Abstract:Objective: To explore the diagnostic markers as well as the potential therapeutic targets and drugs for colorectal cancer (CRC) through bioinformatics approach. Methods: The microarray data of GSE74602 was downloaded from the public data platform Gene Expression Omnibus (GEO) of the National Center for Biotechnology Information (NCBI), which contained 30 CRC tissue samples and 30 normal colorectal tissue samples. The differential expressed genes between CRC tissue and normal colorectal tissue were identified by Limma package of R language. Then, the differential expressed genes were subjected to Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis using DAVID online tool. At the same time, Protein-protein interaction networks of the differential expressed genes were generated by using the STRING server and visualized by Cytoscape software. Subnetwork module analyses were performed through the MCODE plugin to screen out the core genes for CRC carcinogenesis. Finally, the small molecule compounds potentially against CRC were searched from the Connectivity Map (cMap) database. Results: A total of 231 differential expressed genes were picked up, among which 122 were up-regulated and 109 were down-regulated. The GO analysis showed that the up-regulated genes were enriched for biological processes that mainly included cell cycle and cell division, while the down-regulated genes were enriched for biological processes such as immune response, intracellular signaling cascade and defense response. KEGG pathway analysis showed the up-regulated genes were mainly involved in the signaling pathways associated with the intracellular nitrogen and mineral metabolism and secretion (such as bile and pancreatic juice), while the down-regulated genes were mainly involved in the signaling pathways associated with drug metabolism, cell cycle and p53. Some genes playing critical roles in regulating the occurrence of CRC were identified, such as KIF20A, CENPF, NCAPG, PYY, and IQGAP3. Several small molecule drugs potentially against CRC were screened out after the differentially expressed genes in the protein-protein interaction networks were submitted to the cMap database, such as viomycin, harmalol and ikarugamycin. Conclusion: The identified pivotal genes may probably be used as the new biomarkers for diagnosis of CRC or therapeutic targets of CRC. Moreover, the screened small molecule compounds may potentially be developed into novel drugs for the treatment of CRC.