INTERNAL DNA DELETION WITHIN THE BCL-6 GENE ON UNTRANSLOCATED CHROMOSOME IN NONHODGKINS LYMPHOMA WITH 3Q27 ABNORMALITY

Chromosomal translocations involving the band 3q27 are recognized as c ommon specific cytogenetic abnormalities in B cell non-Hodgkin's lymph oma (NHL), and the BCL-6 gene, identified on 3q27 was shown to be disr upted by these translocations. previously, we have reported biallelic BCL-6 rearrangements occurring in some patients with B cell NHL. In th e present study, we describe a NHL patient with t(3;22)(q27;q11) trans location. In this patient, biallelic BCL-6 abnormalities were indicate d by Southern blot analysis. Further studies revealed that one of the two independent abnormalities was a juxtaposition to the immunoglobuli n (Ig) A gene associated with chromosomal translocation, whereas the o ther was an internal DNA deletion of 1.5 kb area on untranslocated chr omosome 3. Deletion junctions were located within the first exon and t he 5' region of the first intron. The result provides the evidence tha t, besides chromosomal translocation, submicroscopic local DNA recombi nation can cause structural alteration of the BCL-6 gene.