Model systems of epithelium-mesenchyme transitions.

This contribution discusses which factors bring about the transformation of epithelium to mesenchyme. Amongst biological agents which have this role are a number of cytokines (e.g. EGF, FGF-1, TGF-beta, HGF/SF) and extracellular matrix macromolecules, such as collagens. The coordinated changes in cell morphology, associated with the induction of cell motility and the loss of inter-cellular junctions, are under the control of signaling molecules that transduce the signal emanating from the plasma membrane, which ultimately lead to changes in gene expression.