New clues to the molecular pathogenesis of myelodysplastic syndromes.

During the past few years our understanding of the genetic basis for the myelodysplastic syndromes (MDS) has improved significantly. A few subgroups have been studied in detail and the genetic alterations are now to a great extent revealed. In 5q- syndrome haploinsufficiency of the ribosomal gene RPS14 appears to cooperate with loss of two micro-RNAs miR-145 and miR-146 to induce key features of the disease. Some mutations are specific for certain categories of MDS while others, such as TET2 seem to occur across the various categories. JAK2 mutations are mainly found in patients with myeloproliferative characteristics. The prognostic implications of most of the novel mutations are not yet fully understood, moreover, functional studies are required in order to understand the interplay between the different lesions; how they give rise to the disease and how some may lead to disease evolution including leukemic transformation. An improved understanding of the pathophysiology of MDS may lead to the identification of suitable targets for future drug development.