CD274 and neoplasm: Native anti-PD-L1 IgG antibody (89Zr-DFO-C4) was compared with a neonatal Fc receptor (FcRn) low-affinity mutant (89Zr-DFO-C4Fc-MUT) in a murine syngeneic glioblastoma model.15 Transcranial focused ultrasound was applied before antibody injection to disrupt the blood–brain and blood–tumor barrier and facilitate antibody entry into the brain.