Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Breast cancer is a highly heterogeneous disorder with regard to biologic and clinical characteristics. Identification of patients with different biologic subtypes is important both prognostically and therapeutically. The recent introduction of estrogen and progesterone receptor measurement has considerably increased our ability to identify patients with hormone-dependent tumors who are likely to respond to endocrine therapy and enjoy a longer survival. Assessment of the tumor growth fraction by autoradiographic or flow cytometric methods and measurement of EGF receptors in tumor specimens are likely to produce additional independent information on the clinical outcome of patients with breast cancer. The endocrine therapy of breast cancer has been greatly facilitated with the introduction of newer forms of therapy such as antiestrogens and aromatase inhibitors. These forms of treatments are well established, not only in patients with metastatic disease but also in selected subgroups of women with operable breast cancer following surgery. In view of its low toxicity and ease of administration, modern endocrine therapy has obviated the need for major ablative procedures such as surgical adrenalectomy and hypophysectomy. Unfortunately, duration of response and survival have not been prolonged by these newer endocrine treatments when compared with traditional hormonal therapy. Thus, new treatment strategies need to be developed, since current therapy does not cure any patient with advanced disease and at best only a small fraction of women with early breast cancer. Hormonally induced manipulation of tumor cell kinetics may provide a tool to enhance the efficacy of cytotoxic chemotherapy, in both metastatic as well as locally advanced disease. This potential approach needs to be further evaluated in prospective randomized clinical trials. Prostate cancer is the male counterpart of hormone-dependent neoplasia. Conventional therapy of this malignancy consists of surgical or medical castration. However, despite a high initial response rate, disease progression invariably occurs with poor response to secondary forms of therapy. Potential new treatment strategies currently being tested in the attempt to improve clinical outcome include simultaneous early blockade of both adrenal and testicular androgens as well as hormonally induced tumor cell growth synchronization and recruitment prior to administration of cytotoxic chemotherapy.
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PMID:Endocrine therapy of breast and prostate cancer. 266 86

The relative radioresponsiveness of human prostate cancer compared to malignant melanoma is well known. The effects of beta-estradiol or testosterone on the X-irradiation survival of several human cell lines were studied, including: human prostate carcinoma cell lines PC3 and DU145 and human malignant melanoma cell lines A375 and A875. Lines PC3 and DU145 demonstrated 55-61 fmol per 10(6) cells of androgen receptor with no detectable estrogen or progesterone receptor. Cells were irradiated at 120 cGy/min dose rate. There was no detectable toxicity of up to 10(-4) M testosterone or beta-estradiol on PC3 or DU145 cells in the absence of X-irradiation. At plating efficiencies from 11-13%, and plating densities of 1 x 10(4) cells per 60 cm2 flask, cell lines PC3 and DU145 demonstrated a Do of 108.5 +/- 6.5, n 2.1 +/- 0.7 cGy, and Do of 143.5 +/- 1.5 cGy, n 2.4 +/- 0.5, respectively. The addition of testosterone or beta-estradiol at 10(-4) to 10(-10) M prior to or after, X-irradiation did not alter radiosensitivity. At the same dose rate of 120 cGy/min, malignant melanoma cell lines A375 and A875 had a Do of 125 +/- 2.5 cGy, n 1.56 +/- 0.8 SF2 0.65 +/- 0.03 and line A875 demonstrated a Do of 129 +/- 4.5 cGy, n 1.58 +/- 0.4 SF2 0.55 +/- 0.04, respectively. The radiosensitivity of melanoma cell lines did not decrease at low dose rate 5 cGy/min. Thus, the in vitro radiosensitivity of androgen receptor positive prostate cancer cell lines is not necessarily altered by the presence of androgen before or after irradiation. The data support the concept that all malignant melanoma cell lines do not show a broad-shouldered cell survival curve in vitro and intrinsic cellular radioresistance.
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PMID:Radiosensitivity of human prostate cancer and malignant melanoma cell lines. 277 56

