{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Cytokeratin 14 (CK14) is a type I acidic high molecular weight intermediate filament protein that is part of the cytokeratin family, which forms the cytoskeleton of epithelial cells. It is particularly abundant in basal keratinocytes, which are found in the basal layer of stratified epithelia such as the skin, oral mucosa, and esophagus. Cytokeratin 14 is usually found as a heterotetramer with cytokeratin 5, a type II basic high molecular weight cytokeratin protein."}]},{"type":"paragraph","children":[{"type":"text","value":"CK14 expression is commonly observed in basal-like breast cancers, a subtype of breast cancer often lacking expression of hormone receptors (estrogen receptor, progesterone receptor, and HER2) and proliferating at a fast rate. CK14 is also expressed in squamous epithelial cells and is often detected in tumors derived from squamous epithelia, such as squamous cell carcinomas of the skin, oral cavity, esophagus, and cervix."}]}]}