BACKGROUND: The developmental process of Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) has not been clearly demonstrated, especially in its relation to intestinal metaplasia and epithelial EBV infection.METHODS: Gastritis and intestinal metaplasia was histologically evaluated in non-neoplastic gastric mucosa that surrounded early carcinoma of EBVaGCs ( n = 23) and EBV-negative gastric carcinomas (GCs) (intestinal type, n = 139; diffuse type, n = 44). Helicobacter pylori infection was evaluated by immunohistochemistry. EBV infection in the gastric mucosa was examined by both RNA probe in situ hybridization (ISH) and polymerase chain reaction (PCR) for the BamHI-W region of EBV DNA, the latter of which was applied to the microdissected mucosa.RESULTS: Marked grade of atrophy and moderate to marked grade of lymphocytic infiltration were significantly more frequent in EBVaGCs (74% and 78%, respectively), compared to intestinal-type (49% and 12%)and diffuse-type (27% and 12%) of EBV-negative GCs. Only 13% of EBVaGCs were surrounded by intestinal metaplasia, in contrast to 41% of intestinal-type EBV-negative GCs. Immunohistochemistry revealed nearly the same frequencies of H. pylori infection (70%) in three types of GCs. RNA probe ISH for EBV-DNA failed to identify any positive cells in nonneoplastic mucosa, including intestinal metaplasia. Two of 118 microdissected samples of EBVaGC and 5 of 62 samples of EBV-negative GCs showed amplification of EBV-DNA, consisting of 3 pyloric and 4 fundic but no metaplastic gland samples.CONCLUSIONS: EBVaGC may develop from rare EBV-infected epithelial cells with severe atrophic gastritis, but the process is not directly related to intestinal metaplasia or H. pylori infection.