Tamoxifen is widely used for the treatment of hormonally responsive breast cancers. However, some resistant breast cancers develop a growth proliferative response to this drug, as evidenced by tumor regression upon its withdrawal. To elucidate the molecular mediators of this paradox, tissue samples from a patient with tamoxifen-stimulated breast cancer were analyzed. These studies revealed that...

Tamoxifen is a widely used breast cancer therapeutic and preventative agent. Although functioning as an estrogen antagonist at the cellular level, transcriptional profiling revealed that at the molecular level, tamoxifen functions largely as an agonist, virtually recapitulating the gene expression profile induced in breast cancer cells by estrogen. Remarkably, tamoxifen induces transcription fa...

In a control randomized cross-over trial, 117 patients with advanced breast cancer were treated initially either with tamoxifen (10 mg p.o. twice daily) or aminoglutethimide (250 mg p.o. 4 times daily) with hydrocortisone (20 mg twice daily). Patients failing to respond or relapsing were switched to the alternative treatment. Eighteen (30%) of the 60 patients initially treated with tamoxifen ac...

STUDY OBJECTIVE Comparison of tamoxifen and mastectomy in treatment of breast cancer in elderly patients. DESIGN Randomised trial of treatment of operable breast cancer by wedge mastectomy or tamoxifen, with median follow up 24 and 25 months respectively (range 1-63). SETTING University hospital; most patients from primary catchment area. PATIENTS 135 consecutive patients with breast canc...

Several metabolites of tamoxifen, including 4-hydroxy-N-desmethyltamoxifen (metabolite BX), 4-hydroxytamoxifen (metabolite B), N-desmethyltamoxifen (metabolite X), the primary alcohol (metabolite Y), and N-desdimethyltamoxifen (metabolite Z) were identified and their concentrations determined in fluids and feces from patients receiving chronic tamoxifen treatment. The biological samples investi...

PURPOSE Resistance to tamoxifen is linked to overexpression of HER2, and aromatase inhibitors show particular benefit in progesterone receptor (PR)-negative patients. We previously reported reduced survival in patients overexpressing HER1, HER2, and HER3. We now show that both HER1-3 and PR status predicts for early relapse in estrogen receptor (ER)-positive tamoxifen-treated breast cancer pati...

Tamoxifen is a widely utilized antiestrogen in the treatment and chemoprevention of breast cancer. Clinical studies document that tamoxifen administration markedly enhances the systemic elimination of other drugs. Additionally, tamoxifen enhances its own clearance following repeated dosing. The mechanisms that underlie these clinically important events remain unresolved. Here, we report that ta...

BACKGROUND Tamoxifen, a selective estrogen receptor modulator (SERM), is converted to 4-hydroxy-tamoxifen and other active metabolites by cytochrome P450 (CYP) enzymes. Selective serotonin reuptake inhibitors (SSRIs), which are often prescribed to alleviate tamoxifen-associated hot flashes, can inhibit CYPs. In a prospective clinical trial, we tested the effects of coadministration of tamoxifen...

ObjectivesMost breast cancer cases in Ghana occur premenopausal and perimenopausal (PPM) women. This study evaluated the cost-effectiveness of tamoxifen compared with no for adjuvant treatment hormone receptor–positive (HR+) early (EBC) among PPM Ghanaian women.MethodsA Markov model was constructed to synthesize data on effectiveness, costs, health benefits tamoxifen. Effectiveness utility were...

AIM To study the effects of tamoxifen on the proliferation index and oestrogen receptor (ER) and progesterone receptor (PR) expression in postmenopausal endometrium. METHODS A total of 125 endometrial specimens of postmenopausal women, comprising benign endometria from tamoxifen users (n = 35) and non-users (n = 24), and endometrial cancer from tamoxifen users (n = 15) and non-users (n = 51),...