MUC16 and neoplasm: To further confirm that the tissue distribution of the bsAb is dependent on tumor-specific target and/or CD3 binding, the biodistribution of 89Zr-labeled MUC16xCD3M was assessed in the presence of a saturating dose of unlabeled parental anti-CD3 and/or parental anti-MUC16 antibodies that block the binding of the radiolabeled bsAb.