Hong Sun and Hui Zhang (both Chemistry and Biochemistry) laboratories recently published a research article titled, “,” in eLife, Feb 12, 2024. This research revealed how the stability of mammalian PRC2/EZH2, the major epigenetic regulator that trimethylates lysine 27 of histone H3, is controlled by a switch to regulate hematopoietic stem cells and downstream hematopoietic populations in bone marrows, liver, and spleen. The overexpression of PRC2/EZH2 is associated with various cancers and other diseases.