Anti-Cytokeratin 17, clone E3

1 mg/ml in 1X PBS, BSA free, sodium azide free. Cytokeratin 17 (CK17, Keratin 17) is a member of the Cytokeratin subfamily of intermediate filament proteins (IFP's). It is unique in that it is normally expressed in the basal cells of complex epithelia but not in stratified or simple epithelia. Cytokeratin 17 is expressed in the nail bed, hair follicle, sebaceous glands and other epidermal appendages. Antibody to cytokeratin 17 is an excellent tool to distinguish myoepithelial cells from luminal epithelium of various glands such as mammary, sweat and salivary. It 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 cytokeratin 17 antibody marks basal cell differentiation. Cytokeratin 17 can be useful when included in a panel of antibodies against TTF-1, napsin A, CK5&6, p63, and SOX-2 for diagnostic differentiation between lung adenocarcinoma (LADC) and lung squamous cell carcinoma (SCLC), especially for poorly-differentiated lung carcinoma. Cytokeratin 17 is expressed in SCLC much higher than in LADC. In breast carcinomas, approximately 20% of patients show no expression of ER, PR and Her2, which are defined as triple negative tumor. Eighty-five percent of the triple negative breast carcinomas immunoreact with basal cytokeratins including cytokeratin 17 antibody. Also important is that cases of triple negative breast carcinoma with expression of keratin 17 show an aggressive clinical course. The histologic differentiation of ampullary cancer, intestinal vs. pancreatobiliary, is very important for treatment. Usually antibody to cytokeratin 17 and MUC1 immunoreactivity represents pancreatobiliary subtype whereas antibody to MUC2 and CDX2 positivity defines intestinal subtype. Protein function: Type I keratin involved in the formation and maintenance of various skin appendages, specifically in determining shape and orientation of hair. Required for the correct growth of hair follicles, in particular for the persistence of the anagen (growth) state. Modulates the function of TNF-alpha in the specific context of hair cycling. Regulates protein synthesis and epithelial cell growth through binding to the adapter protein SFN and by stimulating Akt/mTOR pathway. Involved in tissue repair. May be a marker of basal cell differentiation in complex epithelia and therefore indicative of a certain type of epithelial "stem cells". Acts as a promoter of epithelial proliferation by acting a regulator of immune response in skin: promotes Th1/Th17-dominated immune environment contributing to the development of basaloid skin tumors. May act as an autoantigen in the immunopathogenesis of psoriasis, with certain peptide regions being a major target for autoreactive T-cells and hence causing their proliferation. [The UniProt Consortium]