After 4 wk of treatment with the blocking RANKL antibody, we detected a significantly lower leukemia cell burden in the spleens and the bone marrow than that in the vehicle control (Fig. 6 C), which demonstrates that the RANKL–RANK axis contributes to the leukemia-supportive CLL microenvironmental crosstalk in vivo. The gene discussed is TNFSF11; the disease is leukemia.