The comparison of serum levels of selected biomarkers in monoclonal gammopathy of undetermined significance and multiple myeloma

BACKGROUND: The aim of the study was the evaluation of serum levels of 12 selected biomarkers in monoclonal gammopathy of undetermined significance (MGUS) and in initial, asyptomatic phase of multiple myeloma, especially from the view of potential differentiation of these conditions in clinical practice. METHODS AND RESULTS: Analyzed group of 268 individuals consisted of 89 individuals with MGUS and 179 patients with MM examined in time of diagnosis before treatment initiation. For evaluation of serum levels were used following methods: radioenzymatic method (thymidinekinase), enzymatic immunoassay (beta2-M, IL-6R, ICAM-1, VCAM-1, ICTP, PINP and OPG) and quantitative sandwich enzymatic immunoassay (HGF, VEGF, syndecan-1/CD138 and Fas). Pearson's chi2-test and test according to Mann-Whitney were used for statistical evaluation (p < 0.05). Wide statistic differences in serum levels of analyzed markers in MGUS vs. MM were detected in case of beta2-M, TK, ICTP, OPG, HGF and syndecan-1 (p < 0.0001), lower differences in case of VCAM-1, PINP and VEGF (p = 0.003, 0.001 and 0.04), and without difference in case of Fas. Except for thymidinekinase (p = 0.014) and syndecan-1 (p = 0.001) was not detected statistically important contrast of measured values in MGUS individuals and in patients with initial, asymptomatic phase of MM (stage 1), but these markers cannot be used in clinical practice due to significant overlap of serum values. Continuous downgrade of serum values of VEGF due to degree of MM progression (stages 1-3 according to Durie-Salmon) was unexpected. RESULTS: Although the significant differences in 9 of 12 evaluated serum levels of selected biomarkers in groups of MGUS and MM were seen, the results revealed that these markers are unprofitable to bring discriminatory potential capable of being used to distinguish between MGUS and initial, asymptomatic phase of MM.