Diagnostic and prognostic potential of serum angiopoietin-2 expression in human breast cancer.

BACKGROUND

Accumulating evidence demonstrated a link of increased expression of Angiopoietin-2 (Ang-2) with invasive and metastatic phenotypes of various types of human cancers. However, until now, the serum level and its diagnostic and prognostic potential in breast cancer have not been investigated.

METHODS

Enzyme-linked immunosorbent assays were used to measure the levels of Ang-2. Sensitivity, specificity and area under curve (AUC) for serum Ang-2 levels were determined using receiver operator characteristic (ROC) analysis. Survival curves were plotted using the Kaplan-Meier method and differences in survival rates were analyzed using the log-rank test. Prognostic relevance of each variable to overall survival (OS) and disease-free survival (DFS) were analyzed using the Cox regression model.

RESULTS

Serum expression of Ang-2 in patients with breast cancer was significantly higher than healthy control group (3171 ± 1024 vs. 1800 ± 874 pg/ml, P < 0.0001). ROC curve analysis showed that at the optimal cut-off (2558.5 pg/ml), serum level of Ang-2 had a sensitivity of 78.3% and a specificity of 77.0% for distinguishing breast cancer patients from healthy controls with an area under the curve (AUC) of 0.836 (P < 0.001, 95% confidence interval: 0.787-0.885). The 5-year OS of high Ang-2 expression group was significantly shorter than that of low Ang-2 expression group (55.9% vs. 80.3%; P = 0.018). Moreover, the 5-year DFS of high Ang-2 expression group was also significantly shorter than that of low Ang-2 expression group (46.0% vs. 68.7%; P = 0.029).

CONCLUSIONS

Our data indicate that serum Ang-2 level has potential value for early detection of breast cancer. Furthermore, Ang-2 has prognostic value in patients with breast cancer.