Epstein–Barr virus‐associated primary gastrointestinal lymphoma in non‐immunocompromised patients in Korea

We examined 81 cases of primary gastrointestinal lymphomas in Korea, including 64 gastric lymphomas and 17 intestinal lymphomas, for EBV expression by EBER-1 in situ hybridization (ISH) and EBNA-1 PCR. In EBER-1 positive cases, we performed immunohisto-chemistry for latent membrane protein-1 (LMP-1) and EBV diffuse early antigen (EA(D)) to compare EBV latent gene expression and lytic process. EBER-1 was detected in 15 of 81 cases of lymphomas. EBER-1 expression showed three different patterns on tumour cells; diffuse 4/81 (5%), localized 4/81 (5%), and a few scattered pattern 7/81 (9%). We regarded diffuse pattern and localized pattern as EBER-1 positive group (8/81: 10%). Diffuse pattern of EBER-1 was shown in all three T-cell lymphomas and one B-cell lymphoma. A localized pattern was seen all in B-cell lymphomas. The EBER-1 expression was ll% in the stomach (7/64) and 6% in the intestine (1/17). Five of the eight EBER-1 positive gastric lymphomas were histologically diffuse large B-cell lymphomas, and the other three were peripheral T-cell lymphoma, unspecified, one angiocentric lymphoma, and one intestinal T-cell lymphoma by REAL classification. Eight MALT type gastric B-cell lymphomas showed no EBV association. EBV nuclear antigen (EBNA-1) was detected in 15 of 45 resected cases (33%) by PCR. EBER-1 positive cases were all EBNA-1 positive. Twelve EBNA-positive/EBER-nega-tive cases consisted of seven cases showing a few scattered EBER-1 positive lymphocytes. LMP-1 and diffuse early antigen (EA(D)) was detected in five and three cases, respectively. Although follow-up information in our series was incomplete, it seemed that there was no significant difference in their staging or prognosis between EBER-positive cases and EBER-negative group. It is concluded that EBV is associated with some lymphomas among Koreans without overt pre-existing immunodeficiency, especially in T-cell lymphomas.