Evidence of lytic infection of Epstein-Barr virus (EBV) in EBV-positive gastric carcinoma.

Twenty-one cases of gastric carcinoma were tested for the presence of Epstein-Barr virus (EBV) genome by polymerase chain reaction (PCR) analysis. EBV genome was detected in 3 (14%) of the 21 cases. In situ hybridization for EBV-encoded small RNA 1 showed that EBV genomes were present in almost all carcinoma cells of the 3 cases. Southern hybridization for terminal repeats of the EBV-DNA revealed that the cases carried an individual monoclonal EBV genome. The analysis demonstrated the presence of linear form of EBV-DNA indicating lytic EBV infection in one of the cases. The expression of EBV genes in the cases was analyzed by reverse transcription-PCR. The mRNA for EBV-determined nuclear antigen (EBNA) initiating from the BamHI-Q promoter was detected, while both BamHI-W and -C promoters were not detected. EBNA2 and latent membrane protein (LMP) 1 mRNAs were not detected in all cases, while LMP2A mRNA was detected in 2 cases. The transcripts of EBV immediate-early genes, BZLF1 and/or BRLF1 were detected in 2 of the cases. The transcripts of late lytic genes (BcLF1 and BLLF1) were detected partly in the 3 cases. Our results indicate that lytic EBV infection occurs in EBV-positive gastric carcinomas.