CXCL12 and Miyoshi myopathy: Studies [52,136] have confirmed that the CXCR4/CXCL12 axis plays a particularly critical role in MM cell proliferation, invasion, and chemoresistance; in addition, CXCR4 also plays a pleiotropic role in the expansion and colonization of MM cells in the BM and in the homing, adhesion, invasion, migration, and mobilization of MM cells out of the BM.