Role of MMP-9 and its tissue inhibitor TIMP-1 in human osteosarcoma: findings in 42 patients followed for 1-16 years.

Background The activity of matrix metalloproteinases (MMPs) in degrading extracellular matrix is controlled by activation of proenzymes and inhibition of MMP tissue inhibitors (TIMPs). Patients and methods To assess the proteolytic cascade imbalance in malignancy progression, tissue expression and serum levels of MMP-2, MMP-9 and of their inhibitors TIMP-2 and TIMP-1 respectively were evaluated in 42 selected patients with high-grade osteosarcoma (OS). MMP-2, MMP-9, TIMP-2 and TIMP-1 were studied in biopsies by immunohistochemistry and in serum by ELISA test. Patients were subdivided into 3 groups according to their follow up: continuously disease-free, diagnosis of metastasis during follow-up, and metastasis at diagnosis. Results Immunohistochemistry demonstrated an imbalance between MMPs and TIMPs, with a more evident role for MMP-9 than for MMP-2 in tumor progression. TIMP-1 inhibitor in plasma was higher in patients with osteosarcoma than in a control group. This high value of TIMP-1 was particularly ...