Bcl-2 protein frequency in patients with high-risk diffuse large B-cell lymphoma

Abstract

Context and objective: Gene expression and immunohistochemical profiling of diffuse large B-cell lymphoma (DLBCL) have revealed important prognostic subgroups: germinal center B-cell-like (GCB-like) DLBCL and activated B cell-like (ABC-like) DLBCL. Although few reports on high-risk DLBCL are available, the prognosis for the GCB-like subgroup has been shown to be better than that of the ABC-like subgroup. The role of Bcl-2 as a predictor of survival in DLBCL cases is unclear and its expression varies between the two subgroups of DLBCL. In this study, we analyzed the frequency and prognostic impact of Bcl-2 protein expression in high-risk DLBCL cases. Design and setting: Retrospective cohort study among DLBCL patients treated at Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP). Methods: The prognostic impact of the expression of the proteins CD10, Bcl-6, MUM1 (multiple myeloma oncogene-1) and Bcl-2 on high-risk DLBCL cases was evaluated by means of immunohistochemistry. Seventy-three patients aged 18-60 years were evaluated for all these markers. Results: Twenty-four cases (32.9%) were GCB-like and 49 (67.1%) were ABC-like, with no difference regarding complete remission, disease-free survival or overall survival rates. Twenty-seven patients (37%) showed Bcl-2 expression, which was the only independent factor predicting a worse prognosis for overall survival according to multivariate analysis. Conclusion: Bcl-2 protein was expressed in 37% of the high-risk DLBCL patients, without any difference between the ABC-like DLBCL and GCB-like DLBCL cases.