KRAS and lung adenocarcinoma: In the subgroup of 1153 patients with lung adenocarcinoma, the frequencies of EGFR mutations (341/570 [59.8%] vs. 153/434 [35.3%], P < 0.001) and ALK rearrangements (46/566 [8.1%] vs. 18/436 [4.1%], P = 0.010) were significantly higher in never-smokers than in ever-smokers, whereas the frequency of KRAS mutations was significantly lower in never-smokers than in ever-smokers (29/466 [6.2%] vs. 50/377 [13.3%], P < 0.001) (Fig. 1).