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Concept: Estrogen receptor

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BACKGROUND: Endocrine disrupting chemicals and carcinogens, some of which may not yet have been classified as such, are present in many occupational environments and could increase breast cancer risk. Prior research has identified associations with breast cancer and work in agricultural and industrial settings. The purpose of this study was to further characterize possible links between breast cancer risk and occupation, particularly in farming and manufacturing, as well as to examine the impacts of early agricultural exposures, and exposure effects that are specific to the endocrine receptor status of tumours. METHODS: 1006 breast cancer cases referred by a regional cancer center and 1146 randomly-selected community controls provided detailed data including occupational and reproductive histories. All reported jobs were industry- and occupation-coded for the construction of cumulative exposure metrics representing likely exposure to carcinogens and endocrine disruptors. In a frequency-matched case–control design, exposure effects were estimated using conditional logistic regression. RESULTS: Across all sectors, women in jobs with potentially high exposures to carcinogens and endocrine disruptors had elevated breast cancer risk (OR = 1.42; 95% CI, 1.18-1.73, for 10 years exposure duration). Specific sectors with elevated risk included: agriculture (OR = 1.36; 95% CI, 1.01-1.82); bars-gambling (OR = 2.28; 95% CI, 0.94-5.53); automotive plastics manufacturing (OR = 2.68; 95% CI, 1.47-4.88), food canning (OR = 2.35; 95% CI, 1.00-5.53), and metalworking (OR = 1.73; 95% CI, 1.02-2.92). Estrogen receptor status of tumors with elevated risk differed by occupational grouping. Premenopausal breast cancer risk was highest for automotive plastics (OR = 4.76; 95% CI, 1.58-14.4) and food canning (OR = 5.70; 95% CI, 1.03-31.5). CONCLUSIONS: These observations support hypotheses linking breast cancer risk and exposures likely to include carcinogens and endocrine disruptors, and demonstrate the value of detailed work histories in environmental and occupational epidemiology.

Concepts: Cancer, Breast cancer, Oncology, Estrogen, Endocrinology, Estrogen receptor, Endocrine system, Endocrine disruptor

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BACKGROUND: Postmenopausal women experience estrogen deficiency-related menopausal symptoms (e.g., hot flashes and mood swings) and a dramatic increase in the incidence of chronic diseases. Although estrogen-replacement therapy (ERT) can reduce mortality from cardiovascular disease and improve osteoporosis and menopausal symptoms, its side effects have limited recent use. This study investigated the estrogen-like activity of aqueous extract from Agrimonia pilosa Ledeb. METHODS: The estrogenic activity of A. pilosa was investigated by using several in vitro assays. The binding activity of A. pilosa on estrogen receptors was examined using a fluorescence polarization-based competitive binding assay. The proliferative activity of A. pilosa was also examined using MCF-7 cells. Furthermore, the effect of A. pilosa on the expression of 3 estrogen-dependent genes was assessed. RESULTS: Using liquid chromatography-mass spectrometry, the 3 major peaks of A. pilosa aqueous extract were identified as apigenin-hexose, luteolin-glucuronide, and apigenin-glucuronide. The aqueous extract induced the proliferation of estrogen receptor-positive MCF-7 cells (p < 0.05). A. pilosa-stimulated proliferation was blocked on adding the estrogen antagonist ICI 182,780. Moreover, A. pilosa treatment increased the mRNA expression of the estrogen-responsive genes pS2 and PR (p < 0.05). CONCLUSIONS: These results suggest A. pilosa can be used to improve estrogen deficiency-related menopausal symptoms or to treat diseases in postmenopausal women.

