Urokinase-type plasminogen activator and its inhibitor type 1 predict disease outcome and therapy response in primary breast cancer

Combined determination of urokinase-type plasminogen activator (uPA) and its inhibitor, activator inhibitor type 1 (PAI-1), supports risk-adapted individualized therapy concepts, particularly in node-negative breast cancer. The prognostic impact of both factors in primary breast cancer was substantiated by a pooled analysis of > 8000 patients with breast cancer and a multicenter prospective randomized therapy trial in node-negative breast cancer; findings achieved the highest level of evidence for tumor biomarkers. Patients with node-negative breast cancer with low antigen levels of uPA and PAI-1 in their primary tumor tissue have a very good prognosis and therefore may be spared the burden of adjuvant chemotherapy, whereas those with elevated uPA/PAI-1 antigen levels carry an increased risk of disease recurrence. Recent retrospective analysis of > 3000 patients indicated that patients with breast cancer with high uPA/PAI-1 values derive a significantly greater benefit from adjuvant chemotherapy than patients with low uPA/PAI-1 levels. Similarly, in the multicenter prospective Chemo N0 trial, administration of cyclophosphamide/methotrexate/5-fluorouracil-based chemotherapy led to a substantial reduction in risk of disease recurrence in patients with high uPA/PAI-1. However, benefit from adjuvant endocrine therapy appears to be independent of a patient's uPA/PAI-1 status. In metastatic breast cancer, retrospective studies showed that elevated uPA or PAI-1 present in the primary tumor tissue are associated with a poor response to later palliative endocrine therapy. These findings suggest that high levels of uPA and/or PAI-1 do reflect an aggressive phenotype that may be overcome or suppressed by early systemic therapy in the adjuvant setting but may be too advanced for response to palliative therapy at a later stage.     

Predictive impact of urokinase-type plasminogen activator: plasminogen activator inhibitor type-1 complex on the efficacy of adjuvant systemic therapy in primary breast cancer

One of the most thoroughly studied systems in relation to its prognostic relevance in patients with breast cancer, is the plasminogen activation system. This system comprises of, among others, the urokinase-type plasminogen activator (uPA) and its main inhibitor (PAI-1). In this study we investigated whether the uPA:PAI-1 complex is associated with the responsiveness of patients with primary breast cancer to adjuvant systemic therapy. Quantitative enzyme-linked immunosorbent assays were used to assess the levels of uPA, PAI-1, and uPA:PAI-1 complex in 1119 tumors of patients with primary invasive breast cancer. These patients were followed for a median follow-up time of 59 months (range, 2-267 months) after the primary diagnosis. Correlations with well-known clinicopathological factors, and univariate and multivariate survival analyses were performed. High uPA:PAI-1 complex levels were correlated with an adverse histological grade, and inversely associated with negative estrogen and progesterone receptor status. High tumor levels of uPA:PAI-1 complex predicted an early relapse in the univariate relapse-free survival analysis (P < 0.001). The multivariate analysis showed that high uPA:PAI-1 complex levels were associated with a decreased relapse-free survival time (P = 0.033), independently of age, tumor size, number of lymph nodes affected, progesterone receptor status, uPA, adjuvant endocrine, and chemotherapy. More important, it was demonstrated that there is a larger benefit from adjuvant chemotherapy for patients with higher versus lower tumor levels of uPA:PAI-1 complex. The results of this study imply that the expression of uPA:PAI-1 complex independently predicts the efficacy of adjuvant chemotherapy in patients with primary breast cancer.     

Clinical relevance of the plasminogen activator inhibitor type 1--a multifaceted proteolytic factor.

