Expression of CCR7 was significantly higher in CLL cells with high ZAP-70ZAP-70 expression within the same patient.CLL cells migrating toward CCL21 had a significantly higher percentage of ZAP-70ZAP-70–positive cells.ZAP-70ZAP-70 signaling induces the expression of CCR7 in B cells through ERK1/2 phosphorylation. The gene discussed is MAPK3; the disease is B-cell chronic lymphocytic leukemia.