Detection and Subtyping of Epstein-Barr Virus in Gastrointestinal Adenocarcinomas and Malignant Lymphomas

ABSTRACT

Epstein-Barr virus (EBV) has been linked to a spectrum of neoplastic conditions, including Burkitt's lymphoma, nasopharyngeal carcinoma, Hodgkin's disease, lymphoepithelioma-like carcinomas and malignant lymphomas in immunocompromised state. To determine the prevalence and the subtype of EBV in gatrointestinal malignancies, fifty cases of adenocarcinomas and seventeen cases of malignant lymphomas were analyzed by EBERs in situ hybridization and polymerase chain reaction using primers for EBNA-1, EBNA-2A and EBNA-2B, on the paraffin sections. In addition, immunohistochemical stain for p53 protein was performed to investigate the potential role of EBV infection on tumor suppressor gene, p53, during tumorigenesis. EBER was detected in 6 of 26 gastric adenocarcinomas, 2 of 24 colon adenocarcinomas, and 8 of 17 malignant lymphomas. EBER was more prevalent in malignant lymphoma arising in the intestine (6/6) than in the stomach (2/11), and was detected in both B and T cell phenotypes. EBNA-1 was positive in 11 of 16 EBER positive cases and the subtyping was possible in 8; both type 1 and 2 were detected in gastric cancers, whereas only type 2 was found in intestinal neoplasms. In adenocarcinomas the high rate of p53 protein overexpression was found in both EBER positive (8/8) and negative cases (32/42), whereas the positive rate was higher in EBER positive cases (7/8) than in EBER negative cases (4/9) of malignant lymphomas. From the results, it can be concluded that EBV infection and the p53 tumor suppressor gene are independently associated in a significant portion of the gastrointestinal malignancies, but the mechanism of action remains to be elucidated.