PET of Human Prostate Cancer Xenografts in Mice with Increased Uptake of 64CuCl2

Our objective was to determine whether human prostate cancer xenografts in mice can be localized by PET using 64CuCl2 as a probe (64Cu PET). Methods: Athymic mice bearing human pros-tate cancer xenografts were subjected to 64Cu PET, followed by quantitative analysis of the tracer concentrations and immuno-histochemistry study of human copper transporter 1 expression in the tumor tissues.Results:Human prostate cancer xenografts expressing high levels of human copper transporter 1 were well visualized on the PET images obtained 24 h after injection but not on the images obtained 1 h after injection. PET quantitative analysis demonstrated a high concentration of 64CuCl2 in the tu-mors in comparison to that in the left shoulder regions (percentage injected dose per gram of tissue: 3.66 1.3 and 0.66 0.3, respec-tively; P 5 0.004), at 24 h after injection. Conclusion: The data from this study suggested that locally recurrent prostate cancer might be localized with 64Cu PET using 64CuCl2 as a probe. Key Words: prostate cancer; positron emission tomography; human copper transporter 1; copper (II)-64 chloride