Bone Marrow Urokinase Plasminogen Activator Receptor Levels are Associated with the Progress of Multiple Myeloma

Objective To determine the mRNA and protein levels of urokinase plasminogen activator receptors(u PAR) in bone marrow fluid and bone marrow tissue from multiple myeloma(MM) patients and assess association of u PAR level with prognosis of MM.Methods u PAR levels in bone marrow fluid of 22 MM patients at the stable and progressive stages and 18 iron deficiency anemia patients with normal bone marrow(control) were examined by ELISA.Furthermore,u PAR expression in bone marrow tissue was investigated by RT-PCR and Western blot,respectively.The distribution of u PAR in MM cells was examined using immunofluorescence staining.The pathological changes in different stages of MM patients were studied by HE staining.Results u PAR level in bone marrow fluid of MM patients(1.52±0.32 μg/ml) was found to be higher than that in the control group(0.98±0.15 μg/ml).Interestingly,u PAR protein(0.686±0.075 vs.0.372±0.043,P<0.05) and m RNA(2.51±0.46 vs.4.46±1.15,P<0.05) expression levels of MM patients at the progressive stage were significantly higher than those at the stable stage.The expression of u PAR in MM bone marrow was confirmed by immunofluorescence staining.Moreover,HE staining revealed a great increased number of nucleated cells and severe impairment of hematopoietic function in the bone marrow of patients with progressive-stage myeloma.Conclusion Our study reveals that u PAR expression is positively correlated with the development and progress of MM.