Similar reductions in CXCR4 surface expression in CLL cells were previously noted with a different PIM inhibitor, K00135.9 In addition, PIM inhibitor in this study also blocked re‐externalization of the CXCR4 receptor, internalized after CXCL12 ligation. This evidence concerns the gene CXCL12 and B-cell chronic lymphocytic leukemia.