CD274 and breast cancer: In addition, not only the expression of PD-L1 on miR-155–overexpressing human primary and murine breast cancer cells was upregulated (Supplemental Figure 14, A–F), but also the expression of PD-L1 on tumor-associated macrophages (TAMs) was significantly upregulated in Bic tumors compared with that in control GFP tumors (Supplemental Figure 14, G–J).