It has thus been shown that NNK stimulates the proliferation of human lung adenocarcinoma cells and their normal cells of origin, small airway epithelial cells, via a cAMP-dependent signaling cascade that includes activation of the transcription factor CREB as well as the PKA-dependent transactivation of the EGFR pathway and the β-AR-mediated release of AA [9,18,20]. This evidence concerns the gene CREB1 and lung adenocarcinoma.