Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The increased expression of proteolytic systems is one of the characteristics of transformed and malignant cells and their evaluations in whole tumor homogenates were considered as possible diagnostic and/or prognostic factors. Abnormal intracellular distribution, increased activities and secretion of cysteine proteinases (CPs) cathepsin B (Cat B) and L (Cat L), were associated with tumor progression. In the present study of matched pairs of breast carcinoma and normal breast tissue, the activities of Cat B and Cat L in breast carcinoma homogenates were found to be 20 and 50 fold higher, respectively, than in normal tissues. In contrast, a decrease in total inhibitory activity of cysteine proteinase inhibitors (CPIs) was observed but an average ratio between tumor and normal tissues was only 0.75. One of the CPIs, stefin A, was also determined immunochemically. The activities of CPs and CPIs were compared to the increased levels of cathepsin D (Cat D) activities in individual patients, but no statistically significant correlations were found. We correlated CPs and CPIs with morphological and receptor data as well as the axillary lymph node metastases. There was no statistical correlation of CP and CPIs with the number of lymph node metastases. However, highly elevated levels of Cat B and Cat L and lowered CPI activities in tumor cytosols were often associated with poorly differentiated carcinomas and those with negative ER and PR values. We conclude that cysteine-dependent proteolysis may play an important role in breast tumors.
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PMID:Cystatins and cathepsins in breast carcinoma. 151 89

With the increasing availability of screening mammography, more women are diagnosed as having breast cancers at an early, node-negative stage. The majority of these patients would be cured with total mastectomy or breast conservation treatment. However, about 30% of the patients would have recurrence of disease in distant sites. In recent randomized clinical trials, adjuvant systemic therapy has been shown to reduce the rate of recurrence in these patients. Proper selection of patients for adjuvant therapy is necessary to avoid exposing many patients with low risk of recurrence to treatments for whom the benefit is not justified by the toxicity and the cost. In this article, we review the clinical and pathologic prognostic factors in early stage, node-negative breast cancer patients, including tumor size, nuclear and histologic grades, estrogen and progesterone receptors, menopausal status, proliferative rate, HER-2/neu oncogene amplification, and cathepsin D level. Favorable prognostic factors include tumor size less than or equal to 2 cm, low nuclear and histologic grades, low S-phase fraction, diploid state, low cathepsin-D level, and positive estrogen and progesterone receptor status. The value of HER-2/neu oncogene overexpression is controversial, and further studies are needed to define its role as a prognostic factor in patients with node-negative breast cancer. Based on these prognostic factors, it is possible to identify subsets of patients who have a low risk of recurrence and would not benefit significantly from adjuvant systemic therapy.
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PMID:Prognostic indicators in node-negative early stage breast cancer. 158 Mar

The lysosomal acidic protease cathepsin D, a recognized independent predictor of prognosis in human breast cancer, has not been studied widely in patients with endometrial adenocarcinoma. Cathepsin D levels (52-kD precursor plus 48-kD intermediate and 34/14-kD mature form) were measured in tumor cytosols from 26 hysterectomy specimens by immunoradiometric assay. Significant correlation between cathepsin D levels and tumor differentiation was noted with linear increase in cathepsin D from 8 pmol/mg (standard error of the mean [SEM], 1.73 pmol/mg) for Grade I tumors to 28 pmol/mg (SEM, 3.91 pmol/mg) for Grade III tumors. A group of four papillary serous carcinomas showed relatively high cathepsin D levels reaching 39 pmol/mg. A significant stepwise increase in cathepsin D levels was associated with increased depth of myometrial invasion. Noninvasive tumors averaged 7 pmol/mg (SEM, 4.0 pmol/mg); intramural tumors averaged 15 pmol/mg (SEM, 2.45 pmol/mg); and transmural invasive tumors averaged 30 pmol/mg (SEM, 3.72 pmol/mg). There was no significant correlation of cathepsin D levels with age, estrogen/progesterone receptor hormone status, clinical stage, and lymph node metastasis. Cathepsin D levels correlate significantly with tumor differentiation and myometrial invasiveness and may show promise as a clinically useful adjunct to prognosis assessment and the planning of therapy for patients with endometrial adenocarcinoma.
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PMID:Correlation of tumor cytosol cathepsin D with differentiation and invasiveness of endometrial adenocarcinoma. 159 96

