Cellular localization of urokinase-type plasminogen activator, its inhibitors, and their mRNAs in breast cancer tissues

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.

Matrix-bound PAI-1 supports cell blebbing via RhoA/ROCK1 signaling

The microenvironment of a tumor can influence both the morphology and the behavior of cancer cells which, in turn, can rapidly adapt to environmental changes. Increasing evidence points to the involvement of amoeboid cell migration and thus of cell blebbing in the metastatic process; however, the cues that promote amoeboid cell behavior in physiological and pathological conditions have not yet been clearly identified. Plasminogen Activator Inhibitor type-1 (PAI-1) is found in high amount in the microenvironment of aggressive tumors and is considered as an independent marker of bad prognosis. Here we show by immunoblotting, activity assay and immunofluorescence that, in SW620 human colorectal cancer cells, matrix-associated PAI-1 plays a role in the cell behavior needed for amoeboid migration by maintaining cell blebbing, localizing PDK1 and ROCK1 at the cell membrane and maintaining the RhoA/ROCK1/MLC-P pathway activation. The results obtained by modeling PAI-1 deposition around tumors indicate that matrix-bound PAI-1 is heterogeneously distributed at the tumor periphery and that, at certain spots, the elevated concentrations of matrix-bound PAI-1 needed for cancer cells to undergo the mesenchymal-amoeboid transition can be observed. Matrix-bound PAI-1, as a matricellular protein, could thus represent one of the physiopathological requirements to support metastatic formation.

Matrix remodeling stimulates stromal autophagy, "fueling" cancer cell mitochondrial metabolism and metastasis

We have previously demonstrated that loss of stromal caveolin-1 (Cav-1) in cancer-associated fibroblasts is a strong and independent predictor of poor clinical outcome in human breast cancer patients. However, the signaling mechanism(s) by which Cav-1 downregulation leads to this tumor-promoting microenvironment are not well understood. To address this issue, we performed an unbiased comparative proteomic analysis of wild-type (WT) and Cav-1(-/-) null mammary stromal fibroblasts (MSFs). Our results show that plasminogen activator inhibitor type 1 and type 2 (PAI-1 and PAI-2) expression is significantly increased in Cav-1(-/-) MSFs. To establish a direct cause-effect relationship, we next generated immortalized human fibroblast lines stably overexpressing either PAI-1 or PAI-2. Importantly, PAI-1/2(+) fibroblasts promote the growth of MDA-MB-231 tumors (a human breast cancer cell line) in a murine xenograft model, without any increases in angiogenesis. Similarly, PAI-1/2(+) fibroblasts stimulate experimental metastasis of MDA-MB-231 cells using an in vivo lung colonization assay. Further mechanistic studies revealed that fibroblasts overexpressing PAI-1 or PAI-2 display increased autophagy ("self-eating") and are sufficient to induce mitochondrial biogenesis/activity in adjacent cancer cells, in co-culture experiments. In xenografts, PAI-1/2(+) fibroblasts significantly reduce the apoptosis of MDA-MB-231 tumor cells. The current study provides further support for the "Autophagic Tumor Stroma Model of Cancer" and identifies a novel "extracellular matrix"-based signaling mechanism, by which a loss of stromal Cav-1 generates a metastatic phenotype. Thus, the secretion and remodeling of extracellular matrix components (such as PAI-1/2) can directly regulate both (1) autophagy in stromal fibroblasts and (2) epithelial tumor cell mitochondrial metabolism.

Peptide screening of cerebrospinal fluid in patients with glioblastoma multiforme

AIMS

To apply modern mass spectrometry based technology to identify possible CSF peptide markers of glioblastoma multiforme (GBM).

METHODS

Mass spectrometry based peptidomics technology enables a systematic and comprehensive screening of cerebrospinal fluid (CSF) with regard to its peptide composition. Differential Peptide Display (DPD) allows the identification of single marker peptides for a target disease. Using both, we analyzed CSF samples of 11 patients harbouring a glioblastoma multiforme in comparison to 13 normal controls.

RESULTS

Four CSF peptides which significantly distinguished GBM from controls in all applied statistic tests could be identified out of more than 2,000 detected CSF peptides. They were specific C-terminal fragments of alpha-1-antichymotrypsin, osteopontin, and transthyretin as well as a N-terminal residue of albumin. All molecules are constituents of normal CSF, but none has previously been reported to be significantly elevated in CSF of GBM patients.

CONCLUSION

The study showed that peptidomics technology is able to identify possible biomarkers of neoplastic CNS disease. It remains to be determined if the identified elevated CSF peptides are specific for GBM. With regard to GBM, however, the more important role of CSF peptide biomarkers than aiding initial diagnosis might be early recognition of disease recurrence or monitoring of efficacy of adjuvant therapy protocols.

Revisiting the biological roles of PAI2 (SERPINB2) in cancer

Tumour expression of the urokinase plasminogen activator correlates with invasive capacity. Consequently, inhibition of this serine protease by physiological inhibitors should decrease invasion and metastasis. However, of the two main urokinase inhibitors, high tumour levels of the type 1 inhibitor actually promote tumour progression, whereas high levels of the type 2 inhibitor decrease tumour growth and metastasis. We propose that the basis of this apparently paradoxical action of two similar serine protease inhibitors lies in key structural differences controlling interactions with components of the extracellular matrix and endocytosis-signalling co-receptors.

Novel distribution pattern of fibrinolytic components in rabbit tissues extract: a preliminary study

OBJECTIVE

The purpose of this work was to investigate the distribution pattern of fibrinolytic factors and their inhibitors in rabbit tissues.

METHODS

The components of the fibrinolytic system in extracts from a variety of rabbit tissues, including tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), plasminogen (Plg), plasmin (Pl) and alpha(2) plasmin inhibitor (alpha(2)PI), were determined by colorimetric assay.

