HBV GENOME INTEGRATION AND GENETIC INSTABILITY IN HBSAG-NEGATIVE AND ANTI-HCV-POSITIVE HEPATOCELLULAR-CARCINOMA IN JAPAN

The aim of this study is to clarify the existence and the form of HCV RNA and HBV DNA genome integration and genetic instability in liver ti ssue with HBsAg-negative and anti-HCV-positive HCC. We investigated 16 Japanese patients with HBsAg-negative and anti-HCV-positive HCC. HBV genome integration into host cell genome by Southern hybridization and PCR was examined. Moreover, we analyzed loss of heterozygosity (LOH) and replication errors (RER) of chromosomes 2p, 3p and 17p using the P CR and an autosequencer to determine the three microsatellite regions D2S123, D3S1067, TP53. Eight (50.0%) of 16 were found to have integrat ed genome of HBV in tumor tissue (T) by PCR. In even the non-tumor reg ions (NT), seven patients (43.8%) were found to have HBV genome integr ation. The coincidence between T and NT was found in 4 (25%). Integrat ion of HBV-X gene in T was revealed in three (18.7%), and HBV-integrat ion was confirmed in all NT. No integration of the X gene alone was fo und in the liver tissue, Five (37.5%) of eight HBV DNA integrated case s simultaneously had HCV RNA minus strand. Concerning the genetic inst ability, RER were detected in two of 16 (12.5%). RER at 2p; D2S123 was observed in one of 16 (6.2%) and at 3p; D3S1067 was observed in one ( 6.2%). LOH at the D2S123 locus was observed in one of 12 tumors with h eterozygosity (8.3%). There was no genetic instability (LOH or RER) of TP53 which was p53 locus on 17p in T. There was only one case of eigh t HBV DNA integrated cases (6.2%) with genetic instability of RER of 3 p simultaneously in T. In conclusion, the majority of HBsAg-negative a nd anti-HCV-positive HCC liver tissue was found to have HCV-RNA and HB V DNA integration, and in some samples, HBV DNA integration and geneti c instability were concurrently confirmed, It is speculated that multi step carcinogenesis may have been proposed for HCC oncogenetic progres sion. (C) 1997 Elsevier Science Ireland Ltd.