Cathepsin D, an aspartyl protease of lysosomes, is overproduced and hypersecreted by breast cancer cells. The prognostic value of its immunoassay in breast cancer cytosol is reviewed from the first retrospective clinical studies available, which show a strong correlation between high concentrations of cathepsin D in the cytosol of primary tumor and further occurrence of metastasis. This new prognostic factor is induced by estrogen in hormone dependent breast cancer but expressed at a high level in hormone independent breast cancer and appears to be independent of other more classical factors. Its value in node negative patients varies according to the studies. In nude mice, transfection of cathepsin D cDNA into tumor cells increases their metastatic potential, suggesting that overexpression of this protease may be one of the factors responsible for metastasis in human breast cancer. The mechanism by which this protease might facilitate metastasis in vivo is still unknown, even though cathepsin D has the potential to initiate a proteolytic cascade, to degrade extracellular matrix and to liberate FGFs like growth factors from the matrix. These studies should stimulate the search for new therapeutical agents in order to inhibit cathepsin D action.
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PMID:Biological and clinical significance of cathepsin D in breast cancer. 162 26

Seventy-three primary human breast cancers were analyzed to assess the presence of estrogen and progesterone receptors, the p29 protein, and the total cathepsin D status. No significant relationship was found between cathepsin D concentration and the presence of ER or PR, either by Fisher's exact test or Spearman's rank correlation (P greater than 0.1). However, a significant association was found between cathepsin D and p29 (Fisher's exact test, P less than 0.001) and between cathepsin D and steroid receptor status in samples expressing both estrogen and progesterone receptors (positive by steroid binding assay and enzyme immunoassay) (P less than 0.05). This association was more significant in tissues expressing estrogen and progesterone receptors as well as p29 (P less than 0.001). In contrast, cathepsin D synthesis was not related to tumor size, lymph node involvement, or patient's age (P greater than 0.05). Steroid receptors and cathepsin D were also assayed in samples of non-malignant tissue from 16 mastectomies; there was a significantly higher relative concentration of cathepsin D in the malignant specimens (Student's t-test, P less than 0.001).
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PMID:Relation of cathepsin D level to the estrogen receptor in human breast cancer. 163 22

Variability in outcome of breast carcinoma among different racial groups has been identified between Japanese and Caucasians and between Caucasians and Blacks living in the United States. These differences are not fully explained by population differences of the known prognostic variables nodal involvement and tumor hormonal receptor status. Further elucidation of the differences in outcome should include a careful examination of other prognostic variables. These include tumor size, nuclear and histologic grade, and indicators of cell proliferation (labelling index and flow cytometric measures of S phase and DNA ploidy). More recent studies indicate that growth factor regulation, oncogene amplification (HER-2/neu) and expression, and cathepsin D levels may help to further identify prognostic subgroups. A review of the literature does not provide an answer to the question of whether there are population differences in response to standard treatments. Differences in drug distribution, elimination, and metabolism which could be related to genetic or dietary factors are intriguing hypotheses to explain why differences may exist. Careful, well controlled studies to answer these questions are urgently needed.
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PMID:Response to treatment of breast cancer. 165 92

Using a sandwich enzyme-linked immunoassay, plasma total cathepsin D concentration was assayed in 40 breast cancer patients and 84 patients with various liver diseases and compared to that of 52 normal subjects. There were no significant variations found in breast cancer patients related to tumor size, node invasiveness or metastases. In normal women, cathepsin D levels were slightly but not significantly increased in the luteal phase and in pregnancy. By contrast, plasma cathepsin D concentration was significantly increased in 70-75% of patients with liver disease (cirrhosis, hepatocarcinoma, hepatitis), but not in those with liver steatosis. Cathepsin D was independent of most of the plasma hepatic function tests and was correlated with alpha-fetoprotein in cirrhosis and with alpha-fucosidase in primary hepatocellular carcinoma. We conclude that plasma cathepsin D is not a useful marker in breast cancer. However, since the cellular level of this protease is associated with risk of metastasis in breast cancer, clinical follow-up will be required to test whether high cathepsin D plasma concentration has any prognostic value in liver cirrhosis and primary hepatocarcinoma.
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PMID:Increased plasma cathepsin D concentration in hepatic carcinoma and cirrhosis but not in breast cancer. 166 31

