CXCL12 and B-cell chronic lymphocytic leukemia: Indeed multiple CK1 inhibitors—D4476, PF-4800567 and PF-670462—were able to block efficiently CXCL12 and CCL19-induced chemotaxis of CLL cells [28,30] and D4476 effectively blocked infiltration of lymphoid organs by CLL cells in the patient-derived xenograft model based on NOD/SCID IL2rγnull mice [28].