CD274 and breast cancer: To this aim, MDA-MB-231 breast cancer cells or lung A-549 cancer cells expressing high levels of PD-L1 and 5T4 were co-cultured with hPBMCs (Effector: Target ratio of 5:1) in the absence or presence of increasing concentrations of the tribodies 53D, 53G, 53L1 and 53L10 for 48 h at 37°C.