EGFR and non-small cell lung carcinoma: In the present study, the involvement of autophagy in the acquired gefitinib resistance in EGFR mutation NSCLC cells was investigated using PC-9/wt cells carrying EGFR exon 19 deletion and the acquired gefitinib-resistant PC-9/gef cells (PC-9/gefB4 and PC-9/gefE3).