Figure 1: Immunohistochemical analyses of expression of TGFα, EGFR, and phosphorylated EGFR on tumor cells and tumor-associated endothelial cells in orthotopically implanted colon tumors. (a) TGFα expression in the tumor cells. (b) EGFR was present on tumor cells (green) and was also detected on the tumor-associated vasculature (yellow). (c) Expression of phosphorylated EGFR was localized to both tumor cells (green) and the supporting vascular network (yellow). Scale bars = 100 μm [50].