A generation of mice with Cre-recombinase-activated conditional oncogenic K-ras allele (K-ras G12D/+), along with either mild Ezh2 overexpression (Ezh2LSL) or lost PRC2 function achieved by conditional deletion of Eed1 (Eedfl/fl), joined with conditional deletion of p53 (Trp53fl/fl), revealed that the genotype K-rasG12D/+; Trp53fl/fl; and Eedfl/fl develops the most aggressive, mucinous NSCLC. Here, KRAS is linked to non-small cell lung carcinoma.