Bcar1/p130Cas protein and primary breast cancer: prognosis and response to tamoxifen treatment.

Background: The product of the Bcar1/p130Cas (breast cancer resistance/p130Crk-associated substrate) gene causes resistance to antiestrogen drugs in human breast cancer cells in vitro. To investigate its role in clinical breast cancer, we determined the levels of Bcar1/p130Cas protein in a large series of primary breast carcinomas.

Methods: We measured Bcar1/p130Cas protein in cytosol extracts from 937 primary breast carcinomas by western blot analysis.

Insulin-like growth factor 1 (IGF-1) and urokinase-type plasminogen activator (uPA) are inversely related in human breast fibroblasts.

Human breast fibroblasts have been shown to express urokinase-type plasminogen activator (uPA). This suggests that fibroblasts are actively involved in the process of uPA-directed breast tumor proteolysis. To investigate a possible role for the insulin-like growth factors (IGFs) in regulating uPA expression in human breast fibroblasts, we correlated the expression of uPA with the expression of IGF-1 and IGF-2 in a paired panel of normal and tumor tissue-derived human breast fibroblasts in vitro.

Regulation of the urokinase-type plasminogen activator system by the von Hippel-Lindau tumor suppressor gene.

The urokinase-type plasminogen activator (uPA) system plays an important role in tumor cell invasion, metastases, and angiogenesis. uPA, uPA receptor, and plasminogen activator inhibitor 1 (PAI-1) are prognostic factors in different solid tumors, e.g.

Cytokine-regulated urokinase-type-plasminogen-activator (uPA) production by human breast fibroblasts in vitro.

It has been shown that, in breast stroma, urokinase-type plasminogen activator (uPA) mRNA is predominantly expressed by myofibroblasts located at the invasive areas of the tumor. To examine which factors present in a tumor environment are candidates responsible for the induction of these uPA-producing myofibroblasts, we studied in vitro the capacity of a paired panel of normal and tumor-derived human breast fibroblasts to produce uPA protein and the myofibroblast marker alpha-smooth-muscle-actin (alpha-SMA) in response to various cytokines implicated in the process of tissue-remodeling during malignant transformation. We found that fibroblasts produced increased amounts of uPA protein after exposure to a-FGF, b-FGF, EGF, PDGF-BB, and IFN-gamma, were unaffected in this respect by IL-6, M-CSF, GM-CSF and Oncostatin M, and produced decreased amounts of uPA protein after exposure to IL-1alpha, TNF-alpha, IGF-I, and IGF-II.

Prognostic value of tissue-type plasminogen activator (tPA) and its complex with the type-1 inhibitor (PAI-1) in breast cancer.

The prognostic value of tissue-type plasminogen activator (tPA) measured in samples derived from 865 patients with primary breast cancer using a recently developed enzyme-linked immunosorbent assay (ELISA) was evaluated. Since the assay could easily be adapted to the assessment of the complex of tPA with its type-1 inhibitor (PAI-1), it was investigated whether the tPA:PAI-1 complex also provides prognostic information. To this end, cytosolic extracts and corresponding detergent extracts of 100,000 g pellets obtained after ultracentrifugation when preparing the cytosolic fractions for routine steroid hormone receptor determination were assayed.

Prognostic value of CD44 variant expression in primary breast cancer.

CD44 is a family of cell surface transmembrane glycoproteins members which differ in the extracellular part by sequences derived by alternative splicing of 10 variant exons (v1-v10). CD44 proteins containing such variant sequences have been implicated in tumor metastasis formation. Here, we have evaluated the expression of CD44 variants by immuno-histochemistry in primary breast cancer samples of 237 node-negative and 230 node-positive patients.

Breast-conserving therapy: proteases as risk factors in relation to survival after local relapse.

Purpose: To evaluate whether cathepsin D, urokinase-type plasminogen activator (uPA), its inhibitor, plasminogen activator inhibitor-1 (PAI-1), or clinical factors can predict which patients are at risk for developing distant metastases after local recurrence (LR).

Patients And Methods: Of 1,630 patients treated with breast-conserving surgery and radiotherapy of the breast between 1980 and 1992, LR developed in 171 as a first event. From the available primary tumor tissues, we determined the cytosolic levels of cathepsin D, uPA and PAI-1.

Clinical relevance of the urokinase plasminogen activator system in breast cancer.

Until recently clinical features and the hormone-receptor status were the only factors used to select systemic (adjuvant) treatment for breast cancer patients. Other biological factors are needed as well to predict the probability of relapse and response with more certainty. The uPA-system is such a prognostic and predictive factor in breast cancer.

