Molecular mechanisms leading to cell junction (cadherin) deficiency in invasive carcinomas

It has been realized for some time that the loss of epithelial differentiation in carcinomas, which is accompanied by higher mobility and invasiveness of the tumor cells, is a consequence of reduced intercellular adhesion. A variety of recent reports have indicated that the primary cause for the 'scattering' of the cells in invasive carcinomas is a loss of the integrity of intercellular adherens junctions often involving loss of a functional cell-cell adhesion molecule E-cadherin. In the present review, permanent and transient molecular mechanisms are discussed which lead to the impairment of junctional integrity of cells and thus the progression of carcinomas toward a more metastatic state.