Objective: Endostatin, a 20-kDa C-terminal fragment of collagen XVIII, specifically inhibits endothelial proliferation and potently inhibits angiogenesis and tumor growth. The aim of this study was to assess the prognostic potentials of serum endostatin levels in epithelial ovarian cancer.
Materials and methods: The preoperative serum levels of endostatin in 61 cases of epithelial ovarian cancer (29 serous, 13 mucinous, 13 endometrioid, 5 clear cell and 1 Brenner cell) were analyzed using a competitive enzyme immunoassay. With regard to staging, 23 cases had stage I disease, 6 had stage II disease, 28 had stage III disease and 4 had stage IV disease.
Results: Serum levels were compared with levels from 22 age-matched healthy volunteer blood donors. The median serum levels were 18.5 ng/ml (range, 6.3-50.3 ng/ml) in patients with epithelial ovarian cancer and 18.4 ng/ml (range, 8.4-27.0 ng/ml) in controls. No significant difference was noted between the two groups. No clinicopathological features (e.g., patients' age at diagnosis, stage of disease, histological subtype and grade) were significantly associated with serum endostatin levels. Survival data were available for all patients. Multivariate Cox regression analysis revealed that FIGO stage III-IV (p = 0.015) and serum endostatin levels (> 2 standard deviations above the control mean; 27.7 ng/ml) (p = 0.035) are independent prognostic factors.
Conclusion: Elevated serum levels of this endogenous inhibitor of angiogenesis may be a pertinent prognostic indicator for patients with epithelial ovarian cancer. It is anticipated that this finding may aid the development of a new therapeutic strategy for epithelial ovarian cancer.