Anti-cytokeratin 7: a positive marker for epithelial dysplasia in flat bowel mucosa.

The aim of this paper is to establish by immunohistochemistry the expression of keratin 7 in inflammatory-regenerative flat bowel mucosa and in different grades of epithelial dysplasia regarding the sub-units expressed in normal and carcinomatous colonic mucosa. Biopsy specimens from 270 patients were examined: 74 were classified as inflammatory-regenerative changes and 196 as dysplastic lesions. There were 108 cases of mild dysplasia, 58 cases of moderate and 30 cases of severe dysplasia, respectively). Demonstration of location and intensity of cytokeratin 7 staining was performed by immunohistochemistry using monoclonal antibody (anti-cytokeratin 7). Findings of cytokeratin 7 in dysplastic lesions were compared with those in normal mucosa, inflammatory -regenerative mucosa and adenocarcinoma. Cytokeratin 7 is not found in normal colonic mucosa. In inflammatory-regenerative mucosa it was found in solitary cells in small number of cases. It is found in all cases of epithelial dysplasia and its expression showed no difference regarding moderate and severe dysplasia. In few cases of adenocarcinoma, cytokeratin 7 is found in traces and showed minimal staining intensity. Having in mind that cytokeratine 7 is primarily found in dysplastic lesions of the flat colonic mucosa it can be a valuable diagnostic tool in the histological interpretation of epithelial dysplasia.