CK

Please find a detailed description of cytokeratins here.

On-slide control TMAs for CKs should include normal tissues as listed below.
CK8/18 and CK-LMW: Liver (liver cells are CK low-expressors).
CK19: Colon/appendix (all enterocytes positive) and oesophagus (basal cells positive).
CK20: Colon/appendix (all enterocytes apart from basal crypt cells positive).
CK5/14 and CK-HMW: Pancreas (scattered columnar epithelial cells of intercalated ducts show a weak to moderate predominantly membranous staining reaction).
CK7: Pancreas (the vast majority of epithelial cells of the intercalating ducts shows an at least weak to moderate cytoplasmic staining reaction, whereas the epithelial cells of large pancreatic ducts shows an intense staining reaction, while no staining is seen in the acinar cells).
CK-PAN: Liver (like CK8/18) and pancreas (like CK5/14).