INTRODUCTION: In the era of implementing novel agents in multiple myeloma (MM) regimens, drug resistance has become a key factor undermining the results of treatment. Identifying biomarkers allows the prediction of therapy outcomes with specific agents and may lead to the avoidance of resistance. OBJECTIVES: This study aimed to identify biomarkers in the pretreatment sera of patients with refractory/ relapsed MM that differ from those in the sera of patients who achieved a better depth of response with bortezomib-containing therapy. PATIENTS AND METHODS: Pretreatment serum samples were obtained from 61 proteasome inhibitor-naive, transplant-eligible patients who were eligible for salvage PAD (bortezomib, doxorubicin, and dexamethasone) or VTD (bortezomib, thalidomide, and dexamethasone) chemotherapy. Based on their response to therapy, patients were classified into 3 groups: complete or very good partial response, partial response, and progressive or stable disease. A comparative proteomic analysis of the groups was performed. RESULTS: The analyzed groups significantly differed in terms of both overall survival and progression‑free survival. In total, 632 proteins were identified. The proteomic signature revealed 54 proteins that differentiated each analyzed experimental group. Functional analysis revealed that the main identified pathways (17 proteins) involved the regulation of hydrolase activity and cellular response to stimuli. The identified proteins included apolipoprotein C1, complement components, and sulfhydryl oxidase 1. CONCLUSIONS: Our results demonstrated that the label-free proteomic analysis is a useful method for describing proteins differentially expressed in the sera of patients with MM. Further studies are needed to analyze the use of identified proteins as biomarkers.
INTRODUCTION: In the era of implementing novel agents in multiple myeloma (MM) regimens, drug resistance has become a key factor undermining the results of treatment. Identifying biomarkers allows the prediction of therapy outcomes with specific agents and may lead to the avoidance of resistance. OBJECTIVES: This study aimed to identify biomarkers in the pretreatment sera of patients with refractory/ relapsed MM that differ from those in the sera of patients who achieved a better depth of response with bortezomib-containing therapy. PATIENTS AND METHODS: Pretreatment serum samples were obtained from 61 proteasome inhibitor-naive, transplant-eligible patients who were eligible for salvage PAD (bortezomib, doxorubicin, and dexamethasone) or VTD (bortezomib, thalidomide, and dexamethasone) chemotherapy. Based on their response to therapy, patients were classified into 3 groups: complete or very good partial response, partial response, and progressive or stable disease. A comparative proteomic analysis of the groups was performed. RESULTS: The analyzed groups significantly differed in terms of both overall survival and progression‑free survival. In total, 632 proteins were identified. The proteomic signature revealed 54 proteins that differentiated each analyzed experimental group. Functional analysis revealed that the main identified pathways (17 proteins) involved the regulation of hydrolase activity and cellular response to stimuli. The identified proteins included apolipoprotein C1, complement components, and sulfhydryl oxidase 1. CONCLUSIONS: Our results demonstrated that the label-free proteomic analysis is a useful method for describing proteins differentially expressed in the sera of patients with MM. Further studies are needed to analyze the use of identified proteins as biomarkers.