Specific glycosaminoglycan isolated from sea cucumber Holothuria leucospilota has the capacity to inhibit thrombin-induced platelet activation and aggregation of platelets, reduce adhesion of the breast cancer cells to platelets and prevent adherence of the platelet-cancer cell complex to fibrinogen, weaken formation of the complexes between platelets and cancer cells and suppress mRNA and protein levels of β1 and β3 integrins, MMP-2 and MMP-9. This evidence concerns the gene MMP9 and cancer.