Based on our recent observations that cimetidine blocked in vitro expression of E-selectin on the surface of vascular endothelial cells as reported by Kobayashi et al. (2000), we examined in this study whether the beneficial effect of cimetidine on colorectal cancer patients was dependent on the degree of expression of sLx and sLa on the tumour cells. The gene discussed is SELE; the disease is neoplasm.