Concepts: Osteoporosis, Hormone replacement therapy, Breast cancer, Menopause, Estrogen, Estrogen receptor, Menstrual cycle, Atrophic vaginitis

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The frequent alterations of the PI3K/Akt/mTOR-growth signaling pathway are proposed mechanisms for resistance to endocrine therapy in breast cancer, partly through regulation of estrogen receptor α (ER) activity. Reliable biomarkers for treatment prediction are required for improved individualized treatment. We performed a retrospective immunohistochemical analysis of primary tumors from 912 postmenopausal patients with node-negative breast cancer, randomized to either tamoxifen or no adjuvant treatment. Phosphorylated (p) Akt-serine (s) 473, p-mTOR-s2448, and ER phosphorylations-s167 and -s305 were evaluated as potential biomarkers of prognosis and tamoxifen treatment efficacy. High expression of p-mTOR indicated a reduced response to tamoxifen, most pronounced in the ER+/progesterone receptor (PgR) + subgroup (tamoxifen vs. no tamoxifen: hazard ratio (HR), 0.86; 95 % confidence interval (CI), 0.31-2.38; P = 0.78), whereas low p-mTOR expression predicted tamoxifen benefit (HR, 0.29; 95 % CI, 0.18-0.49; P = 0.000002). In addition, nuclear p-Akt-s473 as well as p-ER at -s167 and/or -s305 showed interaction with tamoxifen efficacy with borderline statistical significance. A combination score of positive pathway markers including p-Akt, p-mTOR, and p-ER showed significant association with tamoxifen benefit (test for interaction; P = 0.029). Cross-talk between growth signaling pathways and ER-signaling has been proposed to affect tamoxifen response in hormone receptor-positive breast cancer. The results support this hypothesis, as an overactive pathway was significantly associated with reduced response to tamoxifen. A clinical pre-treatment test for cross-talk markers would be a step toward individualized adjuvant endocrine treatment with or without the addition of PI3K/Akt/mTOR pathway inhibitors.

Concepts: Cancer, Breast cancer, Signal transduction, Hormone, Estrogen, Estrogen receptor, Cell signaling, Tamoxifen

141

Uptake of preventive therapy for women at increased breast cancer risk in England is unknown following the introduction of UK clinical guidelines in 2013. Preventive therapy could create socioeconomic inequalities in cancer incidence if it is more readily accepted by particular socio-demographic groups. In this multicentre study, we investigated uptake of tamoxifen and evaluated socio-demographic and clinical factors associated with initiation. We explored women’s experiences of treatment decision-making using qualitative interview data.

Concepts: Cancer, Breast cancer, Metastasis, Estrogen, Estrogen receptor, United Kingdom, England, Tamoxifen

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Tamoxifen (TAM) has been widely used for the treatment of estrogen receptor (ER)-positive breast cancer and its combination with other therapies is being actively investigated as a way to increase efficacy and decrease side effects. Here, we evaluate the therapeutic potential of co-treatment with TAM and BreastDefend (BD), a dietary supplement formula, in ER-positive human breast cancer.

Concepts: Breast cancer, Estrogen, Chemotherapy, Estrogen receptor, Tamoxifen

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Breastfeeding is inversely associated with overall risk of breast cancer. This association may differ in breast cancer subtypes defined by receptor status, as they may reflect different mechanisms of carcinogenesis. We conducted a systematic review and meta-analysis of case-control and prospective cohort studies to investigate the association between breastfeeding and breast cancer by estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status.

Concepts: Epidemiology, Breast cancer, Epidermal growth factor receptor, Epidermal growth factor, Growth factor, Estrogen, Estrogen receptor, Tamoxifen

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Therapies targeting estrogenic stimulation in estrogen receptor-positive (ER+) breast cancer (BC) reduce mortality, but resistance remains a major clinical problem. Molecular studies have shown few high-frequency mutations to be associated with endocrine resistance. In contrast, expression profiling of primary ER+ BC samples has identified several promising signatures/networks for targeting.

Concepts: Cholesterol, Cancer, Breast cancer, Metastasis, Menopause, Estrogen, Estrogen receptor, Breast

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Xenoestrogens are synthetic compounds that mimic endogenous estrogens by binding to and activating estrogen receptors. Exposure to estrogens and some xenoestrogens has been associated with cell proliferation and increased risk of breast cancer. Despite evidence of estrogenicity, parabens are among the most widely used xenoestrogens in cosmetics and personal care products, and generally considered safe. However, previous cell based studies with parabens do not take into account the signaling cross-talk between estrogen receptor (ERα) and the human epidermal growth factor receptor (HER) family.

Concepts: Cancer, Breast cancer, Signal transduction, Epidermal growth factor, Estrogen, Receptor, Estrogen receptor, Breast