68Ga-pentixafor for PET imaging of chemokine receptor 4 expression in lymphoproliferative diseases and solid tumors.

OBJECTIVE: Gallium-68 (68Ga)-pentixafor, a novel positron emission tomography (PET) tracer with high affinity for C-X-C motif chemokine receptor 4 (CXCR4), has recently been introduced in order to assess the CXCR4 expression status in vivo. This study is to investigate the role of 68Ga-pentixafor in detecting various tumors with mice models and to provide references to clinical studies.

MATERIALS AND METHODS: Gallium-68-pentixafor and fluorine-18-fluorodeoxyglucose (18F-FDG) PET was performed in opm-2 (lymphoma), daudi (myeloma) and panc1 (pancreatic cancer)-bearing mice. Tumor and background tissue uptake between 68Ga-pentixafor and 18F-FDG PET were compared. Gallium-68-pentixafor PET/computed tomography (CT) was performed in four patients with lymphoma and three patients with multiple myeloma, and 18F-FDG PET/CT was performed as a reference.

RESULTS: The uptake of 68Ga-pentixafor in background tissues including muscle, liver and kidneys were all lower than those of 18F-FDG. The uptake of 68Ga-pentixafor in the tumors of lymphoma and myeloma-bearing xenografts was comparable or higher than those of 18F-FDG. However, the tumors of panc-1 xenografts had much lower uptake of 68Ga-pentixafor than those in lymphoma and myeloma-bearing mice, and it was also significantly lower than those of 18F-FDG. The high uptake of 68Ga-pentixafor in vivo was confirmed by the high expression of CXCR4 in tumors with immunochemical analysis. Gallium-68-pentixafor PET/CT in patients with marginal zone lymphoma (MZL) and myeloma showed more intense uptake and more extensive involvement than 18F-FDG PET/CT did. Gallium-68-pentixafor and 18F-FDG PET/CT showed comparable uptake in the patient with follicular lymphoma.

CONCLUSION: Gallium-68-pentixafor is a promising agent for the evaluation of lymphoproliferative diseases.