Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0476089 (endometrial cancer)
 11,379 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aromatase P450 (P450arom) is responsible for conversion of C19 steroids to estrogens in a number of human tissues, such as the placenta, gonads, adipose tissue, skin and the brain. Aromatase expression in human tissues is regulated by use of alternative promoters in the placenta (promoter I.1), adipose tissue (promoters I.4, I.3 and II) and gonads (promoter II). Aromatase expression is absent in the disease-free adult liver, adrenal and uterine tissues. Excessive or inappropriate aromatase expression in adipose fibroblasts and endometriosis-derived stromal cells, as well as in testicular, hepatic, adrenal and uterine tumors, is associated with abnormally high circulating estrogen levels and/or with increased local estrogen concentrations in these tissues. Whether systemically delivered or locally produced, elevated estrogen levels will in turn promote the growth of hormone-responsive tissues. We recently studied aromatase expression in testicular tumor and adipose tissue samples from prepubertal boys with gynecomastia, in hepatocellular cancer and adrenocortical tumor samples from adult men with gynecomastia, in breast adipose tissue samples proximal to breast tumors, and in endometrial cancer, leiomyoma and endometriosis tissues. Excessive aromatase activity and P450arom transcript levels were found in these tissue samples or in cultured cells derived from these tissues. In these neoplastic or non-neoplastic tissues or cells, the regulation of aromatase expression was studied in terms of alternative promoter use, both in vivo and in response to various hormonal stimuli. Our results were suggestive of a common metabolic abnormality associated with activation of a cyclic AMP-dependent signalling pathway that gives rise to transcriptional transactivation of aromatase expression via promoters I.3 and II in all of the above tissues. This article describes the common pathophysiological and molecular features of excessive aromatase expression in these disease states.
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PMID:Endocrine disorders associated with inappropriately high aromatase expression. 936 82

Estrogen biosynthesis in adipose tissue increases with age and obesity, and has been implicated in the development of endometrial cancer and breast cancer. In normal human adipose tissue, expression of the CYP19 gene which encodes aromatase P450, the enzyme responsible for estrogen biosynthesis, is regulated by a distal promoter, namely promoter I.4. Stimulation of expression in adipose stromal cells by members of the type 1 cytokine family, i.e. interleukin (IL)-6, IL-11, leukemia inhibitory factor (LIF) and oncostatin M (OSM), is mediated via a Jak-STAT3 signaling pathway and a GAS element upstream of promoter I.4. In contrast, aromatase expression in breast adipose tissue proximal to tumor is increased three- to four-fold to the utilization of another promoter, namely promoter II, proximal to the translation initiation site. In the present report, we show that prostaglandin (PG) E2 is the most potent factor which stimulates aromatase expression via cyclic AMP and promoter II. PGE2 acts via EP1 and EP2 receptor subtypes to stimulate both the PKC and PKA pathways. The combined stimulation of both of these pathways results in the maximal expression of promoter II-specific CYP19 transcripts. Because PGE2 is a major secretory product both of breast tumor epithelial cells and fibroblasts, as well as of macrophages infiltrating the tumor site, then this could be the mechanism whereby estrogen biosynthesis is stimulated in breast sites adjacent to a tumor, leading in turn to increased growth and development of the tumor itself.
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PMID:Transcriptional regulation of CYP19 gene (aromatase) expression in adipose stromal cells in primary culture. 936 91

Tamoxifen is currently established as the endocrine treatment of choice in breast cancer. In advanced breast cancer, response rates of up to 60% in women with oestrogen receptor (ER)-positive tumours have been reported. In early breast cancer, tamoxifen can produce significant benefits, both statistically and clinically, in terms of reduction in relative risk of relapse or death in all patient subgroups (i.e. ER status, aged < or > 50 years) except premenopausal women with ER-negative tumours. The major benefit, however, is seen in women over 50 years old with ER-positive tumours. The results of randomized trials suggest that the optimum duration of tamoxifen therapy is at least 5 years. Two large pragmatic trials (aTTom and ATLAS) are under way to determine whether additional benefit can be gained from continuing tamoxifen treatment beyond 5 years. Recent data also suggest possible synergism between tamoxifen and chemotherapy in the treatment of early breast cancer in post-menopausal women. Other benefits of tamoxifen treatment include reduction in the risk of developing contralateral breast cancer. Included among the non-breast cancer benefits of tamoxifen are reduced risk of cardiovascular disease and protection against bone loss in post-menopausal women. These benefits must be weighed against the possible increased incidence of endometrial cancer. Notwithstanding its undoubted success, there is a need for agents to improve upon tamoxifen. Newer agents, such as the luteinizing hormone-releasing hormone analogue goserelin and the new-generation aromatase inhibitors, such as anastrozole, will add new life to the search for an improved endocrine therapy for early breast cancer.
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PMID:Tamoxifen--the treatment of choice. Why look for alternatives? 974 80

