Despite the limitations of knock-in/out mouse models in the absolute quantification of antibody-based immunotracers, we could quantitatively measure increased and comparable PET uptake patterns of the lymphatic organs and the TME in a syngeneic orthotopic tumor mouse model for 89Zr-hCD4-Mb and 89Zr-mCD4-Mb. The gene discussed is PIGN; the disease is neoplasm.