Utilization of Biomarker Data for Clinical and Environmental Intervention.

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Citation Christiani, David C. 1996. Utilization of biomarker data for clinical and environmental intervention. Environmental Health Perspectives 104: 921-925.

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Utilization of Biomarker Data for Clinical are difficult to detect in epidemiologic studies because the relative risk for low-level and Environmental Intervention exposed, versus nonexposed, people is only slightly elevated (2). Complicating this David C. Christiani problem is the generic aim ofexposure-dose Occupational Medicine and Epidemiology, Harvard School of Public assessment in field studies: imprecise methodology to quantify exposures, espe- Health, Boston, Massachusetts cially those which may have occurred years bias. Of the 189 air toxics listed in the Clean Air Act, a substantial number are important in potentially ago, can lead to misclassification and causing adverse health effects in several organ systems. Although the major health effects are Moreover, the temporal pace of the tradi- manifested as respiratory diseases, especially airways disease, these agents may cause cancer tional cohort study, which must await data and premature mortality, probably from cardiopulmonary disease. Validated biologic markers may from large populations exposed for long be useful in identifying early effects to improve our understanding of exposure-response relation- periods, has become an obstacle. Regulators, ships and clarify susceptibility. However, the knowledge obtained from epidemiologic studies uti- clinicians, and the public are too impatient lizing these new molecular tools will reduce morbidity and mortality from air toxics only when to await such "natural experiments," and they can be applied effectively in the prevention and control of disease. Intervention strategies seek shorter term strategies for studies and using these markers can be used to identify etiologic factors and assess the effectiveness of quicker solutions (2). exposure reduction, and, in some instances, chemoprevention. This paper illustrates examples of Since the concept of molecular epi- these intervention strategies and reviews the current strengths and limitations of environmental demiology was popularized in the early molecular epidemiology in controlling disease caused by air toxics. Environ Health Perspect 1980s (3) to describe an evolving approach 104(Suppl 5):921-925 (1996) to human environmental health research, Key words: biomarkers, intervention strategies, air toxics, molecular epidemiology much work has been done on biomarker development. The theoretical foundation of this work relies on three biologic tenets: a) early biologic effects from a toxic expo- Introduction sure are more prevalent and detectable in This symposium has described the current Much of what we have learned about the population at risk than clinical disease is; state-of-the-art research on biologic mark- the human health effects of toxic exposures b) with technological advances, many toxins ers that may be relevant to air toxics. The has come from epidemiologic studies of can be either directly quantified in body goal of such research is practical: to apply exposed workers and from toxicologic fluids or tissues or indirectly measured by relevant and valid biomarkers of exposure, studies on animals. Astute clinical observa- identification of some predictable, dose- effect, and susceptibility to epidemiologic tions and animal testing have provided the related (early) biological response; and studies of populations exposed to air toxics basis for large-scale epidemiologic studies c) either (or both) of the above may be and to incorporate the resulting informa- of workers exposed to toxic agents such as influenced by susceptibility phenomena tion into public health actions aimed at asbestos and vinyl chloride. The risk of dis- (heritable or nonheritable), which can also controlling exposures and adverse health eases caused by such agents are markedly be accounted for with recent advances in effects. Studies that incorporate the use of increased in exposed workers who have molecular biology. Combining these three biologic markers in human populations are usually been exposed to concentrations principles, a new approach to environmental often referred to as "molecular epidemio- much higher than the general population. health research has emerged that expands on logic studies." A conceptual approach to the However, in the case of community air the traditional epidemiologic paradigm. application of biologic markers to human pollution studies, new challenges have In addition to improved measures of populations is shown in Figure 1. The ulti- arisen. First, we must find ways to eluci- exposure, response, and susceptibility, mate goal for environmental molecular date factors that modestly increase disease side benefits emerge that have direct rele- epidemiology is to fulfill the promise of risk (1). Though such causes could be vance for intervention (4): contributions preventive medicine: environmental disease extremely important from a public health to the understanding of pathogenic mecha- prevention and control. point of view, these kinds of associations nisms at the tissue, cellular, or molecular

This paper was presented at the Conference on Air Toxics: Biomarkers in Environmental Applications Susceptibility held 27-28 April 1995 in Houston, Texas. Manuscript received 24 May 1996; manuscript accepted 5 June 1996. This work was supported by National Institutes of Health grants ES/CA 06409 and ES00002. Address correspondence to Dr. D.C. Christiani, Occupational Medicine and Epidemiology, Harvard School of Public Health, 665 Huntingdon Avenue, Boston, MA 02115. Telephone: (617) 432-3323. Fax: (617) 432-0219. E-mail: [email protected] Abbreviations used: PAH, polycyclic aromatic Figure 1. Relationship of biomarkers to exposure, susceptibility, and disease. Adapted from the National Research hydrocarbon; NAT, /\Nacetyltransferase; IL, interleukin. Council (36).

