PD-L1 in Breast Cancers and its Prognostic Significance

Abstract

Breast cancer is the most common malignancy in females globally. Various factors are responsible for its development which include both genetic and hormonal causes. An important discovery is the role of the PD-1/PD-L1 axis in the development of cancers. The PD-1-/PD-L1 pathway plays a part in allowing tumour cells escape from the host’s immune response and hence permits the proliferation of tumour cells. PD-L1 expression has been observed in various breast cancers at distinct levels such as in tissues and in blood. Different methods have been utilized for its detection including immunohistochemistry, RNA sequencing and ELISA, amongst others. The results have been conflicting regarding the expression of PD-L1 and the prognosis of breast cancer based on parameters such as overall survival and disease free survival. Different immunotherapies have also emerged as a new modality to treat breast cancer. This review intends to explore the prognostic significance of PD-L1 expression in breast cancers