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

Structural variants of nuclear hormone receptors have been found in tumour tissues. Experimental evidence suggests two ways in which these variants may have oncogenic potential: 1. by suppressing the action of the normal hormone receptor, thereby acting as dominant negative oncogenes; 2. by activating hormone-responsive genes in a hormone-independent manner. These mechanisms may not only contribute to oncogenesis but also to the development of hormone resistance in tumours, e.g. breast and prostate cancer.
 ...
PMID:Nuclear hormone receptor variants: their role in malignancy and progression to hormone resistance in cancer. 166 42

Antiandrogens can be used in various androgen-dependent diseases. Depending upon the therapeutic indication, they can be administered systemically or topically. Systemic treatment with an antiandrogen will inhibit androgen action not only in the desired target site but also in all other target tissues; thus, it will block the androgen-dependent feedback regulating the secretion (hypothalamo-pituitary-testis axis) or the action (protein factors) of androgens. In contrast, topical treatment (acting through cutaneous receptors or local metabolism) should not produce systemic side effects especially in man. Pharmacological assays which can select antiandrogens irrespective of the mechanism measure changes in the final androgenic response, but they consume a great deal of time and test compound and bear little relation to therapeutic activity. Therefore, the biological strategy that we report here and which, at Roussel-Uclaf, has led to the selection of a systemic and a topical antiandrogen (RU 23908 and RU 38882) has consisted in successively performing: (1) in vitro assays which measure an effect at a specific level in the mechanism of antiandrogen action, e.g. interaction with the androgen receptor. Assessing interactions with other classes of steroid hormone receptor can be used to predict possible hormonal side-effects, (2) in vitro determinations of agonist or antagonist activity, e.g. in pituitary cells (LH response to LHRH) or mammary tumor cells (induction of androgen-dependent proteins), (3) in vivo antiandrogen assays after a single treatment (induction of mouse kidney proteins, rat prostatic binding protein) or after repeated treatment (inhibition of the growth of rat accessory glands or of hamster sebaceous glands), to determine the active dose of the compound and possibly the absence of systemic effects by the topical route, (4) assays in animal models designed to mimic a therapeutic context e.g. for prostate cancer: inhibition of the "flare-up" effect of LHRH-A or of the trophic effect of perfused adrenal androgens on rat prostate, antitumoral activity in experimental cancer models. For hyperseborrhoea and acne: histological and stereological analysis of rat skin biopsies to measure the volume density of the smooth endoplasmic reticulum vesicles of the differentiating cells of the sebaceous gland.
 ...
PMID:How the study of the biological activities of antiandrogens can be oriented towards the clinic. 305 62

Occurrence of steroid hormone receptor has been evaluated in 30 prostatic cancer-bearing patients: 5 alpha-dihydrotestosterone receptor (DHTR) occurrence was correlated with both tumor grade of differentiation and clinical response to hormone therapy.
 ...
PMID:Correlation between clinical response to antiandrogenic therapy and occurrence of receptors in human prostatic cancer. 615 82

Animal models of human prostate cancer are very limited in number but are of obvious importance to develop. Dr. Morris Pollard (M. Pollard, J. Natl. Cancer Inst., 51: 1235-1241, 1973) has reported that Lobund-Wistar rats develop spontaneous metastatic prostatic cancer when they become old (approximately 25% incidence after 25 months). A chemically induced form of the disease has also been described in Lobund-Wistar rats. However, recent reports suggest that most of the chemically induced adenocarcinomas are not prostatic in origin, with most arising in the seminal vesicle, and thereby raise questions about the origin of the spontaneous cancers. We herein report cancer spontaneously arising in the lateral lobes of the prostates in Lobund-Wistar rats. One of 8 rats killed at 16 months of age showed prostatic carcinoma in situ. Two of 39 rats killed at 20 months displayed early invasive adenocarcinomas with no signs of metastases. Because sectioning of the prostates in this study was limited to face sections from a single block for each rat, it is highly probable that the true incidence of dysplasias and carcinomas is underestimated by these data. Dysplastic or neoplastic changes were not seen in either the seminal vesicles or other portions of the prostatic complex. The nuclei of adenocarcinoma cells showed less labeling with antibody to the androgen hormone receptor than did normal cells. These data strongly support the validity of the Pollard model of spontaneous prostate cancer in Lobund-Wistar rats.
 ...
PMID:Prostatic localization of spontaneous early invasive carcinoma in Lobund-Wistar rats. 752 50

