PECAM1 and acute myeloid leukemia: Using a patient-derived xenograft model of AML, Passaro et al. showed that major niche components, including CD31+ cells, Col1a1+ cells and Nes+ cells, which overlapped with signature of endothelial cells, skeletal cells and smooth muscle cells respectively identified in scRNAseq studies, underwent gene expression changes upon AML engraftment [36].