Bortezomib induces caspase-dependent (▿) or -independent (▾) cell death in primary tumor cells isolated from patients with B-NHL. Tumor cells isolated from patients with (A) follicular lymphoma (n = 8), (B) small lymphocytic lymphoma (SLL, n = 5), (C) germinal center (GCB) diffuse large B-cell lymphoma (DLBCL, n = 2), and (D) non-GCB DLBCL (n = 3) were exposed in vitro to bortezomib (10μM) in the presence or absence of the pan-caspase inhibitor Q-VD-Oph (2.5μM). Viability was determined using the CellTiter Glo luminescent assay after 48 hours of incubation and expressed as percentage of luminescent signal compared with untreated controls. Samples in which caspase-dependent cell death was observed (n = 5) are denoted with an open upside-down triangle (▿) and those where caspase-independent cell death was observed (n = 10) are denoted with a filled upside-down triangle (▾) while those that were found resistant to bortezomib (> 80% viable) have no marks above them. Of interest, in some patient specimens, caspase inhibition further enhanced bortezomib activity (patients 24 and 37).