Prognostic impact of urokinase-type plasminogen activator (uPA) and its inhibitor (PAI-1) in cytosols and pellet extracts derived from 892 breast cancer patients.

To evaluate the clinical relevance of urokinase-type plasminogen activator (uPA) and its type-1 inhibitor (PAI-1) measured by a recently developed enzyme-linked immunosorbent assay (ELISA), we analysed both components in samples derived from 892 patients with primary breast cancer (median follow-up 99 months). The assays were performed in cytosolic extracts as well as in corresponding detergent extracts of pellets obtained after ultracentrifugation, which was carried out when preparing the cytosolic fractions for routine steroid hormone receptor determination. Statistically significant correlations were found between the cytosolic levels and those determined in the pellet extracts (Spearman correlation coefficient r = 0.

Expression of prostate-specific antigen (PSA) correlates with poor response to tamoxifen therapy in recurrent breast cancer.

Prostate-specific antigen (PSA) is a serine protease which may play a role in a variety of cancer types, including breast cancer. In the present study, we evaluated whether the level of PSA in breast tumour cytosol could be associated with prognosis in primary breast cancer, or with response to tamoxifen therapy in recurrent disease. PSA levels were determined by enzyme-linked immunosorbent assay (ELISA) in breast tumour cytosols, and were correlated with prognosis in 1516 patients with primary breast cancer and with response to first-line tamoxifen therapy in 434 patients with recurrent disease.

Cathepsin-D in primary breast cancer: prognostic evaluation involving 2810 patients.

There is controversy regarding the prognostic value of cathepsin-D in primary breast cancer. An increased level of cathepsin-D in tumour extracts has been found to be associated with a poor relapse-free and overall survival. Studies performed with immunohistochemistry or Western blotting have produced diverse results.

Uptake and distribution of doxorubicin in hormone-manipulated human breast cancer cells in vitro.

Background: Kinetic resistance to cytotoxic drugs may account for the moderate responsiveness of breast cancer to chemotherapy. In the present study the in vitro effects of estradiol-mediated DNA stimulation on the cellular uptake of the DNA intercalating drug doxorubicin (DOX) were examined in MCF-7 human breast cancer cells.

Methods: Using the fluorescent properties of the drug, the cellular uptake was investigated by high performance liquid chromatography (HPLC), and by flow cytometry.

External quality assessment of trans-European multicentre antigen determinations (enzyme-linked immunosorbent assay) of urokinase-type plasminogen activator (uPA) and its type 1 inhibitor (PAI-1) in human breast cancer tissue extracts.

High levels of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (PAI-1) in breast cancer tissue extracts have been associated with rapid disease progression. In these studies, different enzyme-linked immunosorbent assay (ELISA) kits have been applied for the quantification, and consequently the ranges of uPA and PAI-1 levels reported differ considerably. Therefore, the Receptor and Biomarker Study Group (RBSG) of the European Organization for Research and Treatment of Cancer (EORTC) and a consortium of the BIOMED-1 project 'Clinical Relevance of Proteases in Tumor Invasion and Metastasis' initiated three collaborative between-laboratory assessment trials aimed at controlling uPA and PAI-1 antigen analyses.

Loss of imprinting of IGF2 and not H19 in breast cancer, adjacent normal tissue and derived fibroblast cultures.

Insulin-like growth factors are involved in the paracrine growth regulation of human breast tumor cells. IGF2 is imprinted in most tissues, and shows expression of the paternal allele only. To investigate whether disruption of this monoallelic IGF2 expression is involved in breast cancer development, a series of primary tumors and adjacent, histologically normal, breast tissue samples, as well as matched primary in vitro fibroblast cultures were studied.

Markers of tumor angiogenesis and proteolysis independently define high- and low-risk subsets of node-negative breast cancer patients.

Purpose: To compare the prognostic impact of tumor angiogenesis factors (vascular endothelial growth factor [VEGF], angiogenin, and basic fibroblast growth factor [bFGF]), tumor proteolysis factors (urokinase-type plasminogen activator [uPA] and plasminogen activator inhibitor-1 [PAI-1]), and conventional tumor markers (stage, grade, and steroid receptors) in early breast cancer.

Patients And Methods: In the primary clinical study, tumor angiogenesis and other factors were detected in frozen biopsies from 305 primary breast tumors. VEGF expression was assessed by chemiluminescence immunosorbent assay (ICMA); angiogenin, bFGF, uPA, and PAI-1 by enzyme-linked immunosorbent assay (ELISA); and steroid receptors (estrogen receptor [ER] and progesterone receptor [PgR]) by enzyme immunoassay (EIA).

