Induction of micronuclei and aneuploidy by the quinone-forming agents benzene and o-phenylphenol.

A number of carcinogens appear to exert their tumorigenic effects through the formation of quinone metabolites. These quinone-forming carcinogens are generally inactive or weakly active in standard gene mutation assays. Accumulating evidence indicates that this class of compounds may exert their genotoxic and carcinogenic effects through the induction of large-scale gene alterations. This article presents an overview of work that has been performed using recently developed molecular cytogenic techniques to investigate the aneuploidy-inducing and clastogenic properties of the major quinone-forming metabolites of benzene, a widely used industrial chemical, and o-phenylphenol, a fungicide and disinfectant. These metabolites of benzene (hydroquinone, catechol, and benzenetriol) and o-phenylphenol (phenylhydroquinone) have each been shown to be capable of interfering with chromosome segregation and inducing chromosomal breakage. These results indicate that both numerical and structural chromosomal aberrations induced by the quinone metabolites of benzene and o-phenylphenol may play a role in the carcinogenic effects of these two agents.