Hum. Reprod. Advance Access originally published online on June 24, 2008
Human Reproduction 2008 23(9):2072-2079; doi:10.1093/humrep/den228
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The effect of mifepristone on breast cell proliferation in premenopausal women evaluated through fine needle aspiration cytology
1 Division of Obstetrics and Gynecology, Department of Woman and Child Health, Karolinska Institutet, Karolinska University Hospital, 171 76 Stockholm, Sweden 2 Department of Pathology and Cytology, Karolinska Institutet, Stockholm, Sweden
3 Correspondence address. Tel: +46-8-517-700-00; Fax: +46-8-517-743-14; E-mail: kristina.gemzell{at}ki.se
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Abstract |
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BACKGROUND: Progestins as well as estrogens have a role in breast cell proliferation and the development of breast cancer. Here, the effect of mifepristone on cell proliferation in human breast tissue in vivo was studied in premenopausal women.
METHODS: A group of 30 women, scheduled for surgical treatment of leiomyomas, were randomized to either 50 mg mifepristone or placebo every other day, for 3 months. Fine needle aspiration biopsies were obtained at baseline and after 3 months. Immunocytochemical analysis of Ki-67 was performed to reflect breast epithelial cell proliferation. Samples from 14 women were included in the final analyses.
RESULTS: The Ki-67 index was significantly reduced after mifepristone treatment compared with baseline (P = 0.012). Furthermore, less individual variation in the Ki-67 index was seen in the mifepristone group. Treatment with mifepristone did not affect cortisol levels, whereas an increase in serum testosterone was noted. Breast symptoms like soreness and swelling were reduced, whereas the incidence of flushes increased.
CONCLUSIONS: The ability of mifepristone to block breast epithelial cell proliferation in premenopausal women may prove beneficial when used for contraceptive purposes or for other gynaecological indications. Future studies should address a possible antiproliferative effect in the post-menopausal breast tissue during hormone replacement therapy. Our results implicate a possible protective effect of mifepristone on the breast epithelium. ClinicalTrials.gov NCT00579475 [ClinicalTrials.gov] .
Key words: mifepristone/breast epithelium/proliferation/fine needle aspiration cytology
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Introduction |
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The breast is a target organ for estrogens and progestins, but the multifactorial mechanisms which regulate breast cell proliferation and apoptosis are still incompletely understood. In contrast to the effect in the endometrium, adding progestins to estrogens does not seem to have any antiproliferative, protective effect in the breast (Santen et al., 2001
). In the endometrium, estrogens increase cell proliferation and this effect is antagonized by progestins. In post-menopausal women, it is well established that the risk of hyperproliferation and endometrial cancer following unopposed estrogen can be counteracted by progestins (Weiderpass et al., 1999). Relatively short-term combined estrogen plus progestin use increases incidence of breast cancer, which is diagnosed at a more advanced stage, and increases the percentage of women with abnormal mammograms. These results suggest that estrogen plus progestin may stimulate breast cancer growth and hinder breast cancer diagnosis (Chlebowski et al., 2003) It is suggested that progesterone is increasing the proliferative activity during the luteal phase (Soderqvist et al., 1997). A more than 4-fold increase in the percentage of Ki-67 positive cells, used as markers of cell proliferation, has been demonstrated in breast biopsies already at 3 months of continuous combined estrogen/progestin therapy in post-menopausal women (Conner et al., 2003). In premenopausal women, the effect of combined hormonal contraception on the breast may increase the risk of breast cancer (Collaborative group on Hormonal Factors in Breast Cancer, 1996). A 2-fold increase in the Ki-67 index was observed in women using combined oral contraception compared with non-users. Furthermore, it was noticed that some pill users reacted with an extreme elevation of Ki-67 index up to 50% (Isaksson et al., 2001). The effects of antiprogestins, such as mifepristone, during the menstrual cycle depend on the timing of treatment and the dose used. Mifepristone has been shown to act as a possible estrogen free contraceptive through an effect on the endometrium (Gemzell-Danielsson et al., 1993). Furthermore, antiprogestins can improve bleeding patterns in women using gestagen only contraceptives (Gemzell-Danielsson et al., 2002). On the basis of the observed effects in the endometrium, there is also an increasing interest in the clinical application of antiprogestins in post-menopausal hormone therapy (Cameron et al., 2003; Slayden et al., 2006). Other potential clinical indications for antiprogestins include treatment of endometriosis and uterine leiomyomas (Grow et al., 1996; Eisinger et al., 2003). However, despite a number of studies on the effect of antiprogestins in the endometrium, there are no studies on the effect on the breast tissue in fertile women in vivo. Recent advances in the field of molecular genetics have provided a molecular basis for the concept that cell division is essential in the complex process of the genesis of human cancer. Cell division per se increases the risk of genetic errors of various kinds. The activation of oncogenes, whether by mutation, translocation or amplification, requires cell division (Preston-Martin et al., 1990). In an in vitro breast cancer cell line, antiprogestin exposure resulted in an apoptotic effect through growth arrest and caspase activation (Gaddy et al., 2004).
