Of note, the PE089 used in our study harbors the epidermal growth factor receptor (EGFR) exon 19 deletion that elicits resistance to the EGFR tyrosine kinase inhibitor (EGFR TKI) [45], implying its potential to serve as a dual chemoresistance study model of NSCLC. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.