Re: B-Cell Non-Hodgkin's Lymphoma: Evidence for the t(14;18) Translocation in All Hematopoietic Cell Lineages

Extract

The chromosomal translocation t(14;18)(q32;q21) can cytogenetically be detected in 80%–85% of follicular lymphomas and in up to 30% of diffuse large-cell lymphomas ( 1 ). Pathogenetically, the translocation t(14;18) juxtaposes the bcl-2 (also known as BCL2) gene in 18q21 to the immunoglobulin heavy-chain locus in 14q32. This subsequently leads to overexpression of the mitochondria membrane protein Bcl-2, which prevents cells from undergoing apoptosis.

In a recent issue of the Journal, Yarkoni et al. ( 2 ) presented data of a combined cytogenetics and fluorescence in situ hybridization (FISH) study of the translocation t(14;18). By FISH, the t(14;18) was detected in eight of 10 bone marrow aspirates from patients with B-cell lymphomas, including a patient with immunoblastic lymphoma. The t(14;18) has so far been reported only in seven patients with immunoblastic lymphoma, three of them presenting a Burkitt translocation as well ( 3 ). In non-Hodgkin's lymphomas that were diagnosed according to the updated Kiel classification, the t(14;18) is restricted to centroblastic lymphomas and rare cases of Burkitt's lymphoma but is never found in immunoblastic lymphoma [( 4 ); our unpublished data].