As part of a WHO consensus conference on diagnosis and prognostic parameters in localized prostate cancer, a working group of experts discussed the role of various modern imaging techniques. Special attention was focused on transrectal ultrasound (TRUS) in combination with biopsies, magnetic resonance imaging (MRI) using endorectal coil and recent advances in these techniques. Some experimental techniques, especially hormone receptor scintigraphy and positron emission tomography were also discussed and new results were presented. We concluded that MRI seems to be superior to other imaging techniques in the preoperative assessment of local tumor stage. TRUS defends its place in the diagnostic armament; it is easily combined with multiple biopsies, the results of which are important in the assessment of the biological aggressiveness of prostate cancer. The present development in the field of nuclear medicine may result in techniques for in vivo characterization of tumors and will most certainly have important implications for diagnosis of prostate cancer in the future.
 ...
PMID:Imaging in the diagnosis and assessment of prognosis in localized prostate cancer. Consensus Conference on Diagnosis and Prognostic Parameters in Localized Prostate Cancer. Stockholm, Sweden, May 12-13, 1993. 752 31

Testicular hormones regulate the growth and development of the prostate. The presence of androgen receptors in prostatic tissue and their importance in the normal development of the prostate has been established. Age-related changes in the hormonal milieu, and perhaps steroid hormone receptor profile, could set in motion pathological changes leading to the onset of benign prostatic hyperplasia (BPH) or prostate cancer which primarily affect older men. The accumulation of dihydrotestosterone with age, the reawakening of the inductive potential of the prostatic stroma, the altered rate of apoptosis with age, and the age-related changes in the ratio of testosterone:estrogen have all been implicated in the etiology of BPH. In addition to androgen receptors, several studies have documented the presence of estrogen and progesterone receptors in BPH and prostate cancer. So far, most studies have focussed on the correlation between the presence/absence of steroid hormone receptors and response to hormonal therapy. The molecular mechanisms by which these steroid hormone receptors regulate the onset or progression of BPH and prostate cancer are not yet clear. The chronological changes in the levels and distribution of steroid hormone receptors in normal prostatic tissue and the effect of such changes on the synthesis of growth factors, growth factor receptors, and oncogenes should be investigated.
 ...
PMID:Androgen, estrogen, and progesterone receptors in normal and aging prostates. 754 76

Circulating androgens are required for normal growth and maintenance of function of the prostate. However, the prostate also contains neuroendocrine peptides, found either in nerve terminals or in prostatic neuroendocrine cells, which are likely to regulate prostate growth or function. The neuronal peptides are likely to participate in the regulation of the synthesis and secretion of prostatic secretory products. While the function of the neuroendocrine cells is undefined, there is evidence for growth-regulating effects of several neuroendocrine cell peptides. Since neuroendocrine differentiation has been correlated with tumor grade and poor prognosis in prostate cancer, the peptide products of the neuroendocrine cells may influence cancer cell replication as well. Recent evidence in other tissues suggests that peptide hormone receptor second-messenger systems may interact with steroid receptors to modulate their actions. These findings raise the possibility that prostatic neuroendocrine peptides may modulate the response of prostate to androgens.
 ...
PMID:Neuroendocrine peptides in the prostate. 754 39

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.
 ...
PMID:The future of antihormone therapy: innovations based on an established principle. 869 Jul 48

