CD274 and cancer: A glycosylated form of PD-L1 of approximately 45 kDa, with high activity, has been observed in cancer cells.132 Further, inhibitors of N-glycosylation, such as tunicamycin, swainsonine, castanospermine, and 1-deoxymannojirimycin, can reduce the affinity of PD-L1 binding to PD-1,137 indicating that N-glycosylation of PD-L1 is necessary for PD-L1 binding to PD-1.