Detection of Epstein-Barr Virus and Helicobacter pylori in Primary Malignant Gastric Lymphomas

We studied five patients diagnosed with primary gastric lymphoma between 1985 and 1995 in Omura Munisipa Hospital to investigate the relationship between Helicobacter pylori, Epstein-Barr virus and primary malignant gastric lymphoma. H. pylori was detected by hematoxylin-eosin stain, Giemsa stain, immunohistochemistry while EBV was detected by in situ hybridization in the lymphoma and background mucosa. H. pylori but not EBV, was detected in all cases. Furthermore, malignant lymphomas were mainly located in the area of the fundic gland where H. pylori was frequently identified and caused inflammation. In contrast, malignant lymphomas were not detected in areas with intestinal metaplasia. Our results suggest that malignant lymphoma may develop in a region where the immune system has been activated by H. pylori. In contrast, EBV is unlikely to play an important role in the development of gastric lymphoma, compared to H. pylori