Bcl-2 gene rearrangement in Jordanian follicular and diffuse large B-cell lymphomas

OBJECTIVE: Follicular lymphoma (FL), a common subtype of non-Hodgkin's lymphoma (NHL) in the West, represents a rare subtype in Jordan. Bcl-2 gene rearrangement plays a crucial role in the biology of the vast majority of FL and a substantial number of diffuse large B-cell lymphoma (DLBCL) in the West; but its presence has not been studied in Jordan. Our aims are to document if bcl-2 gene rearrangement exists in Jordanian FL and DLBCL, and if present to determine whether its frequency among these lymphomas is different from the West and therefore may be responsible for some of the epidemiological differences seen between Jordan and the West.

METHODS: The study was conducted in the year 2001 using polymerase chain reaction (PCR), to detect bcl-2 gene rearrangement in paraffin sections in 5 FL and 23 DLBCL cases diagnosed at the Department of Pathology at Jordan University of Science and Technology, Irbid, Jordan. Two sets of primers including the major breakpoint region (MBR) and the minor cluster region (MCR) were used.

RESULTS: Amplifiable DNA was extracted from all cases. Bcl-2 gene rearrangement was seen among 4 (80%) of 5 FL cases, and 8 (35%) of 23 DLBCL cases. The majority of the rearrangements involved the MBR; however, one fourth of cases (one of 4 FL; 2 of 8 DLBCL) with bcl-2 rearrangement involved the MCR.

CONCLUSION: Bcl-2 gene rearrangement was seen in the vast majority of Jordanian FL cases and approximately one third of all DLBCL cases. 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 presence of bcl-2 gene rearrangement in DLBCL may define a subset of lymphomas that may be biologically and clinically unique and different from the rest of DLBCL.