We examined the impacts of loss-of-function EZH2 mutations on the pathogenesis of myeloid malignancies using Ezh2 conditional knockout mice [87] and demonstrated that an Ezh2 deficiency in combination with a Tet2 hypomorph in mice accelerates the transformation of HSCs and induces MDS and MDS/MPN [88]. The gene discussed is TET2; the disease is myeloproliferative disorder.