The mesenchymal-to-epithelial transition in somatic cell reprogramming

The epithelial-to-mesenchymal transition (EMT) is a process that confers migratory characteristics to epithelial cells. It is a major force driving embryonic development, tissue fibrosis and malignant progression, and can also create cells with properties of stem cells. The mesenchymal-to-epithelial transition (MET) has the opposite course and frequently coexists with the EMT, but the underlying mechanisms are less well studied. The recent discovery that the MET is required for transforming somatic cells into pluripotent stem cells suggests that the intersection between EMT and MET is a fundamental crossroad for cell fate decisions. Further understanding of the molecular events controlling both situations has relevant implications for regenerative medicine and disease.