Screening candidate genes associated with bladder cancer using DNA microarray.

The aim of the present study was to screen candidate genes that are closely associated with bladder cancer and to select the most distinct candidate target genes in order to provide theoretical evidence and direction for improved treatment of bladder cancer. The gene microarray dataset GSE45184 was downloaded from the Gene Expression Omnibus database. There were a total of six expression prolife microarrays from three pairs of freshly frozen bladder cancer tissues and corresponding normal adjacent tissues. Differentially expressed genes (DEGs) were identified using the limma package in R software and then subjected to further biological information analysis, including hierarchical clustering analysis and gene ontology enrichment analysis. Co‑expression networks and functional interaction networks were established using the up‑ and downregulated genes. Pathway enrichment analysis was then performed for the genes in the functional interaction networks. A total of 522 DEGs were identified, including 223 upregulated and 299 downregulated genes. Functional enrichment analysis of the target genes indicated that downregulated genes were associated with the regulation of biological processes, while the upregulated genes participated in the processes involved in the cell cycle. The functional network of the upregulated genes comprised 1,518 connections and 92 gene nodes that were associated with 10 closely‑related functions, while the network of the downregulated genes consisted of 129 connections and 24 gene nodes involving 11 significantly related functions. Pathway enrichment analysis revealed that the downregulated genes were mainly involved in the mitogen‑activated protein kinase signaling pathway, while the upregulated genes were closely associated with the cell cycle. These DEGs and the relevant cell cycle pathways have the potential to be used as targets for the treatment of bladder cancer.