The plasminogen activator inhibitor type-1 (PAI-1) is a multifaceted proteolytic factor. It not only functions as an inhibitor of the protease uPA (urokinase-type plasminogen activator), but also plays an important role in signal transduction, cell adherence, and cell migration. Thus--an apparent paradox considering its name--although it inhibits uPA during blood coagulation, it actually promotes invasion and metastasis. In the early 1990s, clinical evidence associated elevated PAI-1 levels in tumor tissue with poor clinical outcome in primary breast cancer. These clinical data have since been supported by experimental evidence that the concerted action of uPA, its cell surface receptor uPA-R, and PAI-1 facilitates invasion and metastasis. The strong prognostic impact of PAI-1 in primary breast cancer has been validated by international research groups assessing fresh tumor tissue extracts by ELISA. There is clinical evidence that high-risk patients with elevated PAI-1 in their tumor benefit from adjuvant systemic therapy. uPA also has a strong prognostic impact in primary breast cancer. In node-negative breast cancer, risk-group selection for adjuvant systemic therapy based on tumor levels of both PAI-1 and uPA is close to routine clinical use. Also in other malignancies such as ovarian, esophageal, gastric, colorectal or hepatocellular cancer, elevated PAI-1 is associated with tumor aggressiveness and poor patient outcome. This abundant clinical evidence implicating PAI-1 as a key factor for tumor invasion and metastasis renders it a promising target for tumor therapy. Novel therapeutic approaches targeting the PAI-1/uPA interaction are already in pre-clinical testing.     

Clinical relevance of invasion factors urokinase-type plasminogen activator and plasminogen activator inhibitor type 1 for individualized therapy decisions in primary breast cancer is greatest when used in combination.

PURPOSE: A strong prognostic impact of urokinase-type plasminogen activator (uPA) and its inhibitor and plasminogen activator inhibitor type 1 (PAI-1) as individual factors is well established in breast cancer. The improvement in clinical risk assessment gained by combining these factors is evaluated here. PATIENTS AND METHODS: uPA and PAI-1 levels were prospectively measured by enzyme-linked immunosorbent assay in tumor tissue extracts of 761 patients with primary breast cancer. RESULTS: In the clinically important subgroup of node-negative patients without adjuvant systemic therapy (n = 269; median follow-up, 60 months), the clinical value of testing both uPA and PAI-1 is demonstrated. The criterion either or both high identifies with high sensitivity the patients at high relapse risk while keeping more than half in the low-risk group. uPA/PAI-1 is the strongest predictor of disease-free survival and overall survival; patients with high uPA/PAI-1 have an increased relapse risk (P <.001; relative risk, 4.8; 95% confidence interval [CI], 2.5 to 9.1), in particular for early relapse. Even within risk groups stratified by established criteria (nodal or menopausal status, tumor size, grade, or steroid hormone receptors), uPA/PAI-1 provides significant risk group discrimination. In the whole collective, the significant interaction between uPA/PAI-1 and adjuvant systemic therapy suggests a benefit from adjuvant therapy in high-risk patients as defined by uPA/PAI-1. CONCLUSION: The clinical relevance of the two tumor-invasion factors uPA and PAI-1 is greatest when they are used in combination. The particular combination of uPA and PAI-1 (both low v either or both high) is superior to either factor alone and supports risk-adapted individualized therapy decisions.     

Clinical utility of urokinase-type plasminogen activator and plasminogen activator inhibitor-1 determination in primary breast cancer tissue for individualized therapy concepts

Invasion factors urokinase-type plasminogen activator (uPA) and its plasminogen activator inhibitor (PAI-1) are the only novel tumor biological prognostic factors validated at the highest level of evidence with regard to their clinical utility in breast cancer. Antigen levels of both factors present in extracts of primary tumor tissue are determined by standardized, quality-assured enzyme-linked immunosorbent assays. Numerous studies showed that patients with low levels of uPA and PAI-1 have a significantly better survival than patients with high levels of either factor. Recently, these data have been validated by a European Organization for Research and Treatment of Cancer pooled analysis comprising more than 8000 breast cancer patients. The particular combination of both factors, uPA/PAI-1 (both low vs. either or both factors high), outperforms the single factors as well as other traditional prognostic factors with regard to risk group assessment, particularly in node-negative breast cancer. Node-negative breast cancer patients with low levels of uPA and PAI-1 have a very good prognosis and, as such, may be candidates for being spared the burden of adjuvant chemotherapy. In contrast, node-negative patients with high uPA/PAI-1 are at a substantially increased risk of relapse, comparable to that of patients with > or = 3 involved axillary lymph nodes. First results from a multicenter prospective randomized therapy trial in node-negative breast cancer (Chemo N(0)) as well as recent retrospective analyses indicate that these high-risk patients benefit from adjuvant chemotherapy. Thus, combined determination of the invasion factors uPA and PAI-1 supports risk-adapted individualized therapeutic strategies in patients with primary breast cancer, particularly in those with node-negative breast cancer.     

