In addition, myeloma cells also stimulate secretion of receptor activator of nuclear factor-kappa B (NF-κB) ligand (RANKL) and inhibit expression of osteoprotegerin (OPG; the decoy receptor for RANKL) by osteoblasts, resulting in localised promotion of bone resorption by osteoclasts to levels that greatly exceed compensatory bone formation by osteoblasts which in turn are suppressed by humoral factors such as dickkopf 1 (DKK1) (7). The gene discussed is TNFSF11; the disease is plasma cell myeloma.