Efficacy of screening the intermediate cluster region of the bcl2 gene in follicular lymphomas by PCR

Background: The t(14; 18) translocation is a common finding in nodal follicular B cell lymphomas and diffuse large B cell lymphomas, and results in the overexpression of the antiapoptotic bcl2 protein. This chromosome rearrangement can be detected by the polymerase chain reaction (PCR), with most breakpoints in the bcl2 gene occurring within either the major breakpoint region (mbr) or the minor cluster region (mcr). However, recent investigations have revealed several breakpoints between these two regions, which cluster 19 kb 39 of mbr in the "intermediate cluster region'' (icr). Aims/Methods: To analyse a series of 57 B cell follicular lymphomas known to carry the t( 14; 18) by PCR with primers directed against all three cluster regions to determine the efficacy of screening the icr site. Results: Twenty six samples had an mbr rearrangement, four an mcr rearrangement, and three an icr rearrangement. Conclusions: These results suggest that screening for icr is at least as efficacious as screening for mcr rearrangements.