A treatment for cancer, and in particular, of therapeutic compounds which block the ability of cytokines and chemokines to promote metastasis of malignant cells. The therapeutic compound comprises a carboxylated and/or sulfated oligosaccharide, preferably in a substantially purified form, which is a heparin or heparan-sulfate derived saccharide compound. In one embodiment of the present invention, the carbohydrate or oligosaccharide has a molecular weight of no more than about 3000 daltons, preferably lying in the range of about 400 to about 2000 daltons, most preferably between about 400 and about 1100 daltons. Generally, substances of the present invention inhibit tumor cell migration, as determined by biological assays, and comprise molecules of various sugar units of which the basic unit of activity is associated with a disaccharide. However, larger oligosaccharide chains of up to about 10 sugar units, containing the basic disaccharide unit of activity can also function to inhibit such activity.