We observed that Raji cells and primary CLL cells expressing ZAP-70 protein showed an enhanced migration toward CXCL12, despite having comparable levels of CXCR4 expression, indicating that differences must be because of ZAP-70 influence in downstream signaling after CXCR4 stimulation. The gene discussed is CXCR4; the disease is B-cell chronic lymphocytic leukemia.