Glabruquinone A (3-demethylubiquinone Q2, 11) is closely related to the ubiquinones, although lacking the methyl group in the quinoid moiety; it is not a cytotoxin but demonstrated good cancer preventive activity on JB6 Cl 41 cell transformation activated by epidermal growth factor (EGF). The gene discussed is EGF; the disease is cancer.