microRNA and the pathogenesis of ovarian cancer--a new horizon for molecular diagnostics and treatment?

Ovarian cancer is the leading cause of death among gynecologic malignancies and despite advances in treatment, more than 50% of all patients will experience recurrence, resulting in worse overall prognosis. Therefore, identification of novel biomarkers for ovarian cancer is of significant interest. microRNA (miRNA) constitute a class of small gene regulatory RNA molecules (18-24 nt) and by sequence complementarity, they negatively regulate messenger RNA (mRNA) translation of target genes. Rising data are available that miRNA are functionally involved in the pathogenesis of ovarian cancer. In this regard, recent advances in profiling studies revealed a variety of miRNA candidates, differently expressed in ovarian carcinomas and in disease-specific conditions like hypoxia or chemo-resistance. This review abstracts recent efforts on establishing miRNA as novel molecular biomarkers for ovarian cancer and depicts the existing preliminary framework for defining peripheral-blood derived miRNA as novel circulating biomarkers. Beside these clinical implications, we highlight the current functional understanding of miRNA alteration and discuss major challenges in miRNA profiling approaches. Finally, we briefly outline methodologies to therapeutically modulate miRNA expression in cancer and try to assess how miRNA can improve our conceptual understanding and the clinical management of ovarian cancer.