Keratins, also called cytokeratins, are a family of filamentous structural proteins that form the intermediate filaments within epithelial cells. Keratins are differentially expressed depending on both the epithelial cell origin and degree of differentiation. An antibody to any given keratin is useful either as a stand-alone or part of an antibody panel to help identify or clarify tissue origin. Cytokeratin 18 (CK18) is a 45 kD normal constituent of the hepatocyte cytoskeleton and is expressed in combination with cytokeratin 8.
