Endosialin induction during neo-angiogenesis in subcutaneous xenografts of human cancer cells in nu/nu mice. In the colon cancer model Colo 205 (A, B), endosialin is expressed by endothelial cells of the tumor capillaries (A), with a pattern very similar to the reference endothelial marker CD31 (B). In the colon cancer model HT29 (C), endosialin is also induced in the host-derived cancer stroma, but with a cellular pattern that extends to the tumor stromal fibroblasts. In the breast cancer model MCF7 (D), endosialin is seen in the endothelial cells of the cancer stroma. Scale bars: 25 µm.