There has been accumulative evidence that microRNAs (miRNAs) play essential roles in the tumorigenesis and progression of bladder cancer. However, individual studies and small sample size caused discrepant outcomes. Thus, the current study focused on a comprehensive profiling of all differentially expressed miRNAs in a total of 519 bladder cancer tissue samples, based on miRNA microarray data. Altogether, 11 prioritized miRNAs stated by 21 published microarray datasets, including five down-regulated (miR-133a-3p, miR-1-3p, miR-99a-5p, miR-490-5p, and miR-133b) and six up-regulated candidate miRNAs (miR-182-5p, miR-935, miR-518e-3p, miR-573, miR-100-3p, and miR-3171) were analyzed with vote-counting strategy and a Robust Rank Aggregation method. Subsequently, miRNA in silico target prediction and potential pathway enrichment analysis were performed to investigate the prospective molecular mechanism of miRNAs in the tumorigenesis of bladder cancer. We found that most of the relative pathways of the aberrantly expressed miRNAs found in the current study were closely correlated with different biological processes, cellular components, molecular functions, cancer pathogeneses, and some cell signalings, such as Wnt signaling, insulin/IGF, PI3 kinase, and FGF signaling pathways. Hence, a comprehensive overview on the miRNA expression pattern in bladder cancer tissues was gained by the current study. These miRNAs might be involved in the tumorigenesis and deterioration of bladder cancer.

BackgroundIt has been reported that deregulation or dysfunction of microRNAs (miRNAs) plays an essential part in the hepatocarcinogenesis. However, the contribution and mechanism of microRNA-30a-5p (miR-30a-5p) in hepatocellular carcinoma (HCC) remains largely unknown. Therefore, our aim was to investigate the clinicopathological role of miR-30a-5p in HCC tissues and explore its potential pathways in this study.MethodsThe expression of miR-30a-5p was measured in 95 HCC and adjacent noncancer tissues by real-time reverse transcription quantitative polymerase chain reaction. The relationship between miR-30a-5p expression levels and clinicopathological parameters was also analyzed. Furthermore, the potential target genes of miR-30a-5p were collected via online prediction and literature searching. Gene ontology and pathway enrichment analyses were used to identify the possible function of miR-30a-5p in HCC.ResultsCompared with adjacent noncancer tissues (2.23±0.77), expression level of miR-30a-5p was significantly lower in HCC tissues (1.26±0.66, P<0.001). MiR-30a-5p expression was evidently correlated with tumor nodes, metastasis, tumor–node–metastasis stage, portal vein tumor embolus, vascular invasion, and status of tumor capsule (all P<0.05). A total of 878 genes were finally used for the biological informatics analyses. These prospective target genes were highly enriched in various key pathways, for instance, Ubiquitin-mediated proteolysis, Axon guidance, Neurotrophin signaling pathway, Amyotrophic lateral sclerosis, and ErbB signaling pathway.ConclusionIn conclusion, this study clarifies that the downregulation of miRNA-30a-5p might play a vital part in the incidence and progression of HCC via targeting various prospective genes and pathways. Future validation is required to further explore the prospective molecular mechanism of miR-30a-5p in HCC.