Evolving Understanding of Growth Regulation in Human Breast Cancer: Interactions of the Steroid and Peptide Growth Regulatory Pathways

Abstract

Ablation of systemic estrogen production in a breast cancer patient is considered to be one of the first targeted therapies employed for the treatment of a human malignancy. Since Beatson's ( 1 ) initial clinical description of a breast tumor response to oophorectomy in 1896, many approaches that disrupt the estrogen–estrogen receptor (ER) signaling pathway have been developed and used widely in clinical practice. These range from surgical approaches such as oophorectomy, adrenalectomy, and hypophysectomy to the use of highly refined antagonists of the ER and agents that directly target estrogen production, such as aromatase inhibitors. The routine measurement of ER in breast cancers and the relative restriction of hormonally directed therapies to patients with ER-positive tumors has led to a more rational and appropriate use of these modalities.