Abstract
Transforming growth factor-alpha (TGFα) is a member of the epidermal growth factor (EGF) family. Expression of TGFα is highly regulated in response to exogenous cellular signals including cytokines and other growth factors. The growth factor has been found to be indispensable for proper development of many tissues and organs. TGFα has also been implicated in numerous disease states including forms of breast cancer. This minireview summarizes the basic biology of TGFα and its actions during normal and pathogenic development of the mammary epithelium.