KRT23, also known as cytokeratin 23, is a 422 amino acid intermediate filament protein. The human KRT23 gene is located on chromosome 17q21.2. The type I cytokeratins consist of acidic proteins which are arranged in pairs of heterotypic keratin chains. The cytokeratin proteins play a critical role in differentiation, as well as tissue specialization and function, and maintenance of epithelial cells structure. Cytokeratins are described to be differentiation markers in several epithelial cancers.