Cytokeration 20 Antibody Staining Protocol for Immunohistochemistry

Description: Cytokeratins are intermediate filament cytoskeletal proteins essential to development and differentiation of epithelial cells. Approximately twenty different cytokeratins have been identified and are classified and numbered according to molecular weight and isoelectric points. In general, most low molecular weight cytokeratins (40-54 kDa) are distributed in nonsquamous epithelium, Moll’s catalog numbers 7-8 and/or 17-20. High molecular weight cytokeratins (48-67 kDa) are found in the squamous epithelium, Moll’s catalog numbers 1-6 and/or 9-16. CK20 (Clone KS20.8) is to identify epithelial cells in normal and neoplastic tissues using immunohistochemical methods. CK20 is valuable as a histodiagnostic tool for the subtyping of various carcinomas, including adenocarcinomas.1 It is an aid for a more precise classification of many epithelial tumors whose differential diagnosis is otherwise difficult. This antibody reacts with the 46 kDa cytokeratin intermediate filament protein as indicated by immunoblotting of cytokeratin-enriched cytoskeletal preparations isolated from villi of duodenal mucosa. The cytokeratin was initially described as “protein IT” but has recently been designated cytokeratin 201 supplementing the previously described number of the cytokeratin polypeptides. CK 20 is less acidic than the other type 1 cytokeratins and is of particular interest because of its restricted range of expression.