To identify progressive changes of blood vessels in situ during AML progression, we performed IVM of Flk1-GFP transgenic mice, in which phenotypic endothelial cells (ECs) express GFP (Figure 2A) and can be visualized lining BM blood vessels labeled with Cy5-dextran (Figure 2B). The gene discussed is KDR; the disease is acute myeloid leukemia.