Prognostic Significance of BCL-2 and BCL-6 Expression in MYC-positive DLBCL

Abstract

Background: Double-expression lymphoma (DEL) is a rare subgroup of diffuse large B-cell lymphoma (DLBCL), which has coexpression of MYC and BCL-2. Coexpression of MYC and BCL-2 is considered a prognostic marker portending poor outcomes. However, the prognostic effect of BCL-2 and BCL-6 expression in DLBCL remains controversial.

Materials and methods: Immunohistochemical staining was performed to detect MYC, BCL-2 and BCL-6 expression in 212 patients with newly diagnosed DLBCL and assess the prognostic effects of BCL-2 and BCL-6 expression. The DLBCL patients were treated with R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine [Oncovin], prednisone)-like regimens.

Results: Retrospective analysis revealed that BCL-2⁺ and BCL-2⁺/MYC⁺ were prognostic factors indicative of poor outcomes. Patients with BCL-2⁺ and/or MYC⁺ expression had a poorer prognosis than that of patients with BCL-2^- and/or MYC^- expression. Patients with BCL-2⁺/MYC^- expression showed a trend toward poorer survival than those with BCL-2^-/MYC⁺ expression, suggesting that BCL-2 plays a more important role than MYC. Also, patients with BCL-6^-/MYC⁺ expression had poorer progression-free survival than those with BCL-6⁺/MYC⁺ expression. In addition, patients with BCL-2⁺/MYC⁺/BCL-6^- expression had the worst prognosis, suggesting that BCL-6^- is a prognostic factor for poor outcomes for MYC⁺ DLBCL patients. Altogether, our findings have shown that BCL-2 is an independent prognostic factor and possibly plays a more important role than MYC in MYC⁺ DLBCL patients. Furthermore, we found that BCL-6^- expression could also be a prognostic factor portending poor outcomes for MYC⁺ DLBCL patients.

Keywords: Clinic; Diffuse large B-cell lymphoma; Double-expression lymphoma; Prognosis; Retrospective study.