HGF and non-small cell lung carcinoma: As the phosphoinositide 3-kinase (PI3K)/Akt and mitogen-activated protein kinase (MAPK) signaling pathways are critical to EGFR-TKIs resistance of EGFR mutant NSCLC cells [23] and the NF-kappa B pathway is reported to be activated by HGF in many tissues [32, 33], we investigated whether these three pathways are involved in HGF-mediated PD-L1 expression.