On the basis of the existing knowledge, a protective effect of antiprogestins on breast tissue could be hypothesized. Fine needle aspiration (FNA) biopsy from the breast of women in their fertile age is a useful tool for evaluation of the proliferative activity during the normal menstrual cycle (Soderqvist et al., 1997). Therefore, the aim of this study was to investigate the effect of mifepristone treatment on breast proliferation in fertile women. Proliferation was assessed through the expression of Ki-67, by using the MIB-1 antibody and calculating the percentage of positively immunostained nuclei, in relation to quiescent non-proliferating mammary epithelial cells (hereafter called the Ki-67 index), before and after 3 months of treatment with mifepristone or placebo.
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Materials and Methods |
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This prospective randomized placebo controlled study was conducted at the Department of Obstetrics and Gynecology, Karolinska University Hospital, Stockholm, Sweden, between November 2004 and June 2007. The study was approved by the local ethics committee, at the Karolinska Institutet. All women gave their written informed consent prior to inclusion.
Subjects
Study patients were recruited among menstruating premenopausal women referred for surgery due to leiomyoma-related dysfunction. Reasons for planned surgery included menorrhagia and pressure-related symptoms from bladder or bowel or a considered risk of pregnancy complications. None of the women had used any steroidal hormonal therapy for a minimum of 3 months prior to recruitment. The key exclusion criteria included: any history of breast cancer or other malignancy, bleeding not possible to control with tranexamic acid and iron medication implicating a need for urgent surgical treatment, abnormal mammogram and breast biopsy at the baseline investigation, adnexal abnormality or suspicion of myosarcoma upon transvaginal ultrasound examination of the pelvis, elevated FSH-level implicating menopause, any other hormonal dysfunction of clinical significance; laboratory findings that would give suspicion of blood, liver or renal dysfunction, abnormal cervical smear at screening or any contraindication to mifepristone. Among 72 eligible women, 40 women refused to participate, mainly because of the urge to be relieved from their myoma-related problem without further delay. The repeated breast biopsies in the protocol also contributed to the decision not to participate. One patient was considered not suitable because malignancy was not possible to rule out due to increased blood flow and irregular appearance of the myoma structure at ultrasound investigation. Another woman was not included because of psychiatric problems. Thus, 30 of 72 eligible women gave their informed consent to participation and were included in the study.
The women were instructed to use barrier methods for contraception unless sterilized (or having a vasectomized partner).
Mammography at 11 days (1–52 days) before entering the study showed normal conditions except for two cases, each of whom had a dense area mammographically. Biopsies from the corresponding areas showed benign fibroadenomatosis in both cases. Both patients were included in the study.
Breast biopsy, mammography and blood sampling for hormonal status was performed in the luteal phase before the start of treatment. The stage of the menstrual cycle was determined based on hormonal and menstrual data.
A fine needle breast biopsy (FNA) was obtained from the upper outer quadrant of the left breast before the start and at the end of the treatment period. Serum levels of estradiol, progesterone, testosterone, androstenedion and DHAS were analysed at baseline and at the end of treatment, SHBG and albumin were also determined for calculation of the free fraction of testosterone (fT). FSH, LH and 24 h urine cortisol excretion were determined at baseline and after 3 months treatment. Pelvic ultrasound was repeated every 4th week along with assessment of haematological, renal and liver laboratory data. An endometrial biopsy was obtained before the start of medication and after the treatment period during surgery. To control unacceptable bleeding throughout the duration of the study, tranexamic acid and iron medication were used when needed.
Treatment schedule
Women were randomized 1:1 to the two treatment groups using a computer generated randomization list provided by the University Hospital Pharmacy. Medication was packed and labelled by the Pharmacy according to the randomization list.
