Application of long PCR to detect t(8;14)(q24;q32) translocations in childhood Burkitt's lymphoma and B-ALL

Background: Burkitt's lymphoma (BL) and B-ALL are characterized by chromosomal translocations juxtaposing the c-myc gene on chromosome 8 to one of the immunoglobulin loci. Translocations involving the immunoglobulin heavy chain (IgH) on chromosome 14 are found in approximately 75%-90% of these tumors. The breakpoint regions are located over a wide range on both chromosomes. Patients and methods: To detect the translocations, we developed a PCR method to generate long products. After extraction of genomic DNA (QiaAmp System, Qiagen, Hilden, Germany), DNA was amplified using a mixture of Taq and Pwo polymerases (Boehringer Mannheim, Germany). Several primer Fairs from the S mu, JH, CHI and the C alpha regions on IgH and from exon 1 and intron 1 of the c-myc gene were tested in each patient. Results: Lymphoma cells from 20 children with Burkitt's lymphoma and B-ALL characterized by FAB-L3 morphology were examined. In 11/20 patients, recombinations between chromosomes 8 and 14 could be detected with our primer pairs. PCR products from 800 to 3700 bp in length were obtained reproducibly. After amplification, the products were characterized by restriction enzyme digestion, hybridization, and in part by direct sequencing. Conclusions: This PCR-based method will allow us (1) to determine the localization of chromosomal breakpoints in primary turner material, (2) to investigate whether distinct breakpoints are associated with treatment outcome, and (3) to detect the presence of minimal residual tumor cells during or after therapy.