Anti-bcl-6 is a transcriptional regulator gene which codes for a 706-amino-acid nuclear zinc finger protein. Antibodies to this protein stain the germinal center cells in lymphoid follicles, the follicular cells and interfollicular cells in follicular lymphoma, diffuse large B-cell lymphomas, and Burkitt's lymphoma, and the majority of the Reed-Sternberg cells in nodular lymphocyte predominant Hodgkin's Disease. In contrast, anti-bcl-6 rarely stains mantle cell lymphoma and MALT lymphoma. Anti-bcl-6 expression is seen in approximately 45% of CD30+ anaplastic large cell lymphomas but is consistently absent in other peripheral T-cell lymphomas. bcl-6 is protected by U.S. patents 6,174,997 and 6,783,94 (Cancer Genetics, Inc.)