Mucin and differentiation in Epstein-Barr virus-associated gastric carcinoma.

Background/aims: Epstein-Barr virus (EBV) is present in roughly 1 in 10 cases of gastric carcinoma, particularly in undifferentiated adenocarcinomas. To clarify the histological developmental processes in EBV-associated gastric carcinoma, we investigated the presence of EBV infection, changes in the degree of differentiation within lesions, and mucin phenotypes of gastric carcinomas.
Methodology: We had already examined 124 gastric carcinomas using in situ hybridization for EBV-encoded small RNA1 (EBER-1) and 12 lesions were EBER-1-positive. From these lesions we selected 8 carcinomas positive for EBER-1, and then chose 16 EBER-1-negative carcinomas as controls. Hematoxylin and eosin (H&E) stained specimens were examined for changes in histological type within each lesion. Mucin phenotypes of the specimens were determined using human gastric mucin (HGM), MUC2 and CD10 immunostaining.
Results: Of the EBER-1-positive lesions, 50% exhibited the gastric type mucin phenotype, whereas only 19% of the EBER-1-negative lesions were of the gastric phenotype. Changes in the histological type were seen within 75% of the EBER-1-positive lesions and within 62.5% of the EBER-1-negative lesions.
Conclusions: The gastric mucin phenotype tended to be more common in the EBV-associated gastric carcinomas. The influence of EBV infection on the change in the histological type within the lesion was considered to be slight.