Randomized adjuvant chemotherapy trial in high-risk, lymph node-negative breast cancer patients identified by urokinase-type plasminogen activator and plasminogen activator inhibitor type 1.

BACKGROUND: Most patients with lymph node-negative breast cancer are cured by locoregional treatment; however, about 30% relapse. Because traditional histomorphologic and clinical factors fail to identify the high-risk patients who may benefit from adjuvant chemotherapy, other prognostic factors are needed. In a unicenter study, we have found that levels of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (PAI-1) in the primary tumor are predictive of disease recurrence. Thus, we designed the Chemo N(0) prospective randomized multicenter therapy trial to investigate further whether uPA and PAI-1 are such prognostic factors and whether high-risk patients identified by these factors benefit from adjuvant chemotherapy. After 4.5 years, we present results of the first interim analysis. METHODS: We studied 556 patients with lymph node-negative breast cancer. The median follow-up was 32 months. All patients with low tumor levels of uPA (< or = 3 ng/mg of protein) and of PAI-1 (< or = 14 ng/mg of protein) were observed. Patients with high tumor levels of uPA (> 3 ng/mg of protein) and/or of PAI-1 (> 14 ng/mg of protein) were randomly assigned to combination chemotherapy or subjected to observation only. All statistical tests were two-sided. RESULTS: A total of 241 patients had low levels of uPA and PAI-1, and 315 had elevated levels of uPA and/or PAI-1. The estimated 3-year recurrence rate for patients with low tumor levels of uPA and PAI-1 (low-risk group) was 6.7% (95% confidence interval [CI] = 2.5% to 10.8%). This rate for patients with high tumor levels of uPA and/or PAI-1 (high-risk group) was 14.7% (95% CI = 8.5% to 20.9%) (P = 0.006). First interim analysis suggests that high-risk patients in the chemotherapy group benefit, with a 43.8% lower estimated probability of disease recurrence at 3 years than high-risk patients in the observation group (intention-to-treat analysis: relative risk = 0.56; 95% CI = 0.25 to 1.28), but further follow-up is needed for confirmation. CONCLUSIONS: Using uPA and PAI-1, we have been able to classify about half of the patients with lymph node-negative breast cancer as low risk, for whom adjuvant chemotherapy may be avoided, and half as high risk, who appear to benefit from adjuvant chemotherapy.     

Prognostic value of the urokinase-type plasminogen activator,and its inhibitors and receptor in breast cancer patients

Urokinase-type plasminogen activator (uPA), its inhibitors (PAI-1 and PAI-2), and its receptor (uPAR) play a key role in tumor invasion and metastasis. This study was designed to evaluate the prognostic impact of uPA, PAI-1, PAI-2, and uPAR and the combination of these factors in a group of 460 primary breast cancer patients. Concentrations of all 4 components of the uPA system were measured in tumor extracts using enzyme-linked immunosorbent assays (American Diagnostica, Inc, Greenwich, CT). After a median follow-up of 33 months, 18.5% of the patients had relapsed. The Cox proportional hazards model was applied for both univariate and multivariate analyses of disease-free survival (DFS). PAI-1 and PAI-2 were shown to provide independent prognostic information in breast cancer. Patients with either low levels of PAI-1 or high levels of PAI-2 were found to have better DFS (relative risk was 2.08 and 1.78, respectively). The prognostic value could be even further improved by a combination of both inhibitors. Aside from the uPA inhibitors, only nodal status and hormonal receptor status retained independent prognostic value. The other 2 invasion markers, uPA and uPAR, showed no statistically significant impact on DFS. In our patients, who were mostly treated with adjuvant therapy, uPA was not found to be an independent prognostic marker for DFS; this could be a consequence of the predictive value of uPA for response to adjuvant therapy and should be further investigated.     

