Potent arylhydrocarbon receptor (AhR) ligands,4 benzothiazoles induce their own cytochrome P450‐mediated (CYP 1A1; CYP 2W1) biotransformation to electrophilic nitrenium species in sensitive tumour cells only.5, 6 These reactive species generate DNA adducts (N7‐guanine), which lead to lethal double DNA strand breaks7, 8—exclusively in cancer cells expressing cytosolic AhR and inducible CYP1A1 or CYP2W1. The gene discussed is CYP1A1; the disease is cancer.