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 investigated their phenotypic characteristics by mucin histochemistry. Out of 132 gastric carcinomas, 15 were EBV-positive, and they were exclusively located at the proximal part of the stomach; 8 were early and 7 were advanced carninomas. Out of the 15 EBV-positive carcinomas, 10 were so-called gastric carcinoma with lymphoid stroma (GCLS); 4 of the other 5 tumours were moderately differentiated adenocarcinoma (tub 2) showing 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-positive tumours, while the EBV-negative tumours, even with the lace pattern or GCLS, showed phenotypes other than the gastric type (intestinal or mixture of intestinal and gastric). It was inferred that EBV-positive gastric carcinomas show tub 2 with the lace pattern and gastric phenotype in earlier stages, and become GCLS during the tumour progression, but the gastric phenotype tends to remain throughout the history.