Table 2.
Priority chemicals for breast cancer–relevant epidemiology and biomonitoring.
| Chemical | Common exposure sources | Biomarkers |
|---|---|---|
| 1,3-Butadiene | Gasoline, vehicle exhaust, tobacco smoke, heating of some cooking oils | DNA and hemoglobin adducts in blood, derived from epoxide metabolites; mercapturic acid metabolites in urine |
| Acrylamide | Cooked food, tobacco smoke, water-treatment by-products, some consumer products | Hemoglobin adducts of acrylamide and glycidamide in blood; urinary mercapturic acid metabolites of acrylamide and glycidamide |
| Aromatic amines I: TDA and TDIs | Uncured or newly finished polyurethane foam, spray-in insulation, sealants and coatings, some breast implants | TDA and hemoglobin adducts in blood, TDA in urine (Most studies have tested occupationally exposed populations, but many find TDA in “unexposed” controls) |
| Aromatic amines II: benzidine and aniline dyes, combustion products, other | Hair and textile dyes; used in the production of paints, printing inks, liquid crystal displays, and inkjet and laser printers, and in the food industry | Parent compound in blood or urine; DNA and hemoglobin adducts in blood or breast milk |
| Benzene | Gasoline, vehicle exhaust, tobacco smoke, solvents | DNA and protein adducts in blood and dried blood spots; urinary metabolites sPMA (specific to benzene) and ttMA (metabolite of benzene and the common food preservative sorbate) |
| Halogenated organic solvents (e.g., methylene chloride) | Dry cleaning, spot remover, glues, degreasers, paint strippers, aerosol propellants, contaminated drinking water (Use is decreasing over time) | Parent compound in whole blood and urine Infrequently detected in blood from general population but widespread occupational exposure has been documented; parent compounds have been detected in urine from occupationally exposed populations, and methylene chloride has been detected in urine from general population |
| Ethylene oxide, propylene oxide | Tobacco smoke, food and medical sterilization, vehicle exhaust, paint | DNA and hemoglobin adducts in blood; mercapturic acid metabolites in urine |
| Flame retardants and degradation products [2,2-bis(bromomethyl)-1,3-propanediol, 2,3-dibromo-1-propanol] | Flame retardants; primarily used in plastics and foams | Parent compound or metabolite in urine |
| Heterocyclic amines | Grilled meat | Parent compound, protein adducts, and DNA adducts in blood; parent compound in urine and hair |
| Hormones and endocrine disruptors (e.g., endogenous and exogenous estrogens and estrogen mimics) | Pharmaceutical hormones, consumer products, and commercial chemicals with hormonal activity | Clinical and research methods are available to measure endogenous hormone levels in blood and urine; the MCF-7 cell proliferation assay has been used to measure estrogenic activity in extracts of adipose tissue from breast cancer cases and controls; development of methods to conduct this assay in blood, and to distinguish endogenous and exogenous estrogen signals, would allow integrated assessments of exposure to xenoestrogens |
| MX | Water disinfection | Urinary trihaloacetic acids are used as exposure biomarkers for chlorinated drinking water, but improved exposure biomarkers are needed for MX and other highly genotoxic disinfection by-products |
| Nitro-PAHs (e.g., 1-nitropyrene) | Diesel exhaust | Hemoglobin adducts in blood, metabolites in urine |
| Ochratoxin A | Mycotoxin in grains, nuts, pork; also present in moldy environments | Ochratoxin A and its metabolites in blood, urine, breast milk |
| PAHs (e.g., BaP) | Vehicle exhaust, tobacco smoke, charred food | Protein adducts and DNA adducts in blood; oxidized metabolites in urine; parent compounds measured in hair, breast milk (Improved exposure biomarkers are needed) |
| PFOA, related compounds | Grease-, water-, and stainproof coatings; contaminated drinking water | Parent compound in blood and breast milk |
| Pharmaceuticals (nonhormonal) | A number of over-the-counter, veterinary, and prescription medicines that induce mammary tumors | Few exposure biomarkers have been developed for use in the general population, but in many cases LC-MS/MS methods have been reported for the parent compound in plasma or metabolites in urine; in some cases exposure can be ascertained from self-report or medical records |
| Styrene | Building materials and consumer products made from polystyrene; indoor air, cigarette smoke, polystyrene food packaging | Parent compound in whole blood; urinary mercapturic and mandelic acid metabolites |
| Abbreviations: BaP, benzo[a]pyrene; LC-MS/MS, liquid chromatography–tandem mass spectrometry; PFOA, perfluorooctanoic acid; sPMA, S-phenylmercapturic acid; TDA, 2,4-toluene diamine; TDI, toluene diisocyanates; ttMA, trans, trans-muconic acid. For more information, including a list of chemicals in each group, see Supplemental Material, Table S1. | ||