Before revision: We theoretically investigate the mechanical stability of three-dimensional (3D ) foam geometry in a cell sheet and apply its understandings to epithelial integrity and cell delamination. Analytical calculations revealed that the monolayer integrity of cell sheet is lost to delamination by a spontaneous symmetry breaking, inherently depending on the 3D foam geometry of cells;
After revision: We theoretically investigate the mechanical stability of three-dimensional (3D ) vertex model to investigate the mechanical stability of cells arranged in a monolayer with 3D foam geometry of cells;