This invention describes a method whereby human autoimmune antibodies are used as carrier compounds to deliver imaging agents and pharmaceutical drugs to the tumor in the human patient. These autoantibodies have the propensity to localize in necrotic areas of tumors but not in healthy normal tissues. By combining various pharmaceutical agents with these carrier proteins it is possible to localize these agents within the necrotic areas of tumors in cancer patients. The carrier proteins may be combined with a variety of imaging agents for detection and diagnosis of tumors, and/or with a variety of radioactive or cytotoxic compounds for cancer treatment.