In this study, the polyanionic compound suramin was shown to be a potent in vitro growth inhibitor of both hormone-insensitive, estrogen receptor-negative human breast cancer cells (MDA MB231 and SK-BR-3) and hormone-responsive, estrogen receptor-positive human breast cancer cells (ZR 75-1, T47D, and MCF7). The inhibitory effect of suramin was dose dependent, with a median effective dose varying from 7 microM for MDA MB231 cells to 50 microM for MCF7 cells. This result indicated that estrogen receptor-negative cells were more sensitive to the drug. In MCF7 cells, not only did suramin block the mitogenic action of growth factors such as epidermal growth factor (EGF) and insulin-like growth factors I and II (IGF-I and IGF-II, respectively), but it also totally abolished the increase in cell proliferation induced by the steroid hormone 17 beta-estradiol (E2). Maximal inhibition was obtained after 5 days of suramin treatment, and inhibition either was partially reversed by E2, IGF-I, and IGF-II or was not reversible by EGF following removal of drug. In addition, suramin significantly decreased synthesis and secretion of the lysosomal enzyme cathepsin D, which was shown to be associated with a high risk of breast tumor metastasis. These results therefore suggest that, because of its effects on growth and cathepsin D secretion, suramin might be a helpful additional therapeutic tool for breast cancer patients, especially for patients with estrogen receptor-negative tumors which are insensitive to antihormonal strategies.
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PMID:Inhibition of breast cancer growth by suramin. 173 71

Tumor cell invasion and metastasis is a multifactorial process, which at each step may require the action of proteolytic enzymes such as collagenases, cathepsins, plasmin, or plasminogen activators. An enzymatically inactive proenzyme form of the urokinase-type plasminogen activator (pro-uPA) is secreted by tumor cells which may be converted to an enzymatically active two-chain uPA-molecule (HMW-uPA) by plasmin-like enzymes. Action of proteases on pro-uPA may generate the enzymatically active or inactive high-molecular-weight form of uPA (HMW-uPA). Some proteases (plasmin, cathepsin B and L, kallikrein, trypsin or thermolysin) activate pro-uPA by cleaving the peptide bond Lys158 and IIe159. Other proteases (elastase, thrombin) cleave pro-uPA at different positions to yield enzymatically inactive HMW-uPA. HMW-uPA may be split into the enzymatically active LMW-uPA and the enzymatically inactive ATF (amino terminal fragment). ATF may be cleaved between peptide sequence 20 and 40 within the receptor binding domain of uPA (GFD). Such impaired ATF does not bind to uPA-receptors. Action of the bacterial endoproteinase Asp-N from Pseudomonas fragi mutant on pro-uPA or HMW-uPA, however, generates intact ATF which efficiently competes for binding of HMW-uPA or pro-uPA to receptors on tumor cells. High uPA-antigen content (pro-uPA, HMW-uPA, or LMW-uPA) in breast cancer tissue (not in plasma) indicates an elevated risk for the patient of recurrences and shorter overall survival. Thus pro-uPA/uPA-antigen content in breast cancer tissue serves as an independent prognostic parameter for the outcome of the disease. Cathepsin D is also an independent prognostic factor for recurrences and overall survival. High content of cathepsin D in breast cancer tumors is, however, not correlated with elevated levels of pro-uPA/uPA indicating that synthesis and release of cathepsin D and pro-uPA/uPA are independent events.
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PMID:Biological and clinical relevance of the urokinase-type plasminogen activator (uPA) in breast cancer. 180 51

Current research in the area of breast malignancies is focusing on identification of pathogenetic risk factors, chemoprevention, screening policies, local treatment modalities that minimize disfigurement, and improved adjuvant therapeutic and palliative systemic therapies. Although epidemiologic studies have produced contradictory results, oral contraceptive use before age 25 years and before 1st full-term pregnancy appears to increase the breast cancer risk. In need of thorough study is the safest form of estrogen replacement therapy in postmenopause. Screening programs aimed at early detection have been shown to reduce breast cancer mortality by 30% in women 50-69 years of age, but no preventive strategies have been identified for younger and older women. A trend toward breast-conserving primary therapy represents a major shift in this area. As long as the tumor is less than 4 cm in diameter and the resection margins are free of tumor, lumpectomy produces disease-free survival rates comparable to those obtained through total mastectomy. In node-positive patients, hormonal adjuvant systemic therapy is effective in postmenopausal women while chemotherapy is effective in premenopausal women. The data are insufficient to allow recommendations regarding adjuvant treatment of node-negative patients, whose overall survival rate is about 70%. In metastatic breast cancer, tamoxifen is the drug of choice for palliation. Prognostic factors currently under study include oncogene amplification, urokinase plasminogen activator level, expression of growth factors and growth factor receptors, proliferation parameters, mutations, and cathepsin D levels.
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PMID:Breast malignancy. 187 98


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