Hormone replacement therapy (HRT) and endometrial morphology under consideration of the different molecular pathways in endometrial carcinogenesis

Menopausal Hormone Therapy and Risk of Endometrial Cancer: A Systematic Review

Background: Menopausal hormone therapy (MHT) is an appropriate treatment for women with the climacteric syndrome. The estrogen component of MHT effectively alleviates climacteric symptoms but also stimulates the endometrium and thus may increase the risk of endometrial cancer (EC). Materials and Methods: We performed a systematic literature search of the databases PubMed and Cochrane Central Register of Controlled Trials to identify controlled and uncontrolled clinical trials reporting on the prevalence and/or incidence of EC among women using MHT. Results: 31 publications reporting on 21,306 women with EC diagnosed during or after MHT were identified. A significantly reduced risk of EC among continuous-combined (cc)MHT users with synthetic progestins (SPs) was demonstrated in 10/19 studies with odds ratios (ORs)/hazard ratios (HRs) between 0.24 and 0.71. Only one study documented an increased risk of EC among long-term users (≥10 years), not confirmed in three other sub-group analyses of women with ≥6, ≥5, and >10 years of ccMHT use. A significantly increased risk of EC among users of sequential-combined (sc)MHT with SPs was demonstrated in 6/12 studies with ORs/HRs between 1.38 and 4.35. Number of days of progestin per month was a significant modulator of EC risk. A decreased risk of EC was seen in obese women. Two studies documented an increased risk of EC among users of cc/scMHT with micronized progesterone. A significantly increased risk of EC among estrogen-only MHT users was demonstrated in 9/12 studies with ORs/HRs between 1.45 and 4.46. The adverse effect of estrogen-only MHT was greatest among obese women. Conclusion: ccMHT with SPs reduces the risk of EC, whereas estrogen-only MHT increases the risk. scMHT with SPs and cc/scMHT with micronized progesterone increase the risk of EC depending on type of progestin, progestin dosage, and duration of MHT use.

Ginsenoside Rb1 does not halt osteoporotic bone loss in ovariectomized rats

Osteoporosis (OP) is a systemic skeletal disorder, manifesting with a reduction in bone mass and deterioration of the microarchitecture. Mesenchymal stem cells (MSCs) have an innate ability to differentiate into several cell types, including osteoblasts (OB). Ginsenoside Rb1 (GRb1) is an ethanol extract from ginseng and contains a highly concentrated form of ginsenoside. GRb1 shows extensive beneficial health effects such as anti-oxidative and anti-inflammatory functions, modulating the immune system and inhibiting osteoclastogenesis. We hypothesized that GRb1 can promote MSC differentiation into OBs and inhibit bone loss. In the present study, we aimed to address two questions: (1) Will GRb1 have a positive effect on osteogenic differentiation of MSCs? and (2) Will GRb1 halt bone loss in ovariectomized (OVX) rats? We investigated the effects of GRb1 on viability and osteogenic differentiation of rat mesenchymal stem cells (rMSCs). Our results showed that GRb1 at concentrations of 10⁻⁸ M and 10⁻⁶ M can increase alkaline phosphatase activity, mineralization and the expression of osteogenic related proteins, such as osteopontin and osteoprotegerin, while incubating rMSCs with osteogenic induction medium and GRb1. Adding GRb1 into the medium can prevent rMSCs from Oxidative damage at the concentration of 25μM H₂O₂. Furthermore, 40 4-month-old rats were assigned to 5 groups(8 rats per group): the basal group, the sham group, the OVX group, the high dose of GRb1 group (6 mg/kg/day) and the low dose of GRb1 group (3 mg/kg/day). Rats recrived treatment 3days after surgery and last for 14 weeks. Examinations included serum analysis, mechanical testing, Masson-Goldner trichrome staining and bone histomorphometry analysis. The results showed that OVX can lead to dyslipidemia and excessive oxidative stress, whereas GRb1 cannot significantly halt dyslipidemia and excessive oxidative stress in OVX rats. In addition, the bone density of the lumbar vertebra and femur were decreased significantly in the OVX rats, and GRb1 could not inhibit bone loss. Bone histomorphometry analysis showed that the number and width of bone trabecula of the tibia were reduced in OVX rats, and GRb1 could not prevent their occurrence. A bone biomechanics assay showed that GRb1 cannot improve the ability of bone structure to resist fracture of the femur in OVX rats. The current study demonstrated that GRb1 has an obvious effect on osteogenic differentiation in rMSCs but no obvious effect on bone loss in OVX rats. These findings indicate GRb1 has a positive effect on rMSCs but does not have an effect on bone loss in OVX rats at the concentration we used.

