{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Cytokeratins are intermediate-filament keratins found in the intracytoplasmic cytoskeleton of epithelial tissue. There are two types of cytokeratins: acidic type I cytokeratins and basic or neutral type II cytokeratins. Cytokeratins are usually found in pairs comprising a type I cytokeratin and a type II cytokeratin. Expression of these cytokeratins is frequently organ or tissue specific. Cytokeratin 5 (CK 5) is a high-molecular weight, basic type II cytokeratin expressed in basal, intermediate and superficial-cell layers of stratified epithelia as well as transitional epithelia, complex epithelia, mesothelial cells and mesothelioma. Cytokeratin 14 (CK 14) is a type I acidic high molecular weight cytokeratin, 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. CK 14 is usually found as a heterotetramer with CK 5."}]}]}