EGFR inhibition with the TKI gefitinib led to decreased PD-L1 expression in NSCLC tumor cell line models and EGFR-induced PD-L1 expression was shown to be dependent upon ERK1/2 signaling down-stream of EGFR as treatment with the ERK1/2 inhibitor SCH772984 also led to diminished PD-L1 expression (81). This evidence concerns the gene MAPK3 and non-small cell lung carcinoma.