BCR and B-cell chronic lymphocytic leukemia: All CLL samples, irrespective to their BCR-dependent CXCR4 down-regulation, remained responsive to PMA stimulation exhibiting increase of phospho-Ser744/748 and -Ser916 PKD levels, and strongly decreased their membrane CXCR4 (Figure 5C and Supplementary Figure S8), confirming their functional capacity.