a systematic experimental evaluation of microrna markers of human bladder cancer

Background: MicroRNAs (miRNAs) are a class of small RNAs that regulate gene expression. They are aberrantly expressed in many human cancers and are potential therapeutic targets and molecular biomarkers. Methods: In this study, we for the first time validated the reported data on the entire set of published differential miRNAs (102 in total) through a series of transcriptome-wide experiments. We have conducted genome-wide miRNA profiling in 17 urothelial carcinoma bladder tissues and in nine normal urothelial mucosa samples using three methods: 1) An Illumina HT-12 microarray hybridization (MA) analysis 2) a suppression-subtractive hybridization (SSH) assay followed by deep sequencing (DS) and 3) DS alone. Results: We show that DS data correlate with previously published information in 87% of cases, whereas MA and SSH data have far smaller correlations with the published information (6% and 9% of cases, respectively). qRT-PCR tests confirmed reliability of the DS data.Conclusions: Based on our data, MA and SSH data appear to be inadequate for studying differential miRNA expression in the bladder. Impact: We report the first comprehensive validated database of miRNA markers of human bladder cancer.