Among O-linked carbohydrate antigens, sialyl LewisX has been reported to function as a ligand of the endothelial cell adhesion molecule E-selectin (ELAM-1), which adheres human cancer cells to the vascular endothelium (Phillips et al, 1990; Walz et al, 1990; Takada et al, 1993). Here, ESAM is linked to cancer.