Objective: To study the immunophenotypic and genetic features of diffuse large B-cell lymphomas (DLBCLs), and their relationship to prognosis.
Methods: Seventy-three cases of DLBCLs with follow-up data were studied by using immunohistochemistry for CD3, CD10, CD20, bcl-6 and MUM-1. The DLBCLs were classified into germinal center B cell-like (GCB) and non-germinal center B cell-like (non-GCB) subtypes according to Hans' algorithm. Fluorescence in-situ hybridization (FISH) for bcl-6 gene expression (located on chromosome 3q27) was performed on paraffin-embedded tissues of 54 cases.
Results: In the 73 cases studied, 16 cases (21.9%) belonged to GCB subtype and 57 cases (78.1%) belonged to non-GCB subtype. Breakage of 3q27 was detected in 11 of the 54 cases (20.4%) and proliferation was detected in 14 cases (25.9%). The five-year overall survival rate of GCB subtype was significantly higher than that of non-GCB subtype (78% versus 40%, P = 0.011). The bcl-6-positive cases had a better clinical outcome than that of the bcl-6-negative cases (P = 0.041). Breakage of 3q27 predicted a worse overall survival.
Conclusions: The current study shows that the prognosis of GCB subtype of DLBCLs is better than that of non-GCB subtype. The expression of bcl-6 protein predicts a better clinical outcome, while the breakage of 3q27 predicts a worse overall survival.