VCAM1 and neoplasm: We found that although E-selectin and terminal α2,3-sialic acid largely determined firm adhesion, adhesive events did not exclusively depend on the presence of sialyl-Lewis A and/or sialyl-Lewis X. Nevertheless, two of the three sialyl-Lewis A/X−/− tumor cells additionally or fully depended on vascular cell adhesion molecule-1 for firm adhesion.