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levels, potential for more accurate and eti- simultaneously. Lead toxicity provides an of smokers and nonsmokers. DNA adducts ologic classification of environmental dis- example of this combined approach: regula- are formed when chemical carcinogens eases, and the possibility that recognition tory measures are concurrently aimed at react with DNA. Several methods of of early adverse effects could prompt reducing the whole population's exposure detecting adducts in lung and surrogate tis- strategies for secondary prevention or and at monitoring internal dose (blood lead) sue, including the sensitive 32P-postlabeling disease modification. ofindividual children by pediatricians. procedure for PAHs, have been described in Biomarker research does not exist in a These generic intervention strategies detail. Among the class of pulmonary car- vacuum. Its usefulness can only be real- have also been important in cancer preven- cinogens known as PAHs, benzo[a]pyrene ized when it translates into prevention tion and control, such as control of occupa- forms DNA adducts in the lung that are strategies to protect public health. In this tional bladder cancer by substitution of associated with smoking. Recent research short review, I describe how biomarkers benzidine dyes with less toxic compounds; indicates that surrogate tissue (blood may be used in clinical and environmental control of coke-oven-induced lung cancers mononuclear cells) adducts reflect target interventions. by engineering controls and personal protec- organ (lung) adducts in cancer patients tion; and control of bis-chloromethyl ether (Figure 2) (6). Such validation will permit Intervention Approaches induced lung cancer by elimination of that assessment of interventions such as smoking Intervention approaches in public health compound in plastic and glass production. cessation, chemoprevention, and elimina- can be characterized as either the high-risk tion of passive smoking exposures in reduc- or population approach (5). The high-risk Lung Cancer ing PAH-DNA adducts in peripheral approach aims to detect individuals at high Tobacco smoke is implicated in up to 85% blood mononuclear cells. Use of blood risk by using a biologic marker and lower- of the more than 150,000 lung cancer cases adducts will also permit epidemiologic ing risk by clinical intervention or other that occur in the United States every year. study of large populations exposed to action. Usually, the risk marker is moni- Despite the strong and consistent epidemi- PAHs in air pollution. tored concurrently with the intervention. ologic evidence linking tobacco smoking to Although the presence of PAH-DNA In contrast, population approach aims to cancer, the majority of smokers do not adducts has not been definitely associated reduce the overall occurrence of a risk fac- develop lung cancer. Individual variability with lung cancer, it is clear that these tor (exposure) in a population. in carcinogen metabolism may explain dif- adducts appear to be important in the Biologic markers may play different ferential susceptibility to tobacco-induced pathway leading to cancer (7), and inter- roles in each of these approaches. In the lung cancer. In recent years, molecular tech- ventions aimed at reducing their presence high-risk approach, a biologic marker is niques in the epidemiology of tobacco- in high risk individuals are on the horizon. used to either identify exposure or for early related cancer have been applied in three Focusing on this "upstream" marker of diagnosis of (preclinical) disease. For exam- areas: determination of internal and biologi- dose and early effect is particularly impor- ple, serum cholesterol is an exposure cally effective dose, detection of early bio- tant in lung cancer prevention, a condition marker of risk indicating biologically effec- logic effects, particularly mutations and for which there is no effective early detec- tive dose and can be monitored after phar- cytogenetic changes, and assessment of vari- tion marker and for which treatment is an macologic intervention. Other examples of ations in individual susceptibility to carcino- ineffective means of disease control. this approach are shown in Table 1. gens, mainly