MDM2 and leukemia: MDM2 protein levels were down-regulated by the KDM4A knockdown, and the p53-related genes, such as p21CIP1, were up-regulated by KDM4A silencing in both THP-1 and MLL-AF9 GFP+ cells (Figure 4J, Figure S4E), suggesting that KDM4A regulated MDM2-p53 signaling in leukemia cells.