Expression pattern and clinical prognostic relevance of bone morphogenetic protein-2 in human gliomas

Bone morphogenetic protein-2 (BMP-2) is normally expressed in the embryo promoting the development of several organs. Aberrant expression of BMP-2 occurs in various tumors. However, a correlation between BMP-2 expression in human gliomas and patients' prognosis has not been reported. To address this question, this study was to investigate the BMP-2 expression pattern in human gliomas and to evaluate its prognostic relevance.

We analyzed the expression of the BMP-2 antigen in a series of 98 gliomas of various grade and histology by immunohistochemistry on paraffin-embedded sections. Then, the correlation of BMP-2 expression pattern with clinical-pathological features of patients and its prognostic relevance were determined.

Immunohistochemical analysis with anti-BMP-2 antibody revealed dense and spotty staining in the tumor cells and its expression levels became significantly higher as the gliomas' grade advanced (P < 0.001). The median survival of patients with intensively positive BMP-2 expression was significantly shorter than that with negative expression (318 vs. 1197 days, P < 0.0001). The Kaplan-Meier survival curves showed that the BMP-2 expression was not only a significant predictor of survival in high-grade gliomas (grade IV, P = 0.02), but also in lower-grade gliomas (grades II and III, P < 0.001).

These results indicate that BMP-2 is a highly sensitive marker for gliomas prognosis and suggest that the expression level of BMP-2 may be a potent tool for the clinical prognosis of gliomas patients.