浸润与患者生存的关系。最后,使用GEPIA工具分析关键IRGs与巨噬细胞相关趋化因子表达的相关性。结果 通过分析TCGA来源的数据集获得32个预后相关IRGs,分析转录组测序数据获得46个IRGs,二者取交集得到基因:巨噬细胞清道夫受体1 (macrophage scavenger receptor 1,MSR1)和NADPH氧化酶4(NADPH oxidase 4,NOX4)。与正常组织相比,MSR1和NOX4在胃癌组织均为高表达。NOX4高表达与胃癌患者低生存相关,而MSR1表达与患者生存无显著相关性。NOX4表达与患者临床分期及T分期呈显著正相关,未发现与N和M分期的显著相关性。通过免疫浸润分析发现,NOX4表达与M2样巨噬细胞浸润呈正相关,与浆细胞、记忆B细胞浸润呈负相关。而生存分析发现巨噬细胞高浸润与胃癌患者低生存有关。通过相关性分析发现NOX4与M2样巨噬细胞相关趋化因子呈正相关。结论 基于生物信息学筛选出了胃癌免疫浸润的关键基因NOX4,NOX4的高表达与胃癌组织M2样巨噬细胞浸润及不良预后相关。

关键词：胃癌；免疫浸润；巨噬细胞；NADPH 氧化酶4

Abstract：

Objective To identify immune-related genes（IRGs）in gastric cancer（GC）and analyze their prognostic value. Methods First, through the R software, gene expression datasets of GC from the The Cancer Genome Atlas（TCGA）database were analyzed to obtain differentially expressed IRGs. Then the IRGs related to the prognosis were screened out. The RNA-sequencing data of GC tissue were analyzed to obtain differentially expressed IRGs. The key IRGs were the intersection of prognosis-related IRGs from TCGA and IRGs from transcriptome -sequencing. Difference analysis, survival analysis and correlation analysis were conducted via R software . CIBERSORT computational method was applied for estimating the immune infiltration profile. Correlation analysis between key IRGs and immune infiltration was performed. Next, Tumor Immune Estimation Resource （TIMER） database was used to predict the survival rate of GC patient with different immune infiltration level. Finally, Gene Expression Profiling Interactive Analysis （GEPIA） online tool was applied to explore the correlation between IRGs and macrophage -related chemokines. Results There were 32 prognosis-related IRGs from TCGA and 46 IRGs from transcriptome -sequencing. MSR1 and NOX4 were overlapping from the above data. Expression of MSR1（macrophage scavenger receptor 1）and NOX4（NADPH oxidase 4 ）in the tumor samples were significantly higher than that in the normal samples. GC patients with NOX4 high expression had shorter survival than that of NOX4 low expression while MSR1 expression was not significantly correlated with patient survival. Additionally, NOX4 expression was positively correlated with stage and T classification while there was not significant correlation between NOX4 expression and N or M classification. Analysis of immune infiltration profile indicated that NOX4 was positively correlated with infiltration of M2 macrophages but negatively correlated with infiltration of plasma cells and memory B cells. Moreover, proportion of macrophages had negative correlation with GC patient survival. Finally, NOX4 was positively correlated with M2 macrophage-related chemokines. Conclusion Based on bioinformatics analysis, the key gene for immune infiltration of gastric cancer was screened out. The high expression of NOX4 in GC is associated with the infiltration of M2 macrophages and poor prognosis.

Key Words:  Gastric cancer; Immune infiltration; Macrophage; NADPH oxidase 4