Syndecan-1 and angiogenic cytokines in multiple myeloma: correlation with bone marrow angiogenesis and survival

Angiogenesis is a complex process involved in the proliferation and metastasis of malignant tumours, and partly triggered by the secretion of various angiogenic factors by tumour cells or cells in the stromal environment. We investigated the correlation between bone marrow angiogenesis, estimated as microvessel density (MVD), and interleukin-6 (IL-6), basic fibroblastic growth factor (bFGF), hepatocyte growth factor (HGF) and syndecan-1 in 67 patients with newly diagnosed multiple myeloma, and evaluated the prognostic value of these parameters. Circulating levels of IL-6, bFGF, HGF and syndecan-1 were significantly higher in patients than in controls. Moreover, in patients, bone marrow levels of bFGF, HGF and syndecan-1 were higher than peripheral blood levels. Positive correlations were found between MVD and syndecan-1 blood levels (r = 0.33, P = 0.017), syndecan-1 bone marrow levels (r = 0.49, P = 0.046) and HGF blood levels (r = 0.36, P = 0.008) respectively. High MVD and high blood levels of IL-6, HGF and syndecan-1 were predictive of a shorter survival. In a multivariate survival analysis MVD and blood levels of IL-6 retained independent prognostic significance, while in a survival analysis without MVD the peripheral blood levels of HGF and syndecan-1 were strong independent prognostic factors.