Chromosomal translocation involving the BCL6 gene affects not only immunoglobulin (Ig) genes but also a number of non-Ig genes as partners. The molecular anatomy of the BCL6 gene rearrangements in 39 cases with diffuse large B-cell lymphoma (DLBCL) by long-distance polymerase chain reaction-based assays was determined. The results showed that Ig genes were affected in 21 cases; non-Ig genes, 15 cases; a deletion of more than a 1-kb segment, 2 cases; and a point mutation, 1 case. Comparative studies between the 21 cases with Ig gene partners and the 17 cases with non-Ig gene partners, including 2 cases with the deletion, showed that the overall survival of the latter group of patients was significantly inferior to that of the former (P = .0440), and the estimated 2-year overall survival rates were 58.3% vs 17.6% (P = .005). Non-Ig/BCL6 fusion is a poor prognostic indicator of DLBCL, and DLBCL with BCL6 translocation could be subclassified according to the individual partner locus and/or gene. (Blood. 2000;96:2907-2909)