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Query: UMLS:C0476089 (endometrial cancer)
 11,379 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intratumoral metabolism and synthesis of estrogens are considered to play very important roles in the pathogenesis and development of human endometrial adenocarcinoma. The 17beta-hydroxysteroid dehydrogenase (17beta-HSD) isozymes catalyze the interconversion of estradiol (E2) and estrone and thereby serve to modulate the tissue levels of bioactive E2. To elucidate the possible involvement of this enzyme in human endometrial carcinoma, we first examined the expression of 17beta-HSD type 1 and type 2 in 20 normal cycling human endometria, 36 endometrial hyperplasia, and 46 endometrial endometrioid adenocarcinoma using immunohistochemistry, and we then studied immunoreactivity of 17beta-HSD type 2 using immunoblotting analyses, the activity of 17beta-HSD type 1 and type 2 using thin-layer chromatography and their expression using RT-PCR in endometrial endometrioid adenocarcinoma. We correlated these findings with various clinicopathological parameters to examine the biological significance of 17beta-HSDs in human endometrial disorders. 17beta-HSD type 2 immunoreactivity in normal endometrium was present in all cases of secretory phase (n = 14), but not in any endometrial mucosa of proliferative phase (n = 6). In addition, 17beta-HSD type 2 immunoreactivity was detected in 27 of 36 (75%) endometrial hyperplasia and 17 of 46 (37%) carcinoma cases. 17beta-HSD type 1 immunoreactivity was not detected in all the cases examined. In both endometrial hyperplasia and carcinoma cases there were significant positive correlations between 17beta-HSD type 2 and progesterone receptor labeling index (LI). In carcinoma cases, a significant inverse correlation was detected between 17beta-HSD type 2 immunoreactivity and age. In addition, 17beta-HSD type 2 immunoreactivity was also correlated with 17beta-HSD type 2 enzymatic activity, and semiquantitative analyses of 17beta-HSD type 2 messenger RNA. No significant correlations were detected between 17beta-HSD type 2 and estrogen receptor LI, Ki67 LI, amount of aromatase messenger RNA or histological grade. These data indicated that the expression of 17beta-HSD type 2 in hyperplastic and/or neoplastic endometrium may represent altered cellular features through hyperplastic and neoplastic transformation. However, 17beta-HSD type 2 may also play some protective and/or suppressive roles toward unopposed estrogenic effects through inactivating E2 in situ, especially in premenopausal patients.
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PMID:The analyses of 17beta-hydroxysteroid dehydrogenase isozymes in human endometrial hyperplasia and carcinoma. 1144 21

Estradiol production is most commonly thought of as an endocrine product of the ovary; however, there are many tissues that have the capacity to synthesize estrogens from androgen and to use estrogen in a paracrine or intracrine fashion. In addition, other organs such as the adipose tissue can contribute significantly to the circulating pool of estrogens. There is increasing evidence that in both men and women extraglandular production of C(18) steroids from C(19) precursors is important in normal physiology as well as in pathophysiologic states. The enzyme aromatase is found in a number of human tissues and cells, including ovarian granulosa cells, the placental syncytiotrophoblast, adipose and skin fibroblasts, bone, and the brain, and it locally catalyzes the conversion of C(19) 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 that 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, giving rise to increased local estrogen concentrations in these tissues. Whether systemically delivered or locally produced, elevated estrogen levels will 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 kilobases upstream of the translation initiation site) in the placenta. In skin, the promoter is I.4. In adipose tissue, 2 other promoters (I.4 and I.3) located between I.1 and II are used in addition to the ovarian-type promoter II. In addition, promoter use in adipose fibroblasts switches between promoters II/I.3 and I.4 upon treatments of these cells with PGE(2) versus glucocorticoids plus cytokines. Moreover, the presence of a carcinoma in breast adipose tissue also causes a switch of promoter use from I.4 to II/I.3. Thus there can be complex mechanisms that regulate the extraglandular production of estrogen in a tissue-specific and state-specific fashion.
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PMID:Estrogen production and action. 1151 61

Tamoxifen (Nolvadex), a selective estrogen-receptor modulator, or SERM, is currently the endocrine therapy of choice for all stages of hormone-responsive breast cancer. Only tamoxifen has been approved by the US Food and Drug Administration to reduce the incidence of breast cancer in high-risk women. Despite tamoxifen's antiestrogenic effects in breast tissue, it exhibits paradoxical estrogenic effects in other tissues in the body. These effects result in the maintenance of bone mineral density, but a three- to fourfold increase in endometrial cancer in postmenopausal women. Additionally, tamoxifen can result in troublesome hot flashes and serious thromboembolic events. For this reason, current research is focusing on new agents that may maintain the beneficial effects of tamoxifen while reducing its adverse effects. Raloxifene (Evista) is another SERM, approved for the prevention of osteoporosis in postmenopausal women and now being compared with tamoxifen in an ongoing breast cancer prevention trial. Like tamoxifen, raloxifene is associated with hot flashes and thromboembolic events, but its association with the risk of endometrial cancer is unknown. A number of new SERMs are in preclinical or clinical development in an attempt to improve upon the safety profile of tamoxifen. Additionally, selective aromatase inhibitors are being examined in the early breast cancer setting.
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PMID:Selective estrogen-receptor modulators in 2001. 1158 65