Urokinase-type plasminogen activator system in breast cancer: association with tamoxifen therapy in recurrent disease

The prognostic value of components of the urokinase-type plasminogen activator (uPA) system, its receptor uPAR (CD87), and plasminogen activator inhibitors PAI-1 and PAI-2 is well established. We studied the predictive value of these proteolytic factors by evaluating the association of their tumor expression level and the efficacy of tamoxifen therapy in patients with recurrent breast cancer. The antigen levels of the four factors were determined by ELISA in cytosols prepared from estrogen receptor-positive primary breast tumors of 691 hormone-naive breast cancer patients with recurrent disease and treated with tamoxifen as first-line systemic therapy. High tumor levels of uPA (P < 0.001), uPAR (P < 0.01), and PAI-1 (P = 0.01) were associated with a lower efficacy of tamoxifen therapy. In the multivariable analysis, uPA (P < 0.001) provided additional information independent of the traditional predictive factors to predict benefit from tamoxifen therapy. High levels of uPA, uPAR, and PAI-1 predicted a shorter progression-free survival (PFS) on tamoxifen in an analysis of the first 9 months of therapy. However in the analysis during the total follow-up period, high PAI-2 levels (P = 0.01) showed a longer response to tamoxifen. In conclusion, uPA, uPAR, and PAI-1, components of the urokinase system, are predictive for the efficacy of tamoxifen therapy in patients treated for recurrent breast cancer. Knowledge of their tumor expression levels might be helpful for future individualized therapy protocols, including possible new-targeted therapies based on the interference in the urokinase system.     

Metastasis of transgenic breast cancer in plasminogen activator inhibitor-1 gene-deficient mice

The plasminogen activator inhibitor-1 (PAI-1) blocks the activation of plasmin(ogen), an extracellular protease vital to cancer invasion. PAI-1 is like the corresponding plasminogen activator uPA (urokinase-type plasminogen activator) consistently expressed in human breast cancer. Paradoxically, high levels of PAI-1 as well as uPA are equally associated with poor prognosis in cancer patients. PAI-1 is thought to play a vital role for the controlled extracellular proteolysis during tumor neovascularization. We have studied the effect of PAI-1 deficiency in a transgenic mouse model of metastasizing breast cancer. In these tumors, the expression pattern of uPA and PAI-1 resembles that of human ductal breast cancer and plasminogen is required for efficient metastasis. In a cohort of 63 transgenic mice that were either PAI-1-deficient or wild-type sibling controls, primary tumor growth and vascular density were unaffected by PAI-1 status. PAI-1 deficiency also did not significantly affect the lung metastatic burden. These results agree with the virtual lack of spontaneous phenotype in PAI-1-deficient mice and humans and may reflect that the plasminogen activation reaction is not rate limiting for tumor vascularization and metastasis, or that there is a functional redundancy between PAI-1 and other inhibitors of the uPA/plasmin system, masking the effect of PAI-1 deficiency.     

Prognostic impact of proteolytic factors (urokinase-type plasminogen activator, plasminogen activator inhibitor 1, and cathepsins B, D, and L) in primary breast cancer reflects effects of adjuvant systemic therapy.

PURPOSE: Prognostic and predictive impact of five proteolytic factors associated with tumor invasion and metastasis in primary breast cancer were evaluated after long-term follow-up. EXPERIMENTAL DESIGN: Antigen levels of urokinase-type plasminogen activator, plasminogen activator inhibitor-1 (PAI-1), Cathepsins B, D, and L were determined using immunochemical assays in primary tumor tissue of 276 patients. RESULTS: During follow-up (median 109 months), 119 (43%) patients relapsed, and 117 (42%) died. In the whole collective, lymph node status (P < 0.001; RR 3.8), Cathepsin L (P < 0.001; RR 2.6), and PAI-1 (P = 0.027; RR 1.7) were the only independent significant factors in multivariate analysis for disease-free survival (DFS). For overall survival (OS), lymph node status (P < 0.001; RR 2.9), Cathepsin L (P = 0.017; RR 1.9), PAI-1 (P = 0.01; RR 1.9), and grading (P = 0.026; RR 1.7) were significant. In the node-negative subgroup, PAI-1 was the only significant factor for DFS (P = 0.004; RR 3.7) and the strongest factor (P = 0.004; RR 3.7) for OS next to grading (P = 0.017; RR 3.1). In node-positive patients, Cathepsin L was the only significant factor for both DFS (P < 0.001; RR 3.2) and OS (P = 0.003; RR 2.5). For all proteolytic factors but Cathepsin L, the univariate prognostic impact on DFS was substantial in patients without adjuvant systemic therapy but was diminished if adjuvant therapy had been administered. Cathepsin L maintained its strong prognostic impact on DFS even in patients with adjuvant endocrine therapy (P = 0.01; RR 2.8). CONCLUSIONS: The observed effect of adjuvant systemic therapy on their prognostic strength suggests that the assessed proteolytic factors supply predictive information on therapy response.     

