Cytokeratin 18 (CK18) is present in simple，glandular，and transitional epithelial cells，but is absent in stratified epithelial cells. CK18 usually multimerizes with Cytokeratin 8，and Anti-Cytokeratin 18 is useful for detecting adenocarcinomas of simple and glandular epithelium origin，as well as poorly differentiated squamous carcinoma cells.
