Keratin staining of bronchus epithelium (human, adult)

Stain: Anti-keratin-5-7-14-19 (OVTL 12/5 monoclonal antibody with immunoperoxidase staining on frozen sedctions). The pseudostratified epithelium (1) reacts positively (brown-red product), the nuclei of the basal cells are well visible (arrows). Other structures react negatively (blue stain) such as blood vessels (2) slender bundles of smooth muscles (3, subepithelially), cellular infiltrations of non-epithelial origin. This particular antibody against a certain epitope of the keratin filament protein family can be used in the diagnosis of epithelial-derived tumours (e.g. carcinoma) versus non-epithelial-derived tumours (e.g. sarcoma)