Polymorphisms of xenobiotic-metabolizing enzymes and susceptibility to cancer.

The variation in individual responses to exogenous agents is exceptionally wide. It is because of this large diversity of responsiveness that risk factors to environmentally induced diseases have been difficult to pinpoint, particularly at low exposure levels. Opportunities now exist for studies of host factors in cancer or other diseases in which an environmental component can be presumed. Many of the studies have shown an elevated disease proneness for individuals carrying the potential at-risk alleles of metabolic genes, but a number of controversial results have also been reported. This article is an overview of the data published to date on metabolic genotypes related to individual susceptibility to cancer.