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.