Table 1.

Definitions

Epithelial Cell	Cell with apical-basal polarity, intercellular adhesion complexes, polarized actin cytoskeleton and an underlying basal membrane
Squamous epithelium	Layer of flat epithelial cells with irregular boundaries
Columnar epithelium	Layer of tall epithelial cells with polygonal boundaries
Mesenchymal cell	Cell devoid of apical-basal polarity and adhesion complexes that exhibit elongate morphology, filopodia, front end-back end polarity and invasive motility
EMT	Epithelial to mesenchymal transition. Cells lose epithelial morphology and molecular identity and adopt mesenchymal properties
MET	Mesenchymal to epithelial transition. Cells downregulate mesenchymal markers and upregulate epithelial factors and they assume an epithelial morphology
Ingression	Epithelial cells undergo EMT and concomitantly leave an epithelial sheet of cells
Egression	Mesenchymal cells join a pre-established epithelial sheet and concomitantly undergo MET
Delamination	Cells leave an epithelium either via EMT or not
Relamination	Cells form/join an epithelium either via MET or not