B-RAF PROTEIN IMMUNOEXPRESSION IN HEPATOCELLULAR CARCINOMA DUE TO HEPATITIS C VIRUS RELATED CIRRHOSIS

Hepatocarcinogenesis is a multistep process that lead to genetic changes in hepatocytes resulting in neoplasia. However, the mechanisms of malignant transformation seem to differ widely. To know carcinogenesis mechanisms is essential to develop new treatment and prevention methods.

The aim of this study is to analyze B-Raf protein immunoexpression in explants with hepatocellular carcinoma (HCC) related to hepatitis C (HCV), in adjacent cirrhotic tissue and in normal livers. We also associated the immunoexpression with known HCC related histopathogical prognostic features.

Livers from 35 patients with HCV related cirrhosis and HCC that underwent liver transplantation or hepatectomy at Clinical Hospital – UFMG and 25 normal livers from necropsy archives were studied. Tumors were classified according to: tumor size, vascular invasion and differentiation grade. B-Raf protein expression was determined by immunohistochemistry.

B-Raf was strongly expressed in the HCV cirrhotic parenchyma cytoplasm of 17.1% cases and in 62.9% of HCC samples. Strong B-Raf protein staining was associated with tumor tissue (P<0.0001; OR=8.18 (2.62–26.63)). All normal livers showed weak or negative expression for B-Raf. There was no significant association among B-Raf scores and tumor differentiation grade (P=0.9485), tumor size (P=0.4427) or with vascular invasion (P=0.2666).

We found B-Raf protein immunostaining difference in normal livers, in the areas of HCV cirrhosis and in the hepatocarcinoma. We did not find association between B-Raf expression and histopathological markers of tumor progression. Our data suggests that B-Raf may play an important role in initial HCC carcinogenesis. Larger studies are needed to validate these observations.