via metabolic polymorphisms. In recent years, mutations in specific An example of the population approach Among the 3800 chemicals that have genes can be used as "fingerprints" of is the prevention of childhood lead accu- been identified in tobacco smoke, a large specific exposures, as surrogate end points mulation and toxicity by mandating the number are biologically active compounds. of cancer, or for further subtyping of removal of lead from gasoline. In this The most important families of carcinogens cancer to clarify causal associations (8). approach, biomarkers have played an are polycyclic aromatic hydrocarbons Epidemiologic evidence suggests the important role in providing the scientific (PAHs), aromatic amines, nitroso com- association between chemical exposure, basis for regulation-an environmental pounds, volatile organic compounds (e.g., preventive, not clinical, intervention. benzene, formaldehyde), and radioactive 600- Biomarkers for lead continued to play an elements such as polonium-210. Chemical important role in monitoring the interven- compounds derived from tobacco smoke -o *O0 500- tion itself, demonstrating decrease popula- have been measured in biological specimens a) o c; tion lead burden. Other examples of this c,=400- E° approach are shown in Table 2. 0 CD In some instances, both high-risk and Table 2. Examples of population intervention approach. 0)u)CI 300 * 5 population approaches must be employed Problem Intervention 0 0 200 0 Occupational cancer Product substitution Table 1. Examples of high-risk intervention approach. z * / Engineering controls ioo1- /*.o Problem Intervention Lung cancer ETS control *S * S@ SW. Coronary heart disease Lower cholesterol Radon control Hypertension control Carbon monoxide poisoning Auto emission 0 50 100 150 200 250 Smoking cessation Controls MNC aromatic Lung cancer Smoking cessation Lead poisoning Removal of lead from DNA adducts/1010 nucleotides Radon control in home and gasoline paints Figure 2. Lung and peripheral blood mononuclear cell ETS, environmental tobacco smoke. (MNC) PAH-DNA adducts. r= 0.74; p < 0.001.

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tumor-suppressor gene (p53) and onco- aromatic amines (20). Those compounds Asthma in children is associated with gene (k-ras) mutation and cancer occur- have been shown to be associated with blad- atopy, family history, male gender, parental rence (9-13). Investigations concerning der cancer in smokers (21). Epidemiologic (especially maternal) smoking, and possibly the ras oncogene family or the p53 tumor- studies have suggested that the type of with acute respiratory illness in childhood. suppressor gene have considered the associ- tobacco associated with the highest risk of Genetic susceptibility to asthma is best ation between lung cancer and tobacco bladder cancer (air-cured tobacco) is also understood by studing its principal under- smoking. Results of these studies suggest richer in arylamines and that smokers of lying co-morbid conditions for which we that the mutational spectrum of lung air-cured tobacco have higher levels of have phenotype markers: a hypersensitive cancer depends on whether the person was 4-aminobiphenyl-hemoglobin adducts in state or atopy. Atopic individuals suffer a smoker and whether the person was their blood compared with smokers of from rhinitis, eczema, and the asthma syn- exposed to asbestos (14). flue-cured tobacco (22). Some arylamines drome. Up to 90% of asthmatics between Genetic susceptibility to lung cancer has (including 4-aminobiphenyl and 13-2- ages 5 and 40 are atopic (28). been examined in a number of epidemio- naphthylamine) are among the most The central feature of atopic-associated logic studies that incorporate molecular potent human carcinogens. Measurement bronchial asthma is the prolonged produc- markers of susceptibility to carcinogens. It of 4-aminobiphenyl-hemoglobin adducts tion of IgE to common inhaled antigens has been known for over 30 years that provides evidence of another biologically principally triggered by interleukin 4 (IL- smoking and family history are independent effective dose marker used in epidemio- 4) and T- and B-lymphocyte interaction risk factors for lung cancer risk (15). logic investigation. (29). IgE (molecular weight 190 kDa) is Additional evidence has been provided by Another common polymorphic trait in unique among the immunoglobulins in the study of metabolic polymorphisms, i.e., humans, the N-acetylation phenotype, mod- having a site at its Fc region with a high the different ability to metabolize chemical ulates the concentration of 4-amino- affinity for mast cells (which have a high- carcinogens. Traditional monogenic suscep- biphenyl-hemoglobin adducts in both affinity IgE receptor), but also affinity (via tibility to cancer is related to rare diseases smokers and nonsmokers (23). The N- low-affinity receptors) on T- and B-lym- (e.g., xeroderma pigmentosa, Li-Fraumeni acetyltransferase (NAT) polymorphism has phocytes, monocytes and eosinophils (30). syndrome) or small subgroups of common been associated with bladder cancer in epi- Allergen-specific IgE, bound to mast cells diseases (e.g., BRCA1 in familial breast demiologic studies. NAT is a noninducible in the bronchial epithelium, reacts with its cancer) and involves rare mutations that can enzyme that deactivates aromatic amines target antigen, resulting in activation and be identified through linkage analysis. (24). The slow acetylator genotype preva- degranulation of the mast cell. This results Polygenic susceptibility involves frequently lence is about 50% in the white population. in the release of a number of substances that occurring genetic polymorphisms, confers a Slow acetylators exposed to aromatic amines cause the immediate inflammatory response, low to medium elevation of risk for frequent have been reported to have an increased risk including histamine, prostaglandin PGD2, diseases, and is identified through epidemio- of bladder cancer, as well as higher levels of and leukotrienes, including LTE4 (slow- logic (usually case-control) studies. 4-aminobiphenyl adducts (25,26). reacting substance of anaphylaxis) (31). The Examples of this include the CYP2D6poly- late-phase bronchial inflammatory response morphism phenotype and lung cancer risk Nonmalignant Respiratory is associated with influx of CD4 T-lympho- (16) in whites and the CYPlA] and Disease: Asthma cytes and eosinophils (32), which may be GSTMI polymorphisms in lung and bladder During the last decade, a number of obser- partly recruited by release of IL-4 from acti- cancer, respectively, among Japanese (17). vations have raised the public health com- vated mast cells. Activated T-lymphocytes Recent work in the United States sug- munity's interest in asthma: a widespread recruit and activate eosinophils by a number gests that GSTM1 persons with low impression that asthma prevalence has of chemokines, especially IL-3 and IL-5 dietary intake of antioxidants are at high increased in all age groups, dramatic (33). The eosinophils release a number of risk of squamous cell carcinoma of the increases in hospital admissions for asthma, products which further activate mast cells. lung, in contrast to persons with null geno- an increase in asthma severity despite Eosinophils also release a range of potent type and high antioxidant intake (18), improved treatments, relatively abrupt mediators, including platelet-activating fac- after controlling for smoking intensity, changes in the prevalence and nature of tor, leukotrienes, and prostaglandins, and duration, age, and time since quitting asthma in some populations, and an activate radicals, which contribute to further smoking. This kind of investigation may increase in reported asthma mortality from inflammatory change (34). lead to antioxidant chemoprevention in ex- several countries (27). Despite difficulties Asthma is an inflammatory airway dis- smokers and illustrates a dual clinical in defining asthma epidemiologically, there order, and the airway response to allergens approach to disease control: exposure cessa- is some evidence to suggest that the true is mediated through complex mechanisms tion combined with cumulative risk prevalence of asthma has been increasing involving airway inflammation. Current modification on the secondary level. If overall, and there is strong evidence to sup- environmental asthma research has focused genotype-lung cancer risk is modified by a port an increasing prevalence in developing on how pollutants