Epidemiologic studies have reported an association between frequent consumption of well-done cooked meats and
prostate cancer risk. However, unambiguous physiochemical markers of DNA damage from
carcinogens derived from cooked meats, such as
DNA adducts, have not been identified in human samples to support this paradigm. We have developed a highly sensitive nano-LC-Orbitrap MS n method to measure
DNA adducts of several
carcinogens originating from well-done cooked meats, tobacco
smoke, and environmental pollution, including 2-amino-1-methyl-6-phenylimidazo[4,5-
b]pyridine (
PhIP), 2-amino-9H-pyrido[2,3-b]
indole (AαC), 2-amino-3,8-dimethylimidazo[4,5-f]
quinoxaline (MeIQx),
benzo[a]pyrene (B[a]P), and
4-aminobiphenyl (4-ABP). The limit of quantification (LOQ) of the major
deoxyguanosine (dG) adducts of these
carcinogens ranged between 1.3 and 2.2 adducts per 10 9
nucleotides per 2.5 μg of
DNA assayed. The
DNA adduct of
PhIP, N-(deoxyguanosin-8-yl)-PhIP (dG-C8-PhIP) was identified in 11 out of 35 patients, at levels ranging from 2 to 120 adducts per 10 9
nucleotides. The dG-C8 adducts of AαC and MeIQx, and the B[a]P adduct, 10-(deoxyguanosin-N 2 -yl)-7,8,9-trihydroxy-7,8,9,10-tetrahydrobenzo[a]
pyrene (dG-N 2 -B[a]PDE) were not detected in any specimen, whereas N-(deoxyguanosin-8-yl)-4-ABP (dG-C8-4-ABP) was identified in one subject (30 adducts per 10 9
nucleotides).
PhIP-
DNA adducts also were recovered quantitatively from
formalin fixed
paraffin embedded (FFPE) tissues, signifying FFPE tissues can serve as biospecimens for
carcinogen DNA adduct biomarker research. Our
biomarker data provide support to the epidemiological observations implicating
PhIP, one of the most mass-abundant heterocyclic aromatic
amines formed in well-done cooked meats, as
a DNA-damaging agent that may contribute to the etiology of
prostate cancer.