RESULTS

The tissue extracts in renal, small intestine, lung, brain and spleen demonstrated strong fibrinolytic function, in which high activity of tPA, Plg and Pl was manifested; whereas in skeletal muscle, tongue and stomach, higher activity of PAI-1 and alpha(2)PI showed obviously. Also excellent linear correlations were found between levels of tPA and PAI-1, Pl and alpha(2)PI, Plg and Pl. In related tissues, renal cortex and renal marrow showed distinctly higher activity of tPA and lower activity of PAI-1, with the levels of Plg and Pl in renal cortex being higher than those in renal marrow, where the alpha(2)PI level was higher than that in renal cortex. Similarly, the levels of tPA, Plg and Pl in small intestine were higher than those in large intestine, but with respect to PAI-1 and alpha(2)PI, the matter was reverse. In addition, the fibrinolytic activity in muscle tissue was lower, however, the levels of tPA, Plg, and Pl in cardiac muscle were obviously higher than those in skeletal muscles, and the levels of PAI-1 and alpha(2)PI were significantly lower than those in skeletal muscle.

CONCLUSION

Our data demonstrate that a remarkable difference of the fibrinolytic patterns exists in rabbit tissues, which has probable profound significance in understanding the relationship between the function of haemostasis or thrombosis and the physiologic function in tissues.

Deciphering the molecular basis of breast cancer metastasis with mouse models

Breast cancer begins as a localized disease, but has the potential to spread to distant sites within the body. This process--known as metastasis--is the leading cause of death from breast cancer. Whether the ability of cancer cells to metastasize is an intrinsic or acquired feature is currently a topic of considerable debate. Nevertheless, the key cellular events required for metastasis are generally accepted. These include invasion of the surrounding stromal tissue, intravasation, evasion of programmed cell death, arrest within the vasculature at a distant site, extravasation, and establishment and growth within a new microenvironment. The development of mouse models that faithfully mimic critical aspects of human neoplasia has been instrumental in framing our current understanding of multistage carcinogenesis. This review examines the advantages and limitations of existing murine models for mammary carcinogenesis for probing the molecular mechanisms that contribute to metastasis, as well as non-invasive tumor imaging approaches to facilitate these investigations.

Expression of plasminogen activator inhibitors type 1 and type 3 and urokinase plasminogen activator protein and mRNA in breast cancer

BACKGROUND

The urokinase plasminogen activator (uPA) system has been involved in cancer cell invasion and in metastasis. uPA activity is controlled by its principal inhibitor, the PA inhibitor type-1 (PAI-1), but it can also be inhibited by PAI-3. Increased levels of uPA and PAI-1 are known to be associated with a poor prognosis in breast cancer. To our knowledge this is the first study of the expression and role of PAI-3 in human breast cancer tissue.

MATERIALS AND METHODS

Protein and mRNA levels were evaluated for uPA, PAI-1 and PAI-3 in breast cancer tissues from 70 different patients. The localization of antigen and mRNA of these proteins was studied by immunohistochemistry and in situ hybridization, respectively.

RESULTS

No significant differences were observed for PAI-3 mRNA or protein levels between the nodal status groups or the different post-surgical tumor-node-metastasis (pTNM) stages. However, uPA and PAI-1 mRNA and antigen levels significantly increased at the pTNM stage and in node-positive patients. PAI-3 antigen levels were significantly higher in early relapse-free patients, whereas PAI-1 antigen levels were significantly higher in patients who suffered a relapse. PAI-3 protein and mRNA were localized in stromal cells. PAI-1 and uPA protein were detected in cancer, endothelial and stromal cells and their mRNA mainly in stromal cells.

CONCLUSIONS

Our results indicate that PAI-3 is expressed in human breast cancer tissues, and that elevated levels of PAI-3 could be a positive prognostic factor in this disease. A potential mechanism for the contribution of PAI-3 to a positive long-term outcome may involve suppression of tumor invasion through protease inhibition in stroma.

Increased Expression of Urokinase-Type Plasminogen Activator mRNA Determines Adverse Prognosis in ErbB2-Positive Primary Breast Cancer

Purpose

To evaluate and validate mRNA expression markers capable of identifying patients with ErbB2-positive breast cancer associated with distant metastasis and reduced survival.

Patients and Methods

Expression of 60 genes involved in breast cancer biology was assessed by quantitative real-time PCR (qrt-PCR) in 317 primary breast cancer patients and correlated with clinical outcome data. Results were validated subsequently using two previously published and publicly available microarray data sets with different patient populations comprising 295 and 286 breast cancer samples, respectively.

Results

Of the 60 genes measured by qrt-PCR, urokinase-type plasminogen activator (uPA or PLAU) mRNA expression was the most significant marker associated with distant metastasis-free survival (MFS) by univariate Cox analysis in patients with ErbB2-positive tumors and an independent factor in multivariate analysis. Subsequent validation in two microarray data sets confirmed the prognostic value of uPA in ErbB2-positive tumors by both univariate and multivariate analysis. uPA mRNA expression was not significantly associated with MFS in ErbB2-negative tumors. Kaplan-Meier analysis showed in all three study populations that patients with ErbB2-positive/uPA–positive tumors exhibited significantly reduced MFS (hazard ratios [HR], 4.3; 95% CI, 1.6 to 11.8; HR, 2.7; 95% CI, 1.2 to 6.2; and, HR, 2.8; 95% CI, 1.1 to 7.1; all P < .02) as compared with the group with ErbB2-positive/uPA–negative tumors who exhibited similar outcome to those with ErbB2-negative tumors, irrespective of uPA status.

Conclusion

After evaluation of 898 breast cancer patients, uPA mRNA expression emerged as a powerful prognostic indicator in ErbB2-positive tumors. These results were consistent among three independent study populations assayed by different techniques, including qrt-PCR and two microarray platforms.

[The PAI-1 swing: microenvironment and cancer cell migration]

Cancer is a complex and dynamic process caused by a cellular dysfunction leading to a whole organ or even organism vital perturbation. To better understand this process, we need to study each one of the levels involved, which allows the scale change, and to integrate this knowledge. A matricellular protein, PAI-1, is able to induce in vitro cell behaviour modifications, morphological changes, and to promote cell migration. PAI-1 influences the mesenchymo-amaeboid transition. This matricellular protein should be considered as a potential 'launcher' of the metastatic process acting at the molecular, cellular, tissular levels and, as a consequence, at the organism's level.