Hormone-related cancers, namely breast, endometrium, ovary, prostate, testis, thyroid and osteosarcoma, share a unique mechanism of carcinogenesis. Endogenous and exogenous hormones drive cell proliferation, and thus the opportunity for the accumulation of random genetic errors. The emergence of a malignant phenotype depends on a series of somatic mutations that occur during cell division, but the specific genes involved in progression of hormone-related cancers are currently unknown. In this review, the epidemiology of endometrial cancer and breast cancer are used to illustrate the paradigms of hormonal carcinogenesis. Then, new strategies for early detection and prevention of hormonal carcinogenesis are discussed. This includes developing polygenic models of cancer predisposition and the further development of safe and effective chemopreventives that block target sequence activity. We developed polygenic models for breast and prostate cancer after hypothesizing that functionally relevant sequence variants in genes involved in steroid hormone metabolism and transport would act together, and also interact with well-known hormonally related risk factors, to define a high-risk profile for cancer. A combination of genes each with minor variation in expressed activity could provide a degree of separation of risk that would be clinically useful as they could yield a large cumulative difference after several decades. The genes included in the breast cancer model are the 17beta-hydroxysteroid dehydrogenase 1 (HSD17B1) gene, the cytochrome P459c17alpha (CYP17) gene, the aromatase (CYP19) gene, and the estrogen receptor alpha (ER) gene. The prostate cancer model includes the androgen receptor gene (AR), steroid 5alpha-reductase type II (SRD5A2), CYP17 and the 3beta hydroxysteroid dehydrogenase (HSD3B2) gene. We present data from our multi-ethnic cohort to support these models.
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PMID:Hormonal carcinogenesis. 1123 97

It is very important to examine the influence of inhibition of in situ estrogen production on the pathobiology of human sex steroid-dependent tumors in order to understand the clinical effects of aromatase inhibitors. We have examined the biological changes before and after aromatase inhibitor treatment in vitro (endometrial and ovarian cancer) and in vivo (breast cancer). First, we analyzed these changes using histoculture of 15 human endometrial cancers and 9 ovarian cancers. Five of the fifteen endometrial cancers and four of the nine ovarian cancers demonstrated decreased [3H]thymidine uptake or Ki67 labeling index after 14alpha-hydroxy-4-androstene-3,6,17-trione (NKS01) treatment. In ovarian cancer cases, the responsive cases tended to be associated with higher aromatase and estrogen receptor alpha (ER) expression compared with the other cases but this was not seen in the endometrial cancer cases. There were no changes in ER and aromatase expression before and after NKS01 treatment in either ovarian or endometrial cancer cases. We then studied the same primary human breast tumors before and after aminoglutethimide (AMG, n=3) and 4-hydroxyandrostenedione (4-OHA, n=3) treatment. Tumor aromatase activity increased in 3 cases and decreased or was unchanged in 3 cases but aromatase immunoreactivity in stroma and adipocytes was unaltered in 5 cases. There were no changes in the ER labeling index before or after treatment. Five of the six cases including the responsive cases tended to be associated with decreased cell proliferation or Ki67 expression and increased apoptosis when examined by the TUNEL method. These results indicate that aromatase inhibitors may exert their effects on human breast and other cancers through decreasing proliferation and increasing apoptosis, possibly without altering ER status.
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PMID:Effects of aromatase inhibitors on the pathobiology of the human breast, endometrial and ovarian carcinoma. 1073 Nov 9

