Furthermore, some studies have revealed that MM cells secrete cytokines such as CCL5, MIP-1α [170] and large amounts of IL-6 when MDSCs are present [167,170,173], suggesting that not only do MDSCs contribute to MM progression by direct cell–cell contact or exosome intercellular communication, but also through cytokine secretion. This evidence concerns the gene CCL5 and Miyoshi myopathy.