Cytokeratin 5/6

Cytokeratin 5 is a basic protein closely related to cytokeratin 6. They share similar tissue distribution and are found in various proportions in many non-keratinizing stratified squamous epithelia, e.g., tongue mucosa, as well as in basal epithelia of the trachea, basal cells of the epidermis, hair follicles, sebaceous and sweat glands of the skin, luminal cells of the mammary gland, basal cells of the prostate, urothelium, vagina, and endocervical mucosa. Cytokeratins 5 and 6 are expressed in basal cell epitheliomas, squamous cell carcinomas of the skin, tongue, epiglottis, and rectal-anal region. Cytokeratin 5/6 is a useful aid for the classification of epithelioid mesotheliomas.