MM cells directly secrete cytokines capable of generating osteoclasts, including IL-1, IL-3, IL-6, TNF-α, MIP-1α, MIP-1β, and decoy receptor 3.339–344 It has been previously mentioned that RANKL and OPG play a core role in osteoclast differentiation. This evidence concerns the gene TNFSF11 and Miyoshi myopathy.