The women who accepted to participate and who fulfilled the inclusion criteria and none of the exclusion criteria were randomized to treatment with mifepristone (Mifegyne®, Exelgyn, Paris, France) or B-vitamin (TrioBe® Recip, Stockholm, Sweden). The control treatment consisted of B-vitamin complex tablets of the same size and colour as the mifepristone tablets. The study group and medication were blinded to subjects and staff. The only available dosage of mifepristone approved by the Medical Product Agency in Sweden is 200 mg tablets. Therefore, a study nurse instructed the patients how to divide the tablets into four equal pieces with a specially designed cutter suitable for self preparations provided by the University Hospital Pharmacy. The women received once monthly six tablets of 200 mg mifepristone or six tablets of B-vitamin, of which one-quarter of a tablet was taken every other day according to the randomization list starting on the first day of the menstrual cycle and ending on the day before surgery. At the end of treatment, any residual tablets were collected and counted. The overall patient compliance was high.
Patient records
All women were asked to keep daily records on any side effect noted as well as any medication used at the baseline or during the study period. Daily diary notations of bleeding and symptoms such as pain or pressure were collected. In addition, women were asked to complete questionnaires; the Breast Symptom Index (BSI), for registration of breast symptoms, and a Likert scale to quantify local myoma-related pelvic symptoms and general symptoms related to hormonal treatment. The BSI quantifies breast symptoms involving stings, pain, soreness, swelling or sense of increasing volume of the breast registered on a scale from 0 to 10 (Hofling et al., 2007). Evaluation was done every month from baseline until surgery. The 5-graded Likert scale was used to quantify once-weekly myoma-related local and general, possibly hormone-dependent, symptoms. Symptoms ranging from ‘no symptoms’ to ‘very severe’ were graded from 0 to 4, respectively. The symptoms were grouped into two categories. The first group of questions targeted local pelvic symptoms, such as pelvic pain or pressure, bladder pressure, micturition problems, lower back pain, proctodynia and dyspareunia. The second group quantified generalized hormone-related symptoms, such as flushes, headache, nausea, vomiting, diarrhoea, changes in mode or libido, weakness or fatigue.
FNA biopsy
Percutanous FNA biopsies from the upper outer quadrant of the left breast were performed at the baseline, during the luteal phase before start of medication (which was started on the first day of menstruation), and at the end of treatment, prior to the surgical intervention. FNA biopsies were performed using a needle with an outer diameter of 0.6 mm as previously described (Skoog et al., 1990). In order to produce several identical slides, the aspirated cells were mixed with 0.5 ml 4% buffered (pH 7.4) formalin in the syringe used to procure the cells. Volumes of 110 µl were cytocentrifugated for 3 min and the cells were sedimented onto pretreated glass slides.
Immunocytochemistry analysis
Slides were stained for the nuclear antigen Ki-67 with the MIB-1 monoclonal antibody. Ki-67 is present in proliferating cells but absent in quiescent cells. Cell cycle analysis shows that Ki-67 is expressed in the phases of G1, S, G2 and mitosis (Gerdes et al., 1991). The Ki-67 analyses were performed using reagents supplied by Immunotech (Marseilles, France). The staining procedure uses an avidin–biotin peroxidase system, modified for the cytospin technique as previously described (Skoog et al., 1990).
Immunostained cells were quantified by cell counting in the microscope with 200-fold magnification, by two observers simultaneously, blinded to the treatment group.
Sample size calculation
There are no previous data published on the effect of mifepristone on breast tissue in vivo. Sample size was calculated with the main outcome parameter being the reduction in the uterine leiomyoma size. As a secondary outcome, the effect of mifepristone on breast cell proliferation was investigated.
Statistical analysis
Differences within groups were analysed with the Wilcoxon signed rank test and between groups with the Mann–Whitney U-test. Correlations were assessed by the Spearman’s rank correlation test. A P-value of <0.05 was considered as significant.
Correlations of the Ki-67 index difference were calculated against serum levels of progesterone, estradiol, fT, SHBG, DHEAS, FSH and LH values at the baseline and at the end of treatment. Concentrations of free testosterone were calculated from values for total testosterone, SHBG and a fixed albumin concentration of 40 g/l (Sodergard et al., 1982).
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Results |
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A total of 30 women were recruited. In total, 58 breast biopsies were obtained, 30 at the baseline and 28 at the end of treatment. Two women were excluded after the first biopsy. One woman in the control group was excluded due to heavy progressive bleeding not possible to control with symptomatic treatment warranting immediate surgery. Another woman was excluded due to elevated FSH observed during the baseline month. The remaining 28 women completed the treatment (Fig. 1). Subjects received treatment for a mean ± SEM of 85 ± 1 days in the mifepristone group and 83 ± 2 days in the control group. No significant difference in duration was present between the treatment groups.
