The aim of this study was to determine whether colon cancer cells flowing in blood exhibit the same adhesion pattern to the vascular bed as leucocytes using a flow adhesion system. In shear flow conditions, five colon cancer cell lines showed less tethering to E-selectin substrates than polymorphonuclear cells (PMN). However, some of the Colo201 cells formed complete arrest on E-selectin in continuous shear flow which was never observed in PMN cells. Colo201 cells expressed both sialyl Le-x and sialyl Le-a at similar levels in flow cytometry. However, the staining pattern showed marked contrast under the fluorescein microscope. The cell membrane of Colo201 cells was uniformly stained with anti-sialyl Le-a MAb, whereas anti-sialyl Le-x MAb only stained in the patchy areas. Pretreatment of Colo201 cells with anti-sLe-a decreased tethering, while anti-sLe-x significantly inhibited the arrest formation. Our data suggest that E-selectin alone can mediate colon cancer cell lodgement and subsequent metastasis without the contribution of integrin molecules and that the different distribution of E-selectin ligands may affect the adhesion behaviour of colon cancer cells in flow conditions.