Aberrant expression of cytokeratin 7 as a histological marker of progression in primary biliary cirrhosis

Aim: We evaluated the aberrant expression of cytokeratin 7 (CK-7) in hepato cytes as a marker of cholestasis and progression in primary biliary cirrhos is (PBC). Patients and Methods: The expression of CK-7 was studied by immun ohistochemistry in 83 cases of PBC. This expression was compared with bioch emical data, the deposition of copper-associated protein, and previous hist ological classifications. Results: In normal liver, CK-7 was expressed excl usively in bile duct epithelial cells (BDE). In PBC, the expression was als o observed in hepatocytes. The expression pattern was classified as follows : Grade 0, BDE as in normal; Grade I, proliferated bile ductules; Grade 2, periportal hepatocytes in addition to proliferated bile ductules; Grade 3, intralobular hepatocytes; Grade il, the majority of hepatocytes. The grades correlated with serum bilirubin levels but not with serum levels of biliar y enzymes. A discrepancy between the CK-7 grading and Ludwig's classificati on was noted in cases with Stage 1 of the CK-7 grading who were considered Stage 2 or 3 in Ludwig's classification, suggesting that cholestasis and in flammatory activity might be independent events. Conclusions: These results suggest that the aberrant expression of CK-7 in hepatocytes may be a marke r of chronic cholestasis and progression in PBC.