Prognostic significance of urokinase plasminogen activator and plasminogen activator inhibitor-1 mRNA expression in lymph node- and hormone receptor-positive breast cancer

BACKGROUND

One of the most thoroughly studied systems in relation to its prognostic relevance in patients with breast cancer, is the plasminogen activation system that comprises of, among others, the urokinase Plasminogen Activator (uPA) and its main inhibitor, the Plasminogen Activator Inhibitor-1 (PAI-1). In this study, we investigated the prognostic value of uPA and PAI-1 at the mRNA level in lymph node- and hormone receptor-positive breast cancer.

METHODS

The study included a retrospective series of 87 patients with hormone-receptor positive and axillary lymph node-positive breast cancer. All patients received radiotherapy, adjuvant anthracycline-based chemotherapy and five years of tamoxifen treatment. The median patient age was 54 and the median follow-up time was 79 months. Distant relapse occurred in 30 patients and 22 patients died from breast cancer during follow-up. We investigated the prognostic value of uPA and PAI-1 at the mRNA level as measured by real-time quantitative RT-PCR.

RESULTS

uPA and PAI-1 gene expression was not found to be correlated with any of the established clinical and pathological factors. Metastasis-free Survival (MFS) and Breast Cancer specific Survival (BCS) were significantly shorter in patients expressing high levels of PAI-1 mRNA (p < 0.0001; p < 0.0001; respectively). In Cox multivariate analysis, the level of PAI-1 mRNA appeared to be the strongest prognostic factor for MFS (Hazard Ratio (HR) = 10.12; p = 0.0002) and for BCS (HR = 13.17; p = 0.0003). Furthermore, uPA gene expression was not significantly associated neither with MFS (p = 0.41) nor with BCS (p = 0.19). In a Cox-multivariate regression analysis, uPA expression did not demonstrate significant independent prognostic value.

CONCLUSION

These findings indicate that high PAI-1 mRNA expression represents a strong and independent unfavorable prognostic factor for the development of metastases and for breast cancer specific survival in a population of hormone receptor- and lymph node-positive breast cancer patients.

Plasminogen activator inhibitor-1 as a potential marker for the malignancy of colorectal cancer

To test the hypothesis that plasminogen activator inhibitor-1 (PAI-1) may serve as a candidate marker for the malignancy of colorectal cancer (CRC), we performed a quantitative RT–PCR for PAI-1 gene and evaluated the possible relationship between PAI-1 gene expression levels and clinicopathological findings in CRC. A significant increase in PAI-1 expression scores was observed in lymph node metastasis-positive CRCs (2.19±0.43) compared to negative ones (0.35±0.42) (P=0.0037) as well as in distant metastasis-positive CRCs (3.50±1.18) compared to negative ones (0.99±0.30). The PAI-1 expression score markedly increased with the tumour stage (P=0.0063; ANOVA test). Moreover, multivariate analysis revealed the PAI-1 expression score to be a strong and independent prognostic factor for CRC (P=0.0432). These results suggested that PAI-1 might serve as a new parameter for the prediction of prognoses in CRC.

Breast cancer metastasis: markers and models

Breast cancer starts as a local disease, but it can metastasize to the lymph nodes and distant organs. At primary diagnosis, prognostic markers are used to assess whether the transition to systemic disease is likely to have occurred. The prevailing model of metastasis reflects this view--it suggests that metastatic capacity is a late, acquired event in tumorigenesis. Others have proposed the idea that breast cancer is intrinsically a systemic disease. New molecular technologies, such as DNA microarrays, support the idea that metastatic capacity might be an inherent feature of breast tumours. These data have important implications for prognosis prediction and our understanding of metastasis.

Plasminogen activator inhibitor-1 (PAI-1) stimulates human corneal epithelial cell adhesion and migration in vitro

In addition to its role as an inhibitor of urokinase plasminogen activator (uPA), plasminogen activator inhibitor-1 (PAI-1) is hypothesized to regulate epithelial cell adhesion and migration. We have previously reported that PAI-1 may be an important regulatory factor of the uPA system in cornea. The purpose of this study was to extend those observations by determining the effect of exogenous PAI-1 on the migration and adhesion of human corneal epithelial cells (HCEC) in vitro. The expression of PAI-1 in non-transformed early passage HCEC was confirmed by immunofluorescence microscopy and Western blot analysis. Colorimetric assays coupled with function-inhibiting antibody studies using the matrix assembled in situ by cultured cells demonstrate that immobilized PAI-1 serves as an efficient substrate for HCEC adhesion. HCEC attachment to PAI-1 is comparable to that of laminin-10, a known strong adhesion protein for epithelial cells. In addition to serving as an adhesion substrate, PAI-1 also functions as a chemotactic agent for corneal epithelium. Additionally it promotes the random migration of HCEC, from an initial cell cluster, along a culture substrate. Our results in corneal epithelium are consistent with reports from other investigators showing that PAI-1 facilitates both epithelial adhesion and migration. From our studies we conclude that PAI-1 may play a dual role in corneal wound healing. Initially PAI-1 may function to stimulate migration and facilitate the reepithelialization of the wound bed. Post-reepithelization, PAI-1 may ensure corneal epithelial cell adhesion to matrix to promote successful wound healing.

Plasminogen Activator Inhibitor-1 as a Potential Marker for the Malignancy of Esophageal Squamous Cell Carcinoma

PURPOSE AND EXPERIMENTAL DESIGN

To test whether plasminogen activator inhibitor-1 (PAI-1) can serve as a candidate marker for the malignancy of esophageal squamous cell carcinoma (SCC), we performed a quantitative reverse transcription-PCR for PAI-1 gene and evaluated the possible relationship between PAI-1 gene expression levels and clinicopathological findings in esophageal SCC.

RESULTS

Significant increases in PAI-1 scores were observed in metastasis-positive esophageal SCCs (3.08 +/- 0.80) compared with metastasis-negative ones (-0.31 +/- 0.62; P = 0.0042). PAI-1 expression scores significantly increased with tumor stage (P = 0.05, ANOVA).

