CC趋化因子配体20在肝细胞癌组织中的表达及其在肝细胞肝癌预后评估中作用的生物信息学分析

Bioinformatics analysis on CC chemokine ligand 20 expression in hepatocellular carcinoma tissue and its effect on prognostic assessment of liver hepatocellular carcinoma

目的:研究CC趋化因子配体20(CCL20)在肝细胞肝癌(LIHC)组织中的表达,并探讨其对LIHC患者预后的影响,阐述CCL20影响LIHC恶性行为的机制。方法:采用Rstudio(4.03)软件从癌症基因图谱(TCGA)和UCSC Xena平台获取LIHC患者癌组织和癌旁组织中CCL20 mRNA表达水平和临床数据,比较CCL20 mRNA在2种组织中的表达差异,并利用GEPIA联合GTEx数据对上述结果进行验证;采用Kaplan-Meier生存分析和Cox回归分析法分析CCL20 mRNA表达水平与LIHC患者预后的关系。通过Pearson相关分析对LIHC患者CCL20 mRNA表达水平与甲胎蛋白(AFP)水平的相关性进行分析,并通过受试者工作特征(ROC)曲线下面积(AUC)、诺谟图和校正曲线分析LIHC患者CCL20 mRNA表达水平与患者临床诊断和生存预测情况的相关性。采用TCGA数据库对LIHC患者癌组织中CCL20 mRNA的表达进行基因集富集分析(GSEA),分析CCL20 mRNA表达水平与DNA拷贝数突变和DNA甲基化水平的相关性。结果:与癌旁组织比较,LIHC患者癌组织中CCL20 mRNA表达水平明显升高(P<0.01);Kaplan-Meier生存分析,CCL20 mRNA低表达患者的预后明显优于CCL20 mRNA高表达患者(HR=1.789,P<0.01),且Cox单因素和多因素回归分析表明CCL20 mRNA表达水平为LIHC患者的独立预后因素(P<0.05);Pearson相关分析,LIHC患者癌组织中CCL20 mRNA表达水平与AFP水平呈正相关关系(P<0.01);CCL20 mRNA表达水平在LIHC患者临床诊断评估中具有一定的参考价值(AUC=0.69,P<0.01),且可有效预测LIHC患者生存率。GSEA分析,CCL20可通过趋化因子、NOD样受体(NLR)、过氧化物酶体增殖物激活受体(PPAR)和Toll样受体(TLR)等肿瘤相关信号通路参与LIHC细胞黏附、细胞因子与细胞因子受体相互作用和核糖体功能实施等过程。遗传学和表观遗传学分析,与正常二倍体组比较,拷贝数丢失组和拷贝数扩增组样本中CCL20 mRNA表达水平差异无统计学意义(P>0.05);与拷贝数丢失组比较,拷贝数扩增组样本中CCL20 mRNA表达水平明显升高(P<0.05);CCL20 mRNA表达水平与CCL20 DNA甲基化水平呈负相关关系(cor=-0.11,P<0.01)。结论:LIHC组织中CCL20 mRNA表达上调与患者预后不良有明显的关联性,CCL20通过多种信号途径参与LIHC的恶性进程,可作为评估和预测LIHC患者预后和生存的指标之一。

Objective:To investigate the expression of CC chemokine ligand 20(CCL20)in liver hepatocellular carcinoma(LIHC)tissue and explore its influence in the prognosis in the patients with LIHC,and to elucidate the mechanism of CCL20 affecting the malignant behavior of LIHC.Methods The mRNA expression levels and clinical data in cancer tissue and para-cancer tissue of the LIHC patients were obtained from The Cancer Genome Atlas(TCGA)and UCSC Xena platforms using Rstudio(4.03)software,and the differences in the CCL20 mRNA expression between the two kinds of tissues were compared,and these results were validated using GEPIA combined with GTEx data.Kaplan-Meier survival analysis and Cox regression analysis methods were used to analyze the relationship between the CCL20 mRNA expression level and the prognosis of LIHC patients.The correlation between the CCL20 expression level and alpha fetoprotein(AFP)level in the LIHC patients was analyzed by Pearson correlation analysis,and the area under receiver operating characteristic(ROC)curve(AUC),Nomogram and correction curve were used to analyze the correlations between the CCL20 mRNA expression level and the clinical diagnosis and survival prediction in the patients with LIHC.GSEA enrichment analysis of the CCL20 mRNA correlation between the expression level expression in cancer tissue of the LIHC patients was performed using the TCGA database,and the correlation between the expression level of CCL20 mRNA and DNA copy-number alterations(CNA)and DNA methylation level were analyzed.Results:Compared with para-cancer tissue,the CCL20 mRNA expression level in cancer tissue of the LIHC patients was significantly increased(P<0.01).The Kaplan-Meier survival analysis results showed that the patients with low expression of CCL20 mRNA had a significantly better prognosis than those with high expression of CCL20 mRNA(HR=1.789,P<0.01).The Cox univariate and multifactorial regression analysis results showed that the CCL20 mRNA expression level was an independent prognostic factor of the LIHC patients(P<0.05);the Pearson correlation analysis showed a positive correlation between the CCL20 mRNA expression levels and AFP levels in cancer tissue of the LIHC patients(P<0.01).The CCL20 mRNA expression level had certain reference value in assessment of clinical diagnosis of the LIHC patients(AUC=0.69,P<0.01),and could effectively predict the survival rate of the LIHC patients.The GSEA analysis showed that CCL20 could be involved in LIHC cell adhesion,cytokine-cytokine receptor interaction and ribosome function implementation through chemokine,NOD-like receptor(NLR),PPAR and Toll-like receptor(TLR)tumor-related signaling pathways.The genetic and epigenetic analysis showed that compared with normal diploid sample group,the expression levels of CCL20 mRNA in copy number loss group and copy number amplification group had no significant differences(P>0.05);compared with copy number loss group,the CCL20 mRNA expression level in copy number amplification group was significantly increased(P<0.05);the expression level of CCL20 mRNA was negatively correlated with its DNA methylation level(cor=-0.11,P<0.05).Conclusion:The CCL20 expression upregulation in LIHC tissue is significantly associated with the poor prognosis of LIHC patients,which can be involved in the malignant process of LIHC through multiple signaling pathways,and it can be used as one of the indicators for prognostic assessment and prediction of survival of the LIHC patients.