MicroRNAs: shortcuts in dealing with molecular complexity?

Recent studies from Clarke's group published in the journal Cell indicate that miRNAs may be the elusive universal stem cell markers that the field of cancer stem cell biology has been seeking. Distinct profiles of miRNAs appear to reflect the state of cell differentiation not only in breast cancer cells, but also in normal mammary epithelial cells. Moreover, they are conserved across tissues and species. The authors of this work also show evidence that downregulation of miRNA-200c in normal and malignant breast stem cells and in embryonal carcinoma cells has functional relevance, being responsible for the proliferative potential of these cells in vitro and in vivo.