Hormone replacement therapy use dramatically increases breast oestrogen receptor expression in obese postmenopausal women

It is known that use of hormone replacement therapy (HRT) by postmenopausal women increases the risk of breast cancer. In this study, oestrogen receptor (ER)-α expression is examined using standard immunoperoxidase technique. Normal breast samples of 11 Australian postmenopausal women have been included in the ER-α study; the result showed a strong correlation (r² = 0.80) between ER-α expression in normal breast epithelial cells and body mass index (BMI) in normal women who currently use HRT. This finding confirms that the possibility of increased risk of breast cancer associated with increased ER-α expression in normal breast epithelial cells, in turn associated with high BMI and the use of HRT