Keratin 7 staining in squamous metaplasia and dysplasia of the epithelium of a bronchus (human, adult)

Stain: anti-keratin 7 antibody (Pan-Ck 7) immunoperoxidase staining (with aminoethylcarbazole (AEC) substrate). A red-brown staining with AEC indicates a positive reaction for cytokeratin 7. Note that the top layer only reacts weakly positive for keratin 7 (↓). Upon squamous metaplasia the bronchial epithelial cells largely loose keratin 7 expression. Additionally disturbances in the growth and maturing might result in dysplasia of the epithelium with a changed reaction pattern for cytokeratins. Here it is demonstrated that the basal compartments at the bottom which exhibit very mild dysplasia appear totally negative for keratin 7. This antibody can be useful in the study of premalignant changes in complex epithelia (e.g., pseudostratified, squamous stratified epithelia ).