Analysis of integrated hepatitis B virus DNA and cellular flanking sequences cloned from a hepatocellular carcinoma

By digestion with HindIII restriction enzyme, a human hepatocellular carcinoma was shown to contain only 2 hepatitis B virus (HBV) DNA inserts. Both HindIII fragments (8 and 16 kb) were molecularly cloned and the structures of HBV DNA and adjacent host sequences were analyzed. One clone λYH 8) contained part of pre-S(I) through the entire S gene and the other (λYH 16) had the middle section of the S to the end of X gene of HBV DNA. No gross rearrangements were observed in either HBV or cellular DNA sequences in λYH 16 clone. However, the 8 kb HindIII fragment was considered to be amplified together with flanking cellular sequences. Furthermore, the HBV DNA was integrated into cellular genome at the Alu repeated sequences in λYH 8.