CXCR4 and Miyoshi myopathy: The CXCL12/CXCR4 axis plays a key role in the homing of normal plasma cell precursors and MM cells to the BM [9, 10], but the expression and specific role of CXCL12γ, a recently characterized CXCL12 isoform, which binds HSPGs with an extremely high affinity, have not been addressed.