ACKR3 and B-cell chronic lymphocytic leukemia: Thus, while there is overlap in signaling pathways activated by CXCL12 in CLL cells and normal B cells, the differences in migration and CXCR7 expression, and the potential bias towards survival in CLL cells, suggest significant differences in the role that the CXCL12/CXCR4 axis plays in the context of the normal and pathological cells.