Genetics of myelodysplastic syndromes: new insights.

Myelodysplastic syndromes (MDS) are a heterogenous group of hematologic malignancies characterized by clonal expansion of BM myeloid cells with impaired differentiation. The identification of recurrent mutations in MDS samples has led to new insights into the pathophysiology of these disorders. Of particular interest is the recent recognition that genes involved in the regulation of histone function (EZH2, ASXL1, and UTX) and DNA methylation (DNMT3A, IDH1/IDH2, and TET2) are recurrently mutated in MDS, providing an important link between genetic and epigenetic alterations in this disease. The mechanism by which these mutated genes contribute to disease pathogenesis is an active area of research, with a current focus on which downstream target genes may be affected. Recent advances from sequencing studies suggest that multiple mutations are required for MDS initiation and progression to acute myeloid leukemia (AML). The past several years have yielded many new insights, but the complete genetic landscape of MDS is not yet known. Moreover, few (if any) of the findings are sufficiently robust to be incorporated into routine clinical practice at this time. Additional studies will be required to understand the prognostic implications of these mutations for treatment response, progression to AML, and survival.