Epithelial-Mesenchymal Transitions in development and disease: old views and new perspectives

7 pages, 3 figures.Full-text version available Open Access at the journal site.The epithelial to mesenchymal transition (EMT) is a fascinating phenotypic change that is undertaken by embryonic and adult cells in physiological and pathological conditions, respectively. This change in cell behavior involves the loss of epithelial characteristics and the acquisition of migratory properties. While it has long been established as a fundamental process in the generation of many different embryonic tissues, its significance during tumor progression as an initial determining step in the metastatic cascade has remained a matter of debate. Recent molecular analyses coupled with state-of-the-art imaging technology have helped to define the EMT as an important landmark, not only during tumor progression, but also during the development of other pathologies such as organ fibrosis. Spanish groups have contributed to the analysis of EMT both from the developmental and the pathological point of view, in particular assessing the implication of the Snail genes in this process. Interestingly, the contribution of Spanish scientists to the existence of EMT in tumors possibly goes back more than 100 years, when Cajal referred to some "pear-like cells, not attached to each other" in his description of human breast carcinomas.Work in the lab is supported by Spanish Ministry of Education and Science Grants BFU2005-05772, NAN2004-09230-C04-04 and CONSOLIDER-INGENIO 2010 CSD2007-00017 and CSD2007-00023.Peer reviewe