Furthermore, a previous study reported that CXCL12-mediated RAP1 activation was absent in FAK-deficient acute lymphoblastic leukemia cells [47], indicating that FAK is an important regulator of the CXCL12-induced integrin activation pathway, and making it an attractive target for the inhibition of CLL migration. This evidence concerns the gene PTK2 and B-cell chronic lymphocytic leukemia.