Identification of potential biomarkers in pathogenesis and liver metastasis of colorectal cancer: a bioinformatics study

Colorectal cancer (CRC) is the third leading cancer-related death cause worldwide and liver is one of its common metastasis sites. The purpose of this study was to explore the mechanisms of its development and identify some potential therapeutic targets. Gene expression dataset GSE41258 was downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) in primary CRC samples compared with normal mucosae and DEGs in liver metastatic CRC samples compared with the primary CRC samples were obtained through limma package implemented in R. GO and pathway analysis of DEGs were conducted in the Database for Annotation, Visualization and Integrated Discovery. Protein-protein interaction (PPI) and miRNA-Gene regulation network were constructed based on the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and the TargetScan database respectively and visualized via the Cytoscape software. A total of 1048 DEGs, which contained 365 up-and 683 down-regulated ones, and 364 DEGs, which contained 150 up-and 214 down-regulated ones, were obtained in primary and liver metastatic CRC samples respectively. GO and pathway analysis indicated that processes that related to cell activity were enriched in DEGs of primary CRC samples, while for DEGs of liver metastatic CRC samples, substance activity or binding were found to significantly enriched. Besides, the overlaps between those two lists of DEGs were mainly involved in the GO or pathways related to cell activity, substance binding and immune system. What's more, some proved and novel biomarkers, such as MEIS1, TCF21, hsa-miR-142-5p, were screened out in our study, which could improve our understanding about the progression of CRC. Through bio-informatics, we could obtain some potential biomarkers and processes involved in the incidence and development of CRC, which would be helpful in its studies and treatment.