CXCR4 and plasma cell myeloma: Besides the diagnostic use of [68Ga]pentixafor PET, CXCR4-directed radioligand therapy with 90Y- or 177Lu-labeled Pentixather, the therapeutic partner of [68Ga]pentixafor, has been successfully introduced as the compassionate use of treatment for relapsed, advanced stage multiple myeloma, diffuse large B cell lymphoma (DLBCL), and acute myeloid leukemia, in addition to high-dose chemotherapy regimens and followed by subsequent hematopoietic stem cell transplantation [13–16].