Long-range amplification of genomic DNA detects the t(2;5)(p23;q35) in anaplastic large-cell lymphoma, but not in other non-Hodgkin's lymphomas, Hodgkin's disease, or lymphomatoid papulosis

Design: Determine the frequency of t(2;5)(p23;q35) in anaplastic large-cell lymphoma (ALCL), non-Hodgkin's lymphoma (NHL), Hodgkin's disease (HD), and lymphomatoid papulosis (LP). Patients and methods: The t(2;5) was detected with a long-range nested polymerase chain reaction (PCR) using 0.5 μg of DNA (60000-80000 cells), 5'-primers from the NPM gene, 3'-primers from the ALK gene, agarose electrophoresis, hybridization, and autoradiography. Patients were evaluable if a 3016 base pair amplicon could be generated from tumor DNA with β-globin primers. Results: Amplicons were detected by PCR of genomic DNA from three ALCL cell lines and four primary ALCLs known to t(2;5) positive. DNA from t(2;5)-positive cell lines diluted 10 4 -fold or 10 5 -fold generated amplicons in 100% or 20% of reactions, respectively. Archival tumor DNA from 144 patients was amplifiable by β-globin amplicons in 126 (88%) who are considered evaluable for this study. Twenty-two had ALCL, 69 other NHLs, 30 HD, and five LP. Genomic DNA PCR detected the t(2;5) in 5 of 22 with ALCL (23%, 95% confidence intervals [95% CI] 8%-45%) but not in those with NHLs, HD, or LP. Among ALCLs the t(2;5) was confined to 5 of 20 with nodal presentations (25%, 95% CI 9%-49%), among whom it was seen in 5 of 15 with T-cell or null-cell phenotype (33%, 95% CI 12%-62%), in 4 of 11 with age < 40 years (36%, 95%, CI 11%-69%), and in 4 of 9 with nodal presentations, T-cell or null-cell phenotype, and age <40 years (44%, 95% CI 14%-79%). Amplicon sizes were different between cell lines and patients, reflecting unique genomic DNA breakpoints, as confirmed by DNA sequencing, and served as an internal control against specimen cross-contamination in the laboratory. Conclusions: Long-range PCR of genomic DNA detects t(2;5) only in ALCL, but not in other NHLs, HD, or LP. Long-range PCR may be useful in establishing diagnosis, determining prognosis, and monitoring minimal residual disease in ALCL.