Macrophage migration inhibitory factor as a prognostic biomarker in multiple myeloma: clinical significance and in vitro effects.

Macrophage migration inhibitory factor (MIF) emerged in recent years as an important cytokine with a pleiotropic spectrum of biological functions implicated in the pathogenesis of inflammatory diseases and malignancies. A growing body of research indicates that the overexpression of MIF is prevalent across a variety of solid tumors. Howbeit, there are fewer studies regarding the expression and clinical significance of serum MIF in multiple myeloma (MM) patients. In this study, we investigated the clinical significance of serum MIF in newly diagnosed MM (NDMM) patients and explored the effect of exogenous MIF on the proliferation, migration, and invasion of MM cells in vitro. Herein, our study revealed that NDMM patients exhibited markedly elevated serum MIF levels compared to healthy adults. High levels of MIF were associated with advanced International Staging System (ISS) stage and the Second Revision of the International Staging System (R2-ISS) stage. Besides, NDMM patients with high levels of MIF were prone to have a higher incidence of hypercalcemia, renal insufficiency, high tumor burden, and extramedullary lesions. Moreover, we found that serum MIF, creatinine, and lactate dehydrogenase levels were independent risk factors for predicting poor progression-free survival and overall survival in NDMM patients. Meanwhile, in vitro experiments revealed that MIF can promote the proliferation of MM cells and enhance their migration and invasion. Our study confirmed that NDMM patients with high serum MIF levels showed poor clinical characteristics and inferior prognosis. Therefore, MIF may serve as a promising biomarker in the clinical practice of MM.