VCAM1 and acute myeloid leukemia: We found that the VCAM1-VLA-4 axis, specifically VCAM1(AML cells)-VLA-4 (endothelial cells), was crucial in this pathologic process since a dramatic increase of VCAM1 but not VLA-4 was detected in AML-IRF7−/− cells while endothelial cells expressed VLA-4.