ERBB2 and neoplasm: A microscopic study of tumor vascularization showed that full-length HER2 tumors mainly contained few large vessels or vascular lacunae (Figure 3A, 3B and 3K and Supplementary Figure 2), whereas Delta16 tumors were perfused by numerous endothelium-lined small vessels (Figure 3C, 3D and 3L and Supplementary Figure 2).