EPSTEIN-BARR VIRUS-ASSOCIATED GASTRIC ADENOCARCINOMAS AMONG KOREANS

Epstein-Barr virus (EBV)-associated gastric carcinomas have been repor ted from various regions of the world. Epstein-Barr virus appears to b e pathogenetically related to some gastric carcinomas. To determine th e incidence of EBV association with gastric carcinomas among Koreans, the authors have studied EBV genome expression in 89 consecutive patie nts with gastric carcinomas diagnosed at the Catholic University Hospi tals in Seoul, Korea, using in situ hybridization (ISH) for EBV-encode d small RNAs (EBERs), and immunohistochemistry for EBV latent membrane proteins (LMP) and CD21 antigen on paraffin sections. Thirty-seven ga stric specimens with benign ulcer disease were used controls. EBV-enco ded small RNAs were expressed in tumor cell nuclei in 12 patients (13. 5%). None of the controls or benign portions of the cases were positiv e. In the positive cases, all tumor cell nuclei were uniformly stained and the staining intensity was strong. Immunohistochemistry for LMP w as positive in 3 of 12 EBERs positive patients and none of EBERs negat ive patients. EBV latent membrane proteins was localized only in the l ymphoid cells infiltrating the tumor in two patients, and tumor cells as well as infiltrating lymphoid cells in one patient. These results i ndicate that the rate of EBV association with gastric carcinomas in Ko reans is relatively high and comparable to other Far Eastern Asian reg ions. The expression pattern in EBV-associated gastric carcinomas is s imilar to those of nasopharyngeal carcinomas in which clonality analys is using specific probes to the tandem repeat region of EBV yielded si ngle episomal bands suggesting that EBV infection in EBV-associated ga stric carcinomas are also clonal and pathogenetically related to the n eoplasm. However, the mechanism of tumorigenesis remains to be elucida ted.