Tissue architecture and breast cancer: the role of extracellular matrix and steroid hormones

The changes in tissue architecture that accompany the development of breast cancer have been the focus of investigations aimed at developing new cance r therapeutics. As we learn more about the normal mammary gland, we have be gun to understand the complex signaling pathways underlying the dramatic sh ifts in the structure and function of breast tissue. Integrin-, growth fact or-, and steroid hormone-signaling pathways all play an important part in m aintaining tissue architecture; disruption of the delicate balance of signa ling results in dramatic changes in the way cells interact with each other and with the extracellular matrix, leading to breast cancer. The extracellu lar matrix itself plays a central role in coordinating these signaling proc esses. In this review, we consider the interrelationships between the extra cellular matrix, integrins, growth factors, and steroid hormones in mammary gland development and function.