Expression of VEGF, MMP-9 and Neovascularization in Relationship to the Clinical Behavior of Giant Cell Tumors of Bone

ABSTRACT

BACKGROUND: Giant cell tumors (GCT(s)) of bone are benign but can be locally aggressive neoplasms. Their clinical behavior has been difficult to predict on the basis of histology alone. This study investigated the neovascularization and expression of vascular endothelial growth factor (VEGF) as well as matrix metalloproteinase-9 (MMP-9) in GCT(s) of bone; in addition we evaluated their relationship to clinical behavior. METHODS: We evaluated the microvessel number and density in 33 samples of giant cell tumor using CD34 immunohistochemistry. In addition, we examined the immunohistochemical expression of VEGF and MMP-9. RESULTS: The microvessel number alone, not the microvessel density, had statistical association with the clinical stage of GCT(s) (p=0.045). The proportion of cases with strong expression of VEGF increased with advancing clinical stage, however, these results were not statistically significant (p=0.257). The percentage of the cases with strong expression of MMP-9 also increased with advancing clinical stage and this was statistically significant (p=0.022). CONCLUSIONS: These results suggest that intratumor microvessel count and the expression of MMP-9 correlate with GCT stage. Evaluation of their expression may therefore provide prognostic information on the aggressive behavior of GCT(s) of bone.