PEt of human prostate cancer xenografts in mice with increased uptake of⁶⁴CuCl₂

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 prostate cancer xenografts were subjected to ⁶⁴Cu PET, followed by quantitative analysis of the tracer concentrations and immunohistochemistry 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 tumors in comparison to that in the left shoulder regions (percentage injected dose per gramof tissue: 3.6 ± 1.3 and 0.6 ± 0.3, respectively; P = 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.