Urokinase-type-plasminogen-activator (uPA) production by human breast (myo) fibroblasts in vitro: influence of transforming growth factor-beta(1) (TGF beta(1)) compared with factor(s) released by human epithelial-carcinoma cells.

The urokinase-type plasminogen activator (uPA) may be considered as a key enzyme in the processes of cancer cell invasion and metastasis. Evidence has been presented that, in breast stroma, uPA is expressed predominantly by myofibroblasts located at the invasive areas of the tumor. To examine whether transforming growth factor type-1 (TGF beta(1)) produced by breast-carcinoma cells is a candidate responsible for the induction of uPA-producing myofibroblasts, we studied in vitro the capacity of normal and tumor-derived human breast fibroblasts to express uPA and the myofibroblast marker alpha-smooth-muscle actin in response to TGF beta(1).

High prevalence of codon 213Arg-->Stop mutations of the TP53 gene in human ovarian cancer in the southwestern part of The Netherlands.

As in many human malignancies, TP53 mutations are the most common genetic alterations in malignant human ovarian tumours. An approach often used in the determination of TP53 status is immunohistochemical staining of the protein. Non-missense mutations, especially those of the null type, causing premature termination codons and resulting in truncated proteins, may often not be detectable by immunohistochemistry.

Mutations in residues of TP53 that directly contact DNA predict poor outcome in human primary breast cancer.

The tumour-suppressor gene TP53 is frequently mutated in breast tumours, and the majority of the mutations are clustered within the core domain, the region involved in DNA binding. We searched for alterations in this central domain of the TP53gene in 222 human breast cancer specimens using polymerase chain reaction-single-strand conformation analysis (PCR-SSCA) followed by sequencing. TP53 gene mutations were observed in 66 tumours (31%), including three tumours that contain two mutations.

Predictive value of SRC-1 for tamoxifen response of recurrent breast cancer.

Tamoxifen causes an objective response in about one-third of metastatic breast cancer and in only half of the breast cancer patients with estrogen receptor (ER) positive tumors. Steroid-receptor coactivator-1 (SRC-1) appears to be a general coactivator for steroid receptors and rate limiting factor necessary for efficient ER transactivation. We aimed to evaluate whether SRC-1 expression is an additional factor for prediction of response to first-line tamoxifen therapy in patients who developed recurrent disease.

Prognostic significance of cathepsins B and L in primary human breast cancer.

Purpose: Evaluation of the clinical significance of cytosolic tumor levels of the lysosomal cysteine proteases cathepsin B (catB) and cathepsin L (catL) in patients with primary breast cancer.

Patients And Methods: CatB (n = 1,500) and catL (n = 1,391) levels were determined by enzyme-linked immunosorbent assay (ELISA) in cytosols routinely prepared from frozen-tissue samples that were submitted to our laboratory for the assessment of steroid-hormone-receptor status. The median duration of follow-up of patients still alive at the time of analysis was 93 months.

Feasibility, endocrine and anti-tumour effects of a triple endocrine therapy with tamoxifen, a somatostatin analogue and an antiprolactin in post-menopausal metastatic breast cancer: a randomized study with long-term follow-up.

Suppression of the secretion of prolactin, growth hormone and insulin-like growth factor 1 (IGF-1) might be important in the growth regulation and treatment of breast cancer. Because oestrogens may counteract the anti-tumour effects of such treatment, the combination of an anti-oestrogen (tamoxifen), a somatostatin analogue (octreotide) and a potent anti-prolactin (CV 205-502) might be attractive. In this respect, we performed a first exploratory long-term study on the feasibility of combined treatment and possible clear differences in endocrine and anti-tumour effects during such combined treatment vs standard treatment with tamoxifen alone.

p53 protein accumulation predicts poor response to tamoxifen therapy of patients with recurrent breast cancer.

Purpose: Mutations of the p53 gene are frequently observed in primary breast cancer and accumulation of p53 protein has been used as a surrogate marker of p53 inactivation. Previous studies have shown that p53 accumulation is related to poor prognosis in primary breast cancer. We studied whether p53 protein accumulation is a predictive factor for response to tamoxifen treatment in patients with recurrent breast cancer.

Prognostic value of TP53 protein accumulation in human primary breast cancer: an analysis by luminometric immunoassay on 1491 tumor cytosols.

The tumor suppressor gene TP53 is implicated in the regulation of normal cell growth and division, DNA repair and apoptosis. Mutations in this gene usually give rise to a conformationally altered protein which is stably expressed at high levels. We have studied TP53 protein accumulation in routinely prepared cytosols from 1491 human primary breast cancer specimens (median follow-up of patients alive, 66 months), using a quantitative luminometric immunoassay (LIA).