CDC45在甲状腺癌中的表达模式及临床应用价值

Expression pattern and clinical application value of CDC45 in thyroid carcinoma

目的利用生物信息学探索细胞分化周期蛋白45(cell differentiation cycle protein 45,CDC45)在甲状腺癌中的表达模式,并分析其潜在功能及涉及的信号通路,探索CDC45在甲状腺癌中的临床应用价值。方法利用癌症基因组图谱计划(the cancer genome atlas,TCGA)数据库下载甲状腺癌的基因表达和临床生存数据;通过Timer,人类蛋白质图谱(the human protein atlas,HPA)和SPSS分析CDC45在甲状腺癌中的基因及蛋白表达模式;利用Kaplan-Meier曲线分析CDC45表达与预后之间的相关性;使用Cox回归对甲状腺癌预后影响因素进行分析,并利用R软件对结果进行可视化;使用String预测CDC45的蛋白互作网络,并利用基因本体数据库(gene ontology,GO),东京基因与基因组百科全书(Kyoto encyclopedia of genes and genomes,KEGG)和GSEA软件进行功能和通路富集分析;分别通过R软件和Timer分析CDC45与免疫浸润以及各个免疫细胞之间的相关性。结果与癌旁组织相比,甲状腺癌组织中CDC45基因水平显著上调,差异具有统计学意义[(-4.10±1.95)比(-2.04±1.24),t=11.28,P<0.001]。免疫组化染色结果显示,与癌旁组织相比,甲状腺癌中CDC45蛋白表达明显上升。TCGA数据库分析结果显示,CDC45的表达量与甲状腺癌患者年龄、性别以及M分期无关(P>0.05);但N1分期甲状腺癌患者CDC45表达量显著高于N0分期患者,差异具有统计学意义[(-2.19±1.31)比(-1.82±1.09),t=-3.40,P<0.05];甲状腺癌Ⅰ、Ⅲ、Ⅳ期患者CDC45表达水平显著高于Ⅱ期患者,差异具有统计学意义[(-1.99±1.20)或(-1.94±1.20)或(-1.82±1.22)比(-2.56±1.28),t=3.09、3.02、3.05,P值均<0.001]。CDC45对甲状腺癌患者总体生存期(overall survival,OS)和疾病特异性生存期(disease free survival,DSS)无显著影响(P>0.05),但高表达的CDC45显著减少了甲状腺癌患者无疾病间隔期(disease free interval,DFI)和无进展间隔期(progression free interval,PFI),差异具有统计学意义(P=6.2e^(-9),2.5e^(-5))。多因素Cox回归分析发现,CDC45、M分期和T分期都可以作为甲状腺癌患者DFI时间的独立影响因子;而CDC45、年龄和M分期可以作为PFI时间的独立影响因子。通过蛋白互作网络挑选相关性最高的40个基因进行富集分析,GO富集分析结果表明CDC45相关蛋白主要在核浆和染色体中参与DNA的复制、代谢与结合;KEGG富集分析结果表明CDC45相关蛋白主要参与DNA复制、细胞周期、核苷酸切除修复等;GSEA富集分析发现CDC45还富集在免疫相关的通路上。免疫浸润结果表明,CDC45与B细胞,CDC8^(+)T细胞,CD4^(+)T细胞,巨噬细胞,中性粒细胞以及髓样树突细胞之间呈显著正相关,差异有统计学意义(r=0.35、0.25、0.14、0.16、0.27、0.39,P值均<0.05)。结论CDC45在甲状腺癌中显著高表达,可以独立预测甲状腺癌患者的DFI和PFI时间。

Objective To explore the expression pattern of cell differentiation cycle protein 45(CDC45)in thyroid cancer using bioinformatics,analyze its potential function and involved signaling pathways,and investigate the clinical application value of CDC45 in thyroid cancer.Methods The gene expression and clinical survival data of thyroid cancer were downloaded from the cancer genome atlas(TCGA)database.The gene and protein expression of CDC45 in thyroid cancer were analyzed by Timer,the human protein atlas(HPA)and SPSS.Kaplan-Meier curve was used to analyze the correlation between CDC45 expression and the prognosis of thyroid cancer.Cox regression analysis was performed to analyze the prognostic factors of thyroid cancer,and the results were visualized by R software.The protein-protein interaction(PPI)network of CDC45 was predicted by String,and the function and pathway enrichment analyses were performed by gene ontology(GO),Kyoto encyclopedia of genes and genomes(KEGG)and GSEA.The correlation between CDC45 and immune infiltration or immune cells was analyzed by R software and Timer respectively.Results Compared with adjacent tissues,the expression levels of CDC45 gene was significantly upregulated in thyroid cancer tissues[(-4.10±1.95)vs(-2.04±1.24),t=11.28,P<0.001].The immunohistochemical staining results showed that compared with adjacent tissues,the protein expression of CDC45 was significantly increased in thyroid cancer.The results of TCGA database analysis showed that the expression levels of CDC45 were not related to age,gender,and M stage of thyroid cancer patients(P>0.05).However,the expression level of CDC45 in N1 stage patients was significantly higher than that in N0 stage patients[(-2.19±1.31)vs(-1.82±1.09),t=-3.40,P<0.05].The expression levels of CDC45 were also significantly higher in stages Ⅰ,Ⅲ,and Ⅳ thyroid cancer patients compared to stage Ⅱ patients[(-1.99±1.20)or(-1.94±1.20)or(-1.82±1.22)vs(-2.56±1.28),t=3.09,3.02,3.05,all P values<0.001].CDC45 expression did not significantly affect overall survival(OS)and disease-specific survival(DSS)in thyroid cancer patients(P>0.05).However,high CDC45 expression significantly reduced distant failure-free interval(DFI)and progression-free interval(PFI)in thyroid cancer patients(P=6.2e^(-9),2.5e^(-5)).Multivariate Cox regression analysis showed that CDC45,M stage and T stage were independent predictors of DFI time,while CDC45,age and M stage were independent predictors of PFI time in thyroid cancer patients.According to the PPI network,40 genes with the highest correlation were selected for enrichment analysis.GO enrichment analysis results showed that CDC45 related proteins mainly participate in DNA replication,metabolism and binding in the cytoplasm and chromosomes.The KEGG enrichment analysis results showed that CDC45 related proteins mainly participate in DNA replication,cell cycle,nucleotide excision repair,etc.In addition,GSEA enrichment analysis indicated that the function of CDC45 was also enriched in immune-related pathways.The immune infiltration results manifested that CDC45 was positively correlated with B cells,CDC8^(+)T cells,CD4^(+)T cells,macrophages,neutrophils and myeloid dendritic cells(r=0.35,0.25,0.14,0.16,0.27,0.39,all P values<0.05).Conclusion CDC45 is significantly up-expressed in thyroid cancer and can independently predict DFI and PFI time in thyroid cancer patients.