CXCR4 is often expressed in high concentration by the monoclonal plasma cells, and a recent study performed in 14 relapsing MM suggested potential of 68Ga-Pentixafor, a specific ligand showing a high affinity for CXCR4, offering an excellent contrast in CXCR4-positive patients [16]. This evidence concerns the gene CXCR4 and Miyoshi myopathy.