The relevance of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor (PAI) type 1 in predicting the survival probability of patients with advanced ovarian cancer after radical surgery and adjuvant chemotherapy by assessing the patients' primary tumors has recently been shown by us (W. Kuhn et al., Gynecol. Oncol., 55: 401-409, 1994). In the present study, we determined uPA, uPA receptor, PAI-1, and PAI-2 concentrations in primary tumors and tumor-infiltrated omentum and retroperitoneal lymph nodes of ovarian cancer patients. The group consisted of 39 patients with advanced ovarian carcinoma stages Fédération Internationale de Gynécologie et d'Obstétrique (FIGO) IIIc or IV; for comparison 7 patients with early carcinoma stage FIGO I were also included. In metastases of the omentum from ovarian cancer stage FIGO IIIc or IV patients, we noted a 4-fold elevated uPA content, a 2-fold increase in PAI-1, and also a significant increase in uPA receptor and PAI-2 over primary tumors. In metastases of the lymph nodes the levels of the respective antigens were also increased when compared to primary tumors. These data may indicate that elevated levels of components of the fibrinolytic system at sites of metastases may contribute to the aggressive potential of cancer cells by favoring their reimplantation and/or the consolidation of a new tumor stroma.