EGFR and adenocarcinoma: Several studies have shown that sensitizing EGFR mutations are almost exclusively observed in NSCLC patients with adenocarcinoma, rather than in those with other histologies; this observation is even more striking in East Asian populations, where EGFR mutations are present in up to 78% of adenocarcinomas, as opposed to only 10–16% of adenocarcinomas in other ethnicities [19,20,21].