Substantial progress has been achieved in our understanding of the pathogenesis of MDS through the characterization of somatic gene mutations, such as gene encoding transcription factors (TP53 or ETV6), epigenetic regulators involved in methylation (DNMT3A), the hydroxymethylation of cytosine (TET2, IDH1, IDH2) or the covalent modifications of histones (EZH2, ASXL1)6, 7. The gene discussed is EZH2; the disease is myelodysplastic syndrome.