Cytokeratins are proteins of keratin-containing intermediate filaments found in the intracytoplasmic cytoskeleton of epithelial tissue. Cytokeratin represents an excellent marker for the discrimination of specific subtypes of adenocarcinoma. Keratin, type I cytoskeletal 19 also known as cytokeratin-19 (CK-19) or keratin-19 (K19) is a protein that in humans is encoded by the KRT19 gene.# Keratin 19 is a type I keratin. Alternative Names: Cytokeratin 19, Cytokeratin 19 protein, Cytokeratin-19 protein, Cytokeratin 19, Cytokeratin-19, Keratin K19 protein