Aromatase (P450AROM) is the enzyme complex with converts testosterone to estradiol and androstendione to estrone. This enzyme was detected in various normal tissues and uterine pathology such as uterine myoma, endometrial cancer and endometriosis. The aim of the study was to estimate expression of P450AROM messenger ribonucleic acid (mRNA) in normal, hyperplastic and malignant endometrium, and the ability to convert androstenedione to estrone by endometrial cancer tissue. Normal endometrium was obtained from 16 (12 proliferative phase, 4 secretory phase) regularly cycling women after hysterectomy for myomas, hyperplastic endometrium (n = 5) and endometrial cancer (n = 5) from postmenopausal women. The ability to convert androstenedione to estrone was estimated in 16 cases of endometrial cancer in postmenopausal women. P450AROM mRNA was measured by a quantitative assay based on reverse transcribing the mRNA into cDNA with reverse transcriptase (RT) then amplification of the cDNA using the polymerase chain reaction (PCR). The mean (+/- SEM) expression of aromatase gene in proliferative endometrium was 84.4 +/- 14.0 pg mRNA/microgram DNA and in secretory endometrium 200.3 +/- 87.8 pg mRNA/microgram DNA. The mean (+/- SEM) P450AROM mRNA expression in endometrial hyperplasia was 92.9 +/- 17.8 pg mRNA/microgram DNA, in endometrial cancer was 14.3 +/- 7.7 pg mRNA/microgram DNA. Androstenedione to estrone conversion in endometrial cancer tissue culture was 252.5 +/- 91 fmol/g tissue/h. Our data confirm that human normal, hyperplastic and malignant endometrium do express P450AROM mRNA and that aromatase activity is present in endometrial cancer tissue.
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PMID:[Aromatase (P450AROM) mRNA expression in normal, hyperplastic and malignant endometrium and aromatase activity in endometrial cancer tissue culture]. 1084 13

Cessation of ovarian estrogen secretion is the key event during the climacteric. An enzyme termed aromatase in a number of human tissues and cells, including ovarian granulosa cells, the placental syncytiotrophoblast, adipose and skin fibroblasts, bone, and the brain, catalyzes the conversion of C19 steroids to estrogens. Aromatase expression in adipose tissue and possibly the skin primarily accounts for the extraglandular (peripheral) formation of estrogen and increases as a function of body weight and advancing age. Sufficient circulating levels of the biologically active estrogen, estradiol, can be produced as a result of extraglandular aromatization of androstenedione to estrone, which is subsequently reduced to estradiol in peripheral tissues, to cause uterine bleeding and endometrial hyperplasia and cancer in obese anovulatory or postmenopausal women. Extraglandular aromatase expression in adipose tissue and skin (via increasing circulating levels of estradiol) and bone (via increasing local estrogen concentrations) is of paramount importance in slowing the rate of postmenopausal bone loss. Moreover, excessive or inappropriate aromatase expression was demonstrated in adipose fibroblasts surrounding a breast carcinoma, endometriosis-derived stromal cells, and stromal cells in endometrial cancer and gave rise to increased local estrogen concentrations in these tissues. Whether systemically delivered or locally produced, elevated estrogen levels promote the growth of these steroid-responsive tissues. Finally, local estrogen biosynthesis by aromatase activity in the brain may be important in the regulation of various cognitive and hypothalamic functions. The regulation of aromatase expression in human cells via alternatively used promoters, which can be activated or inhibited by various hormones, increases the complexity of estrogen biosynthesis in the human body. Aromatase expression is under the control of the classically located proximal promoter II in the ovary and a far distal promoter I.1 (40 kb upstream of the translation initiation site) in the placenta. In adipose tissue, two other promoters (I.4 and I.3) located between I.1 and II are used in addition to the ovarian-type promoter II. To add a further twist, promoter use in adipose fibroblasts switches between promoters II/I.3 and I.4 upon treatment of these cells with prostaglandin E2 (PGE2) versus glucocorticoids plus cytokines. Moreover, the presence of a carcinoma in breast adipose tissue causes a switch of promoter use from I.4 to II/I.3. Molecular and cellular mechanisms responsible for estrogen formation and their physiologic and clinical relevance will be reviewed in this article.
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PMID:Aromatase in aging women. 1085 74

