26th Annual San Antonio Breast Cancer Symposium, San Antonio, Texas, USA, 3-6 December 2003: update on preclinical and translational research.

The San Antonio Breast Cancer Symposium is the largest annual meeting devoted solely to breast cancer research. The late William L McGuire's vision for this meeting was to stimulate 'translational research', many years before this term became popular. In this way, the San Antonio Breast Cancer Symposium represents a forum in which basic and clinical researchers present their research side by side.

Rapid induction of IGF-IR signaling in normal and tumor tissue following intravenous injection of IGF-I in mice.

The detection of IGF-IR signaling in animal models has important implications for determining the role of this receptor in normal physiology and tumor growth. While many reports have correlated changes in plasma IGF-I levels in vivo with biological responses, few have shown that altered IGF-I levels can directly affect signaling within normal or tumor tissue. Here, we present new data that shows how the intravenous (IV) injection of IGF-I can be used to directly examine IGF signaling at the tissue level.

Developmental and hormonal signals dramatically alter the localization and abundance of insulin receptor substrate proteins in the mammary gland.

Insulin receptor substrates (IRS) are central integrators of hormone, cytokine, and growth factor signaling. IRS proteins can be phosphorylated by a number of signaling pathways critical to normal mammary gland development. Studies in transgenic mice that overexpress IGF-I in the mammary gland suggested that IRS expression is important in the regulation of normal postlactational mammary involution.

Cross-talk among estrogen receptor, epidermal growth factor, and insulin-like growth factor signaling in breast cancer.

Since the cloning of the estrogen receptor alpha (ERalpha) and subsequent identification of a second distinct form of ER, termed ERbeta, a large volume of research has begun to define the molecular mechanisms of ER action. However, although great progress has been made, ER action is still poorly understood. It is expected that a better understanding of ER action may lead to novel strategies and targets for breast cancer prevention and treatment.