ABSTRACT
OBJECTIVE: In diffuse large B-cell lymphoma (DLBCL), there is an unmet medical need to select patients who would benefit from intensified frontline treatments such as adding etoposide to an R-CHOP regimen. METHODS: The present work included a retrospective clinical analysis of two patient cohorts and an in vitro study. Primary biopsy samples from DLBCL patients treated with an etoposide-containing high-dose regimen (n = 37) and etoposide-containing frontline treatment (n = 69, R-CHOEP) were studied using immunohistochemical thioredoxin-1 (Trx1) staining. Two DLBCL cell lines expressing Trx1 were cultured, and their expression was silenced using the small interfering RNA knockdown technique. Chemoresistance was tested with doxorubicin, etoposide, vincristine, prednisolone and carboplatin. RESULTS: Thioredoxin-1 knockdown sensitised DLBCL cells to doxorubicin (P < .0001) but decreased etoposide-induced cell death (P < .00001). In DLBCL patients who received etoposide-containing frontline treatment, low cytoplasmic Trx1 expression was associated with inferior 5-year overall survival (46% vs 76%, P = .026) and disease-specific survival (68% vs 90%, P = .026). CONCLUSIONS: Strong Trx1 expression appears to increase drug resistance to doxorubicin but sensitises cells to etoposide. This implies that Trx1 expression might be the first predictive biological marker to select the patients who might benefit from adding etoposide to R-CHOP immunochemotherapy.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Biomarkers , Lymphoma, Large B-Cell, Diffuse/drug therapy , Thioredoxins/metabolism , Adult , Aged , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Cell Line, Tumor , Cyclophosphamide/adverse effects , Cyclophosphamide/therapeutic use , Doxorubicin/adverse effects , Doxorubicin/therapeutic use , Etoposide/administration & dosage , Female , Gene Expression , Gene Knockout Techniques , Humans , Immunophenotyping , Lymphoma, Large B-Cell, Diffuse/diagnosis , Lymphoma, Large B-Cell, Diffuse/etiology , Male , Middle Aged , Neoplasm Staging , Prednisone/adverse effects , Prednisone/therapeutic use , Prognosis , Retrospective Studies , Risk Factors , Rituximab/adverse effects , Rituximab/therapeutic use , Thioredoxins/genetics , Treatment Outcome , Vincristine/adverse effects , Vincristine/therapeutic useABSTRACT
BACKGROUND/AIM: Diffuse large B-cell lymphoma (DLBCL) is an aggressive malignancy where antioxidant enzyme peroxiredoxin 6 (Prx6) has previously been associated with adverse outcomes. Its systemic effects in DLBCL are unknown. MATERIALS AND METHODS: This study included 53 patients with DLBCL, five patients with primary central nervous system lymphoma (PCNSL) and 20 healthy controls. The expression of Prx6 was evaluated immunohistochemically in DLBCL tissue samples and compared to its expression in blood serum. RESULTS: Prx6 expression was the highest in healthy controls, followed by DLBCL patients and PCNSL patients. Febrile neutropenic infection after the first treatment course was associated with low pre-treatment Prx6 serum levels (<14 ng/ml) (p=0.025, OR=8.615, 95% confidence interval=1.032-71.933). Serum levels of Prx6 recovered after treatment (p=0.006). CONCLUSION: Patients with low Prx6 levels might be more prone to treatment-related adverse effects through elevated levels of oxidative stress.
