摘要Background:Lung adenocarcinoma,the most prevalent lung cancer subtype,is increasingly diagnosed in non-smokers and females.The cell cycle regulator CDC20(Cell Division Cycle 20),a crucial activator of the Anaphase-Promoting Complex/Cyclosome(APC/C),is frequently overexpressed in various cancers,including lung adenocarcinoma,and is implicated in tumor-igenesis.Preclinical studies indicate that inhibiting the CDC20-APC/C signaling axis can enhance chemotherapy-induced apopto-sis.Analysis of The Cancer Genome Atlas(TCGA)data confirms that elevated CDC20 expression in lung adenocarcinoma is sig-nificantly associated with poorer patient prognosis and correlates with immune cell infiltration.These collective findings highlight CDC20 as a promising prognostic biomarker and a potential novel therapeutic target for lung adenocarcinoma.Methods:We collected 539 patients with LUAD and 59 normal controls of clinical data from the Cancer Genome Atlas(TCGA)for bioinformatics analysis to investigate the role of CDC20 in LUAD and address the above questions.We evaluated the association between CDC20 expression and clinicopathological features using the Kruskal Wallis test and multivariate logistic regression.Prognostic values were assessed using Cox regression and Kaplan-Meier survival analyses.We further used single-sample gene set enrichment analysis(ssGSEA)to explore correlations between CDC20 expression and immune infiltration levels.Results:CDC20 expression in LUAD tissues was significantly higher than that in normal controls(p<0.001)and showed high diagnostic accuracy(AUC[area under the curve]=0.979).Kaplan-Meier analysis revealed that high CDC20 expression pre-dicted poorer overall survival(OS;HR=1.47,95%CI:1.10-1.97,p=0.009),although no significant association emerged with progression-free interval(p=0.172).ssGSEA indicated a strong positive correlation between CDC20 and T helper 2 cell infil-tration(R=0.764,p<0.001),but negative correlations with mast cells(R=-0.469,p<0.001)and eosinophils(R=-0.343,p<0.001).Functional enrichment analyses(Gene ontology/Kyoto Encyclopedia of Genes and Genomes[GO/KEGG])of CDC20-associated genes provided additional mechanistic insights.Conclusions:The significantly elevated expression of CDC20 in LUAD tissues,coupled with its high diagnostic accuracy(AUC=0.979),underscores its potential utility in differentiating LUAD from normal tissue.More importantly,the strong association be-tween high CDC20 expression and poorer overall survival(OS)establishes its independent prognostic value for predicting adverse patient outcomes.Beyond its correlation with clinical parameters,our findings illuminate potential mechanisms underlying CDC20's oncogenic role.The distinct positive correlation with T helper 2(Th2)cell infiltration and negative correlations with mast cells and eosinophils suggest that CDC20 may actively shape an immunosuppressive tumor microenvironment,potentially facil-itating tumor immune evasion and progression.Functional enrichment analyses of CDC20-coexpressed genes further support its involvement in key oncogenic pathways,including cell cycle regulation and mitotic processes.Collectively,this study not only val-idates CDC20 as a valuable prognostic factor but also provides novel mechanistic insights linking its overexpression to altered im-mune landscapes in LUAD.