[In situ detection of Epstein-Barr virus in the non-neoplastic gastric glands and infiltrated lymphocytes].

Recently, clonal EBV-DNA and/or EBV-encoded small RNA(EBER1) have been detected in some gastric carcinomas. We reported the first observation of EBV infection in gastric glands with intestinal metaplasia, and characterized the EBV-infected lymphocytes which infiltrated in gastric mucosa. To determine the cellular location of EBV, EBER1 in situ hybridization(ISH) with an EBER1 oligonucleotide probe was applied to paraffin sections of the non-neoplastic gastric mucosa in 80 cases of gastric carcinoma and 49 cases of gastric ulcer. Not only was EBER1 expression detected in the nucleus of gastric cancer cells(5 cases) but also in non-neoplastic gastric epithelial cells(3 cases) and in infiltrated lymphocytes(40 cases). A single or a few shedding non-neoplastic epithelial cells in 2 cases of EBV-associated gastric cancer showed EBER1 expression. In one case, EBER1 was observed in all of the epithelial cells of a few gastric glands with intestinal metaplasia, suggesting that the stem cells of the metaplastic gastric glands were infected with EBV. EBV DNA was also detected in the EBER1-positive metaplastic glands scratched from the paraffin section by a single cell PCR method with a BamHI W primer pair. However, immunohistochemical examination showed that these metaplastic glands lacked expression of EBNA2 and LMP-1. The observation of these rare EBV-infected metaplastic glands reinforces the pre-transformation EBV infection hypothesis for EBV-associated gastric carcinoma. The double staining using ISH and immunohistochemistry revealed that EBER1 positive lymphocytes showed a B cell marker of L26(< 50%) but not T cell markers of UCHL1 and OPD4.