CD274 and breast cancer: Sabatier et al. analyzed 5454 BCs DNA microarrays and PD-L1 mRNA of 45 BC cell lines, and their finding showed PD-L1 overexpression in 20% of clinical samples and 38% of basal tumors, and they suggested that PD-L1 overexpression was related to decreased T cell cytotoxic immune response51.