CD274 and ovarian carcinoma: The overexpression on PD-L1 on tumor cells would interact with the PD-1 on the T-cell surface, inhibiting the T-cell to destroy the foreign (tumor) cell (J. Naidoo et al., 2014) Overexpression of PD-L1 has been reported in many different tumor types, such as melanoma (40%–100%), NSCLC (35%–95%), glioblastoma (100%), ovarian cancer (33%–80%), and colorectal adenocarcinoma (53%) (Chen et al., 2012).