EZH2 and acute lymphoblastic leukemia: However, in cancers of the immune system like acute lymphoblastic leukemia, myelodysplastic malignancies are characterized by loss of function mutation in EZH2 (Ernst et al. 2010; Chase et al. 2020), and therefore would not be able to facilitate PRC2-dependent transcription repression owing to an inability to catalyze H3K27me3 repressive chromatin marks.