A pilot study of urokinase-type plasminogen activator (uPA) overexpression in the brush cytology of patients with malignant pancreatic or biliary strictures.

We have previously demonstrated that uPA is overexpressed in pancreatic tumors. In an attempt to diagnose these tumors earlier, we sought to determine whether uPA could be identified in endoscopic retrograde cholangiopancreatography obtained brushings in patients with malignant pancreatic and biliary strictures. Secondarily, uPA was measured in the serum of this patient population. uPA overexpression was identified in the cytologic tissue in 8 of 11 patients (72.7%). Serum analysis demonstrated a 2-fold higher concentration of uPA in the pancreaticobiliary cancer patients (1.27 versus 0.56 ng/mL; P = .0182). Also, uPA overexpression correlated with serum levels (P < .0001). This study confirms that uPA can be detected in the ERCP cytologically obtained tissue and is frequently present in a higher concentration in the serum of pancreaticobiliary cancer patients. A larger sample size will be required to address its value as a sensitive marker for the diagnosis of pancreatic or biliary cancers.

Co-expression of urokinase with haptoglobin in human carcinomas.

BACKGROUND: We have shown that colon and breast cancer contains large amounts of urokinase (uPA), and that these cells are the actual sites of its synthesis. We isolated a large complex molecule consisting of the beta-chain of uPA, both chains of haptoglobin (Hp), and part or all of an NCAM-like molecule. The question arose whether it would be possible to show the presence of Hp in the same cells where uPA was found. MATERIALS AND METHODS: Human colon and breast adenocarcinomas were investigated for expression of Hp and uPA by immunohistochemistry. Fluorescence in situ hybridization was used to identify the cells of origin of these antigens. RESULTS: Hp was expressed in 8 of 11 colon adenocarcinomas, and in 10 of 12 breast tumors. uPA was demonstrable on the cell membrane and in the cytoplasm of all 11 colon adenocarcinomas studied, and cytoplasmic uPA-mRNA was found in all cases. While uPA was also detected in some stromal and inflammatory cells, Hp was present abundantly in such cells, as well as in capillary endothelial cells. Hp-mRNA was also found in both colon and breast tumors wherever the antigens were expressed. CONCLUSIONS: uPA and Hp are produced by the cancer cells and are not taken up by stromal elements. While the role of uPA in the malignant process is well documented, that of Hp is largely unexplored. Its ubiquity, shown here, suggests that it is also involved in some aspects of that process.

Plasminogen activator system localization in 60 cases of ductal carcinoma in situ.

BACKGROUND: The lack of prognostic factors in ductal carcinoma in situ (DCIS) that reliably identifies biologically aggressive tumors adversely affects optimal management. The urokinase-type plasminogen activator (uPA) system, comprised of its receptor, uPAR, and its inhibitor (PAI-1), are critical elements for tumor invasion and their expression in invasive breast cancer can predict clinical outcome. Expression of the uPA system in DCIS may be relevant in defining histological subsets of DCIS with invasive potential. METHODS: Localization of uPA, uPAR, and PAI-1 was investigated immunohistochemically in 60 DCIS tumors. FISH experiments were performed to determine whether uPA was present in cancer cells themselves or derived from stromal elements. RESULTS: uPA was ubiquitously expressed in the malignant ductal epithelium of 95% (57/60) of DCIS tumors studied. uPA-mRNA was detected in the malignant ductal epithelium but not the adjacent normal ductal epithelium and stromal elements. uPAR was expressed in 27% (6/22) of high-grade and 24% (9/38) of non-high-grade DCIS. In comparing coexpression, uPA and uPAR were coexpressed in only 25% (15/60) of tumors. PAI-1 was infrequently expressed in high grade (3/22) and absent in non-high-grade DCIS. CONCLUSIONS: This study identifies the presence of uPA, uPAR, and PAI-1 in both high-grade and non-high-grade DCIS. It may be speculated that coexpression of uPA and its receptor may identify subsets of DCIS with an increased risk for progression to invasive disease. If so, then expression of uPA system components may have prognostic and therapeutic significance in DCIS.

Overexpression of urinary plasminogen activator (uPA) protein and mRNA in thyroid carcinogenesis.

