miRNA and long non-coding RNA: molecular function and clinical value in breast and ovarian cancers.

INTRODUCTION: The elucidation of tumor molecular hallmarks and the identification of novel molecular markers are of first translational priority in breast and ovarian cancer research, aiming to support personalized disease treatment and monitoring decisions. Recent high-throughput studies have revealed that ~ 80% of the genome is transcribed into RNAs without protein-coding potential, namely non-coding RNAs (ncRNAs), challenging the concept of 'junk DNA'. Undoubtedly, microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) represent the best-studied family classes, emerging as the most powerful gene-expression regulators at epigenetic, transcriptional and post-transcriptional levels. Areas covered: Cancer research has highlighted the active implication of ncRNAs, most notably of miRNAs and lncRNAs, in almost every aspect of the cancer cells' biology as well as their deregulated expression in both breast and ovarian tumors. In the present manuscript we discuss the existing knowledge regarding the involvement of miRNAs and lncRNAs in the molecular background of breast and ovarian malignancies, to highlight their clinical utility in improving disease management. Expert commentary: miRNAs and lncRNAs represent central mediators of cancer cells' phenotype, and promising molecular markers and therapeutic targets to support precision medicine in breast and ovarian cancers.