Figure 6

Overexpression of ErbB-2 results in enhanced neovascularization. Immunohistochemical analysis of MCF7-ErbB-2 and -AP2 mammary fat pad tumor sections. Tumors were fixed, embedded in paraffin, and stained with hematoxylin and eosin or immunolabeled for ErbB-2, VEGF, or PCNA. To visualize the blood vessel endothelial cells, cryosections of tumors were stained with anti-CD31 antibody by using DAB as the chromogen. Sections were counterstained with hematoxylin. For negative controls (−), the primary antibodies were omitted. Bar, 400 μm. (B) Quantitation of vascularization in MCF7-AP2 and -ErbB-2 tumors. Tumors were quantitated for vessel staining as described in MATERIALS AND METHODS. Results were obtained from three independent tumor sections. Values represent the mean ± SD of quadruplicate determinations. *p < 0.01, compared with AP2.