Figure 1.

Developmental versus pathological EMT. (A) Developmental EMT is a process that involves the entire epithelial tissue. (a) Specification of cells that will undergo EMT occurs through coordination of cell–cell, cell-ECM, and soluble signals. (b) Degradation or disruption of the basement membrane is followed by cell ingression and morphogenesis of the retained epithelial cells to close the gap. (c) The fully detached cell undergoes phenotypic mesenchymal shift. (B) Activation of the EMT program in pathological conditions can occur in a disorganized and more cell-autonomous fashion.