Cytokeratin 8 (CK8) belongs to the type II (or B or basic) subfamily of high molecular weight cytokeratins and exists in combination with cytokeratin 18 (CK18). Cytokeratin 8 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. Hepatocellular carcinomas are defined by the use of antibody that recognizes only cytokeratin 8 and 18. Cytokeratin 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 Cytokeratin 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).