Following the observation that female gender was one of the clinical features associated with a benefit from anti-EGFR tyrosine-kinase inhibitors (TKIs) (together with Asian origin, adenocarcinoma histology and smoking habits) [8,9], deeper insights into the EGFR biology allowed to identify somatic mutations in the kinase domain of the EGFR gene [10]. Here, EGFR is linked to adenocarcinoma.