Endometrial cancer (EC) is estrogen-dependent tumor in the hormonal treatment of which mostly progestins are used. During last 5-7 years feasibility of aromatase inhibitors use in EC is discussed without any special practical move in this direction. To evaluate possible biological response of tumor and patients to such treatment, we conducted a short pilot study involving 10 primary postmenopausal EC patients, mostly stage Ia,b (average age 59) who received letrozole (Femara, Novartis) 2.5 mg/day during 14 days before operation. Clinical, sonographical, morphological, cytological and hormonal-metabolic (blood estradiol, FSH, LH, glucose, lipid fractions by RIA or enzyme-colorimetric methods; tumor progesterone receptors by LBA and aromatase activity by 3H-water release assay) studies were included into the protocol before and after treatment. Tolerability of letrozole was satisfactory in all patients. 2 patients reported decrease of pain and pathological secretions from uterine cavity. In 3 patients, decrease in M-sonographical endometrial signal was registered; average value after treatment was 31.1% lower than before it. Tendency to the decrease in estrogenicity of vaginal smears was revealed. Average decrease in blood estradiol was 37.8% and in progesterone receptor level and aromatase activity 34.4% and 17.5% respectively. Decrease of aromatase activity in tumor tissue was registered mostly in normal weight patients. A more detailed and longer randomized study of aromatase inhibitors in EC performed in neoadjuvant setting deserves consideration.
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PMID:[Neoadjuvant use of the aromatase inhibitor letrozole in uterine cancer: endocrine and clinical effects]. 1178 98

Epidemiological, experimental, and clinical data strongly support the possibility that breast cancer will be prevented by using anti-estrogenic interventions in healthy women. Three trials involving over 20,000 women have so far been reported using tamoxifen 20 mg/day or placebo in healthy women to chemoprevent breast cancer. The American National Surgical Adjuvant Breast and Bowel P-1 Project randomized over 13,000 women to take tamoxifen or placebo and showed a 49% reduction in the early incidence of breast cancer. This was associated with a reduction in osteoporotic fractures but increases in the risks of endometrial cancer, cataract, and thromboembolism. The Royal Marsden tamoxifen trial randomized 2,500 women, and the Italian national trial randomized 5,000 women. Interim analyses from these two trials showed no effect on the early incidence of breast cancer. These results, therefore, have not been able to clearly show an overall clinical benefit of giving tamoxifen to healthy women, nor have they shown which women are likely to benefit. Another selective anti-estrogen (SERM), raloxifene, has been used in a clinical trial to prevent osteoporotic fractures in women with low bone mineral density. Annual mammography in this trial has shown an approximate 80% reduction in the early incidence of breast cancer, and further follow-up of this trial continues. New trials in chemoprevention of breast cancer being started or being proposed use luteinizing-hormone-releasing hormone analogues, aromatase inhibitors, and other SERMs.
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PMID:Breast cancer prevention. 1185 47

Postmenopausal estrogens originate from the peripheral conversion of androgens, which are produced by the adrenal glands and the ovaries. Estrogens are considered to contribute to the neoplastic development of endometrium. Hyperplasia of ovarian stroma is associated with an increased androgen production by the ovaries and with the development of endometrial pathology. We hypothesize that, in cases of endometrial pathology, an increased production of aromatizable androgens by postmenopausal ovaries will lead to elevated prehormone availability for estrogen formation in utero. Following the conversion of ovarian androgens, a reaction catalyzed by the cytochrome p450 aromatase, estrogens may function as a local mitogenic factor eventually leading to the development of endometrial cancer. We consider the local availability of androgens and the local activity of aromatase relevant for this process. If this hypothesis proves to be right it may give rise to the introduction of aromatase inhibitors in treatment strategies of hormone dependent endometrial malignancies.
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PMID:The postmenopausal ovary as an androgen-producing gland; hypothesis on the etiology of endometrial cancer. 1238 55

Anastrozole, a nonsteroidal selective aromatase inhibitor, has recently been approved in the US and several other countries for the adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer. In the Arimidex, Tamoxifen alone or in Combination (ATAC) trial, anastrazole 1mg was significantly more effective than tamoxifen 20mg or combined treatment (17 and 19% relative risk reduction) for disease-free survival in postmenopausal women with early breast cancer. black triangle Anastrazole was also significantly more effective than tamoxifen for time to tumour recurrence and the odds of a primary contralateral tumour as a first event. During the first 2 years of treatment with anastrozole, tamoxifen or the combination, patient quality of life was similar in all treatment groups. Compared with tamoxifen, anastrozole was associated with a significantly lower incidence of vaginal bleeding, vaginal discharge, hot flushes, endometrial cancer, ischaemic cerebrovascular events, venous thromboembolic events and deep vein thrombosis including pulmonary embolism; tamoxifen was associated with a lower incidence of musculoskeletal disorders and fracture.
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PMID:Anastrozole: in early breast cancer. 1242 Nov 8

