PDCD1 and endometrial cancer: In the United States, pembrolizumab, an antibody against programmed cell death protein 1 (PD-1), is approved for advanced endometrial cancers with high levels of microsatellite instability (MSI-high) and for recurrent or progressive metastatic cervical cancer positive for programmed death-ligand 1 (PD-L1), suggesting that these parameters could serve as predictive biomarkers.