Anti-CK-39 antibodies enable researchers to detect and measure the CK-39 antigen in biological samples. This target is a reported synonym of the KRT39 gene, which encodes keratin 39. This protein is known to function in epithelial cell differentiation, among other biological roles. The human version of CK-39 has a canonical amino acid length of 491 residues and a protein mass of 55.7 kilodaltons. CK-39 is a member of the Intermediate filament protein family.