PD-1/PD-L1 Pathway in Non-small Cell Lung Cancer: What Achieves So Far?

Programmed cell death factor 1(PD-1) which is expressed in cell membrane and cytoplasm is coded by PDCD-1 gene. It is a kind of T cell inhibitory receptors. PD-1 and its ligands PD-L1(B7-H1/ CD274), PD-L2(B7-DC/CD273) play an important role in regulating immune responses and maintaining of peripheral immune tolerance. PD-1/PD-L1 pathway promotes the development of tumor by inhibiting T lymphocyte proliferation, survival, and function, inducing the antigen specific T cell apoptosis, and promoting CD4+ T cells differentiation to Foxp3⁺ regulatory T cells. The research of the monoclonal antibodies against PD-1(BMS-936558 etc.) and the monoclonal antibodies of PD-L1 (BMS-936559 etc.) have brought a promising future for the treatment of non-small cell lung cancer(NSCLC).