HT-1080 (EphA2-expressing human fibrosarcoma) xenograft mice were intravenously administered [<sup>89</sup>Zr]Zr-EphA2 mAb (n = 6) for PET scanning, and [<sup>177</sup>Lu]Lu-EphA2 mAb (n = 12) to evaluate the biodistribution and specificity of uptake in HT-1080 xenografts in a blocking study. This evidence concerns the gene EPHA2 and fibrosarcoma.