68Ga-Pentixafor PET/CT for Detection of Chemokine Receptor CXCR4 Expression in Myeloproliferative Neoplasms.

C-X-C motif chemokine receptor 4 (CXCR4) is an attractive target for cancer diagnosis and treatment, as it is overexpressed in many solid and hematologic malignancies. This study investigated the feasibility of CXCR4-directed imaging with PET/CT using 68Ga-pentixafor to visualize and quantify disease involvement in myeloproliferative neoplasms (MPNs). Methods: Twelve patients with MPNs (4 with primary myelofibrosis, 6 with essential thrombocythemia, and 2 with polycythemia vera) and 5 controls underwent 68Ga-pentixafor PET/CT. Imaging findings were compared with immunohistochemical stainings, laboratory data, and splenic volume. Results:68Ga-pentixafor PET/CT was visually positive in 12 of 12 patients, and CXCR4 target specificity could be confirmed by immunohistochemical staining. A significantly higher tracer uptake could be detected in the bone marrow of MPN patients (SUVmean, 6.45 ± 2.34 vs. 4.44 ± 1.24). Dynamic changes in CXCR4 expression determined by 68Ga-pentixafor PET/CT corresponded with treatment response. Conclusion:68Ga-pentixafor PET/CT represents a novel diagnostic tool to noninvasively detect and quantify the extent of disease involvement in MPNs.