PHENOTYPIC CHARACTERISTICS OF EPSTEIN-BARR-VIRUS-ASSOCIATED GASTRIC CARCINOMAS

We identified Epstein-Barr-virus(EBV)-associated gastric carcinomas by in situ hybridization that targets EBV-encoded small RNA, and investi gated their phenotypic characteristics by mucin histochemistry. Out of 132 gastric carcinomas, 15 were EBV-positive, and they were exclusive ly located at the proximal part of the stomach; 8 were early and 7 wer e advanced carninomas. Out of the 15 EBV-positive carcinomas, 10 were so-called gastric carcinoma with lymphoid stroma (GCLS); 4 of the othe r 5 tumours were moderately differentiated adenocarcinoma (tub 2) show ing a ''lace pattern''. This pattern was also seen in the intramucosal parts of 6 (3 early and 3 advanced) GCLS. As for the mucin phenotype of the cancer cells, the gastric type was predominant in the EBV-posit ive tumours, while the EBV-negative tumours, even with the lace patter n or GCLS, showed phenotypes other than the gastric type (intestinal o r mixture of intestinal and gastric). It was inferred that EBV-positiv e gastric carcinomas show tub 2 with the lace pattern and gastric phen otype in earlier stages, and become GCLS during the tumour progression , but the gastric phenotype tends to remain throughout the history.