CD274 and cancer: Tumor location and margins in mouse tumor resection can be clearly seen with real-time NIRF imaging.489 Aiming at the T cell immune resistance induced by the interaction between programmed PD-L1 and PD-1 on T cells in gastric cancer, Luo et al. combined folic acid (FA) and disulfide (SS)-polyethylene glycol (PEG)-conjugated polyethyleneimine (PEI) with a superparamagnetic iron oxide nanoparticles (SPIONs) composite as a PD-L1 siRNA delivery system, which could effectively target PD-L1 in gastric cancer and be used as a T2-weighted contrast agent for cancer MRI.490