[Present and future cancer risk assessment of carcinogenic heterocyclic amines in humans]

Heterocyclic amines are formed during high temperature cooking of foods such as meat and fish. Although heterocyclic amines are known mutagens and some of them are shown to be carcinogenic to experimental animals, the carcinogenic potential of heterocyclic amines in humans has yet to be established. The most important criteria in determining the relationship between heterocyclic amines and human cancers are the strength and consistency of the association, the presence of a dose-response relationship, and the biological plausibility of heterocyclic amines being human carcinogens. To date, there are too few data to evaluate the strength, consistency, and dose response of this relationship in humans. To investigate cancer risk posed by heterocyclic amines to humans, an accurate estimation of exposure is needed. Validated methods for exposure assessment of heterocyclic amines are not available. At present, without any available long-term biomarkers of heterocyclic amines, it is crucial to improve exposure assessment. Most studies concerning the cancer risk assessment of heterocyclic amines are based on the exposure levels calculated only by information on the consumption of cooked foods and the mean levels of heterocyclic amines in cooked foods. Inaccurate exposure assessment can lead to incorrect cancer risk. This review describes the present and future problems of the exposure assessment and cancer risk assessment of heterocyclic amines.