EGF and breast cancer: Epidermal growth factor (EGF) is a major inducer of cell migration in breast cancer cells and functions in this capacity by activating a phosphatidyl-inositol 3-kinase (PI3K) signal transduction cascade which then leads to the activation of the Rho family of small GTPases (including Rho, Rac, and Cdc42) [7, 10, 21–23].