WDR5 and leukemia: Thus, disruption of WDR5-MLL1 interaction can selectively inhibit MLL1′s catalytic activity in vitro, although as described above, more convincing evidence is needed to clarify whether targeting such PPI as well as MLL1-catalyzed H3K4 methylation affects MLL1-mediated hematopoiesis and MLL1-r leukemia.