This article describes the origins and evolution of “antiestrogenic” medicines for the
treatment and prevention of breast cancer. Developing drugs that target the estrogen
receptor (ER) either directly (tamoxifen) or indirectly (aromatase inhibitors) has improved the
prognosis of breast cancer and significantly advanced healthcare. The development of the
principles for treatment and the success of the concept, in practice, has become a model for
molecular medicine and presaged the current testing of numerous targeted therapies for all …