It is already known that the BCR signaling modulates the activity of the CXCL12/CXCR4 axis, in fact the blockade of the BCR signaling with a BTK inhibitor decreases the migration of CXCR4-expressing CLL cells toward CXCL12 produced by SCs [30]. This evidence concerns the gene CXCR4 and B-cell chronic lymphocytic leukemia.