Before revision:  Additionally, taking into account the cell-intrinsic force generation on apical and basal sides , which are also broadly observed in morphogenesis, homeostasis, and carcinogenesis, we found apically/basally directed cell delaminations and pseudostratified structures, which could universally explain mechanical regulations of epithelial geometries in both physiology and pathophysiology{\it   .
After revision:  Additionally, taking into account the cell-intrinsic force generation on apical and basal sides , which are also broadly observed in morphogenesis, homeostasis, and carcinogenesis, we found apically/basally directed cell delaminations and pseudostratified structures, which could universally explain mechanical regulations of epithelial geometries in both physiology and pathophysiology{\it and consistently explain cell extrusions under a wide range of physiological and pathophysiological conditions. Our results illustrate the importance of a mechanical understanding of cell extrusion and provide a basis by which to link molecular regulation to physical processes .