BACKGROUND: MicroRNAs (miRNAs), which are endogenously expressed regulatory noncoding RNAs, have an altered expression in tumor tissues. MiRNAs regulate cancer-related processes such as cell growth and tissue differentiation, and therefore, might function as oncogenes or tumor-suppressor genes. The aim of our study was to assess the expression of mir-20a, let-7a, miR-15a and miR-16 in prostate cancer (PCa) and benign prostatic hyperplasia (BPH) tissue and to investigate the relation between the expression of miRNAs and the clinicopathological features of PCa. PATIENTS AND METHODS: The study group comprised 138 patients: 85 patients with BPH and 53 patients with PCa. The total RNA was isolated from the tissue specimen core and miRNA expressions were quantified using a real-time RT-PCR method (TaqMan MicroRNA Assays). U6snRNA was used for the normalization of the miRNA expression. RESULTS: miR-20a expression was significantly higher in the group of patients with a Gleason score of 7-10 in comparison with the group of patients with a Gleason score of 0-6 (p=0.0082). We found no statistical differences in the miRNA expressions (mir-20a, let-7a, miR-15a and miR-16) in the PCa tissue samples in comparison with the BPH tissue samples. CONCLUSION: Our result shows that the more dedifferentiated PCa cells have a higher expression of miR-20a and this supports the oncogenic role of miR-20a in PCa carcinogenesis. The evaluation of miRNA expression could yield new information about PCa pathogenesis.

Department of Internal Medicine 2 Faculty of Medicine in Pilsen Charles University Prague University Hospital in Pilsen Czech Republic