CONCLUSIONS

These results suggested that PAI-1 might serve as a new parameter for prediction of prognosis in esophageal SCC.

The myofibroblast is the predominant plasminogen activator inhibitor-1-expressing cell type in human breast carcinomas

The tumor level of plasminogen activator inhibitor-1 (PAI-1) is an informative biochemical marker of a poor prognosis in several cancer types. However, the tumor biological functions of PAI-1 and the identity of PAI-1-expressing cells are controversial. With the aim of immunohistochemically localizing PAI-1 in formalin-fixed, paraffin-embedded invasive ductal breast carcinoma samples, we raised new polyclonal antibodies against PAI-1 from different expression systems. The antibodies were affinity purified by absorption on immobilized preparations of PAI-1 different from those used for immunization. The specificity of the antibodies was ensured by immunoblotting analysis. In immunohistochemistry, the staining pattern obtained with the antibodies showed a good correlation with the PAI-1 mRNA expression pattern. In all 25 cases analyzed, PAI-1 immunoreactivity was predominantly localized in fibroblast-like cells. Double-immunofluorescence analyses showed co-expression of PAI-1 and alpha-smooth muscle actin in these cells, suggesting that they are myofibroblasts. PAI-1 was also seen in some myoepithelial cells surrounding occasional foci of ductal carcinoma in situ (9 of 25), some endothelial cells (8 of 25), some cancer cells (3 of 25), and some mast cells (6 of 25). In conclusion, we have provided a robust immunohistochemical procedure for detection of PAI-1 and shown that the majority of the PAI-1-expressing cells in invasive ductal breast carcinomas are myofibroblasts.

Gene expression profiling of normal human pulmonary fibroblasts following coculture with non-small-cell lung cancer cells reveals alterations related to matrix degradation, angiogenesis, cell growth and survival

Increasing evidence supports a major role for the microenvironment in carcinoma formation and progression. The influence of the stroma is partly mediated by signalling between epithelial tumor cells and neighboring fibroblasts. However, the molecular mechanisms underlying these interactions are largely unknown. To mimic the initial steps of invasive carcinoma in which tumor cells come in contact with normal stromal cells, we used a coculture model of non-small-cell lung cancer tumor cells and normal pulmonary fibroblasts. Using DNA filter arrays, we first analysed the overall modification of gene expression profile after a 24 h period of coculture. Next, we focused our interest on the transcriptome of the purified fibroblastic fraction of coculture using both DNA filter arrays and a laboratory-made DNA microarray. These experiments allowed the identification of a set of modulated genes coding for growth and survival factors, angiogenic factors, proteases and protease inhibitors, transmembrane receptors, kinases and transcription regulators that can potentially affect the regulation of matrix degradation, angiogenesis, invasion, cell growth and survival. This study represents to our knowledge the first attempt to dissect early global gene transcription occurring in a tumor-stroma coculture model and should help to understand better some of the molecular mechanisms involved in heterotypic signalling between epithelial tumor cells and fibroblasts.

N-Acetyl-seryl-aspartyl-lysyl-proline inhibits TGF-beta-mediated plasminogen activator inhibitor-1 expression via inhibition of Smad pathway in human mesangial cells

Recent large clinical trials indicate that angiotensin-converting enzyme inhibitors (ACE-I) attenuate the detrimental outcome of progressive renal disease. The hemoregulatory tetrapeptide N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP, AcSDKP) is hydrolyzed by ACE, and plasma Ac-SDKP level is increased by fivefold after treatment with ACE-I. Ac-SDKP was found to ameliorate cardiac and renal fibrosis in hypertensive animal models. However, the molecular mechanisms by which Ac-SDKP mediates anti-fibrotic effects remain unclear. This study is an examination of the interaction between Ac-SDKP and transforming growth factor-beta (TGF-beta), one of the key cytokines in the progression of renal disease, in human mesangial cells. Ac-SDKP inhibited TGF-beta1-induced plasminogen activator inhibitor-1 (PAI-1) and alpha2 (I) collagen mRNA. Ac-SDKP suppressed not only TGF-beta1-induced Smad2 phosphorylation at Ser-465/467 in a dose-dependent manner, but also the nuclear accumulation of receptor-regulated Smads (R-Smad), Smad2 and Smad3. As expected, Ac-SDKP inhibited TGF-beta-responsive Smad-dependent luciferase reporters, 3TP-luc and 4xSBE-luc. Immunofluorescence analysis revealed that the inhibitory Smad, Smad7, was exported to the cytoplasm from the nucleus by the treatment with Ac-SDKP. These findings provide novel evidence that Ac-SDKP inhibits TGF-beta signal transduction through the suppression of R-Smad activation via nuclear export of Smad7, highlighting an alternative mechanism involved in the reno-protective efficacy of ACE-I.

High tumor tissue concentration of plasminogen activator inhibitor 2 (PAI-2) is an independent marker for shorter progression-free survival in patients with early stage endometrial cancer

Previous studies including various tumor types have shown different associations between tumor tissue levels of plasminogen activator inhibitor 2 (PAI-2) and patient survival. High tumor tissue concentrations of PAI-2 have been associated with good prognosis in patients with breast cancer, small cell lung cancer and ovarian cancer, but with poor histologic differentiation and poor prognosis in patients with colorectal cancer. On the other hand, high tumor tissue concentrations of urokinase plasminogen activator (uPA), uPA receptor (R) and PAI-1 have more consistently been associated with poor histologic differentiation and poor prognosis. Our study quantified PAI-2 and uPAR using specific enzyme-linked immunosorbent assays in homogenates of 274 samples of endometrial cancer tissue. The prognostic power of each factor was analyzed in the subgroup of patients with early stage disease, i.e., International Federation of Gynecology and Oncology (FIGO) surgical stage I-II (n = 188). This group had a median follow-up time of 6.8 years (range 0.7-9.9), and 23 progressions were observed. The 80(th) percentile for PAI-2 and uPAR was used to dichotomize the material, and the results were analyzed for associations with clinical data including progression-free survival. The results were also compared with DNA ploidy status, S-phase fraction, uPA and PAI-1, which we reported in a previous study (Fredstorp Lidebring et al., Eur J Cancer 2001; in press). A high PAI-2 level was associated with shorter progression-free survival in univariate analysis and was an independent prognostic factor in bivariate analyses, which included PAI-1, uPA and DNA ploidy status. In contrast, a high level of uPAR had no association with prognosis in early stage endometrial cancer. The combination of high PAI-2 and PAI-1 levels in tumors revealed a small group of stage I-II patients with an accumulative progression rate of 50%.

