Cytokeratin 17 [E3]

CK17 is an intermediate filament protein expressed in the basal cells and myoepithelial cells of complex epithelia, including glandular epithelium with myoepithelial component, transitional and pseudostratified epithelia. CK17 is a marker in the identification of breast cancer with basal phenotype. Squamous cell carcinoma is also labeled by CK17 antibody. Antibody against CK17 may be an aid in distinguishing cholangiocarcinoma (CK17+) from hepatocellular carcinoma (CK17-). In combination with MUC1, CK17 antibody has been found to be useful in distinguishing pancreatobiliary adenocarcinoma (CK17+) from extrapancreatobiliary nonmucinous adenocarcinoma (CK17-).