A previous study revealed that combined activity of Kdm4a, Kdm4b, and Kdm4c is required for AML with a rearrangement of the mixed‐lineage leukemia gene (MLL‐AF9‐translocated AML) in vitro and in vivo, using Kdm4a−c triple knockout mice.51 This evidence concerns the gene KDM4B and leukemia.