W L van Putten

Urokinase-type plasminogen activator (uPA) may be responsible for the invasive and metastasizing capacity of tumor cells. Evidence has been presented that primary breast cancer patients with tumors containing high levels of uPA experience a worse prognosis. In the present study we have assessed uPA status in routinely prepared cytosols of 671 primary human breast tumors and have evaluated its association with disease-free and overall survival. Isotonic regression analysis with length of disease-free survival as an end point revealed 1.15 ng/mg protein as the best cutoff point to discriminate between uPA positive (32% of the tumors) and uPA negative. In both Cox univariate and multivariate regression analysis (including also patient's age, menopausal status, lymph node status, and the number of positive lymph nodes, tumor size, and estrogen and progesterone receptor status), uPA positivity was significantly associated with increased rates of relapse and death. Corrected for all relevant factors in multivariate analyses for subgroups of patients, uPA positivity was significantly associated with an increased relapse rate in the subgroups of node-negative (P = 0.002; relative failure rate, 2.33), node-positive (P < 0.0001; relative failure rate, 1.95), postmenopausal (P < 0.0001; relative failure rate, 2.59), and steroid receptor-positive patients (P < 0.0001, relative failure rate, 2.76). We conclude that uPA positivity of human primary breast tumors is an important independent variable for the identification of patients at high risk for recurrence, also in clinically important subgroups of patients.

PURPOSE: Evaluation of the relationship between plasminogen activator inhibitor-1 (PAI-1) and the metastatic potential of primary breast cancer, and to compare the prognostic impact of PAI-1 in multivariate analysis with those of conventional prognostic factors, including steroid-hormone receptors, and those of urokinase plasminogen activator (uPA), pS2-protein (PS2), and cathepsin D. PATIENTS AND METHODS: Cell biologic prognostic factors were analyzed in 657 cytosols routinely prepared from frozen-tissue biopsies that were submitted to our laboratory for the assessment of steroid-hormone receptor status. The median duration of follow-up in patients still alive at the time of analysis was 48 months. Estrogen receptor (ER) and progesterone receptor (PgR) status were assessed by radioligand binding assay, PS2, and cathepsin D by radiometric immunoassay, and uPA and PAI-1 by enzyme-linked immunosorbent assay (ELISA). RESULTS: PAI-1 levels were found to be strongly positively correlated with the rates of relapse (P < .0001) and death (P < .001). Relating the levels of PAI-1 with those of other cytosolic prognostic factors, we found a positive association with the metastasis-related proteases uPA (P < .0001) and cathepsin D (P < .0001). On the other hand, PAI-1 levels were found to be negatively correlated with ER (P < .005) and PgR (P < .001), and the estrogen-regulated pS2-protein (P < .001), which are proteins associated with a favorable prognosis. In multivariate regression analysis for 5-year relapse-free survival, and using an optimized cutoff point for discrimination between PAI-1-positive and -negative, independent predictors of the rate of relapse were found to be PAI-1 (P < .0001) and uPA (P = .01) of the cytosolic parameters, and tumor size, lymph node status, and premenopausal age of the clinical parameters. In multivariate analysis in patients with node-negative disease, only PAI-1 (P < .001) and tumor size (P = .03) were positively and premenopausal age negatively (P < .001) associated with the rate of relapse. In patients with node-positive disease, PAI-1 (P < .001), uPA (P = .02), tumor size (P < .001), and the number of positive lymph nodes (P < .001) were all positively associated with the rate of relapse. CONCLUSION: We conclude that the PAI-1 level measured in routinely prepared cytosols is an important parameter to predict the metastatic potential in both node-negative and node-positive human primary breast cancer.

The prognostic significance, as well as the relationship with known prognostic factors in breast cancer, of insulin-like growth factor 1 receptor (IGF-1-R), epidermal growth factor receptor (EGF-R), and somatostatin receptor (SS-R) was evaluated. IGF-1-R was positively correlated with estrogen receptor and age, but not significantly with progesterone receptor, lymph node status, and tumor size. EGF-R was negatively correlated to estrogen receptor and progesterone receptor, whereas no association was found with age, lymph node status, and tumor size. The levels of the tumor contents of IGF-1-R and EGF-R were not significantly related to tumor recurrence in 214 patients (test for trend, P = 0.20 and P = 0.08, respectively). However, patients with tumors containing intermediate levels of EGF-R (0.5 to 2.0 fmol/mg of membrane protein) experienced a longer disease-free survival than did patients with tumors possessing lower or higher levels of EGF-R. This effect was most pronounced in the subgroup of patients with positive axillary lymph nodes: 66% disease-free after 5 yr compared with 38% and 46% for the groups with lower and higher EGF-R levels, respectively. The relapse-free survival for patients with tumors containing SS-R (15%) was significantly longer than for patients with SS-R-negative tumors (82% versus 46% disease free after 5 yr, P = 0.04). Assessment by multivariate analysis showed that lymph node status, tumor size, and differentiation grade were independent prognostic factors for relapse. In the Cox model, estrogen receptor and progesterone receptor were both negatively correlated with tumor recurrence, whereas overall EGF-R and IGF-1-R did not show such a relation.