Cytokeratin 8 (CK8) belongs to the type II (or B or basic) subfamily of high molecular weight cytokeratins and exists in combination with cytokeratin 18 (CK18). This MAb recognizes all simple epithelia including glandular epithelium, for example thyroid, female breast, gastrointestinal tract, respiratory tract, and urogenital tract including transitional epithelium. All adenocarcinomas and most squamous carcinomas are positive but keratinizing squamous carcinomas are usually negative. This antibody is useful in demonstrating the presence of Paget cells; there is very little keratin 18 in the normal epidermis so only Paget cells are stained.