FOS and carcinoma: Second, a variety of carcinoma signal and transcription factors such as MYC, ALK, hypoxia-inducing factor 1/2 (HIF-1/2), STAT3, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), activator protein 1 (AP-1), mitogen-activated protein kinases (MAPK), PI3K and epidermal growth factor receptor (EGFR) were involved in the regulation of PD-L1 expression.