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At baseline, FNA was performed on average of 6 days before the start of treatment with placebo or mifepristone which was started on the first day of menstruation. Menstrual and hormonal data verified luteal phase at the time of the baseline biopsy (Table I). Owing to logistic reasons, concerning the scheduling of surgery, it was not always possible to perform the second biopsy in the mid-luteal phase. Progesterone levels showed no significant difference between the groups at the baseline or at the end of treatment, although a tendency to lower progesterone levels with less variation was seen in the mifepristone-treated group (P = 0.062, Table I).
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Only samples containing >50 epithelial cells were considered adequate for analysis. On the basis of previous work on FNA evaluation in vivo of the normal breast, at least 40 cells are required to give the expected frequency of one proliferative cell per 40 non-proliferative mammary cells (Ki-67 index just >2%) (Soderqvist et al., 1997
; Conner et al., 2003). On average, 155 cells in the baseline biopsies and 194 in the biopsies obtained at the end of treatment were assessable in the two groups. A total of 56 (28 pairs of) biopsies were analysed. Of the 28 patients, 14 (50%) had assessable samples. Biopsies from the remaining 14 patients were excluded due to an insufficient total cell count (Fig. 1). Previous studies show corresponding dropout frequency for repeat biopsies, where both must meet the assessability criteria of at least 40–50 non-proliferative cells per biopsy (Soderqvist et al., 1997; Conner et al., 2003).
The difference in the Ki-67-index at baseline between the groups was not significant (P = 0.478, Table II). In the mifepristone-treated group, the Ki-67 index was significantly reduced within the group when baseline values were compared with the values after 3 months of treatment (P = 0.012, Figs 2–4). The difference in Ki-67 index between the mifepristone-treated group and controls at the end of study did not reach significance (P = 0.061). Expressed as delta value or percentage reduction of Ki-67 index between baseline and after 3 months, the differences between the treatment groups were significant, P = 0.020 and P = 0.024, respectively (Table II, Fig 5). In addition to a lower Ki-67 index, the mifepristone-treated group showed less inter individual variation compared with the control group (Fig. 5, Table II). In the control group, there were no significant differences in the Ki-67 index between women with progesterone values pre-surgery indicative of mid-luteal phase (n = 3) compared with women with values indicative of anovulation or late luteal phase values (P < 10 nmol/l) (n = 3).
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Effects on hormonal levels, endometrial morphology and bleeding pattern
Progesterone, estradiol, testosterone, fT and androstenedione were significantly changed following mifepristone treatment, whereas no significant changes occurred within the control group, except for progesterone (Table I). An elevation in androgen (fT and androstenedione) levels was observed after treatment with mifepristone (Table I). Calculated fT at the end of treatment correlated statistically with the delta Ki-67 index from baseline to the end of treatment (P = 0.026 r = 0.555), as well as the percentage reduction (P = 0.023, r = –0.613) in Ki-67 index during treatment. The correlations were significant when the data were pooled but not when calculated for the separate treatment groups. The significant correlation was evident for the whole treatment group (n = 28), as well as for the subgroup with assessable biopsies (n = 14).
No differences were found between or within the groups in 24 h urinary excretion of cortisol (Table I).
Endometrial morphological analysis excluded any hyperplasia or atypia in the endometrium before or after the treatment. In addition, no changes in endometrial thickness measured by vaginal ultrasound were noted. The mean ± SEM was 9.33 ± 0.85 for the mifepristone group and 8.77 ± 0.94 for the control group at the end of treatment. All biopsies obtained prior to treatment, as well as those obtained pre-surgery, in the control group showed a secretory endometrium.
Only occasional bleeding episodes occurred in the treatment group. One patient with one bleeding day and another with two bleeding days were registered during the second 28 day period of treatment. During the remaining third treatment period, only one patient reported 1 day of bleeding. The number of patients completely free of vaginal bleeding was 86% during treatment days 28–56, and 93% during the remaining last 28 day period of treatment. Women in the control group reported 11 (3–26) days of uterovaginal bleeding during the second 28 day treatment period and 7 (0–27) days with bleeding during the remaining 28 day period. At the end of the study, there was a strong significant difference in the number of bleeding days between the groups (P = 0.001).
