Whereas the cytotoxic drugs preferentially target tumour cells, TNF mainly affects the tumour associated vasculature, possibly resulting in destruction of the vessels and augmented accumulation of the drugs in the tumour tissue (Eggermont et al, 1997; de Wilt et al, 2000c; ten Hagen et al, 2000; Van Der Veen et al, 2000). This evidence concerns the gene TNF and neoplasm.