The associations between serum VEGF, bFGF and endoglin levels with microvessel density and expression of proangiogenic factors in malignant and benign ovarian tumors

• Serum VEGF levels negatively correlate with tumor VEGF expression in ovarian cancer.
• Angiogenic factors serum levels reflect ovarian cancer microvasculature and angiogenesis state.
• Serum VEGF levels correlate positively with CD34 MVD and negatively with CD105 MVD.

Aim of the studyTo investigate whether serum levels of VEGF, bFGF and endoglin correlate with tumor VEGF and bFGF expression or microvessel density (MVD) in ovarian cancer.Patients and methodsForty five patients with epithelial ovarian cancers (EOCs) and 38 patients with benign ovarian tumors (BOTs) were included into the study. Serum levels of VEGF, bFGF and endoglin were assessed using ELISA. The expression of VEGF and bFGF in tumor samples were evaluated using ELISA of supernatants obtained from tumor homogenization. MVD was analyzed using immunohistochemistry with antibodies against CD31, CD34 and CD105.ResultsSerum VEGF levels were significantly higher in EOCs than in BOTs (436.6 pg/ml [19.67–2860] vs 295.5 pg/ml [123–539], P = 0.025). Serum endoglin levels were lowered in the group EOCs when compared to BOTs (33,720 g/ml [12,220–73,940] vs 42,390 pg/ml [19,380–56,910], P = 0.015). There were no differences in bFGF levels between studied groups. EOCs have significantly higher CD105 MVD (25 vessels/mm2 [0–57] vs 6 vessels/mm2 [0–70], P < 0.001) and tumor VEGF (405.9 pg/mg protein [0–3000] vs 2.225 [0–634.7], P < 0.001) expression than BOTs, while, bFGF expression was higher in BOTs than in EOCs (2076 pg/mg protein [668.1–8718] vs 847.3 pg/mg protein [188.9–8333], P = 0.003). In patients with EOCs we have observed negative correlation between serum VEGF concentration and its tissue expression (r Spearman = − 0.571, P = 0.0261), and serum VEGF concentration correlated positively with CD34-MVD (r Spearman = 0.545, P = 0.0289). In a multiple regression analysis we have observed only the negative correlation between serum VEGF and CD105-MVD (r = − 0.5288, P = 0.0427).ConclusionsSerum VEGF is a useful marker for prediction of ovarian cancer MVD and tumor VEGF expression.