influence acute airway factor amenable to intervention, such as countries and migrant populations. Asthma inflammatory responses in individuals with dietary intake of antioxidants (19), then appears to be more prevalent in Australia, different host characteristics, including air- dietary changes and/or supplementation New Zealand, Canada, and England than way responsiveness, IgE antibody isotype, may be a useful intervention strategy for in the United States and Scandinavia. The and major histocompatibility complex class individuals who are attempting to quit or role of air pollution (outdoor and indoor) II allotypes. We need to understand how have already quit smoking. in the etiology, severity, and progression of host factors modify an individual's acute Tobacco smoke contains significant asthma is a topic of active investigation in airways response to air pollutants. For amounts of another class of carcinogens, many countries today. example, host factors characteristic of atopy

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may contribute to up-regulation of and composition of the cellular infiltrate in Conclusions modification of the inflammatory response the airways after pollutant exposure. Current biomarker research in environ- to nonantigenic pollutants (and vice versa). A second possible mechanism of pollu- mental health has fostered the development There are biomarkers of susceptibility tant-associated airway hyperresponsiveness of a new research endeavor, molecular epi- and effect available in the study of asthma. was suggested by Fujimaki et al. (35), who demiology, which expands upon the tradi- Investigation of the genetic susceptibility of showed that, in mice, inhaled particulate tional toxicologic or epidemiologic research atopic asthma has led to direct assay of IgE pollutants enhance or stimulate IgE anti- paradigms. This development has led to responsiveness. Measurement of total body production. Fly ash and aluminum sil- exciting opportunities in environmental serum IgE by solid-phase immunoassay icate instilled to the lung acted as adjuvants health research, which will add greatly to offers one method of high-risk phenotype for production ofIgE and IgG antibody. our understanding of the human health analysis. Altered structure/function can be Even as our knowledge of the patho- effects of toxic exposures. However, much easily measured using standardized genesis of asthma increases, additional more basic research in environmental mol- bronchial challenge testing with histamine areas of uncertainty continue to arise. The ecular epidemiology needs to be accom- or methacholine. complex interaction between pollutants, plished before effective environmental and Baseline (preexposure) airway hyperre- allergens, and host characteristics in asthma clinical interventions can be instituted for sponsiveness may modify the airway remain unclear. However, mechanistic diseases such as cancer and neurologic dis- response to pollutants, leading to an research has expanded the range of poten- orders. The basis of such interventions will altered inflammatory response, which in tial biomarkers available for the study of be exposure-disease associations, dose- turn may lead to a positive feedback loop asthma and air pollution. Borrowing from response relationships, detection of early whereby the altered inflammatory response the paradigm used for cancer, these are pathophysiological effects of exposure, and further increases airway reactivity. obvious parallels in the research approach gene-environment interactions. Realiz- Repeated episodes of pollutant exposure that can be used to elucidate the causal ation of our goal to prevent disease from may subsequently lead to airway hyperre- pathway between exposure and asthma. air toxics will require expanded multidisci- sponsiveness and clinical asthma. A possi- Clarifying these events may help to guide plinary research efforts in both toxicology ble mechanism of this proposed feedback environmental interventions aimed at min- and epidemiology. phenomenon is that increased airway imizing exposure to the whole popultion responsiveness, as well as other host fac- and guide clinical interventions focused at tors, may modulate the intensity and high-risk individuals.

