Health / Medical Topics |
Cytokeratin
Pronunciation
Definition 1
A type of protein found on epithelial cells, which line the inside and outside surfaces of the body. Cytokeratins help form the tissues of the hair, nails, and the outer layer of the skin. They are also found on cells in the lining of organs, glands, and other parts of the body. Certain cytokeratins may be found in higher than normal amounts in patients with different types of epithelial cell cancers, including lung, breast, colorectal, bladder, and head and neck cancers. Measuring the amount of specific cytokeratins in the blood may help to plan cancer treatment or find out how well treatment is working or if cancer has come back. A cytokeratin is a type of tumor marker. Also called keratin. (NCI Dictionary)
Definition 2
Cytokeratins are a family of cysteine-rich fibrous structural proteins that form tough filaments or sheets. These proteins are the main component of intermediate filaments in the epidermis, hair, nails, horny tissues, and the organic matrix of tooth enamel. (NCI Thesaurus)
Definition 3
A class of fibrous proteins or scleroproteins important both as structural proteins and as keys to the study of protein conformation. The family represents the principal constituent of epidermis, hair, nails, horny tissues, and the organic matrix of tooth enamel. Two major conformational groups have been characterized, alpha-keratin, whose peptide backbone forms an alpha-helix, and beta-keratin, whose backbone forms a zigzag or pleated sheet structure. (NLM, Medical Subject Headings)