INVOLVEMENT OF THE BCL3 GENE IN 2 PATIENTS WITH CHRONIC LYMPHOCYTIC-LEUKEMIA

The t(14;19)(q32;q13) is a recurring translocation found in some patie nts with chronic lymphocytic leukemia (CLL), and the t(14;19)juxtapose s the BCL3 gene on chromosome 19 with the immunoglobulin heavy chain g ene (IGH) locus on chromosome 14. Genomic DNAs from 49 patients with c hronic B-cell leukemia and the related lymphomas were examined by Sout hern blot hybridization using 2 separate probes, named palpha1.4P and palpha.5B, from the BCL3 gene locus. None of the 18 patients with leuk emic manifestations of non-Hodgkin's lymphomas had detectable BCL3 rea rrangements. Of 31 patients with CLL, 2 had the BCL3 rearrangements. A comigration study using the Calpha and Cepsilon constant gene probe f rom IGH indicated that the t(14;19) translocation occurred in these 2 patients, and they were diagnosed with CLL/prolymphocytic (PL) accordi ng to the French-American-British (FAB) classification. Probes for the IGH locus revealed that leukemia cells of the 2 patients each were cl onal, indicating that both small lymphocytes and prolymphocytoid cells found in the peripheral blood of one patient had the t(14;19), as wel l as a major population of the small lymphocytes in the peripheral blo od of a second patient. It thus appears that tumor cells carrying the t(14;19) constitute a distinct disease entity in a group of chronic B- cell leukemia, that has a converting potential to more aggressive form s.