EGF and breast cancer: For instance, work in a spontaneous mammary tumor model showed that IL-4/IL-13-activated TAMs, when exposed to tumor-derived colony-stimulating factor-1 (CSF-1; Box 1), produce epidermal growth factor (EGF), which in turn promotes motility and intravasation of EGF receptor (EGFR)-expressing tumor cells (Wyckoff et al., 2004).