Evidence for a role of ovarian factors in the growth of metastatic breast cancer was first recognized over 100 years ago. Today, anti-estrogens are central to the treatment of breast cancer of all stages. We now understand that the action of estrogen is mediated by the estrogen receptors (ER) which are members of the nuclear receptor family of ligand-regulated transcription factors. In this article we review the molecular mechanisms through which ER activates transcription of target genes and through which available anti-estrogens mediate their therapeutic effects. We discuss possible mechanisms of failure of treatment with current anti-estrogens and how newer anti-estrogens under development attempt to address these problems. In addition an expanded view of the molecular mechanisms of estrogen action is leading to the development of novel selective ER modulators or SERMs.European Journal of Endocrinology 150 243-255

ScFv(FRP5)-ETA is a recombinant single-chain antibody-toxin with binding specificity for ErbB2/HER2. Previously potent antitumoral activity of the molecule against ErbB2 overexpressing tumor cells was demonstrated in vitro and in animal models. Here we report on the first application of scFv(FRP5)-ETA in human cancer patients summarizing case reports collected in four different clinical centers. Eleven patients suffering from metastatic breast and colorectal cancers and from malignant melanoma were treated on a compassionate-use basis by intratumoral injection of scFv(FRP5)-ETA into cutaneous lesions once daily for 7-10 days. Total daily doses ranged from 60 to 900 microg, and total doses per treatment cycle ranged from 0.6 to 6.0 mg. Treatment caused injected tumors to shrink in six of the 10 cases evaluated (60%). Complete regression of injected tumor nodules was accomplished in four patients (40%) and partial reduction in tumor size in another two patients (20%). Adverse reactions were restricted to local symptoms such as pain and inflammation at injection sites which were fully reversible. Only in one patient treated at the highest daily doses systemic liver toxicity of grade 2 was observed and treatment was discontinued on day 7. No hematologic, renal, and/or cardiovascular toxicities were noted. Our results demonstrate that local therapy with scFv(FRP5)-ETA can be effective against ErbB2 expressing tumors justifying further clinical development of this reagent.

Purpose: Breast cancer (BC) is the most frequent female carcinoma and the major cause of death in women aged 35–50 years. The total number of patients surviving BC and especially the morbidity rate of patients below the age of 55 years has increased significantly in the last several years. As a consequence, the number of BC patients suffering from the long-term effects of estrogen deficiency due to adjuvant treatment is increasing. At present, hormone replacement therapy (HRT) following BC treatment is applied individually and mainly depends on the severity of postmenopausal symptoms (PMS) experienced by these patients. Patients and Methods: In a retrospective study (total n = 185 BC patients, 64 with and 121 without HRT), the effect of HRT during or after adjuvant therapy [chemotherapy and/ or (anti-) hormonotherapy] has been investigated. The surveillance period was up to 60 months. Evaluated were HRT effects on (1) PMS measured by a comprehensive life quality questionnaire, (2) bone mineral density (BMD) measured by osteodensitometry and (3) morbidity as well as mortality rates. Results: Both groups did not differ with regard to tumor stage, lymph node involvement, metastasis, grading, and steroid hormone receptor status. A reduction in PMS was significant in women taking HRT (p < 0.001), especially in the subgroup of women ≤50 years (p < 0.0001). For both age groups, the median reduction in BMD (z-score) was less in women receiving HRT (≤50 years: without HRT –1.99 vs. with HRT –0.95, p < 0.05; >50 years: without HRT –2.29 vs. with HRT –1.19, p < 0.01). There were no statistically significant differences regarding morbidity and mortality (p = 0.29). Conclusion: In this study of BC patients, the use of HRT shows positive effects on PMS and BMD. There was no significant influence on morbidity or mortality. However, a reevaluation of HRT in the routine management of BC patients should await the results of prospective randomized trials.

Proliferation of breast and endometrial cells is under the control of ovarian steroid hormones (SHs) such as oestrogen and progesterone. They mediate diverse physiological functions via interaction with nuclear-localised steroid hormone receptors (HRs). The SH receptor complex modifies the expression of SH-regulated genes by binding to conserved binding sites in their promoter region or through cross-talk with other transcription factors. In non-malignant tissues, HRs are in balance with other factors regulating proliferation, differentiation and apoptosis. While dysfunction of the regulatory mechanisms is a part of malignant transformation, functional SH receptors can promote growth of SH-responsive tumours. Therefore, anti-hormones that block the interaction of steroid hormones with the SH receptor are useful tools for the treatment of SH-responsive carcinomas. However, a portion of ER-positive breast cancers and most endometrial cancers do not respond to anti-oestrogens and continued treatment results in hormone resistance, mostly without loss of the ER. This review focuses on the mechanisms of action of hormones and anti-hormones in breast and endometrial carcinomas.

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