Thioredoxin‐1 as a biological predictive marker for selecting diffuse large B‐cell lymphoma patients for etoposide‐containing treatment

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