PECAM1 and cancer: Figure 4 depicts the histology of the mouse shown in Figure 2. This histology shows that the right gland (Figure 4(b)), which has a larger tumor and not only has more vessels but also more vascular complexity, as compared to the left gland (Figure 4(a)). An experienced breast pathologist (JM) identified cancers and blood vessels from H&E-stained slices. Previous studies in the lab correlated MRI-TOFA results with both H&E-stained and CD31-stained slices, demonstrating the usefulness of MRI-TOFA in the use of H&E stained and CD31 stained histology [16].