KRAS and lung cancer: We used Ad-Cre administered intranasally to induce the activation of the Kras and p53 mutant genes in KrasLSL-G12D/+; p53LSL-R172H/+ mice (129 mice with KRASLSL-G12D/+; p53LSL-R172H/+) to establish a lung cancer model that maximally simulates the process of lung cancer development triggered by Kras and p53 mutations in humans.