ABSTRACT
Osteosarcoma [OS] is a highly malignant bone tumor and is the most frequent malignant bone tumor in children and adolescents. The majority of patients with this disease harbor "micrometastasis" at diagnosis, a fact that demonstrates the need for molecular variables which can predict the presence or absence of micro-metastasis. Matrix metalloproteinases [MMPs] are a class of matrix - and basement membrane-degrading enzymes whose expression is associated with tumor cell invasive and metastatic behavior. One of these enzymes, MMP-9 is expressed in developing and remodeling bone in OS cell lines. The current study investigated the expression of MMP-9 by immunohistochemistry and its correlation with the prognosis in OS patients treated at Mansoura Clinical Oncology and Nuclear Medicine Department. MMP-9 was examined immunohistochemically using a monoclonal antibody in 20 patients with OS. The range of follow-up was 16 to 53 months with a median of 31.5 months. Correlation of the positivity of staining with prognosis was analyzed with Kaplan-Meier method. We found that MMP-9 immunohistochemical expression was positive in 85% of cases [17/20] and increased MMP-9 expression was significantly associated with poor prognosis in overall, metastasis-free and recurrence-free survivals [p=0.001, 0.001, and 0.002 respectively]. These results suggest that MMP-9 expression is common in OS and demonstrate the correlation of MMP-9 expression and the oncological outcome of OS patients