CD274 and ovarian serous adenocarcinoma: Supporting our observations are analyses of post-treatment metastatic biopsies from high-grade serous ovarian cancer patients treated with platinum-based chemotherapy, in which an enhanced host immune response was detected following NACT, but evidence was also found that the effect was tempered by the co-occurrence of increased levels of immune checkpoint molecules (PD-1, CTLA4 and PD-L1) [28].