REFERENCES 1. Robins JM, Cullen MR, Welch LS. Improved methods for dis- asbestos. IntJ Cancer 53:250-256 (1993). cerning health impacts of current technologies. In: 12. Suzuki H, Takahashi T, Kuroishi T, Suyama M, Ariyoshi Y, Environmental Impacts on Human Health (Draggen S, Takahashi T, Ueda R. p53 Mutations in non-small cell lung Cohrssen JJ, Morrisson RE, eds). New York:Praeger, cancer in Japan: association between mutations and smoking. 1987;165-192. Cancer Res 52:734-736 (1992). 2. Cullen MR. The role of clinical investigations in biological 13. Vahakangas KH, Samet JM, Metcalf RA, Welsh JA, Bennett marker research. Environ Res 50:1-10 (1989). WP, Lane DP, Harris CC. Mutations of p53 and ras genes in 3. Perrera FP, Weinstein IB. Molecular epidemiology and car- radon-associated lung cancer from uranium miners. Lancet cinogen-DNA adduct detection: new approaches to studies of 339:576-580 (1992). human cancer causation. J Chron Dis 35:581-600 (1982). 14. Wang X, Christiani DC, Wiencke JK, Fischbein M, Xu XP, 4. Hulka BS, Wilcosky T. Biological markers in epidemiologic Cheng TJ, Mark E, Wain JC, Kelsey KT. Mutations in the p53 research. Arch Environ Health 43:83-89 (1988). gene in lung cancer are associated with cigarette smoking and 5. Rose G. The Strategy of Preventive Medicine. Oxford:Oxford asbestos exposure. Cancer Epidem Biomarkers Prev 4:543-548 University Press, 1992. (1995). 6. Wiencke J, Varkonyi A, Semey K, Kelsey K, Wain J, Mark E, 15. Sellers TA, Bailey-Wilson JE, Elston RC, Wilson AE, Elston Christiani D. Validation of blood mononuclear cell DNA- RC, Rotschild H. Evidence for Mendelian inheritance in the adducts as a marker of DNA damage in human lung. Cancer pathogenesis of lung cancer. J Natl Cancer Inst 82:1272-1279 Res 55:4910-4915 (1995). (1990). 7. Wogan GN, Gorelick NS. An overview of chemical and bio- 16. Amos CI, Caporaso NE, Weston A. Host factors in lung cancer chemical dosimetry of exposure to genotoxic chemicals. risk: a review of interdisciplinary studies. Cancer Epidemiol Environ Health Perspect 62:5-18 (1985). Biomarkers Prev 1:505-513 (1992). 8. McMichael AJ. "Molecular epidemiology": new pathway or 17. Nakachi K, Imai K, Hayashi S, Kawajiri K. Polymorphisms of new traveling companion? Am J Epidemiol 40:1-11 (1994). the CYPlAI and glutathione S-transferase genes associated 9. Hollstein M, Sidransky D, Vogelstein B, Harris CC. p53 with susceptibility to lung cancer in relation to cigarette dose in Mutations in human cancers. Science 253:49-53 (1991). a Japanese population. Cancer Res 53:2994-2999 (1993). 10. Slebos RJC, Hruban RH, Dalesio 0, Mooi WJ, Offerhaus JA, 18. Garcia-Closas M, Kelsey KT, Wiencke J, Christiani DC. Rodenhuis S. Relationship between K-ras oncogene activation Nutrient intake as a modifier of the association between lung and smoking in adenocarcinoma of the human lung. J Natl cancer and glutathione S-transferase p deletion. In: Proceedings Cancer Inst 83:1024-1027 (1991). of the Eighty-sixth Annual Meeting of the American 11. Husgafvel-Pursiainen K, Hackman P, Ridanpaa M, Anttila S, Association for Cancer Research, Toronto, Canada, 1995;28 1. Karjalainen A, Partanen T, Taikina-aho 0, Heikkila L, Vainio 19. Ames BN, Shinenaga MK, Hagen TM. Oxidants, antioxidants H. K-ras mutations in human adenocarcinoma of the lung: and the degenerative diseases of aging. Proc Natl Acad Sci USA association with smoking and occupational exposure to 90:7915-7922 (1993).

