AIM The estrogen receptor coactivator Amplified in Breast Cancer 1 (AIB1) has been associated with an improved response to adjuvant tamoxifen in breast cancer, but also with endocrine treatment resistance. We hereby use metachronous contralateral breast cancer (CBC) developed despite prior adjuvant tamoxifen for the first tumor as an "in vivo"-model for tamoxifen resistance. AIB1-expression in ...

BACKGROUND Tamoxifen has been the mainstay of breast cancer therapy. Over time, resistance to tamoxifen may develop. The aromatase inhibitors have proven to be a powerful drug for use in hormone-sensitive early breast cancer. The switching strategy was designed to combine the apparent superior efficacy of aromatase inhibitors with tamoxifen favourable effects. METHODS This study was performed...

three major flavonoid fractions were separated from a methanol extract of calendula officinalis flowers by preparative tlc. these fractions were evaluated for the inhibition of parent and tamoxifen resistant t47d human breast cancer cells. we also examined the effect of quercetin and isorhamnetin on the growth of parent and resistant t47d cells in the presence and absence of tamoxifen. it was f...

The trial designs were generally similar. Arimidex-Nolvadex (ARNO) 95 trial included 979 women who were randomly assigned after 2 years of tamoxifen to either 3 additional years of tamoxifen or 3 years of anastrozole. The Italian Tamoxifen Arimidex (ITA) trial included 448 women who were randomly assigned after 2 – 3 years on tamoxifen to either tamoxifen or anastrozole for 2 – 3 years. In the ...

Tamoxifen is widely used in the treatment of breast cancer and has been proposed as a prophylactic agent in this disease. Tamoxifen is an effective antioxidant and protects membranes and low-density lipoprotein (LDL) particles against oxidative damage. This antioxidant action is shared by endogenous and synthetic oestrogens. The ability of tamoxifen to protect LDL particles against the oxidativ...

Tamoxifen is a central component of the treatment of estrogen receptor (ER)-positive breast cancer as a partial agonist of ER. It has been clinically used for the last 30 years and is currently available as a chemopreventive agent in women with high risk for breast cancer. The most challenging issue with tamoxifen use is the development of resistance in an initially responsive breast tumor. Thi...

Tamoxifen is a widely used chemotherapeutic agent, which has been associated with prolongation of the QT interval. Other studies have reported that acute exposure to tamoxifen can reduce cardiac K(+) currents. However, in vivo tamoxifen is largely metabolized and most of its activity is attributable to its major metabolite, 4-hydroxytamoxifen (4OH-tamoxifen). Accordingly, in the present study, ...

Antiestrogen resistance often develops with prolonged exposure to hormone therapies, including tamoxifen, and is a major problem in the treatment of breast cancer. Understanding the mechanisms involved in the development of antiestrogen resistance is an important step in the development of new targeted therapies. Two forms of antiestrogen resistance exist: de novo resistance and acquired resist...

BACKGROUND To date, the impact of the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-24 trial reported in 1999 on the use of tamoxifen after surgery for ductal carcinoma in situ (DCIS) is unknown. The current study was designed to evaluate the impact of NSABP B-24 on current practices at a comprehensive cancer center. METHODS The records of 350 consecutive patients with DCIS wh...

BACKGROUND We have previously shown that a retinoid X receptor (RXR)-selective ligand (a rexinoid), called LGD1069, is highly efficacious in both the chemoprevention and the chemotherapy for N-nitrosomethylurea-induced rat mammary carcinomas. To evaluate a possible role for rexinoids in breast cancer therapy further, we have designed and characterized a novel carcinogen-induced model to mimic t...