HER2 status in hormone receptor positive premenopausal primary breast cancer adds prognostic, but not tamoxifen treatment predictive, information.
Background Overexpression of human epidermal growth factor receptor 2 (HER2) or amplification of its gene is a prognostic factor in primary breast cancer and a predictor for tamoxifen treatment efficacy in oestrogen receptor (ER) positive disease. In the present study we explored a defined cohort of breast cancer patients included in a randomised trial in order to assess prognostic and tamoxifen t