TNF and cancer: TNF-α and IL-6, which are pleiotropic cytokines, may have anti-tumour properties (Gluckman et al, 1997; May et al, 1988; Tanaka et al, 1997), and may be of benefit as chemotherapy agents in experimental cancer and even in the clinical treatment of colorectal cancer (de Vries et al, 1998, 1999; Lindner et al, 1999; Scheid et al, 1994; Tomita et al, 1998), and might act in synergy with conventional chemotherapeutics such as 5-FU (Oka et al, 1997; Watanabe et al, 1988).