A three dimensional (tissue equivalent) culture model is being developed that will recapitulate more faithfully the in vivo nature of normal airway epithelium. Specifically, mesenchymal cells are being combined with collagen. The metabolic activities of the mesenchyme cells cause changes in the structure of the collagen fibrils resulting in their contraction and producing a mesenchyme-like tissue structure. Subsequently, normal human bronchial epithelial cells are inoculated on the surface of the pseudo-mesenchyme to allow for their differentiation into a muco-ciliary epithelium. A similar three dimensional culture model is being developed that recapitulates more faithfully the in vivo nature of normal liver tissue. These airway epithelium and hepatocellular models are also being developed to study the actions of premalignant and malignant epithelial cells when they are in association with normal epithelial cells and a mesenchyme.