Physiological and pathological changes of plasma urokinase-type plasminogen activator, plasminogen activator inhibitor-1, and urokinase-type plasminogen activator receptor levels in healthy females and breast cancer patients

The plasma urokinase-type plasminogen activator (uPA), plasminogen activator inhibitor-1 (PAI-1), and urokinase-type plasminogen activator receptor (uPAR) levels were measured in healthy volunteers and breast cancer patients. In pre-menopause healthy females, blood was sampled weekly during one menstruation cycle and menstruation phases (follicular, ovulatory, luteal) were determined by FSH/LH levels. uPA, PAI-1, and uPAR levels were at the nadir during ovulatory phase. uPA level was highest at follicular phase while PAI-1 level was highest at luteal phase. In comparison between pre- and post-menopause states, uPA and uPAR levels were higher in post-menopause state while PAI-1 level was higher in pre-menopause state. In breast cancer patients, uPA, PAI-1, and uPAR positive rates were low when we use the menopause-state-unmatched cut-off points. As we adjusted the cut-off points by menopause states, the PAI-1 positivity increased mainly in post-menopause cancer patients. These findings suggest that there is a minor but possible sequential change of these molecules during menstruation cycle which might blur the pathological positivity in pre-menopause cancer patients. The pathological elevation of PAI-1 was well detected in post-menopause cancer patients, but this elevation did not correlate with tumor burden such as number of metastatic sites or metastatic location. In conclusion, adjustment of physiological changes of uPA, PAI-1, and uPAR is required in determining pathological elevation of the plasma levels in cancer patients, especially in females.This revised version was published online in October 2005 with corrections to the Cover Date.     

Urokinase-type plasminogen activator system and breast cancer (Review)

Malignant tumors have a capacity to degrade the extracellular matrix (ECM) by controlled proteolysis. One proteolytic system involved in these processes is the urokinase-type plasminogen activator (uPA) system, which consists of uPA, uPA receptor (uPAR) and uPA inhibitors 1 and 2 (PAI-1 and PAI-2). In the past two decades, study of the uPA system in human breast cancer has yielded valuable insights. Increased levels of uPA, PAI-1 and uPAR have been reported to be associated with poor prognosis in patients with breast cancer. Furthermore, uPA and PAI-1 may be new prognostic markers for axillary node-negative patients. To date, a growing body of evidence has suggested that uPA system promotes tumor metastasis by several different mechanisms, not just by breaking down the ECM. This article is focused on reviewing the current understanding of uPA system members as prognostic markers in breast cancer, and their cellular localization and tissue distribution. Correlations of the uPA system with other informative markers of breast cancer are also discussed.     

Significance of urokinase-type plasminogen activator and plasminogen activator inhibitor-1 (PAI-1) expression in human colorectal carcinomas.

Despite the advances in the medical care of colorectal carcinoma patients, the prognosis has improved only marginally over recent decades. Thus, additional prognostic indicators would be of great clinical value to select patients for adjuvant therapy. In the present study, the antigen levels of urokinase-type plasminogen activator (uPA) and its inhibitor PAI-1, and their immunohistochemical staining were compared in paired colorectal tumor (n = 64) and background colon tissue of the same patients with clinical and pathological staging. The antigen levels, measured with an ELISA method, were found to be significantly higher in cancer tissue (mean 1.92 ng/mg protein for uPA and 7.08 for PAI-1) than in corresponding normal mucosa (0.29 ng/mg protein for uPA and 1.11 ng/mg protein for PAI-1). There was a positive correlation between uPA and PAI-1 antigen levels and clinicopathological parameters such as grade (p < 0.001 and p = 0.01, respectively), while for Dukes' stage, only PAI-1 correlated positively (p = 0.018). Nodal status correlated positively with uPA but not with PAI-1 antigen levels. Immunohistochemical localization of both antigens was observed mainly in cancer cells and much less in stromal cells. Staining intensity increased from adenoma to adenocarcinoma. The degree of staining was associated with grade, Dukes' stage and nodal status for uPA (p < 0.001, p = 0.002, p < 0.001, respectively) and only with grade for PAI-1 (p = 0.007).     

