Wide versus cell type restricted deletion of four tumor suppressor genes determines the type of high grade neuroendocrine lung cancer

Here we describe novel murine models of High Grade Neuroendocrine Lung Carcinomas driven by the loss of four tumor suppressors: deletion of Rb, PTEN, and p53, in a Rbl1 null background, in a wide variety of lung epithelial cells produces Large Cell Neuroendocrine Carcinoma whereas inactivation of these genes exclusively in basal cells leads to the development of Small Cell Lung Carcinoma, showing that Keratin K5 expressing cells contribute to the development/act as cell of origin of Small Cell Lung Carcinoma differentially influencing the lung cancer type developed. Conditional ablation of Rb1, Trp53 and Pten in pulmonary cells was achieved by intratracheal administration of purified Ad5-CMVcre or Ad5-K5cre (Du Page et al, 2009) to Rb1F/F;Trp53F/F;PtenF/F;Rbl1−/− 8–10 week old mice. Mice were sacrificed 3 to 5 months after the Ad5-cre infection and tumors processed for whole transcriptome analysis. As control animals, RbF/F;p53F/F;PtenF/F;Rbl1−/− littermates were used. Gene expression was studied in control mouse lung (Rbl1-/-) and in lung tumours from Rb1F/F;Trp53F/F;PtenF/F;Rbl1−/− mice treated by intratracheal administration of Ad5-CMVcre or Ad5-K5cre to ablate Rb1, Trp53 and Pten in pulmonary cells.