Assessment of endothelial progenitor cells, VEGF-A and SDF-1α in Hodgkin's lymphoma

Recently, there is great interest in vasculogenesis, a process of the formation of new blood vessels from progenitor cells or angioblasts, in the pathogenesis of cancer. To the best of our knowledge, the evaluation of endothelial progenitor cells (EPCs) in Hodgkin's lymphoma has not yet been reported. The aim of the present study was to assess the number of EPCs and selected cytokines, such as vascular endothelial growth factor (VEGF-A) and stromal cell-derived factor (SDF-1 alpha) involved in vasculogenesis in Hodgkin's lymphoma patients. The study was conducted in a group of 42 patients with Hodgkin's lymphoma (eight patients with relapsed Hodgkin's lymphoma and 34 patients before the first treatment) and 30 healthy controls. The number of EPCs defined as CD31(+), CD34(+), CD45(-), CD133(+) was analysed on FacsCalibur flow cytometer and the concentration of VEGF-A and SDF-1 alpha was assessed by ELISA. The study showed that there was a significantly higher EPCs number and VEGF-A concentration in the blood of Hodgkin's lymphoma patients compared to healthy individuals (8.20 vs. 0.55 cells/mu l; P < 0.000001; 85.10 vs. 25.33 pg/ml, P = 0.000017; respectively). Detailed analysis revealed that there was elevated EPCs number in both study subgroups as compared to the control group. However, there was no difference in VEGF concentration between recurrent Hodgkin's lymphoma patients and the control group. A significant positive correlation was found between the number of EPCs and VEGF-A concentration (R = 0.31, P = 0.047). Significantly higher EPCs number combined with increased VEGF-A concentration, found in Hodgkin's lymphoma patients before the first treatment, suggest stimulation of new blood vessels formation, which may in turn contribute to tumour growth and metastasis in these patients.