Plasminogen activator inhibitor type 1 is the most significant of the usual tissue prognostic factors in node-negative breast ductal adenocarcinoma independent of urokinase-type plasminogen activator

PURPOSE: The aim of the present investigation was to evaluate the prognostic significance of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) tissue contents in primary breast adenocarcinoma. PATIENTS AND METHODS: Patients from 3 medical centers were included between 1994 and 2001. Biologic factors in tumor extracts were all assayed in the same laboratory. PAI-1 and uPA were treated as continuous or dichotomized variables. Metastasis-free survival analyses were performed using the Cox model and the classification algorithm and regression tree (CART) in the whole population and in the subsets of node-negative (pN0) or positive (pN+) cases. Kaplan curves of metastasis-free survival were designed for different groups in relation to uPA/PAI-1 combinations. Urokinase-type plasminogen activator tumor level appears related to the anatomic degree of extension; conversely, PAI-1 tumor content is independent of tumor size and nodal extension. RESULTS: In univariate analysis, adjusted on usual prognostic factors, the metastasis risk increased with PAI-1 level in all patients (HR [hazard ratio], 3.1; P < .001), in pN0 (HR, 4.3; P < .001), and pN+ patients (HR, 2.3; P = .019). It increased also with uPA in all patients (HR, 2.6; P = 0.006). In multivariate analysis, when both variables were included, PAI-1 remained significant in all patients (HR, 2.4; P = .002) and pN0 patients (HR, 3.2; P = .003) but not uPA. CART analyses confirmed that the best partitioning factor was PAI-1. CONCLUSION: There was no evidence for any additional impact of uPA. PAI-1 is an independent prognostic factor in particular in pN0 breast ductal carcinoma.     

Complex of urokinase-type plasminogen activator with its type 1 inhibitor predicts poor outcome in 576 patients with lymph node-negative breast carcinoma

BACKGROUND: The ability of a solid tumor to grow and metastasize has a significant dependence on protease systems, such as the plasminogen activation system. The plasminogen activation system includes the urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (PAI-1), among other molecules. Both uPA and PAI-1 are established prognostic factors for patients with breast carcinoma. In the current study, the authors investigated whether the complex of uPA with PAI-1 is also associated with the natural course of this malignancy. METHODS: Cytosolic levels of uPA, PAI-1, and the uPA:PAI-1 complex were measured in tumor tissue from 576 patients with lymph node-negative invasive breast carcinoma using quantitative enzyme-linked immunosorbent assays. Patients did not receive adjuvant systemic therapy, and the median follow-up duration was 61 months (range, 2-187 months) after primary diagnosis. Correlations with well known clinicopathologic factors were assessed, and univariate and multivariate survival analyses were performed. RESULTS: uPA:PAI-1 complex levels were positively associated with adverse histologic grade and inversely correlated with estrogen and progesterone receptor status. On univariate analysis, increased levels of the uPA:PAI-1 complex were found to be associated with reduced recurrence-free survival (RFS) and overall survival (OS) rates. On multivariate analysis, uPA:PAI-1 complex levels were found to be an independent predictor of OS (P = 0.039), but not RFS (P = 0.240). When uPA and PAI-1 levels were not included in the multivariate analysis, uPA:PAI-1 complex levels became a significant predictor of both RFS and OS (P = 0.029 and P = 0.007, respectively). CONCLUSIONS: The results of the current study demonstrate that uPA:PAI-1 complex levels have prognostic value on univariate analysis. In addition, increased uPA:PAI-1 complex levels were significantly associated with poor OS on multivariate analysis. Increased uPA:PAI-1 complex levels were also significantly associated with reduced RFS rates after the exclusion of uPA and PAI-1 levels from the multivariate analysis model.     

Urokinase plasminogen activator: a prognostic marker in multiple types of cancer.

