Analysis Of Gene Expression Profiling Data In Lung Adenocarcinoma And Clinical Significance Of CDC20、TOP2A Expression

Objective: Lung adenocarcinoma(ADC),a histological subtype of non-small cell lung cancer(NSCLC),accounts for 40% of all confirmed cases of lung cancer and is the most common histological type in lung cancer.In this study,the lung adenocarcinoma gene expression profiles in GEO and TCGA were analyzed to identify the hub up-regulated genes that negatively correlated with the prognosis of lung adenocarcinoma patients,and the m RNA level and protein level were verified.The aim of this study is finding out novel Cancer biomarkers and potential molecular therapeutic targets to improve the quality of life of patients with lung adenocarcinoma.Methods: This study was divided into two parts: bioinformatics analysis and experimental verification.In the first part,we downloaded the gene expression profiles of three lung adenocarcinoma datasets from the GEO database-GSE10072(58 tumor cases,49 normal cases),GSE43458(80 tumor cases,30 normal cases),GSE83213(11 tumor cases,46 normal cases),we also downloaded the gene expression profile of the TCGA lung adenocarcinoma dataset(517 tumors cases,59 nomal cases)in the R language environment through the RTCGA data package.Then we used the limma package and edge R to screen the differentially expressed genes of GEO’s three datasets and TCGA datasets respectively,and selected a series of hub up-regulated genes using the STRING database and the Cytoscape visualization tool.Survival analysis of these hub up-regulated genes in TCGA resulted in the observation of up-regulated gene that was negatively associated with patient prognosis.In the second part,we verified the protein and m RNA levels of the genes screening from the first part by WB and real-time PCR in 6 pairs of fresh lung adenocarcinoma tissues and then performed immunohistochemistry in 84 lung adenocarcinoma sections.The result was performed in SPSS to analyze the correlation of gene expression and clinicopathological factors,single factor and multi-factor analysis of OS and RFS.Results: In this study,54 common up-regulated and 164 common down-regulated genes were screened out from the four lung adenocarcinoma datasets by bioinformatics analysis.19 hub up-regulated genes were obtained by comparing the degree of each gene— CDKN3、 BUB1,、TYMS、 COL3A1、 CEP55、SPP1、PLAU、COL1A1、MMP1、TPX2、MMP7、TOP2A、CENPF、NUSAP1、ASPM,DLGAP5、ECT2、CCNB2、PRC1,and the expression levels of these 19 genes in TCGA are only two genes-CDC20 and TOP2 A were significantly negatively correlated with the prognosis of patients(P value was less than 0.01),and the average expression levels of these two genes in TCGA lung adenocarcinoma tumor tissues were significantly higher than those in normal lung tissues(P values ? ? were less than 0.01).).In the second part,we verified hypothesis in 6 pairs of fresh lung adenocarcinoma tissues and found that the expression of CDC20 was increased in 5tumor samples(relative to adjacent tissues),while the expression of TOP2 A was increased in 6 tumor samples.Immunohistochemistry results showed that the positive rate of CDC20 in lung adenocarcinoma was too low,while the high expression rate of TOP2 A in 84 lung adenocarcinoma patients was 46.4%,and the analysis with clinical pathological factors showed that the expression level of TOP2 A was not related to primary tumor size(T stage),regional lymph node involvement(N stage)and TNM stage of patients.Univariate and multivariate survival analysis indicated that the TNM stage of patients and the expression level of TOP2 A may be an independent poor prognostic factor in the cohort of lung adenocarcinoma patients.Conclusion: 1.The 19 hub up-regulated genes screened out from this study may play an important role in the tumorigenesis and progression of lung adenocarcinoma;2.CDC20 and TOP2 A are highly expressed in TCGA database and negatively correlated with prognosis of patients;3.The high expression rate of TOP2 A in lung adenocarcinoma tissue sections was 46.4%,and its expression level was not related to the TNM stage of patients.Univariate and multivariate survival analysis showed that the TNM stage of patients and the expression level of TOP2 A may be an independent poor prognostic factor for patients with lung adenocarcinoma.