These in vitro results indicate that [89Zr]Zr-DFO-PD-L1 mAb would be appropriate for in vivo tumor imaging with low to moderate PD-L1 expression (>20 000 receptors per cell) as was observed with the HCC-827 and MDA-MB231 cells, whereas tumors with lower PD-L1 expression (<2200 sites per cell) as in the case of MKN-45 tumors would not be clearly discernable. The gene discussed is CD274; the disease is neoplasm.