In the two cohorts where Lkb1 was deleted after induction of KRAS, we observed acquisition of squamous characteristics to the same degree as observed with the concomitant model, with approximately 40% of mice harbouring at least one tumour with purely squamous characteristics at the end of the study (P=0.96 concomitant versus 10 week; Fig. 1c). This evidence concerns the gene KRAS and neoplasm.