Immunophenotype as prognostic factor for diffuse large B-cell lymphoma in patients undergoing clinical risk-adapted therapy

Background: For patients with diffuse large B-cell lymphoma (DLBCL), the International Prognostic Index (IPI) predicts the likelihood for cure with chemotherapy. Biological parameters, including expression of Bcl-6, Bcl-2, CD10, major histocompatibility complex class II, and categorization as germinal center (GC) type have been described as IPI-independent prognostic factors. Patients and methods: Biological parameters were evaluated retrospectively by immunohistochemistry in 60 consecutive DLBCL patients of the prerituximab era. Forty-one of 60 patients underwent a risk-adapted treatment strategy including autologous stem-cell transplantation for high-risk patients (age-adjusted IPI = 2-3; slow response to chemotherapy). Results: Bcl-6 expression was associated with superior overall survival (OS) independently of the IPI. Inferior progression-free survival (PFS) was independently correlated with high expression of Bcl-2 and low positivity for HLA-DR and CD10. Distinction into GC and non-GC DLBCL on the basis of Bcl-6, CD10, and IRF-4 expression had no independent prognostic value. Within the risk-adapted treatment strategy, only HLA-DR retained a prognostic impact on OS (P = 0.0058) and PFS (P = 0.0002). Conclusions: in 60 patients with DLBCL treated with risk-adapted therapy, immunohistochemical subcategorization of DLBCL into GC and non-GC type has little clinical value. The IPI-associated risk appears to be mitigated by intensified upfront therapy. Low HLA-DR expression is associated with poor outcome after intensified upfront therapy. Therefore, additional treatment modalities appear to be required.