All mice in the baseline 89Zr-DFO-CD4 responding group presented with a maximum tumor-to-heart ratio >9 (average 9.79 ± 0.37), whereas the non-responding group presented with a maximum 89Zr-DFO-CD4 tumor-to-heart ratio of 7.73 ± 0.35. The gene discussed is CD4; the disease is neoplasm.