Immunohistochemical stainings for E- and N-cadherin and β-catenin during saccular period of developing human lung. 3A and 3B. A strong positivity for E-cadherin is seen in the epithelial cells of a bronchiole (arrows) and type II pneumocytes of alveoli are also positive for E-cadherin (short arrows). 3C. Alveolar epithelium is negative for N-cadherin (arrows). 3 D. A few epithelial cells of a bronchiole are positive for N-cadherin (arrows). 3E and 3F. Positive staining for β-catenin is seen in the epithelial cells of a bronchiole (arrows) and alveolar epithelial cells (short arrows). 3G. A high power field image showing a positive expression for β-catenin within alveoli. Some alveolar epithelial cells exhibit nuclear staining (arrows). 3 H. A negative control in which the primary antibody has been substituted with non-immune serum. Scale bars = 40 μm in 3A, 3C, 3E and 3H; scale bars = 20 μm in 3B, 3D, 3F and 3G.