IMMUNOHISTOCHEMICAL DETECTION OF AFLATOXIN B-1-DNA ADDUCTS AND HEPATITIS-B VIRUS-ANTIGENS IN HEPATOCELLULAR-CARCINOMA AND NONTUMOROUS LIVER-TISSUE

Monoclonal antibodies recognizing the stable imidazole ring-opened for m of the major N7-guanine aflatoxin B1-DNA adduct have been used in co mpetitive enzyme-linked immunosorbent assays (ELISA) and indirect immu notluorescence assays to quantitate adduct levels in liver tissue. Met hods were developed in AFB1-treated animals, then applied to paired tu mor and nontumor liver tissues of hepatocellular carcinoma patients fr om Taiwan. An avidin-biotin complex staining method was also used for of the detection of hepatitis B surface (HBsAg) and X (HBxAg) antigens in liver sections. A total of 8 (30%) hepatocellular carcinoma (HCC) samples and 7 (26%) adjacent nontumor liver tissue samples from Taiwan were positive for AFB1-DNA adducts. For HBsAg 10 (37%) HCC samples an d 22 (81%) adjacent nontumorous liver samples were positive, and 9 (33 %) HCC samples and 11 (41%) adjacent nontumor liver samples were HBxAg positive. No association with AFB1-DNA adducts was observed for HBsAg and HBxAg. These methods should be useful in determining the role of exposure in the induction of HCC in Taiwan.