Collaboration between PcG proteins and MLL fusions in Leukemogenesis: an emerging paradigm.

PcG and TrxG proteins mostly with opposite transcriptional activities play key roles in normal and malignant development. In this issue of Cancer Cell , Tan et al. report an unexpected collaboration between CBX8 and MLL-AF9 in leukemia, revealing a far more complicated functional crosstalk between these master epigenetic regulators in oncogenesis.