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.

Upregulation of the tissue inhibitor of metalloproteinase-1 protein is associated with progression of human non-small-cell lung cancer.

PURPOSE: Tissue inhibitors of metalloproteinases (TIMPs) are naturally occurring inhibitors of matrix metalloproteinases (MMPs). It has been shown that TIMP-1 may be a multifunctional protein. Little is known about the role of TIMP-1 in progression and metastasis of human lung cancer (tumor inhibiting or tumor promoting), although studies using a variety of techniques have analyzed the expression of TIMP-1 mRNA and/or protein in human cancers. PATIENTS AND METHODS: We examined the expression of TIMP-1 protein by immunohistochemistry in patients (n = 160) with primary respectable (stage I to IIIA) non-small-cell lung cancer (NSCLC). RESULTS: Twenty-seven percent of the tumors (43 of 160) demonstrated elevated expression of this protein. We demonstrate that overexpression of TIMP-1 protein is associated with an adverse outcome. In addition, disease stage, patient's age, and performance status were all significantly related to survival. In multivariate analyses, patients with high TIMP-1 expression had a 90% increased risk of death when compared with those with low expression (relative risk, 1.92; 95% CI, 1.19 to 3.09; P =.008). TIMP-1 expression did not correlate with expression of MMP-2 and MMP-9. CONCLUSION: These results suggest that TIMP-1, independent of its inhibiting activity of MMPs, may have other function(s) critical for NSCLCs. The significance of our results is two-fold. The adverse outcome in patients with overexpression of TIMP-1 indicates its potential prognostic value in NSCLC. Thus, TIMP-1 overexpression may serve to help identify patients with particularly aggressive disease for adjuvant treatments. In addition, the TIMP-1 molecule may represent a novel therapeutic target for treatment of some NSCLCs.

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.

Tumor antigens and markers for breast and ovarian cancers.

Use of vaccines to prevent and treat breast and ovarian cancer is a highly attractive approach because of the expected minimal side effects and the potential to predict individuals likely to benefit from vaccination. To fully harness the capacity of the immune system for this purpose, it is necessary to characterize tumor antigens for these cancers so that purified antigens can be tested for their immunogenicity in individual patients and for their suitability as targets of vaccine-induced immunity. Discovery of novel breast and ovarian tumor antigens is also necessary for developing multi-antigen vaccines composed of multiple tumor antigens. Such vaccines are expected to induce diverse immune responses and minimize emergence of antigen-loss variant tumors that are resistant to vaccine-induced immunity. With the exception of melanomas, for most human cancers including breast and ovarian cancers the repertoire of known tumor antigens remains relatively small. In this review we will discuss the importance of characterizing tumor antigens for use in vaccination against cancer and then summarize antigens that have been characterized for human breast and ovarian cancers. We will also emphasize that identification of a novel tumor antigen, while an important first step, needs to be followed by a multi-step process of validation of that antigen. The steps in this validation process are i) to demonstrate that a tumor antigen is over-expressed at a reasonable frequency in primary tumors and in metastases; ii) to demonstrate the immunogenicity of a tumor antigen in an appropriate animal model; iii) to demonstrate its immunogenicity and safety in humans. Additional considerations in this review include: i) discussion of the potential of breast and ovarian tumor antigens as markers for early detection and for monitoring tumor burden in cancer patients; ii) discussion of their potential as prognostic markers of breast and ovarian cancers; and iii) discussion of a unique class of tumor antigens and markers that induce expression of multiple other tumor antigens and markers. Finally, we will discuss the present evidence for potential for autoimmunity that might accompany antitumor vaccination.