CD274 and clear cell adenocarcinoma: Notably, anti-PD-1, also known as anti-programmed cell death protein 1, or anti-PD-L1 (also known as anti-programmed cell death ligand (1), is frequently expressed at high levels in EC; rates of this expression vary from 40 to 80% in endometrioid adenocarcinomas, 10% to 68% in plasma cancers, and 23% to 69% in clear cell carcinomas [5, 6].