Serum levels of VEGF and TNF-α and their association with C-reactive protein in patients with endometriosis

Objective: To compare serum levels of vascular endothelial growth factor (VEGF), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP) throughout the menstrual cycle in women with and without endometriosis and to quantify the association between these serum markers. Methods: Twenty five endometriosis patients (ASRM stage III–IV) and 13 controls were followed through one menstrual cycle. VEGF, TNF-α and CRP concentrations were measured with enzyme-linked immunosorbent assay in each of the four cycle phases (early and late proliferative and early and late secretory). Non-parametric methods and Pearson’s correlation coefficients were used for statistical analysis. Results: Increased serum levels of VEGF in secretory phases and of TNF-α in all cycle phases were observed. A positive correlation between CRP and VEGF was found in endometriosis patients but not in controls. Conclusions: Our results suggest that excessive systemic angiogenic activity is a feature of patients with endometriosis.