Urokinase plasminogen activator (uPA) is a serine protease causally involved in cancer invasion and metastasis. Consistent with its role in cancer spread, uPA has been shown to be a prognostic marker in a variety of malignancies, especially breast cancer. Approximately 20 different groups have shown that high levels of uPA in breast tumor tissue predict poor outcome. As a prognostic marker in breast cancer, uPA provides information that is independent of traditionally used factors such as tumor size, tumor grade, axillary node status and estrogen receptor status. Furthermore, uPA is prognostic in node-negative patients, and a clinical trial is currently under way to assess whether uPA and its inhibitor, plasminogen activator inhibitor-1, can differentiate between the majority of node-negative breast cancer patients who are cured by surgery from the minority who might benefit from adjuvant therapy. uPA is also prognostic in other malignancies, such as gastric, colorectal, esophageal, renal, endometrial, and ovarian cancers. uPA may thus be a prognostic indicator for multiple types of adenocarcinoma.     

Her-2/neu and urokinase-type plasminogen activator and its inhibitor in breast cancer.

PURPOSE: Recent studies suggest that HER-2/neu specifically promotes the invasive capacity of tumor cells by up-regulating secretion of the proteolytic enzyme, urokinase-type plasminogen activator (uPA), or its inhibitor, plasminogen activator inhibitor-1 (PAI-1), in colon and gastric cancer. It was the purpose of this study to: (a) evaluate the association between HER-2/neu and uPA and PAI-1 expression in a large primary breast cancer cohort; (b) perform the first multivariate analysis, including HER-2/neu, uPA, and PAI-1 in breast cancer; and (c) define the effect of HER-2/neu overexpression on uPA and PAI-1 expression in breast cancer cells. EXPERIMENTAL DESIGN: HER-2/neu, uPA, and PAI-1 were measured as continuous variables by ELISA in primary breast cancer tissue extracts from 587 patients with clinical follow-up and analyzed for correlations with clinical outcome. Furthermore, a full-length human HER-2/neu cDNA was introduced into five human breast cancer cell lines to define the effects of HER-2/neu overexpression on uPA and PAI-1 expression. In addition, we tested whether HER-2/neu antibodies could reverse any given alteration of uPA and PAI-1 levels. RESULTS: Our findings indicate a weak positive association between HER-2/neu and uPA (r = 0.147; P < 0.001) and no association between HER-2/neu and PAI-1 (r = 0.07; P = 0.085). HER-2/neu overexpression (> or =400 fmol/mg) and high levels of uPA/PAI-1 (> or =5.5 ng/mg and/or > or =14 ng/mg, respectively) were significantly associated with shorter disease-free survival (DFS; P < 0.001 and P = 0.003) and metastasis-free survival (MFS; P = 0.015 and P < 0.001). Multivariate analysis revealed prognostic independence between HER-2/neu and the uPA/PAI-1 axis for DFS and MFS. Both uPA and PAI-1 had no significant discriminatory effect among HER-2/neu-positive patients for DFS. The prognostic value of HER-2/neu overexpression for MFS, however, was significantly enhanced by elevated uPA expression (P = 0.053). Stable transfection of the HER-2/neu gene into multiple human breast cancer cell lines resulted in consistent down-regulation of uPA or PAI-1 expression. In addition, anti-HER-2/neu antibodies did not significantly affect uPA or PAI-1 expression in human cancer cell lines naturally overexpressing HER-2/neu. CONCLUSIONS: The present findings suggest that the invasive phenotype elicited by HER-2/neu overexpression in breast cancer is not a direct effect of uPA or PAI-1 expression. HER-2/neu and the uPA/PAI-1 axis have been shown to affect the invasive capacity of breast cancer independently. Determination of uPA can provide significant additional prognostic information for MFS in HER-2/neu-positive and -negative patients.     

uPA and PAI-1 as biomarkers in breast cancer: validated for clinical use in level-of-evidence-1 studies

