Molecular analysis of primary central nervous system and primary intraocular lymphomas.

Primary central nervous system lymphoma (PCNSL) is usually a large B-cell, high grade non-Hodgkin's lymphoma (NHL) classified as a diffuse large cell lymphoma (DLCL). In rare cases, however, T cell lymphomas have been described. Although a relatively rare tumor, the incidence of PCNSL has increased dramatically over the past 15 years in both immuno-competent and immunocompromised patients. The disease is aggressive with a 5-year survival rate of less than 25 %. The cause of death is progressive and recurrent disease in the CNS, despite aggressive treatment. Approximately 20-25% of patients with PCNSL also have primary intra-ocular lymphoma (PIOL). PCNSL and PIOL are closely related and inter-connected pathologies involving two immune privileged sites. The study of PCNSL and PIOL has been limited due to the fact that viable malignant cells are rare and difficult to recognize. Moreover, the cells are difficult to culture and to date there is no good animal model for the disease. Here, we will present the current literature on the disease. In particular, we will present data suggesting that PCNSL in immuno-compromised and AIDS patients may correspond to two different pathologies. Furthermore, we will discuss how the study of these lymphomas can benefit from new advanced molecular biology techniques including single cell PCR and laser capture microdissection (LCM). PCNSL and PIOL are aggressive tumors, therefore, early diagnosis and prompt, aggressive treatment may improve prognosis. Advanced molecular biology will help delineate the oncogenesis of PCNSL and PIOL.