Identification of key mi RNA s and genes associated with stomach adenocarcinoma from The Cancer Genome Atlas database

Stomach adenocarcinoma (STAD) is the second leading cause of cancer death and a fuller understanding of its molecular basis is needed to develop new therapeutic targets. mi RNA and mRNA data were downloaded from The Cancer Genome Atlas database, and the differentially expressed mi RNA s and genes were identified. The target genes of differentially expressed mi RNA s were screened by prediction tools. Furthermore, the biological function of these target genes was investigated. Several key mi RNA s and their target genes were selected for validation using quantitative real‐time polymerase chain reaction ( qRT ‐ PCR ). The Gene Expression Omnibus ( GEO ) dataset was used to verify the expression of selected mi RNA s and target genes. The diagnostic value of identified mi RNA s and genes was accessed by receiver operating characteristic analysis. A total of 1248 differentially expressed genes were identified in STAD. Additionally, nine differentially expressed mi RNA s were identified and 160 target genes of these nine mi RNA s were identified via target gene detection. Interestingly, they were remarkably enriched in the calcium signaling pathway and bile secretion. qRT ‐ PCR confirmed the expression of several key mi RNA s and their target genes. The expression levels of hsa‐miR‐145‐3p, hsa‐miR‐145‐5p, ADAM 12 , ACAN , HOXC 11 and MMP 11 in the GEO database were compatible with the bioinformatics results. hsa‐miR‐139‐5p, hsa‐miR‐145‐3p and MMP11 have a potential diagnostic value for STAD. Differential expression of the mature form of mi RNA s (hsa‐miR‐139‐5p, hsa‐miR‐145‐3p, hsa‐miR‐145‐5p and hsa‐miR‐490‐3p) and genes including ADAM 12 , ACAN , HOXC 11 and MMP 11 and calcium and bile secretion signaling pathways may play important roles in the development of STAD.