BCL-6: rearrangement and mutation in lymphoma

BCL-6 is a zinc finger transcription factor that is highly expressed in normal germinal center B-cells. Its function is to prevent differentiation and apoptosis and allow growth. BCL-6 also is expressed in various lymphoproliferative conditions, for example, diffuse large cell lymphoma, Burkitt's lymphoma, and follicular lymphoma as well as lymphocyte predominant Hodgkin's disease. Expression also has been demonstrated in some T-cell lymphomas. In diffuse large cell lymphoma, BCL-6 is involved in translocations with a number of different translocation partners but most commonly the immunoglobulin heavy chain locus. The first intron of BCL-6 is heavily mutated, and detailed analysis reveals two "hotspots." The mutated region appears to be within a transcriptional control region, and there is the potential for alterations to contribute to overexpression of BCL-6. Methods for deoxyribonucleic acid extraction from lymphoma samples and amplification by polymerase chain reaction of the hypermutated intronic region are described.