CD274 and neoplasm: However, TAM PD-L1 expression may result from a reactive response to various inflammatory stimuli in an immunologically “hot” tumor (65), such as GM-CSF (71), S100A8/TLR4/MyD88 (69, 72), IL10 and IL-27 (73), IL32/PFKFB3 (74), TGF-β/PKM2 (75), and classical M1 TNF-α/NFkB and MAPK (73, 76–78) through the activation of STAT1 and, in particular, STAT3 (79, 80).