Keratin 17 Antibody / Cytokeratin 17 / CK17

Cytokeratin 17 (CK17) is normally expressed in the basal cells ofcomplex epithelia but not in stratified orsimple epithelia. Antibody to CK17 is an excellent tool to distinguish myoepithelial cells from luminal epithelium of various glandssuch as mammary, sweat and salivary. CK17 is expressed in epithelial cells of various origins, such as bronchial epithelial cells and skin appendages. It may be considered as epithelial stem cell marker because CK17 Ab marks basal cell differentiation. CK17 is expressed in SCLC much higher than in LADC. Eighty-five percent of the triple negative breast carcinomas immunoreact with basal cytokeratins including anti-CK17. Also important is that cases of triple negative breast carcinoma with expression of CK17 show an aggressive clinical course. Additionally, anti-CK17 and anti-MUC1 immunoreactivity represents pancreatobiliary subtype whereas anti-MUC2 and anti-CDX-2 positivity defines intestinal subtype.