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 microgram of DNA (60,000-80,000 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 beta-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 beta-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.

Amplification of genomic DNA demonstrates the presence of 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.

Anaplastic large cell lymphoma (ALCL) is a distinct clinicopathologic variant of intermediate grade non-Hodgkin's lymphomas (NHL) composed of large pleomorphic cells that usually express the CD30 antigen and interleukin (IL)-2 receptors, and is characterized by frequent cutaneous and extranodal involvement. With variable frequency ALCL bear the t(2;5)(p23;q35) chromosomal translocation that fuses the nucleophosmin (NPM) gene on chromosome 5q35 to a novel protein kinase gene, Anaplastic Lymphoma Kinase (ALK), on chromosome 2p23. We determined the frequency of this translocation with a novel DNA polymerase chain reaction (PCR) technique using 0.5 microgram of genomic DNA, 5'-primers derived from the NPM gene and 3'-primers derived from the ALK gene and hybridization with internal probes. The presence of amplifiable DNA in the samples was tested with the inclusion in the PCR reaction of oligonucleotide primers designed to amplify a 3016-bp fragment from the beta-globin locus. NMP-ALK fusion amplicons were detected using DNA isolated either from all three ALCL cell lines tested, or from all four primary ALCL tumors known to contain the t(2;5)(p23;q35) translocation. Nested amplicons were detected by hybridization in 100% of specimens diluted 10(4)-fold and in 20% of those diluted 10(5)-fold. We subsequently examined archival genomic DNA from 20 patients with ALCL, 39 with diffuse large cell, 2 with mantle cell, 20 with peripheral T cell, 13 with low-grade NHL, 31 with Hodgkin's disease (HD), and 6 with lymphomatoid papulosis. Fusion of the NPM and ALK genes was detected in three of 18 patients with ALCL who had amplifiable DNA (17%, 95% confidence intervals 4% to 41%), but not in any patients with other NHL, HD, or lymphomatoid papulosis. The amplicon sizes were different in all cell lines and patients reflecting unique genomic DNA breakpoints. We conclude that with genomic DNA-PCR the rearrangement of the NPM and ALK loci is restricted to patients with ALCL. Further studies are needed to determine the prognostic significance of the NPM-ALK rearrangement, to determine whether its detection can aid in the differential diagnosis between ALCL. Hodgkin's disease, and lymphomatoid papulosis, and to establish the usefulness of the genomic DNA PCR in the monitoring of minimal residual disease in those patients whose tumors bear the t(2;5).