High XBP1 expression is a marker of better outcome in multiple myeloma patients treated with bortezomib

Multiple myeloma (MM) is a hematologic tumor characterized by accumulation of monoclonal plasma cells (PCs) in the bone marrow (BM) producing antigen-specific immunoglobulins. The transcription factor X box binding protein 1 (XBP1), the interferon regulatory factor 4 (IRF4) and the transcriptional