Described is a cancer therapeutic agent comprising a polymer to which is linked three or more anti-tumor cell antibodies. Soluble polymers of between 6-8 Kd in size are preferred. The antibodies of the polymer can bind to a tumor cell antigen of a tumor cell and induce apoptosis or cell death of the tumor cell. The polymer may be linked to different antibodies to the same tumor antigen or to different tumor antigens. Methods of treating an individual with cancer using the cancer therapeutic agent are also described.