Loss of Cadherin-Catenin Adhesion System in Invasive Cancer Cells

As described in the previous chapter, the loss of E-cadherin is the key event in epithelial–mesenchymal transition. While downregulation of E-cadherin could occur via aberrant Akt signaling, direct somatic mutations in E-cadherin are frequent in epithelial tumors such as diffuse-type gastric and lobular breast cancers, where they can be found in up to 50% of primary neoplasms (Berx et al. 1998). E-cadherin mutations were also observed in primary endometrial and ovarian carcinomas, albeit with a lower frequency (Risinger et al. 1994; Muta et al. 1996). The consequences of these mutations for EMT and tumor cell invasion are discussed below