Estrogen and Progesterone Receptors of Adenomyosis in Postmenopausal Breast Cancer Patients Treated with Tamoxifen

Abstract

Adenomyosis is an ectopic endometrial tissue located in the myometrium. It has been reported to develop at a higher rate among postmenopausal breast cancer patients on tamoxifen (TAM) treatment than in untreated patients. It has also been reported to be stimulated by estrogen. Assessing receptor levels in adenomyotic tissue may indicate the adenomyotic cell’s potential to interact with TAM. In the present study the estrogen receptor (ER) and progesterone receptor (PR) were analyzed by an immunohistochemical technique in adenomyotic and the corresponding endometrial tissues of 14 postmenopausal breast cancer patients treated with TAM and in 15 healthy postmenopausal patients who served as controls. All TAM-treated patients had normal postmenopausal serum estradiol levels. Overall the ER and PR contents in adenomyotic tissue (42.9 and 71.4%) and in the endometriotic tissue (64.3 and 78.6%) obtained from the study patients were similar to those obtained from the control group (adenomyosis, ER and PR = 46.7 and 86.7%; endometrium, ER and PR = 40 and 73.3%; p = NS). In the study group, the ER content was lower in the adenomyotic (42.9%) than in the endometriotic tissue (64.3%). No correlation was found between the duration of TAM therapy, the TAM dosage level or the ER or PR content in the adenomyotic or endometrial tissues. The finding of a relatively low ER content in the adenomyotic tissue than in the endometriotic tissue in postmenopausal TAM-treated patients without endogenous estrogens, similar to that observed in healthy premenopausal women, may be attributed to the estrogen-like effect of TAM.

Pathogenesis of adenomyosis: an update on molecular mechanisms

“…Furthermore, the altered regulation of 17ß-hydroxysteroid dehydrogenase type 2 (17β-HSD2) in the eutopic endometrium of women with adenomyosis causes a decreased local oestrogen metabolism (Kitawaki et al, 2000) (Figure 2). The evidence that adenomyosis is an oestrogen-related process is also supported by the observation that postmenopausal women with breast cancer treated with tamoxifen have a higher rate of adenomyosis than those untreated (Cohen et al, 1998). Therefore, prolonged tamoxifen therapy, as a result of its oestrogenic effects, may promote the development of adenomyosis or its persistency in postmenopause (McCluggage et al, 2000).…”

Tumorigenic Effects of Tamoxifen on the Female Genital Tract

“…The proliferative activity within the adenomyosis was higher in the tamoxifen group. In postmenopausal tamoxifen-treated patients, ERs and PRs have been described in adenomyosis in similar concentrations as in premenopausal non-tamoxifen users (Cohen et al 1998b). …”

Adenomyosis: Epidemiology, Risk Factors, Clinical Phenotype and Surgical and Interventional Alternatives to Hysterectomy

“…Adenomyosis is relatively rare in postmenopausal women but a higher incidence of adenomyosis has been reported in women treated with tamoxifen for breast cancer [46][47][48][49]. Tamoxifen is an antagonist of the estrogen receptor in breast tissue via its active metabolite, hydroxytamoxifen.…”