Increased Plasma GDF15 Is Associated with Altered Levels of Soluble VEGF Receptors 1 and 2 in Symptomatic Multiple Myeloma

Introduction: In multiple myeloma, there is an increase in bone marrow microvascular density and enhanced renal lymphangiogenesis. Increased levels of the proangiogenic protein growth differentiation factor-15 (GDF15) have previously been reported to be associated with poor prognosis in myeloma. A possible association between GDF15 and the soluble forms of vascular endothelial growth factor receptors (sVEGFR) 1 and 2 has not yet been investigated, and a role for these receptors in pathological angiogenesis in myeloma is still to be defined. Methods: Plasma levels of GDF15 and sVEGFR1 and 2 were determined by ELISA in patients with smouldering multiple myeloma (sMM), patients with symptomatic multiple myeloma (abbreviated as MM), and healthy controls. The levels were compared between the three groups, and correlation coefficients were calculated, as were Kaplan-Meier curves for GDF15 and sVEGFR1 and sVEGFR2. Results: Levels of GDF15 were significantly higher in MM than in both patients with sMM and controls. A gradual decrease in mean sVEGFR1 concentration was observed, with MM > sMM > controls. Mean sVEGFR2 was lower in patients with MM than in controls. There was a positive correlation between GDF15 and sVEGFR1, and GDF15 correlated negatively with sVEGFR2. High GDF15 (>3 ng/mL) was associated with poor prognosis. Conclusion: In multiple myeloma, increased expression of GDF15 correlates positively with sVEGFR1 and negatively with sVEGFR2. It is possible that the altered levels of sVEGFR1 and 2 contribute to the increased angio- and lymphangiogenesis observed in myeloma.