KRT16 (Cytokeratin 16, CK16) is a type I cytokeratin that partners with Keratin 6A to form keratin intermediate filaments. KRT16 is found in non-keratinizing squamous epithelium of the esophagus, tongue, oral cavity, tonsil, ectocervix, vagina, and in melanocytes, hair follicles and nails. Increased expression is found in conditions involving hyperplastic keratinocytes, including psoriasis, and decreased expression is observed in cervical carcinoma. Mutations are associated with pachyonychia congenita, non-epidermolytic palmoplantar keratoderma and unilateral palmoplantar verrucous nevus syndromes. References: J Anat 2009 214(4):516; Am J Dermatopath 2005 27(6):476; Exp Dermatol 2013 22(12):838; Human Mol Genet 2019:doi.org/10.1093/ddz050