Promigratory effect of plasminogen activator inhibitor-1 on invasive breast cancer cell populations

The urokinase-type plasminogen activator (uPA) system is a dynamic complex in which the membrane receptor uPAR binds uPA that binds the plasminogen activator inhibitor (PAI)-1 localized in the extracellular matrix, resulting in endocytosis of the whole complex by the low-density lipoprotein receptor-related protein (LRP). High expression of PAI-1 is paradoxically associated with marked tumor spreading and poor prognosis. We previously reported a nonproteolytic role of the [uPAR:uPA:PAI-1:LRP] complex operative in cell migration. Here we explored whether matrix PAI-1 could be used as a migration support by human breast cancer cells. We showed that the uPA system and LRP are localized at filopodia of invasive cells, and that formation/internalization of the [uPAR:uPA:PAI-1:LRP] complex is required for attachment and migration of cancer cells on plastic and on a PAI-1 coat. PAI-1 increased both filopodia formation and migration of cancer cells suggesting a chemokine-like activity. Migration velocity, expression of the uPA system, use of the [uPAR:uPA:PAI-1:LRP] complex to migrate, and promigratory effects of PAI-1 paralleled cancer cell invasiveness. Phenotyping and functional analysis of invasive cancer cell subclones indicated that different cell subpopulations may use different strategies to migrate depending on both the environment and their expression of the uPA system, some of them taking advantage of abundant available PAI-1.

Plasminogen activator inhibitor-1 as a measure of vascular remodelling in breast cancer

The generation of urokinase plasminogen activator (uPA) by tumours is an important pathway for neoplastic cell invasion and metastasis. Indeed in several tumour types, elevated levels of uPA, its receptor (uPAR) or its inhibitor plasminogen activator inhibitor-1 (PAI-1) is associated with a poorer prognosis. Since endothelial cells also use this proteolytic system to remodel the extracellular matrix during angiogenesis and since angiogenesis, as assessed by microvessel density, is also a predictor of patient survival, this study was designed to investigate the relationship between angiogenesis and the urokinase system in breast tumours. The aims were to assess whether the uPA, uPAR and/or PAI-1 correlates with angiogenic activity and could therefore be a useful objective clinical measure of tumour neovascularization; and to clarify whether the poor outcome associated with high levels of the urokinase system is due to its association with angiogenesis. The study also sought to examine the relationship between the uPA system and vessel remodelling using loss of a basement membrane epitope (LH39) normally associated with established capillaries. The cytosolic levels of uPA, PAI-1 and uPAR were therefore measured by enzyme linked immunoabsorbent assay, together with tumour vascularity, in 136 well-characterized invasive breast carcinomas. There were significant relationships between uPA and uPAR (Spearman r=0.37, p<0.0001), uPA and PAI-1 (Spearman r=0.19, p=0.03) and between uPAR and PAI-1 (Spearman r=0.23 p=0.01). A significant correlation was also observed between PAI-1 and vessel remodelling (Spearman r=0.34, p=0.04), patient age (p=0.01), nodal status (p=0.047) and tumour grade (p=0.04), but no association between tumour vascularity and PAI (p=0.96), uPA (p=0.69) or uPAR (p=0.81) was present. No significant association was seen between any of the urokinase variables and expression of the angiogenic factor thymidine phosphorylase. Furthermore, no significant associations were found between any of the studied parameters and overall survival in a univariate analysis of the cancer patients. A multivariate Cox proportional hazard model of overall survival showed that uPA (p=0.15), but not uPAR (p=0.52) or PAI-1 (p=0.61), gave no additional prognostic information. These findings show that uPA may work via an independent pathway to angiogenesis and therefore combined blockade of uPA and angiogenesis may have additional therapeutic benefits. It also shows, as recently demonstrated in animal models, that PAI-1 may be a key regulator of vascular remodelling in human cancer.

Clinicopathological significance of tumor nest configuration in patients with esophageal squamous cell carcinoma

BACKGROUND

Cancer-stromal interactions are an important mediator of cancer invasion and metastasis.

METHODS

The authors investigated the clinicopathological significance of tumor nest configuration and the surrounding stroma in 159 patients with advanced esophageal squamous cell carcinoma (ESCC). The tumors were classified microscopically into two types. Type A tumors had oval-shaped or sheet-like tumor nests (with > 80% of the tumor area showing these features). Type B tumors had asteroid-shaped or scattered small tumor nests (with > 20% of the tumor area showing these features).

RESULTS

Of the 159 tumors examined, 38 (24%) were type A and 121 (76%) were type B. Type B tumors had a significantly deeper invasion depth, more frequent lymphatic permeation and lymph node metastasis, more prominent active fibroblastic stroma, and less frequent inflammatory cell infiltration (P < 0.05). Both univariate (P < 0.05) and multivariate (P < 0.05) analysis of the patients' survival showed that the prognosis for patients with type B tumors was significantly worse than for patients with type A tumors.

CONCLUSIONS

This study showed that tumor nest configuration, which corresponded to the behavior of tumor cells against stromal cells, correlated well with the aggressiveness of the tumor.

