EZH2 and neoplasm: EZH2 overexpression in patients is associated with a higher risk of relapse.78 PRC2 plays a major role in self-renewal of hematopoietic stem cells;83–86 its dysregulation is often found in multiple blood cancers87–92 in which EZH2 can behave both as a tumor suppressor85,93,94 or an oncogene95–98 depending on the cell context (reviewed in80) (Fig. 3a).