RESUMO
Epstein Barr virus (EBV) has been reported to be present in a minority of gastric carcinomas and may be implicated in its pathogenesis. This study was aimed at determining the occurrence of EBV in 43 consecutive gastrectomy specimens with a variety of benign and malignant lesions. In situ hybridisation was used for detection of EBER RNA, the marker for latent EBV infection. Only 1/20 (5%) gastric cancers was EBER positive; a moderately differentiated adenocarcinoma with a heavy lymphocytic infiltration. The interstitial lymphocytic infiltrate was predominantly of B cell type, but the majority of lymphocytes overlying the tumour cells were CD8+ T cells. The other gastric lesions examined, which included 15 peptic ulcers, 6 stromal tumours and 2 lymphomas, were all EBER negative. Using a biotin detection system, scattered EBER positive cells were seen in adjacent normal gastric and/or duodenal mucosa in 9 sections from 8 cases (i.e., in 19% of all 43 cases examined). However, on using a digoxygenin detection system, no reactivity was found in these normal cells. An immunoperoxidase stain for chromogranin A showed that these apparently 'EBER positive' cells corresponded to normal chromogranin positive neuroendocrine cells within the gastric and duodenal mucosa. We conclude that EBV infection occurred only in the lymphoepithelioma type of gastric carcinoma and was absent from the other adenocarcinomas and from normal and benign tissues. The occasional EBER positive reaction encountered in normal cells was probably the result of a false signal arising from neuroendocrine cells as a consequence of the biotin-containing detection system.