For the past 25 years, the estrogen antagonist tamoxifen has been considered the 'gold standard' for the treatment of breast cancer, despite certain tolerability issues and the risk of developing resistance. The aromatase inhibitors work by blocking the conversion of androgens to estrogen and were developed for use in patients where ovarian function had ceased (naturally, surgically or pharmacologically). Anastrozole, a third-generation nonsteroidal aromatase inhibitor that is a highly potent and selective inhibitor of the aromatase enzyme, has been shown to be superior to the gold standard tamoxifen for the first-line treatment of postmenopausal women with advanced breast cancer. As second-line therapy, anastrozole has shown superior survival compared with megestrol acetate and is also efficacious as neoadjuvant treatment in postmenopausal women and in combination with goserelin for the treatment of premenopausal women with advanced breast cancer. More recently, the results of the ATAC (anastrozole, tamoxifen, alone or in combination) trial, a large study in 9366 patients, demonstrated that anastrozole was significantly superior to tamoxifen for the treatment of postmenopausal women with early breast cancer, with regards to disease-free survival (p = 0.013) and incidence of contralateral breast cancer (p = 0.007). In addition, anastrozole was shown to be significantly better tolerated than tamoxifen with respect to endometrial cancer (p = 0.02), vaginal bleeding/discharge (p < 0.0001 for both), ischaemic cerebrovascular events (p = 0.0006), thromboembolic events (p = 0.0006) and hot flushes (p < 0.0001), while tamoxifen was associated with significantly less musculoskeletal disorders and fractures than anastrozole (p < 0.0001 for both). This review focuses on both the clinical pharmacology and the clinical data of anastrozole with emphasis on its future applications.
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PMID:Anastrozole (Arimidex) in clinical practice versus the old 'gold standard', tamoxifen. 1250 8

Levels of aromatase, a key enzyme in estrogen biosynthesis, were assayed in tumor tissue sampled from 25 patients with endometrial cancer. In addition, estradiol concentrations were compared in normal and altered endometrial tissue from 78 patients suffering uterine cancer. Unlike breast cancer, aromatase was not detectable in altered endometrium unless tissue estrogens could be identified in both normal and tumor tissue. Hence, aromatase presence served as an indicator of malignant transformation. Its concentration in samples of uterine tissue varied 0-28.4 fM/mg protein/hr (an average of 12.9(1.7 fM/mg protein/hr). There was hardly any correlation between this level, on the one hand, and menopause and body mass, on the other. Yet, it tended to increase in step with stage of disease and cell differentiation decline. Estradiol concentrations in malignant endometrium in both reproductive and menopausal patients were higher than in macroscopically normal ones, while still cycling women tended to show higher values than menopausal ones. Although there was no significant difference in estradiol levels in the altered endomentrium of patients with pathogenetical patterns of uterine cancer stage I and II, they did show a direct correlation with clinical stage of tumor process and depth of invasion into the underlying myometrium. Hence, unlike estrogens circulating in blood, those contained in tissue ("intratumor") ones did enhance the aggressiveness of endometrial cancer course. It will be for further investigations to show whether it is due to an estrogen fraction being carried away by tumor from the circulation, or estrogens being synthesized by aromatase in tumor itself.
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PMID:[Tumor tissue aromatase and estrogen levels versus clinical course of endometrial cancer]. 1271 71

Breast cancer is the most frequent female malignant disease in developed countries. Various approaches are being developed for breast cancer prevention. Medical prevention called chemoprevention is reviewed. Prior to any intervention estimation of breast cancer risk is mandatory. For practical reasons distinction of two risk groups is useful. In the high risk group inherited gene mutation showing high penetrance may be suspected, while in the medium risk group hormonal factors play an important role. The antiestrogen tamoxifen has been extensively investigated in breast cancer and also tested for the prevention of breast cancer. The results of four randomized tamoxifen prevention studies have been published. In the largest, American trial the number of invasive or "in situ" breast cancers was halved by tamoxifen. Particularly estrogen receptor positive and relatively good prognosis breast cancers were reduced. Similar results were obtained in the "International Breast Intervention Study". Tamoxifen has been registered for breast cancer prevention for high risk individuals in the United States. The Italian and English ("Royal Marsden Hospital") studies did not prove significant preventative effect for tamoxifen that may be explained by the characteristics of the study protocols and study populations. Increased rates of endometrial cancer, thromboembolic events and cataract were observed under tamoxifen treatment, especially over the age of 50. Prevention has an increased importance in gene mutation carriers. Besides prophylactic mastectomy and close surveillance tamoxifen and bilateral oophorectomy or the use of gonadotropin releasing-hormone analogs seem efficient in this group. Various new chemoprevention strategies are under testing. Raloxifene and the aromatase inhibitors show advantage in menopausal women, the retinoid fenretinide and the gonadotropin releasing-hormone analogs seem promising for premenopausal individuals. The use of these agents are investigated in clinical trials. It is likely that not one single method will be applied for breast cancer prevention in the future. Preferably individual prevention strategies based on individual risk assessment will be developed.
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PMID:[Breakthrough in breast cancer chemoprevention]. 1272 84


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