A water-soluble, synthetic aziridinylbenzoquinone with potential antineoplastic activity. Bioactivation of aziridinylbenzoquinone RH1 occurs through the two-electron reduction of the quinone to the hydroquinone by the two-electron quinone reductase DT-diaphorase (DTD). The resultant hydroquinone selectively alkylates and cross-links DNA at the 5'-GNC-3' sequence, inihibiting DNA replication, inducing apoptosis, and inhibiting tumour cell proliferation. DTD is over-expressed in many tumours relative to normal tissue, including lung, colon, breast and liver tumors.