Updates and current challenges in microRNA research for personalized medicine in ovarian cancer.

INTRODUCTION: Ovarian cancer (OC) is the second most common and the most lethal of the gynecological malignancies. Currently, there exists no effective screening tool for OC. MicroRNAs (miRNAs) are endogenous 18-23 nucleotide non-coding RNAs that refine gene expression. MiRNAs have been found to be aberrantly expressed in OC tumor tissue as well as detectable in biological fluids such as the blood, urine, and ascites and have been proposed as biomarkers and therapeutic targets for OC. Areas covered: This review summarizes the current knowledge regarding the application of miRNAs as diagnostic, prognostic, and predictive biomarkers in OC. It describes the various tissues allowing for the analysis of miRNAs such as tumor tissue, blood, ascites and urine. It also highlights the potential of miRNAs as a therapy in other cancers and how these therapies may be applied to ovarian cancer. Expert opinion: The study of miRNAs is an innovative and promising field for the diagnosis and treatment of ovarian cancer. Methodological issues surrounding their detection and application therapeutically remain, such as the study of various OC histotypes within the same cohort, the choice of 'normal tissue' for comparison and the difficulties surrounding the choice of a normalization miRNA.