Growth factor signalling networks in breast cancer and resistance to endocrine agents: new therapeutic strategies.

Recent evidence demonstrates that growth factor networks are highly interactive with the estrogen receptor (ER) in the control of breast cancer growth and development. As such, tumor responses to anti-hormones are likely to be a composite of the ER and growth factor inhibitory activity of these agents, with alterations/aberrations in growth factor signalling providing a mechanism for the development of anti-hormone resistance. In this light, the current article focuses on illustrating the relationship between growth factor signalling and anti-hormone failure in our in-house tumor models of breast cancer and describes how we are now beginning to successfully target their actions to improve the effects of anti-hormonal drugs and to block aggressive disease progression.