The sulfatase pathway for estrogen formation: targets for the treatment and diagnosis of hormone-associated tumors

The extragonadal synthesis of biological active steroid hormones from their inactive precursors in target tissues is named "intracrinology." Of particular importance for the progression of estrogen-dependent cancers is the in situ formation of the biological most active estrogen, 17beta-estradiol (E2). In cancer cells, conversion of inactive steroid hormone precursors to E2 is accomplished from inactive, sulfated estrogens in the "sulfatase pathway" and from androgens in the "aromatase pathway." Here, we provide an overview about expression and function of enzymes of the "sulfatase pathway," particularly steroid sulfatase (STS) that activates estrogens and estrogen sulfotransferase (SULT1E1) that converts active estrone (E1) and other estrogens to their inactive sulfates. High expression of STS and low expression of SULT1E1 will increase levels of active estrogens in malignant tumor cells leading to the stimulation of cell proliferation and cancer progression. Therefore, blocking the "sulfatase pathway" by STS inhibitors may offer an attractive strategy to reduce levels of active estrogens. STS inhibitors either applied in combination with aromatase inhibitors or as novel, dual aromatase-steroid sulfatase inhibiting drugs are currently under investigation. Furthermore, STS inhibitors are also suitable as enzyme-based cancer imaging agents applied in the biomedical imaging technique positron emission tomography (PET) for cancer diagnosis.

Hormone replacement therapy and the endometrium

The life-expectancy for women has increased significantly in the 20th century, although the time of onset of menopause has not. Almost a third of a woman's life is now postmenopausal and therefore many postmenopausal women consider using hormone replacement therapy (HRT) to improve their quality of life. Most cases of endometrial carcinoma arise in postmenopausal women and this raises concern among patients and clinicians with regard to the safety of HRT in this age group. Whenever the use of HRT is considered, a careful consideration of the actual benefit in terms of symptom relief and quality of life must be balanced against the risks for each individual woman. This review discusses the effects of HRT on the endometrium and the evidence regarding HRT use and risk of endometrial cancer.

[Carcinogenesis theory based on estrogen deficiency]

Earlier, estrogens were considered simply the most important hormones involved in female physiology and reproduction. Nowadays it has become familiar that they have pivotal roles in gene regulation of cell differentiation and proliferation. There are many contradictions concerning the associations of female sexual steroids and cancer. Cancers of the highly estrogen dependent organs are in the forefront of tumors as they are regarded as hormone associated ones. However, re-evaluation of earlier results supporting the carcinogenic capacity of estrogen exhibited many shortcomings and controversies. Recently, the clinical studies on hormone replacement therapy in postmenopausal women justified beneficial anticancer effects in several organs even in the female breast. The newly revealed association between estrogen deficiency and oral cancer risk also means a contradiction of the traditional concept of estrogen-induced cancer. Distinction between cancers of moderately and highly estrogen dependent tumors can be based on their different epidemiological features. The vast majority of the so-called smoking associated malignancies of the moderately estrogen dependent organs occur typically in the late postmenopausal life of women when the ovarian estrogen production is fairly decreased. However cancers of the highly estrogen dependent organs such as breast, endometrium and ovary exhibit both premenopausal and postmenopausal occurrence. In spite of the different epidemiological data of these two groups of cancers the mechanism of gene regulation disorder in the background of tumor initiation cannot act through quite opposite pathways. This suggests that in moderately estrogen sensitive organs a serious, in the highly estrogen dependent sites even a mild estrogen deficiency is enough to provoke gene regulation disorders. The new findings both on smoking associated and hormone related cancers might lead to the same conversion; not estrogen but rather its deficiency may provoke cancer initiation.

[Endometrial cancer in HNPCC syndrome]

