In conclusion, our novel mouse model, combining constitutive RANK signaling with TCL1 expression in B-cells, not only promotes CLL formation but also mirrors aggressive forms of human myeloma and thereby for the first time highlights a possible role of this signaling pathway in a cell-intrinsic manner in MM development or propagation. The gene discussed is TNFRSF11A; the disease is B-cell chronic lymphocytic leukemia.