{"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 18 (CK18) is a type I acidic cytokeratin and is typically partnered with cytokeratin 8, a type II basic cytokeratin. They are expressed in simple and glandular and transitional epithelial cells but not in stratified epithelial cells. According to literature, cytokeratin 18 can be detected in adenocarcinomas originating from simple and glandular epithelium, and also in poorly differentiated tumor cells of squamous carcinoma."}]}]}