HIGH EXPRESSION OF LATENT MEMBRANE-PROTEIN-1 OF EPSTEIN-BARR-VIRUS AND BCL-2 ONCOPROTEIN IN ACQUIRED IMMUNODEFICIENCY SYNDROME-RELATED PRIMARY BRAIN LYMPHOMAS

Nearly all primary brain lymphomas in acquired immunodeficiency syndro me (AIDS) patients are associated with Epstein-Barr virus (EBV). The r ole of EBV in lymphomagenesis is not totally elucidated, One possible mechanism is the overexpression of the BCL-2 oncoprotein, because the latent membrane protein 1 (LMP1) has been reported to transactivate th e bcl-2 gene in vitro. To study the interrelationship between LMP1 and BCL-2 in vivo, we have analyzed and compared their expression in 11 A IDS-related primary brain lymphomas and 57 AIDS-related systemic lymph omas by immunoperoxidase technique on frozen sections. In AIDS-related primary brain lymphomas, LMP1 and BCL-2 were expressed in all cases b ut 1. All positive cases exhibited morphologic immunoblastic features. In contrast, the only negative case was histologically close to Burki tt's lymphoma. In systemic lymphomas, LMP1 was expressed in 21 cases, whereas BCL-2 was positive in only 3 cases, all of which were extranod al. These results indicate that, in addition to the histologic type, t he role of EBV genes and BCL-2 expression in lymphomatous cells differ as a function of their localization. In AIDS-related primary brain ly mphomas, this correlation between LMP1 and BCL-2 overexpression may ha ve a major implication in lymphomagenesis. (C) 1995 by The American So ciety of Hematology.