摘要: Epithelial cells, and the tight junctions between them, form a polarized barrier luminal serosal fluid compartments segregate growth factors from their basal-lateral receptors. Breakdown of this should allow access in to receptors on cell membranes, as recently demonstrated for heregulin erbB airway epithelia. It also stroma. This property may have adaptive value epithelial tissues general, an elegant response injury, but promote cancer formation premalignant which become chronically leaky factors.