Differential efficacy of bortezomib plus chemotherapy within molecular subtypes of diffuse large B-cell lymphoma

Abstract

Gene expression profiling of diffuse large B-cell lymphoma (DLBCL) has revealed distinct molecular subtypes that include germinal center B cell-like (GCB) and activated B cell-like (ABC) DLBCL. ABC DLBCL has a worse survival after upfront chemotherapy and is characterized by constitutive activation of the antiapoptotic nuclear factor-kappa B (NF-κB) pathway, which can inhibit chemotherapy. We hypothesized that inhibition of NF-κB might sensitize ABC but not GCB DLBCL to chemotherapy and improve outcome. As the proteasome inhibitor bortezomib can inhibit NF-κB through blocking IκBα degradation, we investigated bortezomib alone followed by bortezomib and doxorubicin-based chemotherapy in recurrent DLBCL. Tumor tissue was analyzed by gene expression profiling and/or immunohistochemistry to identify molecular DLBCL subtypes.As a control, we showed that relapsed/refractory ABC and GCB DLBCL have equally poor survivals after upfront chemotherapy. Bortezomib alone had no activity in DLBCL, but when combined with chemotherapy, it demonstrated a significantly higher response (83% vs 13%; P