Significant differences in the pharmacokinetics of the two radioimmunoconjugates were observed in tumor-bearing immunocompromised NSG mice, but these differences failed to materialize in immunocompetent C57BL/6 and FcγR-humanized C57BL/6 mice with B16F10-FUT3 xenografts. This evidence concerns the gene FCGR2A and neoplasm.