99m Tc-labeled rHuEpo for imaging of the erythropoietin receptor in tumors.

To analyze erythropoietin receptor (EpoR) status in tumors, recombinant human erythropoietin (rHuEpo) was labeled with 99m Tc by 99m Tc-centered 1-pot synthesis, resulting in high radiochemical purity, stability, and biological activity. Both in vitro cell culture experiments and biodistribution studies of normal rats demonstrated successful EpoR targeting. The biodistribution of labeled rHuEpo in a NCI-H1975 xenograft model showed tumor accumulation (tumor-to-muscle ratio, 4.27 ± 1.77), confirming the expression of active EpoR in tumors. Thus, as a novel single positron emission computerized tomography tracer for the imaging of EpoR expression in vivo, 99m Tc-rHuEpo is effective for exploring the role of EpoR in cancer growth, metastasis and angiogenesis.