{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Cytokeratin 8 belongs to the Type II (basic) subfamily of low molecular-weight keratins and exists in combination with Cytokeratin 18 (Type I [acidic] subfamily of low molecular weight keratins). They are perhaps the most commonly found products of the intermediate filament gene family, and are expressed in single-layer epithelial tissues of the body."}]},{"type":"paragraph","children":[{"type":"text","value":"Cytokeratins 8 and 18 can be found in most simple epithelium (e.g., thyroid, female breast, gastrointestinal tract, and respiratory tract). Adenocarcinomas and most Non-keratinizing Squamous Carcinomas will stain, but Keratinizing Squamous Carcinomas will not. This antibody is used when attempting to demonstrate the presence of Paget cells; there is very little keratin 18 in the normal epidermis so only Paget cells will stain. This approach facilitates the interpretation using immunostains and is more sensitive than mucin histochemistry."}]}]}