Abstract: Methods of treating Kaposi's sarcoma (KS) by inhibiting the effect of scatter factor (SF), also known as hepatocyte growth factor (HGF), are provided. The methods of the present invention include antibody therapy wherein an antibody to SF is introduced into a patient to decrease active SF levels thereby decreasing the incidence of new tumors as well as leading to regression of established tumors by blocking SF-mediated tumor cell proliferation and neovascularization. The present invention further provides methods of inhibiting the effects of SF by introducing into a patient means for inhibiting binding of SF to the SF receptor, the c-met proto-oncogen. Means for inhibiting SF binding to the receptor include introducing into a patient an antibody to the c-met receptor or introducing a non-stimulatory ligand that will bind and thereby inhibit the receptor.