DNA was extracted from archival CPs of B-cell NHL cases with previous fluorescence in situ hybridization (FISH) assays for MYC rearrangement and/or IGH/BCL-2 translocation.
Translocations involving 3q27 that affect the BCL6 gene are common and specific chromosomal abnormalities in B-cell precursor non-Hodgkin lymphoma (mainly diffuse large-cell and follicular lymphoma), but they have not been reported in Burkitt lymphoma.
Small deletions occur in highly conserved regions of the LAZ3/BCL6 major translocation cluster in one case of non-Hodgkin's lymphoma without 3q27 translocation.
Using fluorescence in situ hybridization and molecular analyses, we report here on the rearrangement of the RhoH/TTF gene, at band 4p13, in four cases of NHL with t(3;4)(q27;p13) translocation and its fusion to the LAZ3/BCL6 gene at band 3q27, in three of these cases.
Twenty cases of Japanese non-Hodgkin's lymphoma with B cell markers were studied with respect to their immunoglobulin heavy (IgH) chain gene loci on chromosome 14 and BCL2 loci on chromosome 18.
This study was planned with the aim to investigate the association between bcl-2 gene rearrangements and apoptotic changes during chemotherapy in patients with non-Hodgkin's lymphoma.
The gene was identified by fusion to the BCL6/LAZ3 oncogene in an initially described t(3;4)(q27;p11) translocation in a non-Hodgkin's lymphoma cell line.
In B cell lymphomas, structural alterations of the BCL-6 promoter region, including chromosome translocation and somatic hypermutation, represent the most frequent genetic lesions associated with non-Hodgkin lymphoma, especially of diffuse large cell lymphoma, a malignancy often derived from germinal centre (GC) B cells.
The presence of a bcl-2 gene rearrangement in de novo DLCL suggests a possible follicle center cell origin and perhaps a distinct clinical behavior more akin to low-grade non-Hodgkin's lymphoma (NHL).
These figures are similar to those reported in the West, and therefore bcl-2 gene rearrangement does not help in explaining the epidemiological differences of NHL between Jordan and the West.
The t(14;18)(q32;q21) translocation, involving the BCL2 gene and junctional segments (JH) of the immunoglobulin heavy chain gene (IGH), constitutes the most common chromosomal translocation in non-Hodgkin's lymphoma of B-cell type.
In addition, two other genes, BCL6 and BCL2, which are classically related to apoptosis and non-Hodgkin lymphoma, were shown for the first time to be involved in amplification.
Our results are compatible with previous cytogenetic reports in which the 3q27 translocation was observed in 15-20% of NHL; however, patients with the LAZ3 rearrangements exhibited a wide range of clinico-pathologic characteristics.