The binding of E- and P-selectins, expressed on the luminal surface of endothelial cells, to terminal glycan residues including α2,3-linked sialic acid and α1,3/α1,4-linked fucose, expressed on circulating tumor cells (CTCs) (Varki et al. 2009), initiates the adhesion of CTCs to endothelial cells lining the vasculature at a future metastatic site. The gene discussed is SELP; the disease is neoplasm.