Estrogens have been proposed as a major etiological factor in the pathogenesis of benign prostatic hyperplasia in man. The presence of estrogen receptor in benign prostatic hyperplasia would support this concept. Using the receptor stabilizer, sodium molybdate, and a hydroxylapatite assay we assayed human benign prostatic hyperplasia for the presence of cytosolic estrogen receptor. For comparison, we assayed estrogen receptor in cytosols of prostatic cancer and normal tissue, and we also measured androgen receptor and progesterone receptor concentrations in the 3 tissue types. Estrogen receptor was present in 8 of 15 benign prostatic hyperplasia specimens at a mean concentration of 9.2 fmol./mg. protein for the estrogen-receptor-positive samples. Sucrose gradient analysis of the estrogen receptor of benign prostatic hyperplasia revealed that it sedimented in the region of 8S, and steroid specificity studies confirmed that the binding to estrogen receptor was estrogen-specific. Estrogen receptor was also found in normal (3 of 3) and malignant (4 of 6) tissues, and all tissues were positive for androgen receptor. The presence of estrogen receptor in human benign prostatic hyperplasia supports the proposal that circulating estrogens may have a role in the pathogenesis of this disorder.
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PMID:Estrogen receptor in human benign prostatic hyperplasia. 619 Oct 47

The presence of specific steroid hormone-binding receptors has been correlated with the clinical response to hormonal therapy in a number of different neoplasias, including breast and prostate cancer. In this article, we investigated the expression of the androgen, estrogen, glucocorticoid, and progesterone receptor messenger ribonucleic acid (mRNA) and protein in a number of astrocytic neoplasms of various histological grades. Androgen and glucocorticoid receptor mRNA were detected in all astrocytic neoplasms examined, regardless of histological subtype. In contrast, progesterone receptor mRNA was observed more frequently in high-grade tumors than in low-grade tumors. Estrogen receptor mRNA was undetectable in all astrocytic tumors examined. These studies suggest a possible adjunct clinical use of hormonal therapy for the treatment of astrocytomas. Specific antagonists and agonists may allow the modulation of the growth of these tumors. Development of this body of knowledge may lead to the development of better treatment for these aggressive tumors.
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PMID:Steroid hormone receptors in astrocytic neoplasms. 750 Nov 16

The androgen receptor (AR) is a member of the steroid receptor superfamily that plays an important role in male sexual differentiation and prostate cell proliferation. Mutations or abnormal expression of AR in prostate cancer can play a key role in the process that changes prostate cancer from androgen-dependent to an androgen-independent stage. Using a yeast two-hybrid system, we were able to isolate a ligand-dependent AR-associated protein (ARA70), which functions as an activator to enhance AR transcriptional activity 10-fold in the presence of 10(-10) M dihydrotestosterone or 10(-9) M testosterone, but not 10(-6) M hydroxyflutamide in human prostate cancer DU145 cells. Our data further indicated that ARA70 Will only slightly induce the transcriptional activity of other steroid receptors such as estrogen receptor, glucocorticoid receptor, and progesterone receptor in DU145 cells. Together, these data suggest that AR may need a specific coactivator(s) such as ARA70 for optimal androgen activity.
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PMID:Cloning and characterization of a specific coactivator, ARA70, for the androgen receptor in human prostate cells. 864 7

Endocrine therapy of mammary and prostate cancer has been established for decades. The therapies available to block sex-hormone-receptor-mediated tumor growth are based on two principles: (i) ligand depletion, which can be achieved surgically, by use of luteinizing-hormone-releasing hormone analogues or inhibitors of enzymes involved in steroid biosynthesis or by interfering with the feedback mechanisms of sex hormone synthesis at the pituitary/hypothalamic level; (ii) blockade of sex hormone receptor function by use of antihormones. The antiestrogen tamoxifen, which is the compound of choice for the treatment of mammary carcinoma, has the drawback of being a partial agonist. A complete blockade of estrogen receptor (ER) function can be achieved by a new class of compounds, pure antiestrogens. In contrast to aromatase inhibitors, pure antiestrogens are able to block ER activation by ligands other than estradiol and can also interfere with ligand-independent ER activation. In addition to estradiol, progesterone has a strong proliferative effect in mammary carcinomas. Antiprogestins are promising new tools for clinical breast cancer therapy. These compounds clearly need a functionally expressed progesterone receptor to block tumor growth, but there is strong experimental evidence that their tumor inhibition is based on more than just progesterone antagonism. The ability of these compounds to induce tumor cell differentiation that leads to apoptosis is unique among all other endocrine therapeutics. In prostate tumors that have relapsed from current androgen-ablation therapies the androgen receptor (AR) is still expressed and, compared to the primary tumors, its level is often even enhanced. Mutated AR that can be activated by other compounds such as adrenal steroids, estrogens, progestins and even antiandrogens have been detected in recurrent tumors. Thus, relapse of tumors under the selective pressure of common androgen-ablation therapies can be caused by acquired androgen hypersensitivity and AR activation by ligands other than (dihydro-)testosterone. There is a clinical need for future compounds that produce a complete blockade of AR activity even in recurrent tumors. Preclinical experiments indicate that combination therapy as well as the extension of endocrine treatments to several other tumor entities are promising approaches for further developments. Examples are the combination of antiestrogens and antiprogestins for breast cancer treatment, or the treatment of prostate carcinomas with antiprogestins.
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PMID:The future of antihormone therapy: innovations based on an established principle. 869 Jul 48

