title: Biomonitoring the cooked meat carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine in hair: impact of exposure, hair pigmentation, and cytochrome P450 1A2 phenotype.
abstract: BACKGROUND
  Hair is a promising tissue to assess exposure to 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a carcinogen formed in cooked meats. However, an understanding of how dietary exposure to PhIP, cytochrome P450 1A2 activity-a key enzyme involved in PhIP metabolism, and hair pigmentation affect the level of PhIP accrued in hair is required to determine the reliability of the PhIP hair level as a biomarker of exposure to this carcinogen.
  
  
  METHODS
  We examined the impact of PhIP exposure, cytochrome P450 1A2 activity, and hair pigmentation on the levels of PhIP accumulated in the hair of volunteers on a 4-week semicontrolled diet of cooked meat containing known quantities of PhIP.
  
  
  RESULTS
  The amount of PhIP in hair increased, on average, 15-fold in light- and dark-haired individuals during consumption of cooked meat. PhIP levels in hair were correlated to PhIP intake (ρ = 0.53; P < 0.001), and the relationship was strengthened when PhIP levels were normalized for the melanin content of hair (ρ = 0.71; P < 0.001). However, PhIP accrual in hair was not correlated to cytochrome P450 1A2 activity, as assessed by the caffeine test, or to the levels of unmetabolized PhIP in urine or to the metabolic ratio of the major urinary metabolite N(2)-(β-1-glucosiduronyl-2-(hydroxyamino)-1-methyl-6-phenylimidazo[4,5-b]pyridine to unmetabolized PhIP.
  
  
  CONCLUSIONS
  The use of the PhIP hair biomarker should take hair pigmentation into account for accurate exposure assessment of PhIP.
  
  
  CONCLUSIONS
  PhIP hair levels can serve as a biomarker in epidemiologic studies investigating the association of heterocyclic aromatic amine (HAA), cooked meat, and cancer risk.
authors: Corresponding Authors: Robert J. Turesky, Division of Environmental Health Sciences, Wadsworth Center, Albany, NY 12201, USA. Rturesky@wadsworth.org
authors: Robert J
authors: RJ
authors: Turesky
authors: Lin
authors: L
authors: Liu
authors: Dan
authors: D
authors: Gu
authors: Kim M
authors: KM
authors: Yonemori
authors: Kami K
authors: KK
authors: White
authors: Lynne R
authors: LR
authors: Wilkens
authors: Loïc
authors: L
authors: Le Marchand
mesh_terms: D000293:Adolescent; D015415:Biomarkers / Q000032:analysis*; D002273:Carcinogens / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D003296:Cooking; D019388:Cytochrome P-450 CYP1A2 / Q000235:genetics*; D016903:Drug Monitoring; D005260:Female; D006197:Hair / Q000737:chemistry*; D006200:Hair Color; D006801:Humans; D007093:Imidazoles / Q000032:analysis*; D008297:Male; D008460:Meat; D010641:Phenotype; D011379:Prognosis; D016482:Urinalysis
chemical_list: D015415:Biomarkers; D002273:Carcinogens; D007093:Imidazoles; C049584:2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine; D019388:Cytochrome P-450 CYP1A2