EPSTEIN-BARR-VIRUS INVOLVEMENT IN GASTRIC-CANCER - BIOMARKER FOR LYMPH-NODE METASTASIS

EBV involvement in gastric cancer is characterized by episomal monoclo nality, high antibody titers, EBV encoded small RNA and EBV nuclear an tigen 1 expression in all tumor cells, and in the intramucosal stage, by a unique morphology. EBV involvement varies by population (similar to 7% of gastric cancers in Japan and >15% in Western countries), sex, histological type, and tumor location. The present study compares fre quency of lymph node metastasis (LNM) between 170 EBV-positive and 159 0 EBV-negative gastric cancer cases in Japan by level of invasiveness, Frequency of LNM increased with increasing depth of invasiveness but was consistently and significantly greater for EBV-negative cases (P = 0.0018), In particular, there were no instances of LNM among 75 EBV-p ositive cases as compared with 53 among 562 EBV-negative cases restric ted to the mucosa and submucosa (odds ratio, 0; 95% confidence limits, 0-0.20). The finding suggests that genetic control of metastasis may differ between EBV-related and other gastric cancers, Also, the possib ility that EBV-positive, noninvasive gastric cancers may not require l ymph node dissection suggests that routine assay of biopsy specimens f or EBV involvement could be important in populations, like that of Jap an, where early gastric cancers are seen frequently.