Increasing expression of tissue plasminogen activator and plasminogen activator inhibitor type 2 in dog gingival tissues with progressive inflammation

Urokinase and tissue-type plasminogen activators (u--PA and t--PA) are serine proteases that convert plasminogen into plasmin, which degrades matrix proteins and activates metalloproteinases. The PAs are balanced by specific inhibitors (PAI--1 and PAI--2). Local production of t--PA and PAI--2 was recently demonstrated in human gingival tissues. The aim now was to investigate the production and localization of t--PA and PAI--2 in gingival tissues from dogs in three well-defined periodontal conditions; clinically healthy gingiva, chronic gingivitis and an initial stage of ligature-induced loss of attachment. At the start of the experiment the gingiva showed clear signs of inflammation. Clinically healthy gingiva were obtained after 21 days period of intense oral hygiene. Attachment loss was induced by placing rubber ligatures around the neck of some teeth. Biopsies were taken from areas representing the different conditions and prepared for in situ hybridization and immunohistochemistry. In clinically healthy gingiva both t--PA mRNA and antigen were expressed in a thin outer layer of the sulcular and junctional epithelia. No t--PA signals or staining were seen in connective tissue. Both mRNA signaling and immunostaining for t--PA were stronger in chronic gingivitis. In areas with loss of attachment, t--PA mRNA as well as antigen were found in the sulcular and junctional epithelia to a similar degree as in gingivitis. Occasionally the connective tissue was involved, especially in connection with vessels. PAI--2 mRNA was seen in a thin outer layer of the sulcular and junctional epithelia in clinically healthy gingiva, but no signals were seen in connective tissue. PAI--2 antigen was found primarily in the outer layer of the sulcular and junctional epithelia. Some cells in the connective tissue were stained. In gingivitis, PAI--2 signals were mainly found in the same locations, but more intense and extending towards the connective tissue. Immunostaining was seen in the outer half of the sulcular and junctional epithelia as well as in the upper part of the connective tissue, close to the sulcular epithelium. In sites with loss of attachment, PAI--2 mRNA was found throughout the sulcular and junctional epithelia, as was the antigen, which stained intensely. No PAI--2 mRNA was seen in connective tissue; the antigen was found scattered, especially near vessels. This study shows that the expression of both t--PA and PAI--2 increases with experimental gingival inflammation in the dog, and furthermore, the two techniques demonstrate a strong correlation between the topographical distribution of the site of protein synthesis and the tissue location of the antigens for both t--PA and PAI--2. The distribution correlates well with previous findings in humans.

High tPA-expression in primary melanoma of the limb correlates with good prognosis

To investigate whether the course of primary melanoma disease correlates with expression of the various components of the proteolytic plasminogen activation (PA) system, immunohistochemical stainings for activators of plasminogen (tissue type (tPA) and urokinase type (uPA)), inhibitors of plasminogen activation (type 1 (PAI-1) and type 2 (PAI-2)) and the receptor for uPA (uPAR) were performed on 214 routinely processed melanoma lesions. All lesions were primary cutaneous melanomas, minimally 1.5 mm thick, and derived from patients with only local disease at the moment of diagnosis (clinically stage II (T(3-4)N(0)M(0)), American Joint Committee on Cancer). Median patient follow-up was 6.1 years. Single variables as immunohistochemical staining results (extent of tumour cell staining, pattern of tumour cell staining and for some components also staining of stromal cells), histopathological and clinical parameters as well as treatment variables were analysed in order to assess their prognostic importance, in terms of time to recurrence, time to distant metastasis and duration of survival. The extent of tPA tumour cell positivity, categorized as 0-5%, 6-50% and 51-100%, appeared to be of importance for these end-points. Lesions with 51-100% tPA-positive tumour cells were found to have the best prognosis, whereas lesions with 6-50% tPA-positive tumour cells had the worst. Moreover, the prognostic significance of Breslow thickness, microscopic ulceration and sex was confirmed in this study. Multivariate analyses, incorporating these relevant factors, showed that the extent of tPA tumour cell positivity was an independent prognostic factor for distant metastasis-free interval (P = 0.012) and for the duration of survival (P = 0.043).

Immunohistochemical expression of uPA, uPAR, and PAI-1 in breast carcinoma. Fibroblastic expression has strong associations with tumor pathology

The urokinase-type plasminogen activator (uPA) system has been implicated in tumor spread. We have used immunohistochemistry to examine three components of this system, ie, uPA, uPA receptor (uPAR), and plasminogen activator inhibitor-1 (PAI-1), in a pilot study on 142 cases of breast carcinoma. We wished to determine whether there were any relationships between expression of the proteins in either tumor cells or fibroblasts and clinical and pathological features. Strong uPA expression in each cell type was significantly related to high tumor grade (P = 0.013 and 0.008, respectively), and was more common in invasive than in in situ carcinomas (P < 0.0001). Fibroblastic expression of uPAR was only related to the presence of invasion (P < 0.0001). Strong PAI-1 expression in both cell types was seen in high-grade tumors (tumor cells, P = 0.012; fibroblasts, P < 0.001), but only fibroblastic expression was related to the presence of invasion (P = 0.042). Fibroblastic expression of both uPA and uPAR were positively correlated with tumor size. Although patients with strong fibroblastic expression of uPA showed a tendency toward a shorter time to relapse, none of the plasminogen activator proteins were significantly associated with relapse-free survival. These results suggest that strong expression of uPA, uPAR, and PAI-1 in fibroblasts rather than in tumor cells have the most impact on the clinical behavior of breast cancer. Larger prospective studies are needed to confirm these findings.

Urokinase plasminogen activator system gene expression is increased in human breast carcinoma and its bone metastases--a comparison of normal breast tissue, non-invasive and invasive carcinoma and osseous metastases

The urokinase plasminogen activator (uPA) system has been widely associated with the development of breast carcinoma. However, the role of the urokinase pathway in the development of osseous breast cancer metastases has been largely overlooked. We studied the expression of uPA, urokinase plasminogen activator receptor (uPAR)- and plasminogen activator inhibitor type-1 (PAI-1) in human breast carcinomas and their bone metastases, using in situ hybridisation. Studies were performed using paraffin-embedded tissue from 13 ductal carcinomas, 23 invasive ductal carcinomas, five normal breasts and 25 bone metastases. The majority of the tumours examined expressed low to moderate levels of uPA mRNA and low to high levels of uPAR and PAI-1 mRNA, which was predominantly localised to the epithelial tumour cells. There was slight over-expression of uPA and PAI-1 mRNA and a marked increase in uPAR mRNA expression in the malignant tumours compared with benign tissue. Overall, uPAR and PAI-1 mRNA expression was found to be more variable than uPA mRNA, suggesting a possible role of the receptor and inhibitor in the regulation of uPA activity. Increased alpha1(I) procollagen (COL) and osteopontin (OPN) mRNA expression was detected, primarily in the stromal cells, in malignant tumours compared with the benign tissue. The increased expression of the components of the uPA system on the epithelial tumour cells may account for the activation of the proteolytic cascade that occurs during breast cancer metastasis to bone. Furthermore, the over-expression of COL and OPN suggests a possible interaction between these matrix proteins and the uPA system.

