Epidermal Growth Factor Receptor (EGFR) Mutation in Exon 19 (p.E749Q) Confers Resistance to Gefitinib in One Patient With Lung Adenocarcinoma

Clinical Practice Points • p.E749Q is an uncommon EGFR mutation in exon 19 with unknown clinical significance. • A patient with lung adenocarcinoma harboring the p.E749Q EGFR mutation does not respond to gefitinib. • The p.E749Q mutation seems to be correlated with resistance to tyrosine kinase inhibitors. • Conventional chemotherapy should be the treatment of choice in patients with the p.E749Q mutation