PD-L1 expression correlates with macrophage and STAT3 gene expression. (A) CD274 (PD-L1) mRNA expression inversely correlates with a B-cell gene signature among DLBCL patients treated in MAIN. (B) CD274 mRNA is highly expressed by purified DCs and macrophages compared with resting B cells. PD-L1 protein expression correlates with a macrophage gene signature among DLBCL patients treated in MAIN (C) and GOYA (D). CD274 mRNA correlates with a macrophage gene signature among DLBCL patients treated in MAIN (E) and GOYA (F). CD274 mRNA correlates with STAT3 gene expression (G) and a STAT3 gene signature (H) among DLBCL patients treated in GOYA.