EGFR and adenocarcinoma: The most common EGFR mutations are present in the tumors of approximately 13–20% of Western and 40–48% of Asian patients with NSCLC of adenocarcinoma histology (corresponding data for non-adenocarcinoma: 3–5% and 8%, respectively) and whilst EGFR mutations may occur in any patient, they show a clear association with Asian ethnicity, female gender, and never-smoker status [6, 8–15].