However, inhibition of PIM slightly inhibited activation of RSK CTKD, as well as NTKD, in primary FLT3-ITD-positive AML cells, but not in MV4-11, while the BRD4 inhibitor JQ1 downregulated expression of RSK1, but not RSK2 in MV4-11 cells (Figure 3G,H,I). Here, BRD4 is linked to acute myeloid leukemia.