Epstein-Barr virus and gastric carcinoma in Western patients: comparison of pathological parameters and p53 expression in EBV-positive and negative tumours

Aims: The presence of Epstein-Barr virus (EBV) was studied in 56 gastric ca rcinomas from Western patients by in-situ hybridization for EBV-encoded RNA s (EBER). EBV-positive and negative carcinomas were compared for various pa thological parameters including p53 overexpression. Methods and results: EBERs transcripts were detected in seven cases overall : four cases of 52 conventional carcinomas (7.7%) and three cases of four g astric carcinomas with lymphoid stroma (75%). EBER positivity was diffuse i n five cases and restricted to a localized area of the tumour in two cases of conventional carcinoma. A monoclonal EBV genomic pattern was demonstrate d in the case tested by Southern blot analysis. By immunohistochemical anal ysis, neither EBV latent or lytic cycle proteins nor C3d/EBV receptor were expressed by neoplastic cells. EBER positivity was significantly correlated with prominent lymphoid reaction (P = 0.0002) which was associated with nu merous PS100-positive dendritic cells and with HLA-DR expression by tumour cells (P = 0.03). p53 immunoreactivity in more than 30% of tumour cells was detected in 25 out 49 EBV-negative cases and was absent in EBV-positive ca ses except in one case with focal EBER-positivity. Conclusions: Focal staining for EBER is an unusual finding in the setting o f gastric carcinoma and these results suggest that there might be two types of EBV-associated gastric carcinoma in which the viral infection will play a different role. The presence of a stromal lymphoid reaction which is str ongly correlated with EBV positivity, is associated with antigen-presenting ability by HLA-DR-positive tumour cells or abundant dendritic cells. The f unction of p53 appears preserved in all EBV-associated carcinomas except in one case with focal EBER expression whereas the immunohistochemical patter n of p53 is suggestive of a mutational phenomenon in 51% of EBV-negative ca ses.