CXCR4 and Miyoshi myopathy: 68Ga-Pentixafor, that targets CXCR4 is a promising PET ligand (51) especially as potential target for myeloma specific treatment (for CXCR4-positive tumors) in a theranostic approach with preliminary encouraging results with good tolerance of the treatment, high initial response rates in advanced-stage MM cases (52).