Detection of BCL6 fusion transcripts by 5′ RACE. Nested PCR and the control PCR products of 5′ RACE were separated by gel electrophoresis. Ethidiumbromide–stained gel shows 2 representative cases of the 13 cases with one BCL6 translocation partner gene (cases 4 [DLBCL] and 29 [DLBCL]), and all 6 cases with 2 or more independent BCL6 translocation partner genes (case 6 [DLBCL], 12 [DLBCL], 14 [DLCLML], 17 [DLCLML], 18 [MALT], and 34 [DLBCL]). The case number is shown above each lane. cDNA: purified control cDNA was amplified with control forward and reverse primers. dA: poly dA-tailed control cDNA was amplified with oligo-dT anchor primer and the control reverse primer. Arrows point to bands representing BCL6 chimeric transcripts (indicating 1 to 4 fusion partners found in individual cases): case 4 (IGH γ3), case 29 (transferrin receptor), case 6 (chromosome 3 clone RP11-49A15 and chromosome 3q clone RP11-45H13), case 12 (IGH γ3 and chromosome 7 clone RP11-611L7), case 14 (chromosome 2 clone RP11-551D18, uncharacterized sequence, and chromosome X clone RP13-12804), case 17 (chromosome 13q clone RP11-114G1, chromosome 7 clone RP11-63005, chromosome 2 clone RP11-211K17, and chromosome 3q clone RP11-489M17), case 18 (chromosome 9 clone RP11-381G8 and chromosome 5 clone CTD-2074D8), case 34 (chromosome 7q11-q22 clone RP5-1164F5, IGLL, and chromosome 19 clone CTD-2331H12). The complete sequences of the chimeric transcripts are available upon request.