Side effects
A significantly reduced total BSI score (P = 0.049) (sum of scores including pain, stings, soreness, swelling and sense of increased volume) during 3 months was observed in the mifepristone group (2.46 ± 1.84) compared with controls (5.43 ± 1.56) at the end of treatment. Within the mifepristone-treated group, there was also a significant reduction of scores for soreness, swelling and sense of increased volume when baseline values were compared with scores at the end of treatment (Table III).
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In addition, there was a significant correlation (P = 0.03, r = 0.58) between serum concentrations of progesterone and BSI total score after 3 months medication.
Reported side effects relating to the pelvic and abdominal organs as well as general symptoms were light to moderate and did not change over time, except for flushes. A moderate elevation in reports on the incidence of flushes was noted during treatment with mifepristone, and there was a significant difference in occurrence of flushes observed between the two treatment groups at the end of treatment (P = 0.029).
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionConclusionFundingAcknowledgementsReferences |
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In this prospective randomized double-blind placebo controlled study, we evaluated breast cell proliferation in vivo during exposure to mifepristone. Breast tissue was collected through FNA biopsies from 30 healthy premenopausal women. A significant reduction in epithelial cell proliferation was found following exposure to mifepristone.
It has previously been shown that it is possible to evaluate cell proliferation in FNA biopsy material from the breasts of post-menopausal women as well as from young, healthy women during the menstrual cycle, or from women taking oral contraceptives. Data from these studies did not reveal any significant influence of age on breast epithelial proliferation, neither in the whole study population nor in the oral contraceptive users and non-users. No differences between women younger and older than 35 years were evident. Furthermore, parity had no influence on the expression of Ki-67 (Soderqvist et al., 1997; Conner et al., 2003).
Proliferation and apoptosis are involved in tissue homeostasis. Multifactorial impingements modify the cell response to different stimuli like growth factors or steroid hormones. In the case of antiprogestins and progesterone, the cellular response differs depending on the physiologic molecular environment. Studying the clinical effects in breast tissue during long-term treatment with mifepristone is of interest as it can contribute to the knowledgebase necessary for expanding the clinical applications of antiprogestins, e.g. in contraception and in the treatment of leiomyoma and endometriosis. Whether the effect of antiprogestins would differ in pre- and post-menopausal women remains to be studied.
In contrast to the present results in premenopausal women, there were no notable differences attributable to antiprogestins on mammary gland proliferation in the ovariectomized macaque (Slayden et al., 2006). In previous studies on breast epithelium among naturally cycling women, the Ki-67 index value was 2.04% (range 0–6%) during the luteal phase. The mean value for the percentage of Ki-67 expressing cells in FNA obtained at different cycle days was 2.2% (range 0–8%) (Soderqvist et al., 1997). Isaksson et al. (2001) found a 2-fold increase in Ki-67 index premenstrually among combined oral contraceptive pill users. No differences depending on the different progestins in the pills were noticed. Interestingly some women had a very high response rate of up to 50% positive for the Ki-67 index, and marked individual variation was registered among the oral contraceptive users. In a subgroup, Ki-67 index was followed during 2 months of combined oral contraceptive use. The percentage of Ki-67 positive cells before treatment was a mean of 1.4% (median 0.5% and range 0–5%) and after 2 months of treatment with combined oral contraceptives, the corresponding figures were significantly different, with a mean of 5.8% (0.8% and 0–50%) (Isaksson et al., 2001). In contrast to the effects of estrogen and progestins, there is only limited and conflicting data available in women concerning the effects on breast epithelial proliferation during anti-estrogen therapy with tamoxifen (Walker et al., 1991; Cline et al., 1998; Bernardes et al., 1999; de Souza Sales et al., 2007). In ovariectomized cynomolgus macaques who have well-documented similarities to women in reproductive endocrinology and breast development, tamoxifen caused an induction of both ER and PR, but neither an increase nor decrease in Ki-67 expression was observed in this post-menopausal, hypoestrogenic situation (Cline et al., 1998).
In the present study, we found increased testosterone serum levels with a significant correlation to Ki-67 reduction and percentage decreases of Ki-67 index at the end of the study as a result of mifepristone treatment. Although the values are still within the normal range, there was a significant increase in both testosterone and androstenedione following treatment with mifepristone. This may indicate that the pituitary/adrenal axis has been activated despite the fact that no rise in urinary cortisol was detected. Alternatively, mifepristone may inhibit ovarian aromatase activity. An effect on endometrial aromatase activity has been reported (Tseng et al., 1986). This question will require further studies.
