The LAZ3 gene has been identified on chromosome band 3q27, which is the breakpoint of reciprocal chromosome translocations observed in B-cell non-Hodgkin's lymphoma (NHL).
We conclude (1) that LAZ3 rearrangements occur in a significant fraction of de novo DAL as well as in a smaller subset of indolent and transformed follicular lymphomas; (2) that LAZ3 message is expressed in both rearranged and nonrearranged B-cell lymphomas; and (3) that mutation of the LAZ3 gene does not contribute to its putative oncogenic role in most 3q27 translocated B-cell lymphomas.
Chromosomal translocations involving the band 3q27 are recognized as common specific cytogenetic abnormalities in B cell non-Hodgkin's lymphoma (NHL), and the BCL-6 gene, identified on 3q27 was shown to be disrupted by these translocations.
We concluded that BCL-6 gene rearrangement was more commonly found in diffuse large B-cell lymphoma of primary gastric origin than its nodal counterpart and it may be playing a more important role in the pathogenesis of gastric large B-cell lymphoma.
Southern blot analysis using probes from the major translocation cluster (MTC) region of the BCL6 revealed rearrangement in 32 of a total of 222 patients with various subtypes of B-cell neoplasm.
Genetic alterations of the BCL-6 gene in mice and man have established BCL-6 as a pivotal regulator of normal differentiation of B and T lymphocytes as well as one of the most frequently translocated oncogenes in human B cell lymphomas.
Here we report the identification of the L-Plastin(LCP1) gene as a novel LAZ3 partner in chimeric transcripts resulting from a t(3;13)(q27;q14) translocation, in two cases of B-cell lymphoma.
Mutations of BCL-6 occur frequently in high grade gastrointestinal MALT-NHL and display characteristics similar to those of BCL-6 mutations harbored by other B-cell lymphomas.
Southern hybridisation studies demonstrated altered organisation of Bcl6 in three primary DLCL and the WEHI 231 B-cell lymphoma cell line but not in low grade tumours.
The BCL6 proto-oncogene, located on 3q27, which is rearranged in some MZBCL and a high proportion of large cell B-cell lymphomas with extranodal localization, represents one of the candidate genes residing in these critical regions.
These results imply that overexpression of BOB.1/OBF.1, like overexpression of Bcl6, might play a role in the pathogenesis of germinal center-derived B cell lymphomas.