RESUMEN
Matrixmetalloproteinases [MMPs] are a class of matrix basement membrane degrading enzymes which were shown to be associated with metastases in several human tumors. This study is aimed to investigate the potential effect of MMP-9 in imparting the frequently reported different behavioral pattern between jaws and long bones osteosarcomas. Tissue blocks of ten cases of jaws osteosarcomas and another ten of long bones osteosarcomas were collected and stained immunohistochemically with monoclonal antibodies to MMP-9. The majority of cases [70%] were positive for MMP-9 expression which indicates a role in tumor spread, however; there was no significant difference between the sites. The study indicates that MMP-9 is probably not involved in the biologic differences between jaws and long bones osteosarcomas