DNA damage response and PD-1/PD-L1 pathway in ovarian cancer.

Ovarian cancer has a poor prognosis due to drug resistance, relapse and metastasis. In recent years, immunotherapy has been applied in numerous cancers clinically. However, the effect of immunotherapy monotherapy in ovarian cancer is limited. DNA damage response (DDR) is an essential factor affecting the efficacy of tumor immunotherapy. Defective DNA repair may lead to carcinogenesis and tumor genomic instability, but on the other hand, it may also portend particular vulnerability of tumors and can be used as biomarkers for immunotherapy patient selection. Programmed cell death 1 (PD-1)/programmed death-ligand 1 (PD-L1) pathway mediates tumor immune escape, which may be a promising target for immunotherapy. Therefore, further understanding of the mechanism of PD-L1 expression after DDR may help guide the development of immunotherapy in ovarian cancer. In this review, we present the DNA damage repair pathway and summarize how DNA damage repair affects the PD-1/PD-L1 pathway in cancer cells. And then we look for biomarkers that affect efficacy or prognosis. Finally, we review the progress of PD-1/PD-L1-based immunotherapy in combination with other therapies that may affect the DDR pathway in ovarian cancer.