Retinoid receptor cross-talk in respiratory epithelium cancer chemoprevention

The rationale for using retinoids in the prevention of respiratory epithelium cancers is based on their ability to coordinately regulate differentiation, proliferation and apoptosis. The complex retinoid signaling pathways and their cross-reactions are modulated by multiple mechanisms that are gradually being elucidated. It is possible that significant molecular changes take place during the very early stages of respiratory epithelial carcinogenesis, which enable cancer cells to escape apoptosis and result in unimpeded proliferation. Here, we propose that a "switch on/off" model dictates the cross-talk between retinoid receptors and other signal transducing pathways during respiratory epithelium carcinogenesis. This model might contribute to the development of novel selective retinoids and their clinical evaluation in combinatorial chemopreventive strategies.