Immunoreactivity for c-erbB-2 oncopeptide in benign and malignant diseases of the liver.

The immunohistochemical detection of the c-erbB-2 oncopeptide (p185erbB2) has been shown to be a valid marker for over-expression of this oncogene. To evaluate the possible relevance of gene expression to the proliferation of hepatocytes and bile ducts in human disease, the authors applied a monoclonal anti-p185 antibody to formalin-fixed, paraffin-embedded tissues from 67 examples of benign proliferative and neoplastic hepatic lesions and fetal liver. Focal membrane-based reactivity for the oncopeptide was detected on tumor cells in two of eight hepatocellular carcinomas and on tumor cells and adjacent bile ducts and hepatocytes in four of six cholangiocarcinomas. Each of the latter four lesions were in patients with primary sclerosing cholangitis. No reactivity was obtained in examples of hepatoblastoma, mixed cholangiocarcinoma-hepatocellular carcinoma, bile duct adenoma, or hepatocellular adenoma. Weak staining for p185erbB2 also was seen in two of seven cases of (sub)massive hepatic necrosis and two examples of postnecrotic cirrhosis, all of which were secondary to either hepatitis B or C virus infection. No other benign proliferative lesions were labeled by the anti-p185 antibody, including cases of chronic allograft rejection, necrosis secondary to hepatic artery thrombosis, metabolic-associated and nonmetabolic-associated cirrhosis, focal nodular hyperplasia, and nodular regenerative hyperplasia. The authors' results indicate that c-erbB-2 may be amplified in specific neoplastic and hepatitis B virus and hepatitis C virus infectious lesions of liver. The authors postulate that: (1) c-erbB-2 immunoreactivity may be a marker for malignant transformation in primary sclerosing cholangitis; and 2) overproduction of p185erbB2 may be an epiphenomenon of hepatitis B virus or hepatitis C virus infection.