Keratins are cytoplasmic intermediate filament proteins expressed by simple-type epithelial cells. Cytokeratin 17 is a type I keratin that is found in nail beds, hair follicles, sebaceous glands and other epidermal appendages. This antibody is useful to discriminate between cervical immature squamous metaplasia and high grade cervical intraepithelial neoplasia (CIN III). It detects myoepithelial cells in the benign breast tissue.