In the mifepristone-treated group, the median Ki-67 index was 0.77 ranging from 0.00 to 1.86 compared with the control group where the corresponding figure was 4.12 (range 0.00–28.51) after 3 months of treatment. There were no significant differences in the control group between women with progesterone values pre-surgery >10 nmol/l compared with women with values <10 nmol/l. Interestingly, a higher Ki-67 index seems to implicate a wider range of individual variation, in our material as well as in a previous study (Isaksson et al., 2001). Our findings are well comparable with earlier studies utilizing FNA, cytospin and immunocytochemical Ki-67 analysis of biopsy material. Repeated FNA seems to reduce the number of subject-pairs possible to evaluate.
The effects of mifepristone treatment included a significant reduction of uterovaginal bleeding which was the most important clinical feature of the treatment. Endometrial morphology showed no hyperplasia or atypia. Furthermore, no changes in endometrial thickness, as measured by vaginal ultrasound, were found.
In the present study, we used rather a high dose of mifepristone due to regulatory and practical restrictions. A lower dose of 5 mg daily has been shown to be effective as a contraceptive method (Baird et al., 2003; Lakha et al., 2007). With this regimen, up to 4 months treatment of mifepristone induced amenorrhea in 49% of women. With this dose regimen, some women developed endometrial cystic changes. Such changes were not seen with the dose regimen in the present study. Since the half time of mifepristone is 
24 h, 50 mg every second day can be expected to give a daily influence on the breast and the endometrium. This was reflected in that interruption of uterovaginal bleeding was induced in almost all patients in the mifepristone group. Whether a lower dose of mifepristone would give the same effect on the breast tissue remains to be studied. Despite the potential of the therapy, concern has been raised about the effect of mifepristone and other progesterone receptor antagonists in the endometrium. Hypothetically, long-term treatment, by inhibiting the effects of progesterone, could result in unopposed estrogen action leading to endometrial hyperplasia and cancer. Countering this concern is the growing evidence that these compounds not only block progesterone action but also exert an antiproliferative effect on the endometrium, despite the formation of specific cystic glandular dilatation (Baird et al., 2003). The molecular mechanism through which progesterone antagonists specifically block E2-stimulated endometrial growth may be mediated via an increase in androgen receptor (AR) observed in the glandular epithelium following mifepristone (Slayden et al., 2001). Because androgens can inhibit the effects of estrogens in the endometrium, increases in endometrial AR could bind endogenous androgens and mediate the antiproliferative effects. Treatment with the anti-androgen flutamide reversed many of the effects of progesterone antagonists on the endometrium (Brenner et al., 2003; Slayden and Brenner, 2003), which is strong evidence that AR are involved in the antiproliferative effect. Interestingly, an increase in serum testosterone levels was seen in the present study with a correlation between fT and Ki-67. Early studies showed that mifepristone also binds to the AR (Moguilewsky and Philibert, 1985). Whether a testosterone increase and/or an increase in AR underlies or is part of the antiproliferative effect observed in the breast epithelium during mifepristone treatment remains to be studied.
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Conclusion |
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In conclusion, treatment with mifepristone resulted in a distinct reduction of mammary glandular epithelial cell proliferation in premenopausal women. Whether this effect would indeed lower the risk for breast cancer development during antiprogestin treatment still remains to be shown. Further studies on the clinical effects in breast tissue during mifepristone treatment extended in time can contribute to the knowledgebase necessary for expanding the clinical applications of antiprogestins for contraception, hormone therapy and treatment of other gynaecological indications such as leiomyomas and endometriosis.
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Funding |
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The study was supported by grants from the Swedish Research Council (2003-3869, K2007-54X-14212-06-3), Karolinska Institutet and Stockholm city county/Karolinska Institutet (ALF).
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Acknowledgements |
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The authors are grateful to research nurses Margareta Hellborg and Lena Elffors-Söderlund, WHO-collaborating centre for taking excellent care of the patients and to Kerstin Bergkvist, Margareta Häggström and the staff at the gynaecological wards at Karolinska University Hospital, Stockholm. The authors would also like to thank Torsten Hägerström Karolinska University Hospital, Stockholm, Sweden, for expert technical assistance and Dr Eva Lundström for providing valuable advice concerning the quantification of breast symptoms with the use of the Breast Symptom Index.
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Submitted on December 21, 2007; resubmitted on May 12, 2008; accepted on May 19, 2008.
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