In T cell acute lymphoblastic leukemia (leukemia), loss of PRC2 core subunits was reported to occur by mutation or deletion in about 25% of all cases, and in a NOTCH1-induced genetic mouse model of leukemia, NOTCH1 antagonizes PRC2 function, leading to a loss of H3K27me3 (Ntziachristos et al., 2012). Here, NOTCH1 is linked to leukemia.