[Myeloma bone disease and RANKL signaling].

Multiple myeloma develops and expands almost exclusively in the bone marrow, and generates devastating bone destruction. Myeloma cells produce a variety of cytokines including MIP-1 to stimulate bone resorption by enhancing RANKL expression, and suppress bone formation by inhibiting osteoblast differentiation, leading to bone destruction and rapid loss of bone. The emerging role of the RANKL/RANK signaling axis provide a molecular rationale for consideration of targeting RANKL/RANK in a bone disease in myeloma. Given formation of vicious cycle between bone destruction and tumor progression, inhibiting RANKL signaling may also contribute to the suppression of myeloma expansion.