To assess the effect of Trf1 abrogation in the context of lung cancer induced by expression of the K-RasG12V oncogene, we crossed K-Ras+/LSLG12Vgeo mice (designated from now on as K-Ras+/G12V) (Guerra et al, 2003) to a strain carrying a floxable allele of Trf1 (Trf1lox/lox) either wild-type or deficient for p53 (p53−/−) (Martinez et al, 2009) (Fig.1A). The gene discussed is TP53; the disease is lung carcinoma.