Cytokeratins may play an important role in transhepatic transport and canalicular secretion. Cytokeratin 7 (CK 7/ KRT7) only stains bile ducts in normal liver, hence it is considered as “bile duct keratin”. CK 7 is widely used in surgical pathology. It acts as a specific marker for mammary and extramammary Pagetμs disease.