The Hereditary Non-Polyposis Colorectal Cancer syndrome (HNPCC) has initially been described as a predisposition to colorectal cancers (CRC). Subsequently, other cancers, such as endometrial cancers (EC), have been added. The objective of this review was to update data on endometrial cancers of HNPCC syndrome. Endometrial cancers of the HNPCC syndrome are characterized by a younger age at diagnosis (46-48 year old), and a higher cumulative risk along life (30% at 70 years). Complex atypical hyperplasia seems to occur before the cancer, but the transition between precursors and cancer seems to be short. Histology of endometrial cancers of the HNPCC syndrome appears quite similar to that of sporadic cases, except for non-endometrioid lesions which seem more frequent and could occur in younger women. Screening of endometrial cancer in predisposed women should associate annual clinical examination, transvaginal sonography and endometrial sampling. Unfortunately, available data on screening by sonography show that this test seems poorly accurate, with no asymptomatic cancer or hyperplasia recognized and interval cancers between screenings. Endometrial biopsy appears as the most interesting method, since 11 asymptomatic cancers and 14 hyperplasia have been diagnosed in 175 mutation carriers. Diagnostic hysteroscopy seems also interesting, but requires further evaluation. Prophylactic hysterectomy confers a complete protection against endometrial cancer. However, perioperative morbidity (especially in women with history of colorectal surgery) and long-term effects of ovarian suppression should also be considered. Screening of endometrial cancer remains the main objective of the management of those patients. Endometrial biopsy should have a larger place.

Histopathology of endometrial hyperplasia and endometrial carcinoma: an update

Endometrial cancer (EC) is the most common malignancy of the female genital tract in the western world. Conceptually, a dualistic model of endometrial carcinogenesis exists for sporadic EC, based on molecular findings with a good correlation to the morphologic phenotype and clinical behavior. Type 1 endometrial carcinoma represents an estrogen-related tumor, which usually arises in the setting of endometrial hyperplasia, has endometrioid histology with low grade, and tends to be biologically indolent. Grade 3 endometrioid cancers, which constitute a minority of EC, also behave aggressively. The type 2 cancers are not estrogen-driven and have a higher grade, various histologies, particularly serous carcinomas and clear-cell carcinomas, and a poorer prognosis. The diagnostic criteria of endometrial hyperplasia, endometrial in situ carcinoma, and of the different histologic types of EC, according to the most recent World Health Organization classification, are given in detail. In addition, the risk of progression of endometrial hyperplasia into endometrioid type EC and their treatment modalities are discussed. Endometrial pathologies in patients with breast cancer, receiving tamoxifen, and women affected by hereditary nonpolyposis colorectal cancer syndrome are described, including their pathogenetic aspects. Finally, a short practical description for the handling of surgical specimens from fractional curetting and hysterctomies is given.

Effects of testosterone treatment on endometrial proliferation in postmenopausal women

CONTEXT

Available data concerning effects of testosterone on endometrium of postmenopausal women are seriously limited.

OBJECTIVE

Our aim was to compare the influence of treatment with testosterone and/or estrogen on endometrial proliferation in healthy postmenopausal women.

DESIGN

This was an open, randomized clinical study with parallel comparison of the groups.

SETTING

The study was conducted at a women's health clinical research unit and a research laboratory at a university hospital.

PARTICIPANTS

Sixty-three women who had experienced natural menopause participated in this study.

INTERVENTIONS

After random assignment, the participants were administered orally testosterone undecanoate (40 mg every second day), estradiol valerate (2 mg daily), or both for 3 months.

MAIN OUTCOME MEASURES

Endometrial thickness was measured, and endometrial proliferation evaluated on the basis of histopathology and expression of Ki-67, a proliferation marker.

RESULTS

Endometrial thickness was significantly increased by treatment with estrogen alone or in combination with testosterone but was unaltered by testosterone alone. Among the women receiving estrogen alone, the proportion exhibiting histopathology indicative of proliferation increased significantly to 50% (P < 0.05), there was a nonsignificant increase to 28% with the combined treatment, whereas testosterone alone had no effect at all. Expression of Ki-67 was up-regulated significantly in both glands and stroma (P < 0.05, respectively) in both estrogen treatment groups. However, the expression was significantly higher in stroma by estrogen treatment alone than after combined treatment (P < 0.05).

CONCLUSIONS

The short-term treatment with testosterone of postmenopausal women does not stimulate endometrial proliferation. In addition, testosterone appears to counteract endometrial proliferation induced by estrogen to a certain extent.

Postmenopausal hormone replacement therapy: endometrial and breast effects

The history of hormone replacement therapy (HRT) dates back to the late 1800s, when animal extracts of ovaries were first used. With the development of synthetic hormones, widespread use in postmenopausal women extended throughout the industrialized world, so that by the late 1900s roughly one-third to one-half of all postmenopausal women in the United States and Europe were taking HRT. Two events changed the course of use of HRT: the association of an increased rate of endometrial carcinoma with estrogen-only HRT and the association of an increased breast cancer rate with combined estrogen and progestin HRT. This review explores the evidence of the effects of HRT on the endometrium and the breast, with emphasis on the pathologic changes.