To determine whether GCs reduced the sensitivity of NSCLC cells to EGFR-TKIs, we treated PC9 cells (EGFRexon19del E746-A750) and NCI-H1975 cells (EGFRL858R/T790M) with gefitinib and afatinib, respectively, either alone or in combination with a GC. Here, EGFR is linked to non-small cell lung carcinoma.