This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. AbstractBackground: MicroRNA-146b (miR-146b) is a critical regulator and prognosis biomarker in several hematological malignancies, whereas its role in multiple myeloma (MM) was unclear. Therefore, this study aimed to investigate the significance of miR-146b in MM patients. Methods:The plasma cells were separated from bone marrow samples of 180 symptomatic MM patients (before treatment) and 50 healthy controls (HCs), and subsequently detected by reverse transcription-quantitative polymerase chain reaction for miR-146b expression. Results: MiR-146b was increased in MM patients compared with HCs (P < .001), and it predicted increased MM risk (area under curve (AUC): 0.879, 95% confidence interval (CI): 0.822-0.936). For clinical parameters, miR-146b was positively correlated with serum creatinine (P = .047), beta-2-microglobulin (P < .001), lactate dehydrogenase (P < .001), bone lesion (P = .027), International Staging System (ISS) stage (P < .001), and t (4; 14; P = .006), while negatively correlated with albumin (P = .004) in MM patients. For prognosis, miR-146b was decreased in complete response (CR) patients compared with non-CR patients (P = .025), as well as in overall response rate (ORR) patients compared with non-ORR patients (P = .036), and it discriminated CR patients from non-CR patients (AUC: 0.610, 95% CI: 0.523-0.698) and distinguished ORR patients from non-ORR patients (AUC: 0.602, 95% CI: 0.501-0.703) in MM patients. Moreover, miR-146b was correlated with worse progression-free survival (P = .007) and overall survival (P = .014) in MM patients. Conclusion: MiR-146b was overexpressed in MM patients and predicted increased MM risk; meanwhile, it correlated with deteriorated clinical properties, increased ISS stage, cacoethic chromosome abnormality, and worse prognosis in MM patients. S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section. How to cite this article: Bao Y, Wei M, Ji X. MicroRNA-146b overexpression associates with deteriorated clinical characteristics, increased International Staging System stage, cacoethic chromosome abnormality, and unfavorable prognosis in multiple myeloma patients. J Clin Lab Anal.