Identification of key pathways and genes shared between Crohn's disease and breast cancer using bioinformatics analysis

Patients with Crohn's disease (CD) have a high risk of developing breast cancer, suggesting that there may be shared molecular mechanisms underlying CD and breast cancer. The purpose of the present study was to identify the critical genes and pathways underlying these molecular similarities using bioinformatics analysis. Publicly available microarray expression data from the Gene Expression Omnibus were analyzed, and a total of 53 overlapping differentially expressed genes (DEGs) between the CD (vs. controls) and breast cancer (vs. controls) groups were identified. These common DEGs were then subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. Subsequently, a gene interaction network of the DEGs was constructed using Cytoscape software, with its plug-in cytoHubba and Molecular Complex Detection. The gene interaction network and module analysis demonstrated that prostaglandin G/H synthase 2, interleukin (IL)1β and CXCL8 were the major hub genes in the upregulated overlapping DEGs. The upregulated overlapping DEGs are found to be enriched in both the IL-17 and NF-kB signaling pathways. Taken together, the critical pathways and genes identified in the present study may help improve our understanding of why and how CD may contribute to the development of breast cancer.