Clinical trials of recombinant human TNF were unable to deliver therapeutic doses systemically because of toxicity (Spriggs and Yates, 1992), but TNF is highly effective in conjunction with chemotherapy in isolated limb perfusion for melanoma and sarcoma, where it has been shown to have selective tumour vascular effects (Lejeune et al, 1998; Ruegg et al, 1998; Eggermont and ten Hagen, 2001). The gene discussed is TNF; the disease is neoplasm.