Keratins (also known as cytokeratins) are intermediate filament proteins primarily expressed in epithelial cells. A keratin heterodimer, composed of one acidic keratin (or type I keratin, keratins 9 to 23) and one basic/neutral keratin (or type II keratin, keratins 1 to 8), polymerizes to form filaments. The tissue-specific and differentiation-specific expression patterns of keratin isoforms enable them to serve as valuable biomarkers. Studies have confirmed that mutations in keratin genes are associated with dermatological disorders, liver and pancreatic diseases, and inflammatory bowel diseases.
