The microRNA signatures: aberrantly expressed miRNAs in prostate cancer.

MicroRNAs (miRNAs) are short, non-coding, conserved, oligonucleotides that are regulatory in nature and are often dysregulated in many cancers including prostate cancer. Depending on the level of complementarity between the miRNA and mRNA target, they can either inhibit translation or degrade the target mRNA. MiRNAs expression is specific to the type of cancer, its stage and level of metastasis, making miRNAs potential stage-specific biomarkers of cancer. Recent research has shown that these miRNAs have the potential to be a diagnostic and prognostic non-invasive biomarker for various cancers including prostate cancer. Various miRNAs have been reported as novel biomarkers for prostate cancer therapy. However, there is inconsistency in the data reported and no overlapping expression pattern could be found. In this review, we have highlighted the most consistently reported dysregulated miRNAs in prostate cancer from the existing literature and discussed the currently available data on their role in regulating the hallmarks of prostate cancer. These four most consistently reported dysregulated miRNAs viz. miRNA-141, miRNA-375, miRNA-221 and miRNA-21 need to be further validated in terms of their regulatory potential in regulating various pathways important for prostate cancer management.