924 Environmental Health Perspectives * Vol 104, Supplement 5 * October 1996 BIOMARKERS FOR INTERVENTION

20. Patrianakos C, Hoffman D. Chemical studies of tobacco inducers, host characteristics. Thorax 36:641-644 (1981). smoke, LXIV. On the analysis of aromatic amines in cigarette 29. Kay AB, Corrigan CJ, Frew AJ. T lymphocytes and Asthma. smoke. J Anal Chem 3:150-154 (1979). In: Asthma: Its Pathology and Treatment (Kaliner MA, Barnes 21. Vineis P. Epidemiological models of carcinogenesis: the exam- PJ, Persson CGA, eds). New York:Marcel Dekker, 1991; ple of bladder cancer. Cancer Epidemiol Biomarkers Prev 247-265. 1:149-153 (1992). 30. Delespesse G, Sarfati M, Wu CY, Fournier S, Letellier M. The 22. Bartsch H, Caparaso N, Coda M, Kadlubar F, Malaveille C, low affinity receptor of IgE. Immunol Rev 125:77-88(1992). Skipper P, Talaska G, Tannenbaum SR, Vineis P. Carcinogen 31. Holgate ST. In: Horizons in Medicine (Boryriewicz LK ed), hemoglobin adducts, urinary mutagenicity, and metabolic phe- Cambridge, UK:Cambridge University Press, 1990; 1-15. notype in active and passive smokers. J Natl Cancer Inst 32. Azzawi M, Bradley B, Jeffrey PK, Frew A, Wardlaw AJ, 82:1826-1831 (1990). Knowles G, Assoufi B, Collins JV, Durham S, Kay AB. 23. Talaska G, Dooley KL, Kadlubar FF. Detection and characteri- Identification of activated T lymphocytes and eosinophils in zation of carcinogen-DNA adducts in exfoliated urothelial cells bronchial biopsies in stable atpic asthma. Annu Rev Respir Dis from 4-aminoliphenyl-treated dogs. Carcinogenesis 142:1407-1413 (1990). 11:639-646 (1990). 33. Kay AB, Ying S, Varney V, Gaga M, Durham SR, Moqbel R, 24. Heim DW. Acetylator genotype and arylamine-induced car- Wardlaw AJ, Hamid Q. Messenger RNA expression of the cinogenesis. Biochim Biophys Acta 948:37-66 (1988). cytokine gene cluster, interleukin-3 (IL-3), IL-4, IL-5, and 25. Vineis P, Caporaso N, Tannenbaum SR, Skipper PL, granulocyte/macrophage colony-stimulating factor in allergen- Glogowski J, Bartsch H, Coda M, Talaska G, Kadlubar FF. induced late-phase cutaneous reactions in atopic subjects. J Exp Acetylation phenotype, carcinogen-hemoglobin adducts and Med 173:775-778 (1991). cigarette smoking. Cancer Res 50:3002-3004 (1990). 34. Venge P. What is the role of the eosinophil? Thorax 26. Vineis P, Bartsch H, Caporaso N, Harrington A, Kadlubar FF, 45:161-163 (1990). Landi MT, Malaveille C, Shields P, Skipper P, Talaska G, 35. Fujimaki H, Kawagoe A, Ozawa M, Yonemoto J, Watanabe N. Tannenbaum SR. Genetically-based N-acetyltransferase meta- Effects of instillation of fly ash in the lung: physiochemical bolic polymorphism and low-level environmental exposure to properties and immune responses. Am Rev Respir Dis carcinogens. Nature 369:154-156 (1994). 140:525-528 (1989). 27. Sears MR, Rea HH, Beaglehole R. Asthma mortality: a review 36. Biological Markers in Environmental Health Research, of recent experience in New Zealand. J Allergy Clin Immunol National Research Council. Environ Health Perspect 77:3-9 80:319-325 (1987). (1987). 28. Dolovich J and Hargreave FE. The asthma syndrome: inciters,

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