MicroRNAs in Ovarian Cancer

Ovarian cancer, consisting predominantly of ovarian carcinoma, is the eighth most common cancer in women and the most lethal gynecologic malignancy. Efforts focus on identifying biomarkers which may aid in early diagnosis and reduce mortality, as well as on characterizing therapeutic targets with the aim of circumventing chemoresistance and prolonging survival at advanced-stage disease. MicroRNAs (miRNAs) are small, non-coding RNAs that post-transcriptionally regulate gene expression, and have been found to play an important role in ovarian carcinoma. Recent research has identified multiple miRNAs involved in the biology and progression of the disease, and supports a role for miRNAs as potential biomarkers, predictive markers and prognostic factors. Many of the studies published to date nevertheless suffer from critical weaknesses which affect data quality and reproducibility, including the comparison of normal ovaries to tumor tissue without compensation for the highly discrepant target cell fraction in these two specimen types and the inclusion of carcinomas of different histotypes, non-epithelial tumors or tumors of non-specified histology. These shortcomings highlight the critical role of pathologists as part of the team in the setting of such research. This review summarizes current knowledge in this area and discusses the potential clinical relevance of miRNAs in ovarian carcinoma, with focus on studies of clinical specimens in which tissue selection has been deemed adequate.