BCL-6 in aids-related lymphomas: pathogenetic and histogenetic implications.

AIDS-related non-Hodgkin's lymphomas (AIDS-NHL) are classified into Burkitt's lymphoma, diffuse large cell lymphoma (DLCL), and body cavity based lymphoma. The molecular pathogenesis of AIDS-NHL is complex and involves the genetic alteration of several cancer related genes, including the BCL-6 proto-oncogene. BCL-6 encodes a zinc finger transcription factor which is selectively expressed by germinal center (GC) B-cells, but not by pre-GC or post-GC B-cells. Genetic alterations of BCL-6 occur frequently among B-cell NHL and comprise gross rearrangements as well as small mutations of the 5′ noncoding region of the gene. Gross rearrangements of BCL-6 among AIDS-NHL cluster with 20% AIDS-DLCL. Conversely, mutations of the 5′ noncoding region of BCL-6 occur at sustained frequency throughout the clinico-pathologic spectrum of AIDS-NHL and represent the most common genetic alteration presently detectable in these lymphomas. The frequency of BCL-6 mutations, as well as their location in the proximity of the BCL-6...