A strong connection is known to exist between initiation/promotion of endometrial cancer and excess of estrogens. Therefore, participation of certain alleles of genetic polymorphisms in steroid biosynthesis or metabolism may be responsible for predisposition to the disease. The present study, comparing CYP19 (aromatase) gene polymorphism in 85 patients and 110 healthy females, pointed to a more frequent occurrence of relatively longer alleles (A6 and A7) of the CYP19 gene in the former group. Furthermore, precisely those genotypes co-occurred more frequently with elevated blood levels of estradiol and testosterone in postmenopausal patients. Hence, CYP19 gene polymorphism may be regarded as a factor of genetic risk for endometrial carcinoma.
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PMID:[A polymorphism study of the CYP19 gene in endometrial cancer patients]. 1097 76

Retinoids have recently been proposed to modulate estrogenic actions in various sex steroid-dependent neoplasms, but little has been studied in human endometrial disorders. Therefore, in this study, we first examined the immunolocalization of retinoic acid receptor alpha, beta, and gamma, and retinoid X receptor (RXR) alpha, beta, and gamma in 20 normal cycling human endometria, 34 endometrial hyperplasia, and 46 endometrioid endometrial adenocarcinomas. We then correlated these findings with other clinicopathological parameters, especially in the correlation between retinoid receptor subtypes and the status of steroid hormone receptors, 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) and aromatase. We also then examined the effects of retinoic acid on the expression of 17 beta-HSD type 2 in cell lines derived from endometrial carcinoma using Northern blotting analysis to examine the possible roles of retinoids in in situ endometrial estrogen metabolism. Among these six retinoid receptors examined, RXR gamma immunoreactivity was exclusively detected in the epithelial cells of the secretory phase endometrium but not of the proliferative phase, which was well correlated with 17 beta-HSD type 2 immunolocalization. However, in endometrial hyperplasia, RXR gamma was not correlated with 17 beta-HSD type 2. In endometrioid endometrial adenocarcinoma, there was a statistically significant correlation between 17 beta-HSD type 2 immunoreactivity and RXR gamma labeling index (LI) (P < 0.001) and between RXR gamma LI and progesterone receptor LI (r = 0.501, P = 0.003). A significant inverse correlation was also detected between RXR gamma LI and patient age (r = 0.449, P = 0.015). No statistically significant correlation was obtained between LIs of receptors and other clinicopathological parameters including the status of intratumoral aromatase examined by immunohistochemistry. In the endometrial carcinoma cell line, RL95-2, retinoic acid markedly increased the level of 17 beta-HSD type 2 messenger RNA in a time- and dose-dependent manner. These results all suggest that retinoic acids may be involved in modulation of in situ estrogen metabolism in both normal and neoplastic human endometrium possibly through RXR gamma by stimulating the expression of 17 beta-HSD type 2.
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PMID:Retinoid receptors in the human endometrium and its disorders: a possible modulator of 17 beta-hydroxysteroid dehydrogenase. 1139 77

Tamoxifen, a selective estrogen receptor modulator (SERM), is the treatment of choice for all stages of hormone-responsive breast cancer and has been shown to prevent breast cancer in high-risk women. Despite acting as an antiestrogen on the breast, tamoxifen has partial estrogenic effects on other target tissues. These partial estrogen agonistic actions produce beneficial effects on bones and the lipid profile in postmenopausal women. However, tamoxifen is associated with an increase in endometrial cancer. Additionally, its antiestrogenic effects in the central nervous system result in hot flashes in postmenopausal women. Raloxifene is another SERM approved for the prevention of osteoporosis in postmenopausal women. Like tamoxifen, raloxifene appears to prevent breast cancer in high-risk women and has not, to date, been noted to increase the incidence of endometrial cancer. The Study of Tamoxifen and Raloxifene will compare the effects of the two agents on breast cancer prevention and endometrial cancer risk. A number of new agents are being developed for breast cancer treatment and prevention and osteoporosis prevention. These include other SERMs, selective estrogen receptor downregulators (SERDs), and aromatase inhibitors. It is hoped that one of these new agents will be the ideal agent, acting as an antiestrogen on breast and endometrium while having estrogenic effects on bones, the lipid profile, and the central nervous system. Semin Oncol 28:260-273.
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PMID:Tamoxifen to raloxifene and beyond. 1140 36


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