Chromobox homolog 8 (CBX8), a Polycomb Group protein that interacts with MLL-AF9 and TIP60, plays an essential role in MLL-AF9 transcriptional regulation and leukemogenesis. CBX8, which is part of one of the PRC1 complexes, regulates proliferation of diploid human and mouse fibroblasts through direct binding to the INK4A-ARF locus.