Expression of urokinase-type plasminogen activator, urokinase-type plasminogen activator receptor, and plasminogen activator inhibitor-1 and -2 in hepatocellular carcinoma

It has become more and more clear in recent decades that the plasminogen activation system, which includes urokinase-type plasminogen activator (uPA), urokinase-type plasminogen activator receptor (uPAR), plasminogen activator inhibitor (PAI)-1 and PAI-2, plays a very important role in the aggressiveness of cancer. Using immunohistochemistry and enzyme-linked immunosorbent assay (ELISA), the expression of these four components of the uPA system was analyzed in 19 cases of hepatocellular carcinoma (HCC) and 18 cases of the adjacent non-cancer tissues which all had chronic active hepatitis with liver fibrosis or liver cirrhosis. Four cases of normal liver tissues, as controls for immunohistochemical stains, were obtained from the hepatectomized liver of patients with metastatic cancer in the liver. The positive rates of uPA, uPAR, PAI-1 and PAI-2 for immunohistochemical stains in cancer tissues were 78.9, 68.4, 57.9 and 31.6%, respectively. Positive signals were mainly distributed in the cytoplasm of the cancer and in stromal cells. Moreover, the strong stains were chiefly located in the invasive front of the cancer cells. No specific stain was detected in four cases of normal liver tissues. In ELISA, there were significant differences between cancer and non-cancer tissues in concentration of uPA, uPAR and PAI-1 (P < 0.0003, 0.0024 and 0.01, respectively), but there was no significant difference in that of PAI-2 (P = 0.37). These results suggest that uPA, uPAR and PAI-1 are related to invasion of HCC.

New prognostic histological parameter of invasive ductal carcinoma of the breast: clinicopathological significance of fibrotic focus

Immunohistochemistry, DNA ploidy analysis and molecular genetics have made it possible to predict the outcome of breast cancer more precisely than routine histological examination alone. However, in routine practice, it is difficult to incorporate these methodologies in all cases. If certain histological parameters can accurately predict the outcome of patients with breast cancer, they would be more practical for routine use. We showed that the presence of fibrotic focus (FF) in invasive ductal carcinoma (IDC) is closely associated with c-erbB-2 or p53 protein expression, high proliferative activity, and high angiogenesis of the tumors. Furthermore, multivariate analyses with well-known prognostic parameters for IDC demonstrated that the presence of FF is the most useful independent parameter to predict IDC patient outcome. In addition, our data suggested that the interaction between tumor cells and stromal fibroblasts may play an important role in the formation of FF in IDC based on growth factor and growth factor receptor protein expression in the tumor cells and fibroblasts forming FF. Based on the results of our clinicopathological studies, we propose a new prognostic classification scheme for the prediction of IDC patient outcome, which consists of FF, nuclear atypia, and fat invasion. This classification has superior predicting power to existing prognostic classifications.

Cellular distribution and clinical value of urokinase-type plasminogen activator, its receptor, and plasminogen activator inhibitor-2 in esophageal squamous cell carcinoma

To assess the participation of the plasminogen activation system in the invasiveness of esophageal squamous cell carcinoma, we performed immunohistochemistry and in situ hybridization to study the distribution of a urokinase-type plasminogen activator (u-PA), u-PA receptor (u-PAR), and plasminogen activator inhibitor-2 (PAI-2). u-PA and PAI-2 were expressed heterogeneously in cancer cells, and restricted expression was found in stromal cells, especially fibroblasts, that were located in the immediate proximity of the cancerous cells. u-PAR was found only in cancer cells located at the periphery of tumors. Compared with patients with u-PA-negative cancer cells, patients with u-PA-positive cancer cells more frequently showed a neoplastic invasion beyond the muscularis propria and lymph node metastases. They also showed a significantly shorter 5-year overall survival. Patients with PAI-2-positive fibroblasts showed significantly lower levels of local invasiveness, represented by a neoplastic invasion beyond the muscularis propria, than those who were PAI-2 negative. Our results suggest that the expression of u-PA in esophageal squamous cell carcinoma is predictive of poor survival, whereas the expression of PAI-2 in the fibroblasts surrounding them is protective. An analysis of u-PA and PAI-2 expression in cancer cells and their surrounding fibroblasts may be useful for predicting the prognosis of patients with esophageal squamous cell carcinoma.

Urokinase gene expression indicates early invasive growth in squamous cell lesions of the uterine cervix

The plasminogen activating system plays a key role in the cascade of tumour-associated proteolysis leading to extracellular matrix degradation and stromal invasion. Changes in the expression of this system, consisting of urokinase- and tissue-type plasminogen activators (uPA and tPA, respectively), plasminogen activator inhibitors (PAI-1, PAI-2) and uPA receptor, have been associated with tumour aggressiveness in a variety of solid malignant tumours. This paper describes a study of squamous intraepithelial lesions (SILs, n=36), squamous cell carcinomas (SCCs, n=42), and normal mucosa (n=5) of the uterine cervix by in situ hybridization with (35)S-labelled RNA probes. uPA transcripts were absent from normal mucosa and non-invasive lesions, but present in atypical epithelial cells of all microinvasive carcinomas ( n=19) and in some of the more advanced invasive carcinomas (n=11). PAI-1 transcripts were found in stromal cells of most tissue samples with, however, significantly increased levels in invasive SCC compared with SIL, microinvasive SCC, and normal mucosa. uPA-positive invasive carcinomas often displayed additional PAI-1 expression by tumour cells. At variance with uPA, tPA transcripts were found in atypical epithelial cells of low- and high-grade SILs. In the majority of SCCs tested (27/29 cases), the HPV 16 E6/E7 oncogene and uPA transcription were correlated. uPA and PAI-1 expression indicates invasive growth when expressed by atypical epithelial cells of squamous cervical lesions. Moreover, the presence of uPA transcripts is indicative of early invasive growth. uPA and tPA seem to have different functions in the development of invasive properties in uterine cervical squamous epithelium.

