PECAM1 and neoplasm: To examine whether iCTCs surviving in the blood stream acquire the phenotype of circulating endothelial cells, cells captured in the CAM-coated wells were immuno-stained with antibodies against epithelial CK and endothelial CD31, and underwent functional analyses using CAM uptake for invasive tumor cells as described [14] and acLDL uptake for circulating endothelial cells as described [18].