In addition, in aCre-knock-in mouse cancer model, lung type II cells, partiallydifferentiated Clara cells of the terminal bronchioles, and bronchioalveolar stemcells all were identified as the cells of origin for K-ras-inducedlung hyperplasia [59].Interestingly, only type II cells progressed to adenocarcinoma [59]. Here, KRAS is linked to adenocarcinoma.