Induction of oncogene expression or loss of tumor suppressor genes in specific cellular compartments using adenoviral delivery or genetically modified mouse models showed that neuroendocrine cells were the most likely cell of origin of small cell lung cancer [48] while both CC10-positive club cells and alveolar type II cells are involved in the initiation of tumor growth in K-RasLSL-G12D/+- or K-RasLSL-G12D/+;p53+/--induced adenocarcinoma [40, 49]. Here, TP53 is linked to adenocarcinoma.