Analysis of the precore and core promoter DNA sequence in liver tissues from patients with hepatocellular carcinoma

To investigate the role of mutant hepatitis B virus (HBV) in the development of hepatocellular carcinoma (HCC), 20 patients with HCC were studied for precore and core promoter mutations in tumorous and nontumorous tissues, The precore and core promoter region was amplified and analyzed by direct sequencing. Among the 20 tumorous and nontumorous tissues, precore mutant HBV was found in 12 (60%) and 18 (90%), respectively. Of the 12 tumorous tissues with precore mutant, nine tissues had a single mutation (1896) and one tissue had another single mutation (1899), The remaining two tissues had a double mutation (1896 and 1899). A single mutation (1896) and a single mutation (1899) were found in 11 and two of the 18 nontumorous tissues with precore mutant, respectively. Among 20 tumorous and nontumorous tissues, HBV with a C to T mutation at nucleotide (nt) 1846 was detected in six and eight, respectively, and was associated with the virus carrying a mutation (1896 or 1899) except in two tumorous tissues. Mutations at nt 1762 and 1764 in core promoter were observed in 16 (80%) tumorous tissues and 18 (90%) nontumorous tissues, Mutations in the precore and core promoter region were found frequently in nontumorous tissue and in tumorous tissue (18/20 and 12/20 in precore region, 18/20 and 16/20 in core promoter respectively). The high prevalence of precore and core promoter mutations in liver tissue from patients with HCC suggests that these mutations may contribute to the development of HCC.