The binding of CXCR5 and CXCL13 stimulates the endocytosis of the receptor, the formation of actin polymers, the activation of ERK1/2 (extracellular signal-regulated protein kinases 1 and 2) and the migration and homing of the CLL cells to the LNs, where they are defended against apoptosis [125,133,134]. Here, CXCL13 is linked to B-cell chronic lymphocytic leukemia.