A large body of evidence indicates that the physical interaction of myeloma cells and MMSCs (cell adherence) induces the non-malignant bystander cells to secrete cyto- and chemokines, such as IL-6, CD40, TRANCE and Ras, which collectively promote myeloma proliferation and survival [43, 44]. This evidence concerns the gene TNFSF11 and plasma cell myeloma.