Many factors that correlate with favorable response occur in patients with particular clinical characteristics, such as a higher frequency of EGFR mutations (which themselves appear to be closely associated with higher likelihood of response to EGFR inhibitors) among Asians vs. non-Asians, women vs. men, never-smokers vs. current or prior smokers, and/or patients with adenocarcinomas vs. squamous histology tumors[4]. Here, EGFR is linked to adenocarcinoma.