Mini-review: Immunology in ovarian cancer

Immunotherapy for ovarian cancer has been studied for many years and programmed cell death protein 1 ligand/programmed cell death protein 1 (PD-L1/PD-1) blockade has been attempted in several clinical trials; however, the expected therapeutic effect has not been achieved. In contrast, the PD-L1/PD-1 blockade has been clinically applied to endometrial and cervical cancers, and a certain therapeutic effect has been observed. In endometrial cancer, promising outcomes have been achieved with a combination of an anti-PD-1 antibody and lenvatinib, regardless of the number of regimens, even in cases of recurrence after platinum administration. Therefore, immunotherapy is expected to have a therapeutic effect on ovarian cancer regardless of platinum resistance. In this review, considering immunotherapy for ovarian cancer, we discuss the immune mechanisms that exist in ovarian cancer and the immunotherapeutic strategies that should be developed.