{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Programmed death-ligand 1 (PD-L1) also known as CD274 or B7 homolog 1 (B7-H1) is a protein that in humans is encoded by the CD274 gene. PD-L1 is a 40 kDa type 1 transmembrane protein belonging to the B7 family of costimulatory molecules that play a major role in suppressing the immune system during events such as pregnancy, tissue allografts, autoimmune disease and other diseases. The upregulation of PD-L1 and interaction with PD-1 on immune cells may allow cancers to evade the immune system."}]}]}