EZH2 and Ewing sarcoma: In particular, EZH2 (the catalytic unit of the PRC2/3 complex), which represses gene expression involved in coordinating induction of tissue differentiation and maintains an undifferentiated, multipotent phenotype [135], is highly regulated by EWS/FLI-1 and is required for oncogenic transformation of Ewing's sarcoma cells [136].