A blocking anti-CD47 antibody inhibits formation of extranodal disease in Raji-engrafted mice. (A) Luciferase-labeled Raji cells were transplanted subcutaneously into the right flank of NSG mice. One week later, mice were administered daily therapy with 200 μg anti-CD47 antibody or mouse IgG control. Tumor volume was measured until end of treatment (posttransplantation day 28). Anti-CD47 antibody treatment reduced tumor volume compared with IgG control. ***P < .0001 (2-way ANOVA). (B) These mice were analyzed in parallel for the presence of luciferase-positive disease to assess tumor dissemination. Spread of disease to secondary sites (red arrows) was detected in IgG control-treated mice 3 weeks after transplantation, whereas no dissemination was observed in anti-CD47 antibody-treated mice. Representative mice are shown (n = 6 per treatment group). (C) Analysis of tumor lesions was performed by MRI at 3 weeks after transplantation, demonstrating tumor nodules (red circles) in controls, but not in mice treated with anti-CD47 antibody. The table reports the number of tumor nodules observed for each mouse, as assessed by a blinded-clinically trained radiation oncologist. (D) Mice were then killed and assessed for gross lesions, which demonstrated diffuse liver involvement in representative mice treated with control IgG, but not with anti-CD47 antibody.