CD274 and breast cancer: In a meta-analysis by Wang et al., PD-L1 overexpression was associated with poorer overall survivals in breast cancer, gastric cancer, urothelial cancer and renal cell carcinoma, while in melanoma, hepatocellular carcinoma, and renal cell carcinoma, PD-L1 overexpression was significantly associated with poorer progression-free survivals [30].