Association of primary central nervous system lymphomas with the Epstein-Barr virus.

The incidence of primary central nervous system lymphoma (PCNSL), previously a rare tumor, has increased significantly over the past few decades, partly due to the AIDS epidemic but also in immunocompetent individuals. Studies from Western countries have shown a consistent association of tumors occurring in immunocompromised individuals with the Epstein-Barr virus (EBV) suggesting an important role for the virus in the pathogenesis of these tumors, but an infrequent association of the virus with PCNSL in the immunocompetent host has also been noted. We studied 11 patients with PCNSL who had no evidence of an immunocompromised state. All the tumors were aggressive B cell lymphomas. EBV association was studied using EBER in-situ hybridization. 10 out of the 11 tumors were negative for EBV, indicating that tumors in immunocompetent individuals in developing countries are also infrequently EBV associated and that a different pathogenetic mechanism is operative in the evolution of these tumors.