Rearrangements of bcl-6, bcl-2, c-myc and 6q deletion in B-diffuse large-cell lymphoma: clinical relevance in 71 patients.

Background: B-diffuse large-cell lymphomas (DLCL) have been associated with some molecular lesions, but the role of such lesions as prognostic markers is still controversial. This report concerns an investigation of the frequency and clinical correlation of bcl-6, bcl-2, c-myc rearrangements and 6(q) deletions in B-DLCL.
Patients and Methods: The presence of these genetic lesions was analyzed in samples of lymph nodes or bone marrow collected at diagnosis in 71 patients with B-DLCL, all treated with an anthracycline-containing chemotherapy regimen.
Results: Rearrangement of bcl-6 was found in 11 patients (15%), rearranged bcl-2 in 12 (17%), 6(q) deletions in 10 patients (14%) and c-myc rearrangement in four (6%). Patients with rearranged bcl-6 tended to have a more aggressive disease than patients with germ-line bcl-6 (intermediate-high/high risk according to IPI criteria: 73% vs. 43%), but there were no differences in three-year survival rates (62% vs. 42%) between the two groups. The numbers of involved extranodal sites were similar in patients with rearranged and those with germ-line bcl-6. Patients with bcl-2 rearrangement appeared to have a less aggressive disease than those with germ-line bcl-2 (low/ low-intermediate risk 75% vs. 47%) and a slightly better three-year survival rate (70% vs. 41%) but again the difference was not significant. Both groups with or without 6(q) deletion had similar clinical characteristics and outcomes. The four patients with c-myc rearrangement had aggressive disease and did poorly.
Conclusions: The analysis of molecular lesions in B-DLCL may be useful for a better diagnostic definition; however, in this study we were unable to show that the evaluated genetic lesions had a significant impact on clinical outcome.