Abstract
The IGF family, composed of ligands, receptors, binding proteins and proteases, is critical during development and in the maintenance of normal tissue homeostasis. This review describes the role of the IGF system in the normal breast but focuses on the changes that occur in breast cancer. It discusses the cross-talk which can occur between the IGF family with other signalling pathways, including estrogen, epidermal growth factor (EGF) and integrins. It also describes various cell and animal models which have been developed to elucidate the function and significance of the IGF family in cancer with a view to developing potential therapeutics.