Screening Potential Sensitivity Biomarkers To Evaluate The Effectiveness Of Neoadjuvant Chemoradiotherapy For Esophageal Squamous Cell Carcinoma Based On Bioinformatics

Objective: Before surgery,Patients with localized advanced esophageal squamous carcinoma usually receive neoadjuvant chemoradiotherapy,but the results of patients treated with neoadjuvant chemoradiotherapy are heterogeneous.Therefore,the purpose of this study is to screen the biomarkers of sensitivity to neoadjuvant chemoradiotherapy in esophageal squamous cell carcinoma by bioinformatics methods,in order to obtain new diagnostic and therapeutic targets.Methods:1.Subjects: Patients with stage III to stage IV esophageal squamous cell carcinoma who initially attended Sichuan Cancer Hospital and received neoadjuvant chemoradiotherapy between 2017 and 2021 was retrospectively collected.And the dataset GSE45670 was downloaded from the Gene Expression Omnibus(GEO)database for analysis.2.Research Methods: Gene microarray data(GSE45670)was analyzed using various bioinformatics methods including protein-protein interaction networks(PPI),differentially expressed genes(DEGs),and weighted gene co-expression network analyzes(WGCNA).The biological functions of candidate genes were studied through the enrichment analysis of Kyoto Encyclopedia of genes and Genomes and Gene Ontology Analysis,and the area under the receiver operating characteristic curve was used to predict the predictive value of candidate genes.Immunohistochemical analysis of pathological tissue samples from ESCC patients was used to verify the differential protein expression of genes MMP 9 and AKR1C3,which further proved that it was associated with neoadjuvant chemoradiotherapy sensitivity of ESCC.3.Statistical methods: The overall survival of ESCC in the TCGAdatasets was estimated using the Kaplan-Meier method.To bulid the association between candidate genes expression and the overall survival in ESCC patients.And The IHC Statistical analysis was performed with Graph Pad Prism 7.0(CA,United States).Mann-Whitney U test or two-tailed unpaired tests were used to determine the level of significance.Results:1.A total of 350 differentially expressed genes(DEGs)were screened out.2.The co-expression network analysis of the GSE45670 dataset by WGCNA identified a total of 13 modules,of which the purple module was determined to be the best module,containing 159 genes.3.DEGs were crossed with 159 genes in the purple module in WGCNA to obtain 5 overlapping genes,and combined with 1 core gene obtained by PPI network,6 candidate genes were finally screened out.4.Through GO enrichment analysis and KEGG pathway analysis,the six candidate genes were found to be mainly associated with the oxidative stress response.And the area under the ROC curve suggests that the six candidate genes had some predictive value for neoadjuvant chemoradiation sensitivity in ESCC.5.Survival analysis suggested that the expression difference between gene AKR1C3 and gene AKR1C1 in ESCC patients was statistically significant in overall survival,And patients with high expression of AKR1C3 and AKR1C1 had significantly poor overall survival.6.Validation of immunohistochemical analysis showed that the protein level of AKR1C3 was mainly expressed in the cell membrane of tissues from NCRT-insensitive patients with esophageal squamous carcinoma,whereas the protein level of MMP9 was mainly expressed in the cytoplasm of tissues from NCRT-sensitive patients with esophageal squamous carcinoma.Conclusions:In this study,we screened biomarkers associated with neoadjuvant chemoradiotherapy sensitivity in esophageal squamous carcinoma,and verified by further immunohistochemical analysis,we found that the differences in protein expression levels of MMP9 and AKR1C3 were correlated with the sensitivity of neoadjuvant chemoradiotherapy in ESCC patients.