There are recent data to suggest that risk factors for breast cancer may differ according to whether the tumor expresses detectable levels of the estrogen receptor (ER) and progesterone receptor (PR). While a family history of breast cancer is one of the most consistent predictors of the disease, we recently reported a modest inverse association with ER+PR- tumors. However, the definition of a family history of cancer did not consider second-degree relatives or cancer sites that may be etiologically related. The current report presents additional data analysis from the Iowa Women's Health Study, a prospective population-based cohort study conducted among 41,837 postmenopausal women. At baseline in 1986, respondents provided information on family history of cancers of the breast, ovaries, or uterus/endometrium in their mothers, sisters, daughters, maternal and paternal grandmothers, and maternal and paternal aunts. Data on family history of prostate cancer in fathers and brothers and age at onset of breast cancer in mothers and sisters were collected in 1992. Cohort members were followed for cancer incidence through the statewide tumor registry. After 7 years and more than 235,000 person-years of follow-up, 939 incident cases of breast cancer were identified. Information was obtained from the tumor registry on ER (+/-) and PR (+/-) status for 610 cases (65.0%). A family history of breast cancer in first-degree relatives was associated with increased risk (relative risk [PR] = 1.4; 95% confidence interval [CI]: 1.1-1.6) for all receptor-defined subtypes of breast cancer except ER+PR- tumors (RR = 0.7; 95% CI: 0.3-1.4). These results were unchanged when data on second-degree relatives were included. When the onset of breast cancer in relatives occurred at or before the age of 45 years, increased risks were evident only for ER-PR+ and ER-PR- tumors (RR = 2.3 and 3.3, respectively). Conversely, when relatives were affected with breast cancer after the age of 45 years, increased risks were most apparent for ER+PR+ and ER-PR+ tumors (RR = 1.3 and 3.2, respectively). A family history of prostate cancer in first-degree relatives was associated with a 1.2-fold increased risk of breast cancer (95% CI: 0.98-1.50), largely a reflection of the association with ER-PR- tumors (RR = 1.5; 95% CI: 0.8-3.0). The small numbers of cases in some categories and the corresponding wide CIs preclude definitive conclusions, but these data are at least suggestive that joint stratification of breast tumors on ER and PR status may be useful in partitioning breast cancer families into more homogeneous subsets.
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PMID:Association between family history of cancer and breast cancer defined by estrogen and progesterone receptor status. 872 47

