About 90% of KRAS mutations occur in exon 2 (codon 12 and 13), while exon 3 (codon 61) is less frequently involved [26, 27]; in never-smokers with lung adenocarcinoma, MUTKRAS is more frequently a transition (G to A) compared to transversion in current smokers [25]. Here, KRAS is linked to lung adenocarcinoma.