Injection of L19-mouse TNFα conjugate (L19mTNFα) induces a dramatic cell death of established tumors in several murine tumor models including the WEHI-164 fibrosarcoma, C51 colon carcinoma (67), and N2A neuroblastoma (65), because it allows therapeutically active doses of TNFα to be reached at the tumor site in which the cytokine increases intravasal coagulation and trombosis around the tumor, further favoring tumor necrosis. The gene discussed is TNF; the disease is fibrosarcoma.