Serum Values of Osteopontin and Vascular Endothelial Growth Factor in Association with Clinical Parameters in Patients with Multiple Myeloma
Authors: Valkovic Toni , Babarovic Emina , Aralica Merica , Stifter Sanja , Duletic-Nacinovic Antica , Lucin Ksenija , Nemet Damir , Jonjic Nives 
Published: October 2019

Abstract
Abstract 4993

Background:
the role of osteopontin (OPN), glyco-phosphoprotein produced by variety of tissues, has been widely investigated in the progression of many solid tumors, but on the other side, there are not many studies performed in multiple myeloma (MM). The role of Vascular Endothelial Growth Factor (VEGF) in tumor angiogenesis, as well as in MM, has been extensively analysed, but the significance of its serum level is still not well recognize. The aim of the present study was to determine the serum levels of both above mentioned cytokines and compare their values with clinical parameters of myeloma patients.

Methods:
serum level of OPN and VEGF was determinated by ELISA in 44 newly-diagnosed, reviously untreated myeloma patients (21 men, 22 women; median age of 69, range 44 – 86) and 24 age-matched healthy persons who consisted control group. The obtained values were correlated with main clinical parameters such as anaemia (hemoglobine value 20 g/L below the lower limit of normal), renal dysfunction (serum creatinine level above the uper limit of normal) and bone disease (any of lytic lesions or severe osteopenia with compressive fractures on standard radiographs of the bones). The level of cytokines were also correlated with serum beta-2 microglobulin as a prognostic factor related to biological behaviour of MM, and Durie-Salmon Staging System as a measure of tumor mass.

Results:
serum value of OPN was significantly higher in myeloma patients (median 6. 5, range 0. 3 – 21. 7) in compare to control group (medain 2. 4, range 0. 2 – 8. 9) (p<0. 0001), while these difference could not be observed with VEGF (52. 5 versus 60. 5) (p=0. 6673). Serum level of beta2-microglobuline was positively associated with value of OPN (p=0. 0461) but not with VEGF (p=0. 79). Patients with lower Durie-Salmon Stage had significantly lower both- OPN and VEGF serum levels (p=0. 0456, p=0, 0371 respectively). Higher OPN serum value was found in MM patients with evident bone lesions (p=0. 0268), while this difference was not observed with VEGF (p= 0. 7962). There was no correlation between serum levels of OPN and anaemia (p=0. 2991) or increased serum creatinine (p=0. 1338). VEGF serum level, also, did not correlated with anemia (p=0. 4309) and renal dysfunction (p=0. 5119).

Conclusion:
our preliminary results support the serum level of OPN as a dual marker of tumor aggressiveness and bone destrucion. On the contrary, present study did not confirm similar clinical value of VEGF serum level which represent a critical angiogenic factor in tumor micro-eco system. However, in our investigation both cytokines positively correlated with tumor burden. Further analysis with more included patient sholud provide definitive information about possible role of OPN as a useful clinical biomarker for monitoring of bone disease and tumor mass, as well as prognostic factor during course of disease.

Disclosures:
No relevant conflicts of interest to declare.