CXCL-12 induces an active VLA-4 conformation on CLL cells; this results in the involvement of VLA-4 in CXCR4-dependent CLL cell migration and adhesion to the stroma via the JAK2/BTK/RhoA signaling cascade [157] (Table 1). Here, CXCL12 is linked to B-cell chronic lymphocytic leukemia.