Human hair follicles, a convenient tissue for genetic studies on carcinogen metabolism

Basal levels of benzo(a)pyrene metabolism were measured in hair follicles of seven monozygotic twins, eight dizygotic twins and ten pairs of unrelated individuals. Organic soluble metabolites were separated by thin-layer chromatography, visualised by autoradiography and quantified by scanning of the films. Activity was expressed as pmol 7,8- and 9,10-dihydrodiol metabolites of benzo(a)pyrene per micrograms DNA per hour. Intra-twin differences in benzo(a)pyrene metabolism for monozygotic twins were smaller than for dizygotic twins and intra-pair differences for dizygotic twins were smaller for pairs of unrelated individuals. The results clearly suggest that individual differences in benzo(a)pyrene metabolism in hair follicles are partly genetically determined. Thus, hair follicles may be used for investigations on the suggested relations between genetic predisposition to carcinogen-induced cancer and individual differences in carcinogen metabolism. The relevance of these findings to research into the induction of neoplasms by carcinogens in epithelial tissues is discussed.