Role of PD-1/PD-L1 in microenvironment of breast cancer

Abstract

Programmed cell death protein 1 (PD-1), as a checkpoint of the immune signaling pathway, is a hotspot in the field of immuno-oncology. Its binding with ligand (PD-L1) is an important negative regulatory mechanism. Application of PD-1/PD-L1 inhibitors in treatments of breast cancer is still being explored at present. Fully understanding the mechanism of PD-1/PD-L1 in the microenvironment of breast cancer will help their inhibitors play a full role. This review will start with the discovery of PD-1 and PD-L1, describe their main signaling pathways, introduce the common types and applications of PD-1/PD-L1 inhibitors, especially in breast cancer, summarize the basic research of PD-1 and PD-L1 in breast cancer microenvironment in recent years, and seek new strategies of PD-1/PD-L1 inhibitors in breast cancer treatment.