It should also be noted that huATN-658 only binds to uPAR on the xenografted tumor and not on the murine host cells.24 Therefore, xenograft models have the limitations of not demonstrating the full complement of effects of huATN-658 that might be observed upon its binding to host uPAR on immune and tumor microenvironment cells. The gene discussed is PLAUR; the disease is neoplasm.