The clinicopathological relevance of microRNA in normal and malignant haematopoiesis.

MicroRNAs (miRNAs) are recently discovered short non-coding RNA molecules that negatively regulate messenger RNA (mRNA) translation to protein. Their discovery heralds a novel mechanism of post-transcriptional gene regulation and has lead to a cascade of studies aimed at identifying how miRNA dysregulation may contribute to disease. Recent studies have provided indisputable evidence for a role of miRNAs in normal haematopoiesis adding a further layer of complexity to the regulatory process. Leukaemia and lymphoma are characterised by dysregulation of survival and differentiation in haematopoietic progenitor cells. There are several lines of evidence supporting the notion that miRNA dysfunction is contributory, whether by extrapolation from miRNA-mediated oncogenesis in other disorders, by miRNA profiling, or by in vivo and in vitro functional studies of miRNAs in haematological malignancies. Further work is underway to delineate the role of miRNAs in the pathogenesis of malignant blood disorders, with the eventual hope that this will aid in the diagnosis and the development of potential novel cures for such diseases, many of which still have an unacceptable prognosis.