Overexpression of miR-20a-5p in Tumor Epithelium Is an Independent Negative Prognostic Indicator in Prostate Cancer — A Multi-Institutional Study

Abstract

<p><i>Background:</i> MicroRNAs (miRs) have critical regulatory roles in cell functions, and are involved in prostate cancer tumorigenesis. miR-20a-5p is a member of the oncogenic miR-17-92 cluster. Overexpressed miR-20a-5p has been shown to increase both cell proliferation and cell migration in cancers. The aim of our cohort study was to evaluate the prognostic role of miR-20a-5p in prostate cancer. <p><i>Methods:</i> Tissue microarrays from 535 patients’ prostatectomy specimens were constructed. In situ hybridization was performed to assess the expression level of miR-20a-5p in different tissue subregions: tumor stroma and tumor epithelium. Lastly, in vitro analysis was performed on prostate cancer cell lines. . <p><i>Results:</i> We found miR-20a-5p associated with biochemical failure in tumor epithelium (p = 0.001) and tumor stroma (p = 0.003). In the multivariable analysis miR-20a-5p in tumor epithelium was found to be an independent prognostic predictor for biochemical failure (HR = 1.56, 95% CI: 1.10–2.21, p = 0.014). In the functional studies, migration and invasion were significantly increased in miR-20a-5p transfected prostate cancer cell lines. <p><i>Conclusion:</i> High miR20a-5p expression in tumor epithelium is a negative independent prognostic factor for biochemical failure in prostate cancer.