However, inside the myeloma cell niche, two soluble mediators, i.e., a proliferation-induced ligand (APRIL) and B-cell activation factor (BAFF) interact with B-cell maturation antigen (BCMA) on the surface of MM cells, play an important role in survival and proliferation of tumor plasma cells. This evidence concerns the gene TNFRSF17 and Miyoshi myopathy.