MLLT3 and acute myeloid leukemia: A growing body of evidence supports an essential role for the PRC2 complex in MLL-r leukemogenesis-- PRC2 is necessary for MLL-AF9-induced leukemogenesis in mouse progenitor cells and cooperates with MLL-AF9 to promote self-renewal of acute myeloid leukemia cells (Shi et al., 2013; Neff et al., 2012).