Urokinase plasminogen activator (uPA) is an extracellular matrix-degrading protease involved in cancer invasion and metastasis, interacting with plasminogen activator inhibitor-1 (PAI-1), which was originally identified as a blood-derived endogenous fast-acting inhibitor of uPA. At concentrations found in tumor tissue, however, both PAI-1 and uPA promote tumor progression and metastasis. Consistent with the causative role of uPA and PAI-1 in cancer dissemination, several retrospective and prospective studies have shown that elevated levels of uPA and PAI-1 in breast tumor tissue are statistically independent and potent predictors of poor patient outcome, including adverse outcome in the subset of breast cancer patients with lymph node-negative disease. In addition to being prognostic, high levels of uPA and PAI-1 have been shown to predict benefit from adjuvant chemotherapy in patients with early breast cancer. The unique clinical utility of uPA/PAI-1 as prognostic biomarkers in lymph node-negative breast cancer has been confirmed in two independent level-of-evidence-1 studies (that is, in a randomized prospective clinical trial in which the biomarker evaluation was the primary purpose of the trial and in a pooled analysis of individual data from retrospective and prospective studies). Thus, uPA and PAI-1 are among the best validated prognostic biomarkers currently available for lymph node-negative breast cancer, their main utility being the identification of lymph node-negative patients who have HER-2-negative tumors and who can be safely spared the toxicity and costs of adjuvant chemotherapy. Recently, a phase II clinical trial using the low-molecular-weight uPA inhibitor WX-671 reported activity in metastatic breast cancer.     

Urokinase plasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1) in breast cancer - correlation with traditional prognostic factors

Background

Urokinase plasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1) play a key role in tumour invasion and metastasis. High levels of both proteolytic enzymes are associated with poor prognosis in breast cancer patients. The purpose of this study was to evaluate the correlation between traditional prognostic factors and uPA and PAI-1 expression in primary tumour of breast cancer patients.

Patients and methods.

606 primary breast cancer patients were enrolled in the prospective study in the Department of gynaecological oncology and breast oncology at the University Medical Centre Maribor between the years 2004 and 2010. We evaluated the traditional prognostic factors (age, menopausal status, tumour size, pathohistological type, histologic grade, lymph node status, lymphovascular invasion and hormone receptor status), together with uPA and PAI-1. We used Spearman’s rank correlation, Mann Whitney U test and χ² test for statistical analysis.

Results

Our findings indicate a positive correlation between uPA and tumour size (p < 0.001), grade (p < 0.001), histological type (p < 0.001), lymphovascular invasion (p = 0.01) and a negative correlation between uPA and hormone receptor status (p < 0.001). They also indicate a positive correlation between PAI-1 and tumour size (p = 0.004), grade (p < 0.001), pathohistological type (p < 0.001) and negative correlation between PAI-1 and hormone receptor status (p = 0.002).

Conclusions

Our study showed a relationship between uPA and PAI-1 and traditional prognostic factors. Their role as prognostic and predictive factors remains to be further evaluated.     

Independent prognostic value of angiogenesis and the level of plasminogen activator inhibitor type 1 in breast cancer patients

Tumour angiogenesis and the levels of plasminogen activator inhibitor type 1 (PAI-1) are both informative prognostic markers in breast cancer. In cell cultures and in animal model systems, PAI-1 has a proangiogenic effect. To evaluate the interrelationship of angiogenesis and the PAI-1 level in breast cancer, we have evaluated the prognostic value of those factors in a total of 228 patients with primary, unilateral, invasive breast cancer, evaluated at a median follow-up time of 12 years. Microvessels were immunohistochemically stained by antibodies against CD34 and quantitated by the Chalkley counting technique. The levels of PAI-1 and its target proteinase uPA in tumour extracts were analysed by ELISA. The Chalkley count was not correlated with the levels of uPA or PAI-1. High values of uPA, PAI-1, and Chalkley count were all significantly correlated with a shorter recurrence-free survival and overall survival. In the multivariate analysis, the uPA level did not show independent prognostic impact for any of the analysed end points. In contrast, the risk of recurrence was independently and significantly predicted by both the PAI-1 level and the Chalkley count, with a hazard ratio (95% CI) of 1.6 (1.01-2.69) and 1.4 (1.02-1.81), respectively. For overall survival, the Chalkley count, but not PAI-1, was of significant independent prognostic value. The risk of death was 1.7 (1.30-2.15) for Chalkley counts in the upper tertile compared to the lower one. We conclude that the PAI-1 level and the Chalkley count are independent prognostic markers for recurrence-free survival in patients with primary breast cancer, suggesting that the prognostic impact of PAI-1 is not only based on its involvement in angiogenesis.