Abstract: OBJECTIVE: To identify potential biomarkers for gastric cancers (GC) through bioinformatics methods. METHODS: Gene Expression Omnibus (GEO) were retrieved from GC-related datasets,followed by R software and Venn analyses for differentially expressed genes (DEGs) in GC. DAVID software was used to distinguish DEGs' functional annotation. Expression patterns of DEGs were analyzed by Oncomine and their prognostic values were examined by Kaplan-Meier plotter. RESULTS: Three GC-related GEO datasets were found and downloaded from NCBI. After integrating them,110 DEGs were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses indicated that these DEGs were significantly enriched in ECM-related functions and pathways. A group of collagen genes was significantly upregulated in the GC tissues and constituted a protein-protein interaction network as important nodes,including COL1A1,COL1A2,COL2A1,COL12A1,COL6A3,and COL10A1. Based on the miRNA-mRNA analysis,hsa-miR-29a-3p,hsa-miR-29b-3p,and hsa-miR-29c-3p which belonged to the hsa-miR-29 family,has the potential for regulation of COL1A1,COL1A2,COL6A3 and COL2A1. Compared with normal gastric tissues,the expression of COL1A1,COL1A2,COL12A1,COL6A3 and COL10A1 were significantly up-regulated in GC (P<0.05). From survival analyses,the GC patients with high expression of COL1A1,COL1A2,COL12A1,COL6A3,COL2A1 and COL10A1 had poorer prognosis than the other GC patients (P<0.05). CONCLUSION: This study identified that expression of collagen genes was significantly up-regulated in GC tissues and associated with GC patients' survival. Their oncogenic roles and prognostic values in GC indicate that collagens could serve as potential therapeutic targets of GC.

Key words: gastric cancer, bioinformatics, differentially expressed genes, collagen