OBJECTIVE: Urinary plasminogen activator (uPA), a protease, is one of the critical components of tumor invasion and metastasis. Its expression in thyroid carcinoma and potential role in thyroid tumorigenesis are unknown. The objective of this study was to determine whether uPA is differentially expressed in benign and malignant thyroid tumors. DESIGN: uPA expression was evaluated by immunohistochemistry (IHC) in 20 thyroid tumors (six classic papillary thyroid cancers (PTC) and three tall cell variants (TCV) and 11 adenomas). To validate IHC results, in situ hybridization was performed on both adenomas and cancer tissues to explore the expression of uPA at the mRNA level. The Fisher exact test was used to compare protein as well as mRNA expressions in adenomas and thyroid cancer. RESULTS: Intense granular cytoplasmic staining for uPA was observed in five of nine (56%) of thyroid cancers: 2/6 classic PTC (33%) and all tall cell variant PTC. Furthermore, uPA mRNA expression was found in the malignant thyroid epithelium but not in adjacent normal thyroid follicles or the stromal elements. None of the adenomas expressed uPA (P = .008). uPA staining was absent in histologically normal follicles adjacent to malignant thyroid follicles. CONCLUSIONS: uPA is expressed in thyroid carcinoma but not in benign adenomas or normal adjacent follicles. The selective expression of uPA in thyroid carcinoma provides evidence that uPA is useful in distinguishing benign and malignant thyroid neoplasms. More importantly, uPA may represent molecular target for therapeutic treatment of this malignancy.

Evaluation of urinary plasminogen activator, its receptor, matrix metalloproteinase-9, and von Willebrand factor in pancreatic cancer.

PURPOSE: Pancreatic cancer remains a devastating problem with the majority of patients succumbing to death from this disease. A hallmark of pancreatic cancer is the loss of basement membrane that may be attributed to the action of urinary plasminogen activator (uPA) and matrix metalloproteinase-9 (MMP-9). These enzymes are also implicated in angiogenesis. uPA and microvessel density have been shown to be good prognostic indicators for breast and colon cancer. MMP-9 and microvessel density have not been investigated in pancreatic cancer. We have therefore investigated by immunohistochemistry: (a) frequency of uPA expression and its receptor uPAR and the site of synthesis of uPA by in situ hybridization (ISH); (b) MMP-9 and its coexpression with uPA; (c) microvessel density as determined by von Willebrand factor staining and its relationship to uPA and MMP-9 expression; and (d) correlation of these parameters with survival. EXPERIMENTAL DESIGN: Archival paraffin sections of 27 pancreatic tumors were semiquantitatively investigated by immunohistochemistry using the following antibodies: (a) monoclonal antibodies (MAbs) uPA(1) and uPA(2) (3689 and 394, respectively); (b) MAb uPAR, (no. 3932); (c) MAb MMP-9 (no. 936); and (d) rabbit anti-F8RA/vWF. ISH was performed using a uPA cDNA. RESULTS: Both uPA antibodies revealed overexpression of uPA (93%) often with uniform staining of tumor cells. uPAR and MMP-9 showed focal staining in only 52 and 37% of tumors, respectively. Morphologically normal appearing ductal cells in close proximity to tumors overexpressed uPA in contrast to distally located normal cells (P = <0.001). uPA staining was also investigated in pancreatic intraepithelial neoplasia (PanIN) lesions. PanIN 1A/B staining for uPA was seen in 8 cases (30%), that for PanIN 2 in 19 cases (70%), and for PanIN3 in 12 cases (44%). Lumen of microvessels in the tumor stroma also revealed staining of uPA in 10 cases (37%). ISH experiments revealed the presence of uPA mRNA not only in the cytoplasm of tumor cells but also in adjacent normal appearing ducts as well as in PanIN lesions. Patients with overexpression of uPA, uPAR, or MMP-9 had a trend toward poorer survival than those who did not express it. Microvessel density did not show any significant relationship with uPA, uPAR, and MMP-9 expression and survival. CONCLUSIONS: We conclude that uPA and MMP-9 are potential prognostic indicators in pancreatic cancer, whereas microvessel density may not be one. This study confirms our previous observation that uPA is made by the tumor cells themselves. Presence of uPA in vessels of tumor stroma suggests that uPA is in circulation, and its measurement and that of MMP-9 in the blood of these patients may aid in prognosis. Patients showing overexpression of uPA and MMP-9 have a trend toward shorter survival time.