PECAM1 and cancer: The hASCs' stemness phenotype was confirmed also by the endothelial/angiogenic gene expression analyses, as well as by CD31 and VEGF proteins analyses, which clearly showed that these factors were upregulated in hASCs cultured alone and strongly downregulated in hASCs co-cultured with cancer cells, thereby reinforcing the hypothesis of a ‘stemness steady state' or maintenance.