PDCD1 and female reproductive organ cancer: Among gynecological cancers, EC displays the highest overexpression of programmed cell death 1 (PD-1, CD279) and programmed cell death ligand-1 (PD-L1, CD274): 40–80% for endometrioid cancers, 10–68% for serous tumors, 23–69% for clear cells tumors, respectively [17,18].