PDX1 and adenocarcinoma: In the PDAC model, Cre recombinase is placed under the control of the Pdx1 promoter, which is activated in progenitor cells of mouse pancreas [23], while in the NSCLC model, adenocarcinomas are generated focally in the lung epithelium by delivering CRE recombinase through intranasal instillation of adenoviruses (Ad-Cre) [24].