SLA and cancer: But now, it is known that sialyl Lewis-X (sLx) and sialyl Lewis-A (sLa) antigens are ligands to E-selectin, and sLx and sLa expressed on cancer cells mediate adhesion of the cancer cells to vascular endothelial cells expressing E-selectin (Phillips et al, 1990; Takada et al, 1991, 1993).