Cytokeratin 8/18 [K8.8&DC10]

Cytokeratin 8 (CK8) is an intermediate filament protein produced early in embryogenesis. It is the only type-II CK occurring in many simple epithelial cells in respiratory, gastrointestinal, male and female reproductive tracts, and thyroid. CK8 is often co-expressed withCytokeratin 18. CK8/18 is the major keratin pair in simple-type epithelia, as found in the liver, pancreas, and intestine. The CK8 antibody is used to detect adenocarcinomas of simple epithelium origin. The difference in staining pattern is useful to distinguish ductal (peripheral staining) from lobular (perinuclear staining) breast carcinoma. Cytokeratin 18 (CK18) is an intermediate filament phosphoglycoprotein that is expressed in simple and glandular and transitional epithelial cells, but not in stratified epithelial cells. CK18 is often co-expressed with CK8. CK8/18 is the major keratin pair in simple-type epithelia. Adenocarcinomas originated from simple and glandular epithelium showed CK18 positive staining. In squamous carcinoma, poorly differentiated tumor cells show CK18 reactivity. Loss of CK 18 expression is associated with progression of breast carcinoma.