Screening of genes related to the prognosis of gastric cancer and the efficacy of 5-fluorouracil based on bioinformatics method / 肿瘤研究与临床

ABSTRACT

Objective:To screen biomarkers related to the prognosis of gastric cancer and the efficacy of 5-fluorouracil based on the bioinformatics method.Methods:Gastric cancer datasets like GSE54129, GSE79973 and GSE51725 based on GPL570 platform were downloaded from Gene Expression Omnibus (GEO) database. Genes related to the overall survival (OS) of the top 500 gastric cancer patients were downloaded from GEPIA2 online gene expression profile.GEO2R was used to identify the differentially expressed genes (DEG) between gastric cancer tissues and adjacent normal tissues, STRING database was used to build protein-protein interaction networks (PPI) and to identify the key genes, the enrichment analysis of gene ontology (GO)and Kyoto Encyclopedia of Genes and Genomes (KEGG) was made by using OmicShare. Kaplan-Meier Plotter was used to calculate the value of key genes in predicting the OS of gastric cancer patients. All patients were divided into the high expression group and low expression group according to the optimal cut-off value of gene expression level.Results:A total of 59 DEG were screened, including 39 up-regulated genes and 20 down-regulated genes. The key up-regulated genes including homeodomain transcription factors 2(PITX2), hepatocyte growth factor (HGF), fibroblast growth factor 1 (FGF1), transforming growth factor β 2 (TGFB2), thromobospondin 1 (THBS1) were analyzed by using PPI. Survival analysis results showed that the OS of gastric cancer patients with low expression of FGF1, HGF, PITX2 and TGFB2 genes was better (all P < 0.01); the OS of gastric cancer patients with low expression of THBS1 gene was poor, while the difference was not statistically significant ( P > 0.05). The patients with low expression of RIEG1 gene who received 5-fluorouracil-based chemotherapy regimen had the better OS ( P < 0.01),while those with THBS1 and HGF low expression had the worse OS ( P < 0.05). It was found that key genes might promote the development of gastric cancer by participating in the regulation of TGF- β signaling pathway, Rap1 signaling pathway, MAPK signaling pathway, PI3K-Akt signaling pathway, Hippo signaling pathway, Ras signaling pathway and focal adhesion pathway. Conclusions:Bioinformatics analysis shows that the expressions of FGF1, HGF, PITX2 and TGFB2 genes are related to the prognosis of gastric cancer, and the expressions of RIEG1, THBS1 and HGF are related to the efficacy of 5-fluorouracil, which may be used as a predictive marker of fluorouracil chemosensitivity in patients with gastric cancer.