Cytokeratin 8 is the product of the KRT8 gene and one of the most abundant keratins. The KRT8 gene is a member of the type II keratin family clustered on the long arm of chromosome 12. Cytokeratin 8 participates in cellular differentiation and signal transduction, protects against apoptosis, stress and injury, and helps maintain cellular structural integrity. It is primarily found in the non-squamous epithelia and is present in majority of adenocarcinomas and ductal carcinomas. It is absent in squamous cell carcinomas. Specific combinations of cytokeratins are associated with certain epithelial cells, and therefore useful in the characterization of poorly differentiated carcinoma. Hepatocellular carcinomas are defined by the use of antibody that recognizes only cytokeratin 8 and 18. Keratin 8 exists on several types of normal and neoplastic epithelia, including many ductal and glandular epithelia such as colon, stomach, small intestine, trachea, and esophagus as well as in transitional epithelium. Antibody to Cytokeratin 8 does not react with skeletal muscle or nerve cells. Epithelioid sarcoma, chordoma, and adamantinoma show strong positivity corresponding to that of simple epithelia (with antibodies against Keratin 8, 18 and 19). Reportedly, Cytokeratin 8 antibody is useful for the differentiation of lobular (ring-like, perinuclear) from ductal (peripheral-predominant) carcinoma of the breast.

Store the Cytokeratin 8 antibody at 2-8°C (with azide) or aliquot and store at -20°C or colder (without azide).