Oncomirs miRNA-221/222 and Tumor Suppressors miRNA-199a/195 Are Crucial miRNAs in Liver Cancer: A Systematic Analysis.

ABSTRACT

BACKGROUND: The high mortality rate of hepatocellular carcinoma (HCC) is partly due to a lack of good diagnostic markers and treatment strategies. Recently, several microRNA (miRNA) profiling studies were conducted with HCC; however, their inconsistency means that their diagnostic or therapeutic value is debatable. AIMS: This study aims to systematically evaluate the consistency of miRNAs from multiple independent studies. METHODS: A systematic analysis of miRNAs from eligible publications was conducted, followed by real-time PCRs. The targets of highly consistent miRNAs were collected using online programs, followed by enrichment analyses for gene ontology terms and Kyoto encyclopedia of genes and genomes pathways. RESULTS: In total, 241 differentially expressed miRNAs were reported in 13 HCC profiling studies, of which 137 were upregulated and 104 downregulated. Among consistently upregulated miRNAs (cutoff > fourfold), miRNA-222, miRNA-21, miRNA-221, miRNA-210, and miRNA-224 were found increased in 8, 6, 6, 5, and 5 different studies, respectively. Among 137 downregulated miRNAs, miRNA-195, miRNA-199a, miRNA-125b, and miRNA-99a were reported in 8, 8, 5, and 5 studies, respectively. These results were confirmed by real-time PCR. Enrichment analyses demonstrated that programmed cell death and proliferation play important roles during the interplay of miRNA with HCC. CONCLUSIONS: miRNAs most consistently related to HCC are oncomirs miRNA-221/222 and tumor suppressors miRNA-199a/195.