“…The prototype drug in this class is mitomycin C (MMC) (Rockwell et al, 1993), which is used in the treatment of breast (Hortobagyi, 1993), non-small-cell lung (Spain, 1993), head and neck (Coia, 1993), colorectal (Cummings et al, 1993) and gastric (Fujita et al, 1998) cancer. Interest in bioreductive agents has been raised by recent studies of combination treatment of MMC with radiation (Boyer, 1997), and by new agents, such as 3-hydroxymethyl-5-aziridinyl-1-methyl-2(1H-indole-4,7-dione)prop-β-en-α-ol (EO9) (Schellens, 1994) and tirapazamine (Bedikian et al, 1997;Miller et al, 1997). The one-electron reducing enzyme, NADPH:cytochrome P450 reductase (EC 1.6.2.4), may be the most important activating enzyme for MMC (Rockwell, 1993), but NAD(P)H:(quinone acceptor) oxidoreductase [EC 1.6.99.2] (DT-diaphorase), a two-electron reducing enzyme, is also a major activator in many systems (Begleiter et al, 1989(Begleiter et al, , 1992Riley and Workman, 1992;Ross et al, 1993).…”