CCL2 and Miyoshi myopathy: Concerning MM-derived exosomes, they were found to be enriched in miR-146a and miR-21, which once transferred to MSCs induced the secretion of cytokines and chemokines (including CXCL1, IL6, IL8, IP-10, MCP-1, and CCL5), and increased MSC proliferation and transformation to cancer-associated fibroblasts, finally resulting in increased MM cell viability and migration [55,56] (see Figure 2).