In AML, where the CXCR4/CXCL12 axis is crucially involved in attraction of leukemic blasts into the protective bone marrow (BM) niche, [68Ga]Pentixafor PET was able to identify CXCR4-positive patients in roughly 50% of cases [12]. The gene discussed is CXCL12; the disease is acute myeloid leukemia.