Screening of new biomarkers for esophageal cancer and preliminary verification for peripheral blood mRNA
Objective To screen and verify the genes that play key role in the occurrence and development of esophageal cancer by u-sing bioinformatics and real-time fluorescence quantitative PCR(qRT-PCR)methods to find new markers for diagnosis of esophageal cancer(ESCA).Methods Using the TCGA database and Wayne plot analysis,the cross genes between the differentially expressed genes of ESCA and the genes which have the most significant impacts on disease-free survival(DFS)rate in esophageal cancer patients were preliminarily identified.Following conducting protein-protein interaction(PPI)network analysis on the overlapping genes,GO and KEGG functional analysis was performed to screen the potential key genes as the diagnostic markers of esophageal cancer.qRT-PCR was used to quantitatively analyze the expression of mRNA of the key gene in peripheral blood.Statistical analysis was con-ducted based on the clinico-pathological characteristics of the patients to determine its potential value as a new diagnostic marker for e-sophageal cancer.Results After overlapping of differentially expressed genes of ESCA and disease-free survival genes in the TCGA database,39 upregulated genes and 20 downregulated genes were found to be differentially expressed,all of which affected disease-free survival rate.After conducting PPI network analysis,15 upregulated genes with core interactions were identified,and the downregulat-ed genes did not form any interaction network.Further enrichment analysis of these 15 core interacting genes through GO and KEGG,revealed that fibronectin 1(FN1)may be a potential biomarker for ESCA diagnosis.The qRT-PCR results showed that compared with the healthy control group,the mRNA expression level of FN1 in the peripheral blood of esophageal cancer patients was significantly ele-vated.After analyzing the clinical characteristics of patients,it was found that the patients with poor differentiation and high clinico-pathological staging had significantly increased peripheral blood FN1 mRNA levels.The model with FN1 mRNA expression levels can distinguish esophageal cancer patients from healthy individuals.Conclusion FN1 mRNA may be a potential non-invasive diagnostic biomarker for esophageal cancer.