Bioartificial liver support system using porcine hepatocytes entrapped in a three-dimensional hollow fiber module with collagen gel: An evaluation in the swine acute liver failure model

The perfusion culture system of hepatocytes entrapped in a three-dimensional hollow fiber module with collagen gel is expected to realize an effective bioartificial liver (BAL) support system. The BAL module contained 5.4 billion porcine hepatocytes, which is approximately 7% of the total liver, supplied adequate metabolic functions, and improved the survival of the experimental acute liver failure swine. Improvement of the prothrombin time by the BAL treatment was not significant; however, the bleeding tendency was suppressed, which resulted in a significantly prolonged survival time of the animals in the BAL treatment group. A drastic up-regulation of the expression of the mRNA for plasminogen activator inhibitor 1 (PAI-1), which is known as an inhibitor for fibrinolysis, may explain the suppression of the bleeding tendency. These results support the efficacy of our BAL system for the treatment of acute liver failure.

Expression of the proteolytic factors, tPA and uPA, PAI-1 and VEGF during malignant glioma progression

Various proteases and their inhibitors have been shown to be important in tumor invasion. Angiogenesis is further a prerequisite for the growth and progression of solid tumors. Since these systems are functionally linked, in situ hybridization and in situ zymography were used to investigate the spatial and temporal expression of factors representative of the plasmin/plasminogen system and of an angiogenic factor in the BT4C glioma model. This tumor is invasive with a high grade of neovascularization. Tissue-type plasminogen activator urokinase-type plasminogen activator and plasminogen activator inhibitor-1 mRNA were expressed in glioma cells during the entire tumor growth. Early in the tumor development the expression was found throughout the small tumor (approximately 10 mm3) while later in the time course the expression was found predominantly in the invasive tumor border of the tumor. The in situ zymography demonstrated that the plasminogen activators were translated into functional proteins. Vascular endothelial growth factor mRNA was expressed following a similar spatial and temporal pattern with an early expression in the entire small tumor while later, in larger tumors, it was exclusively expressed in the invasive tumor edge. In normal brain, the ventricular ependyma, meninges, as well as scattered neurons expressed tissue-type plasminogen activator mRNA. Vascular endothelial growth factor mRNA was observed in the choroid plexus, and in scattered cells in normal brain tissue. Our finding may suggest a functional co-operation of tissue-type plasminogen activator, urokinase-type plasminogen activator, plasminogen activator inhibitor-1 and vascular endothelial growth factor during glioma progression. This model could be of value when evaluating different treatment modalities aimed at blocking the migrating capacity and growth of glial tumors.

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.

Comparison of immunohistochemistry with immunoassay (ELISA) for the detection of components of the plasminogen activation system in human tumour tissue

Enzyme-linked immunosorbent assay (ELISA) methods and immunohistochemistry (IHC) are techniques that provide information on protein expression in tissue samples. Both methods have been used to investigate the impact of the plasminogen activation (PA) system in cancer. In the present paper we first compared the expression levels of uPA, tPA, PAI-1 and uPAR in a compound group consisting of 33 cancer lesions of various origin (breast, lung, colon, cervix and melanoma) as quantitated by ELISA and semi-quantitated by IHC. Secondly, the same kind of comparison was performed on a group of 23 melanoma lesions and a group of 28 breast carcinoma lesions. The two techniques were applied to adjacent parts of the same frozen tissue sample, enabling the comparison of results obtained on material of almost identical composition. Spearman correlation coefficients between IHC results and ELISA results for uPA, tPA, PAI-1 and uPAR varied between 0.41 and 0.78, and were higher for the compound group and the breast cancer group than for the melanoma group. Although a higher IHC score category was always associated with an increased median ELISA value, there was an overlap of ELISA values from different scoring classes. Hence, for the individual tumour cases the relation between ELISA and IHC is ambiguous. This indicates that the two techniques are not directly interchangeable and that their value for clinical purposes may be different.

A proposal for a new histological classification scheme for predicting short-term tumor recurrence and death in patients with invasive ductal carcinoma of the breast

Tumor recurrence rate (TRR) and mortality rate (MR) of invasive ductal carcinoma (IDC) of the breast in short-term follow-up are relatively low. Nevertheless, it is extremely important to identify patients at risk of early recurrence or death after surgery. The aim of this study was to establish a new histological prognostic classification scheme for IDC in order accurately to predict the short-term outcome. The following histological parameters were analyzed in 201 IDCs: 1) tumor size, 2) structural atypia, 3) nuclear atypia, 4) number of mitotic figures, 5) fibrotic focus (FF), 6) vascular invasion, 7) tumor necrosis, 8) skin invasion, 9) muscle invasion, 10) nodal status and 11) extramammary fat invasion. Multivariate analysis showed that nuclear atypia, presence of FF, and the invasive length of fat invasion (ILFI) were the most important histological parameters correlated with TRR or MR of IDCs. Accordingly, a new histological classification based on nuclear atypia, FF and ILFI (Nucleus-Fibrotic focus-Fat invasion, NFF) was devised. Comparative studies were performed with the following existing prognostic classifications: 1) histological grade, 2) modified Scarff-Bloom-Richardson histological grade, 3) prognostic index and 4) pathological TNM (pTNM) stage classifications. Patient grouping defined by NFF classification significantly correlated with tumor recurrence or death of IDCs in all cases, cases at stages I and II, those without lymph node metastasis and those who were estrogen receptor (ER)-positive after adjustment for the other four classifications, using multivariate analysis. NFF classification appeared superior to existing prognostic classifications for the accurate prediction of the short-term outcome for patients with IDCs in low risk groups.