Urokinase-plasminogen-activator levels and prognosis in 69 soft-tissue sarcomas

The local and systemic invasiveness of soft-tissue sarcomas may depend upon an interaction between the primary tumour and the extracellular matrix in which the proteolytic enzyme, urokinase plasminogen activator (uPA), may have an important role. We analyzed the expression of uPA in soft-tissue sarcoma using a luminescent immunoassay technique, and examined the relationships between different uPA levels and tumour characteristics and behaviour. We evaluated 69 adult patients with surgically treated soft-tissue sarcomas (MFH 43, leiomyosarcoma 8, liposarcoma 5, synovial sarcoma 4, others 9) of the extremities and trunk wall. Sixteen developed local recurrences, 26 developed metastases, and 5 had both. The median follow-up for survivors was 55 (30-80) months. The median uPA level was 1.4 (0.04-10.6) ng/mg protein. Increasing uPA levels correlated with increasing grade, malignant fibrous histiocytomas, leiomyosarcomas, DNA non-diploidy, tumour necrosis, local recurrence, and metastasis. Storiform-pleomorphic MFH had higher uPA levels than the myxoid variant. A cut-off value of 0.25 ng/mg protein was identified, above which local recurrence and metastasis occurred more frequently. High uPA levels appear to reflect the malignant phenotype in soft-tissue sarcoma, thus supporting the role of uPA as a prognostic indicator.