The diagnostic value of a new tumor marker, c-erbB-2, was studied in the sera of 50 controls, 112 patients with benign diseases and 534 patients with malignancies. Using 15 U/ml as the cutoff, no healthy subjects, patients with benign diseases (excluding liver cirrhosis) or patients with no evidence of disease (45 patients) had serum levels higher than this limit. Abnormal c-erbB-2 levels were found in 38.5% (10 of 26) of the patients with liver cirrhosis and in 26.7% (8 of 30) of those patients with primary liver cancer. No differences were found between the c-erbB-2 serum concentrations in liver cirrhosis or primary liver cancer, suggesting the possible catabolism of this antigen in the liver. Abnormal levels of this antigen were found in 20% (56 of 278) of the patients with breast carcinoma (locoregional 7%, metastases 41.5%), in 21% (6 of 28) of ovarian carcinomas (stage I-II 0%, stage III-IV 42.8%), in 21% (3 of 14) of the colorectal tumors (locoregional 0%, metastases 30%), and in 13.3% (11 of 83) of the patients with lung cancer (locoregional 11.5%, metastases 16%). C-erbB-2 sensitivity in other patients with advanced disease was: 25% (9 of 36) in prostatic cancer, 22% (2 of 9) in gastric cancer, and 11% (1 of 9) in vesical tumors. When patients with liver metastases were excluded abnormal c-erbB-2 serum levels were only found in breast, lung, prostatic and ovarian carcinomas. C-erbB-2 sensitivity in patients with lung cancer was related to tumor histology with significantly higher value in non-small cell lung cancer (mainly adenocarcinomas) than in patients with small cell lung cancer (p < 0.013). C-erbB-2 concentrations in patients with breast cancer were significantly higher in patients with recurrence (mainly bone and liver metastases) and in patients with progesterone receptor-negative (< 15 fmol/mg) tumors (p < 0.01). In conclusion, c-erbB-2 is not a specific tumor marker and abnormal serum levels may be found in patients with liver pathologies. Its sensitivity suggests its possible application as a tumor marker in breast, ovarian, lung (mainly adenocarcinomas) and prostatic tumors.
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PMID:Serum levels of C-erbB-2 (HER-2/neu) in patients with malignant and non-malignant diseases. 914 15

Prostate-specific antigen (PSA) is a valuable tumor marker for prostate cancer. It was believed that PSA was produced exclusively by the epithelial cells of the prostate gland, but a large body of evidence demonstrates that PSA is not a prostate-specific molecule. PSA has been shown to be expressed in many forms of female tissues. The breast is a major female organ able to produce PSA. PSA is detected in both normal and abnormal breast tissues, as well as in various breast fluids including milk, nipple aspirate, and cyst fluid. Androgens and progesterones, via their receptors, regulate the production of PSA in breast tissue. Clinical studies demonstrate that PSA in breast cancer is associated with the expression of estrogen receptor and progesterone receptor. Women with PSA-positive breast cancer have better disease-free survival as well as overall survival than those with PSA-negative breast cancer. PSA levels in nipple aspirate fluid may be indicative of breast cancer risk. High concentrations of PSA are found in amniotic fluid and the levels change with gestational age. Pregnant women have elevated serum PSA. PSA levels in serum also vary during menstrual cycles and increase in women with excess androgen. Clinical implications of PSA in amniotic fluid and female serum have been suggested. More studies are needed to further explore their utilities.
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PMID:Prostate-specific antigen (PSA) in women. 1023 97

We analyzed the frequency and relevance of mutations in the coding region of the androgen receptor (AR) in genomic DNA extracted from 137 specimens of prostate cancer. The specimens were obtained from the primary tumors of patients affected by stage B disease [15 nonmicrodissected (group 1A) and 84 microdissected (group 1B)] and from the metastatic deposits of individuals with stage D1 disease [8 nonmicrodissected (group 2A) and 30 microdissected (group 2B)] who had not undergone androgen ablation therapy. The study was conducted by PCR-single strand conformational polymorphism (SSCP) analysis of exons 2-8 in the four groups and direct sequence analysis of exon 1 in group 1B. As positive and negative controls, we used genomic DNA extracted from genital skin fibroblasts of patients affected by various forms of androgen resistance with known mutations in the AR. To control for genetic instability, PCR-SSCP analysis of exon 2 of the human progesterone receptor was carried out on each specimen. The overall number of mutations detected was 11 (8%). No mutations were detected in any of the 99 patients with stage B disease. Eleven mutations were detected in exons 2-8 in 8 of the 38 patients with stage D1 disease (all in group 2B). Simultaneous analysis of exon 2 of the progesterone receptor was carried out, and no SSCP changes were identified. These data suggest that AR mutations are rare and presumably do not play a role in the initial phase of prostatic carcinogenesis. The presence of a significant number of AR mutations in metastatic disease indicates that mutations of this molecule may play a role in the most advanced phases of the natural history of this disease, either by facilitating growth or acquisition of the metastatic phenotype.
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PMID:Androgen receptor mutations in prostate cancer. 1070 9


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