Breast cancer is the most frequent malignant tumor in women, whereas it is rare in men. In our own case series the ratio is 175:1. The present paper deals with an evaluation of clinical and morphological findings from a series of 54 de novo male breast cancers observed in our institution from 1978 to 1996 and a comparative discussion of 528 female breast cancers from the same geographic area. We should like to focus on the following observations: At the time of histopathological diagnosis, male patients with breast cancer were on average 67 (34-87) years old and thus 5 years older than women. Below the age of 40, breast cancer is very rare in men. The lag time between first symptoms and surgery was on average 42 weeks, i.e. twice as long as in women. In the vast majority of cases palpation of a retromamillary nodule was the leading diagnostic symptom. Mamillary secretion appeared to be an early symptom with favorable relation to prognosis by tumor size whereas diffuse breast swelling was an unfavorable late symptom. Bilateral carcinoma and double cancer (breast and prostatic cancer) was observed in one case each. Three patients (3/51 = 6%) had a positive family history (breast cancer in 1st and 2nd degree relatives). The average invasive tumor size was nearly identical with 23 mm (s11.02) in men and 25 mm (s13.48) in women. Men presented more frequently with regional lymph node metastases (53% versus 45%), which tended to develop earlier. pT4 cancers were twice as frequent in men compared to women. In situ cancers were found in 2% (1/54) in men and 4% in women. Similar to females, male breast cancers are predominantly of ductal histological type (NOS-cancers), classical lobular carcinoma with LCIS-components were not observed; special forms (tubular, papillary, mucinous) are slightly more common in men. When reviewing our series, need for revision of the origin of tumor was not found in any of the cases. Metastases of prostatic cancer were never misinterpreted as primary breast cancer. In case of isolated NSE-reaction, cancers with carinoid differentiation pattern are to be found in nearly every second tumor. However, when multiple markers were used (chromogranin A or synaptophysin) only 10% displayed such pattern, which corresponded to a positive hormone receptor status in each case. Quantitative (enzyme immunoassay) and semiquantitative (immunohistochemistry) analysis of steroid hormone receptor status was positive in 86% of 35 cases in men and in 75% in women. In contrast to female breast cancer, hormone status proved to be independent of age in males. The average levels of estrogen and progesterone were higher in men. Overlapping results were found only when cases were compared with postmenopausal women. The Nottingham prognostic index, a product of primary tumor size, axillary lymph node status and grading allows an approximative estimate of the course of the disease; its predictive value is higher than that of isolated tumor markers.
 ...
PMID:[Breast carcinoma in the man. Current results from the viewpoint of clinic and pathology]. 915 4

Prostate-specific antigen (PSA) is a valuable tumor marker used for diagnosis and management of prostate cancer. Recently, PSA has been found in various female tissues and body fluids. Female breasts, both normal and abnormal, including cancerous tissues, can produce PSA, and this production is regulated by androgens and progestins. Preliminary data suggested that patients with breast tumors positive for PSA may have better prognosis compared to those with PSA-negative breast tumors. This study examines the prognostic value of PSA in a large cohort study of United States patients. Using a PSA assay that has a lower detection limit of 0.001 ng/ml, we measured PSA in tumor cytosolic extracts of 953 women with primary breast cancer. Other information available for this study included age, follow-up time, survival outcome, tumor size, nodal status, steroid hormone receptor levels, DNA analysis by flow cytometry, and postoperative treatment. The median follow-up time was 73 months. During the follow-up, 200 patients relapsed and 188 died. PSA presence was found to be significantly associated with smaller tumors, tumors with low S-phase fraction, diploid tumors, younger patient age, and tumors with lower cellularity. Survival analysis indicated that the relative risks (RRs) for relapse and death were both significantly lower [RR = 0.67 (P = 0.01) for relapse; RR = 0.72 (P = 0.05) for death] in PSA-positive patients (levels higher than the 30th percentile of PSA values) than in PSA-negative patients. The reduced risks for relapse and death remained statistically significant after other clinical and pathological variables were adjusted in the multivariate analysis [RR = 0.68 (P = 0.02) for relapse; RR = 0.65 (P = 0.02) for death]. Our results suggest that the measurement of PSA in breast tumor extracts provides additional information on the prognosis of patients with primary breast cancer.
 ...
PMID:Prognostic value of prostate-specific antigen for women with breast cancer: a large United States cohort study. 962 67


1 2 3 4 5 6 7 8 9 Next >>