We have already reported the mechanisms of the anti-proliferative effects of IFN-α/5-FU combination therapy, including regulation of cell cycle progression by increasing S-phase fraction (Eguchi et al, 2000), induction of apoptosis through IFNAR2, by downregulating Bcl-xl and by Fas/FasL pathway (Kondo et al, 2005; Damdinsuren et al, 2007; Nakamura et al, 2007; Nagano et al, 2007a), modulation of the immune response by inducing the TRAIL/TRAIL-receptor pathway (Yamamoto et al, 2004) and inhibition of tumour angiogenesis (Wada et al, 2007). The gene discussed is FAS; the disease is neoplasm.