Enhanced expression of the homing receptors CCR2, CXCR3 and CCR7, paralleled by impaired expression of the egress receptor S1PR1 (7) also concurs to retain CLL cells in the lymphoid niche in both CLL patients (7–9) and Eμ-TCL1 mice (4), a well-established CLL mouse model (10). Here, S1PR1 is linked to B-cell chronic lymphocytic leukemia.