LCINS patients with adenocarcinoma frequently carry mutations within the tyrosine kinase domain of the EGFR gene, whereas smokers tend to have KRAS mutations and are associated with resistance to EGFR-TKI, thus emphasising the need for classification of mutational status, prior to targeted therapy studies and clinical trials, to provide guidance for the preferred treatment route. This evidence concerns the gene KRAS and adenocarcinoma.