Heparin has long been known to represent antiheparanase activity that is to keep an endoglycosidase from degrading heparin sulfate, one of the glycosaminoglycans, and to effectively inhibit P-selectin. Despite a striking effect of heparin on tumor progression shown in a number of clinical trials, the use of heparin as anti-cancer agent is limited because of its risk, which might induce adverse bleeding complications. Given those reasons, development of new compounds that target P-selectin is now emerging for cancer therapy. Among them, the inhibitory activity of semisynthetic sulfated tri mannose C-C-linked dimers (STMCs) to P-selectin was shown by the attenuation of tumor metastasis in vivo animal model, indicating the inhibition of interaction between tumor cell and endothelial cell is significant for blocking tumor dissemination.