CXCR4 and B-cell chronic lymphocytic leukemia: In keeping with this observation, the expression of the CXCL12 receptor CXCR4 is higher in CLL B-cells than in normal B-lymphocytes [17], indicating the relevant regulatory role of CXCR4-mediated signaling in B-CLL progression and suggesting that the pharmacological targeting of CXCR4-triggered signal transduction can be a valuable approach to B-CLL therapy.