EGFR and lung adenocarcinoma: Moreover, 18 of 409 EGFR mutation patients (4.40%), all of whom were lung adenocarcinoma patients, harbored two coexisting subtypes of EGFR. There were patients with S768I combined with other EGFR mutations, the most common being G719X (6/9), followed by S768I/L858R (2/9) and S768I/19-Del (1/9).