EZH2 and leukemia: To further explain the contradictory and opposite effects of Ezh2 loss during AML induction and maintenance, we compared genes de-repressed in established MLL-AF9 leukemias following pharmacological inhibition of Ezh2 (62 genes) to genes derepressed during the induction of Ezh2−/− MLL-AF9 leukemias (Fig. 5 d).