MicroRNAs as Diagnostic, Prognostic, and Therapeutic Biomarkers in Prostate Cancer

Prostate cancer is the most prevalent nonskin cancer and a major cause of cancer-related deaths worldwide. Prostate-specific antigen (PSA) testing is routinely used for screening and early detection of prostate cancer; however, it does not reduce death from prostate cancer. Moreover, PSA is not specific for prostate cancer and results in high false-positive rates, and it is poorly correlated with cancer stage. Therefore, the need for another diagnostic and prognostic factor in prostate cancer is apparent. MicroRNAs (miRNAs) are small, single-stranded, noncoding RNAs which are involved in modulation of gene expression posttranscriptionally. Multiple lines of evidence indicate that miRNAs play key roles in various physiological events. Deregulation of miRNAs is related to initiation and development of various diseases such as prostate cancer. It has been shown that various miRNAs (miR-34, miR-21, miR-155, miR-221, miR-222, and let-7) exert their effects by targeting a variety of cellular and molecular pathways (c-Myc, EZH2, c-RSC, BCL2L2, E2F6, ZEB, HMGA251, and CCND2) involved in prostate cancer pathogenesis. Hence, it seems that miRNA expression profiles can be seen as potential candidates for prognosis, diagnosis, and treatment of prostate cancer. Here, we summarize various miRNAs as prognostic, diagnostic, and therapeutic biomarkers for prostate cancer therapy.