Biomarkers Of Environmental Exposure Research Articles

Aristolactam-DNA adducts are a biomarker of environmental exposure to aristolochic acid

Endemic (Balkan) nephropathy is a chronic tubulointerstitial disease frequently accompanied by urothelial cell carcinomas of the upper urinary tract. This disorder has recently been linked to exposure to aristolochic acid, a powerful nephrotoxin and human carcinogen. Following metabolic activation, aristolochic acid reacts with genomic DNA to form aristolactam-DNA adducts that generate a unique TP53 mutational spectrum in the urothelium. The aristolactam-DNA adducts are concentrated in the renal cortex, thus serving as biomarkers of internal exposure to aristolochic acid. Here, we present molecular epidemiologic evidence relating carcinomas of the upper urinary tract to dietary exposure to aristolochic acid. DNA was extracted from the renal cortex and urothelial tumor tissue of 67 patients that underwent nephroureterectomy for carcinomas of the upper urinary tract and resided in regions of known endemic nephropathy. Ten patients from nonendemic regions with carcinomas of the upper urinary tract served as controls. Aristolactam-DNA adducts were quantified by (32)P-postlabeling, the adduct was confirmed by mass spectrometry, and TP53 mutations in tumor tissues were identified by chip sequencing. Adducts were present in 70% of the endemic cohort and in 94% of patients with specific A:T to T:A mutations in TP53. In contrast, neither aristolactam-DNA adducts nor specific mutations were detected in tissues of patients residing in nonendemic regions. Thus, in genetically susceptible individuals, dietary exposure to aristolochic acid is causally related to endemic nephropathy and carcinomas of the upper urinary tract.

Blood/air distribution of volatile organic compounds (VOCs) in a nationally representative sample

Volatile organic compounds (VOCs) in human blood are an effective biomarker of environmental exposure and are closely linked to health outcomes. Unlike VOC concentrations in air, which are routinely collected, blood VOC data are not as readily available. This study aims to develop the quantitative relationship between air and blood VOCs by deriving population-based blood/air distribution coefficients (popKs) of ten common VOCs in the general U.S. population. Air and human blood samples were collected from 364 adults aged 20–59years in 1999–2000 National Health and Nutrition Examination Survey (NHANES). Determinants of popKs were identified using weighted multivariate regression models. In the non-smoking population, median popKs ranged from 3.1 to 77.3, comparable to values obtained in the laboratory. PopKs decreased with increasing airborne VOC concentrations. Smoking elevated popKs by 1.5–3.5 times for aromatic compounds, but did not affect the popKs for methyl tert-butyl ether (MTBE) or chlorinated compounds. Drinking water concentration was a modifier of MTBE's popK. Age, gender, body composition, nor ethnicity affected popKs. PopKs were predictable using linear models with air concentration as the independent variable for both adults and children. This is the first study to estimate blood/air distribution coefficients using simultaneous environmental and biological monitoring on a national population sample. This study was also the first to determine the blood/air distribution coefficient of p-dichlorobenzene, a compound frequently found in indoor environments. These results have applications in exposure assessment, pharmacokinetic analysis, physiologically-based pharmacokinetic (PBPK) modeling, and uncertainty analysis.

ANALYSIS OF TRACE ELEMENTS IN PRE- AND POST-NATAL TOOTH ENAMEL USING MICRO-PIXE

Naturally shed deciduous teeth are potentially useful as a biomarker of environmental exposure. To assess the prenatal environment of child, we tried to present the neonatal line on the elemental maps and investigate the trace elements in pre- and post-natally formed tooth enamel using micro-PIXE. Generally, the neonatal line is observed more clearly in the tooth from child who has some difficulties at birth. In this study, five deciduous teeth from five children with developmental disorders were used for analysis. Seven trace elements ( Na , Mg , Si , Cl , Fe , Zn , and Sr ) were detected in enamel of all five teeth. The line, it was thought neonatal line, was observed on the elemental map of Ca and P in the tooth from the child with serious birth complications. In order to compare the elemental concentration between pre- and post-natal enamel, concentration variation of elements were projected along the line perpendicular to the neonatal line. Lower Ca concentration in prenatal enamel was observed. By tracing the location of neonatal line on the other elemental maps, the concentrations of detected trace elements were compared in the same way. The differences of concentration of these trace elements between pre- and post-natal enamel were not clear because of much statistic variation. We could determine the trace elemental profiles and concentrations around the neonatal line in the enamel from the child with serious birth complications.

Aristolactam-DNA adducts are a biomarker of environmental exposure to aristolochic acid

Aristolactam-DNA adducts are a biomarker of environmental exposure to aristolochic acid

Pilot Study of Environmental Monitoring of Konya Region near Abandoned Mercury Mine in Turkey

Abandoned mines are an important global concern and continue to pose potential threats to human health including environmental damage/s. There is not any specific regulation for mining wastes in Turkey and this situation puts the mining wastes into the dangerous category. Therefore, this study focuses on the environmental effects of the abandoned mercury mines. To demonstrate environmental mercury contamination, fish samples were collected from two different regions which were contaminated and uncontaminated region. As a biomarker of environmental exposure the levels of Hg in fish samples were measured by Cold Vapor-Atomic Absorption Spectrometry (CVAAS). In fish samples, the levels of Hg were 0.504 ± 0.475 (mg/kg) (Mean ± SD) in Group 1 and 0.04 ± 0.054 (mg/kg) (Mean ± SD) in Group 2. Our data suggested that although mercury mine was closed long time ago, mining waste is still a problem and continues to contaminate the environment.

Abstract 4641: Cumulative body burdens of polycyclic aromatic hydrocarbons associate with estrogen bioactivation in pregnant women: Protein adducts as biomarker of exposure

Abstract The objective of this research was to develop a biochemical assay to simultaneously analyze protein adducts of quinonoid metabolites of polycyclic aromatic hydrocarbons (PAHs) and endogenous estrogen in pregnant women in Taiwan and to explore the correlations among them. The methodology, which employs trifluoroacetic acid anhydride (TFAA) and methanesulfonic acid (MSA) to selectively cleave cysteinyl adducts, had previously been applied to measure benzene and naphthalene adducts in albumin (Alb). In this study, we refined the assay to allow measurements of both naphthoquinone- and estrogen quinone-derived adducts in serum albumin derived from pregnant women in Taiwan. The isomeric forms of cysteinyl adducts of naphthoquinones, including 1,2-naphthoquinone (1,2-NPQ) and 1,4-naphthoquinone (1,4-NPQ) as well as estrogen quinones, including estrogen-2,3-quinones (E2-2,3-Q) and estrogen-3,4-quinones (E2-3,4-Q), are characterized by using isotopically-labelled bound internal standards after adducts cleavage by the TFAA/MSA derivatization procedure. We applied this method to analyze the background levels of cysteinyl adducts of naphthalene- and estrogen-derived quinones on human serum albumin(Alb)derived from healthy pregnant women (n=40) and their respective umbilical cords (n=40). Results showed that the background levels of cysteinyl adducts of 1,2-NPQ and 1,4-NPQ on human serum albumin were at levels ranging from 89-941 and 33-615 pmol/g, respectively. Logged levels of 1,2-NPQ-Alb were correlated with logged levels of 1,4-NPQ-Alb (correlation coefficient r=0.500, p<0.001). In addition, cysteinyl adducts of E2-2,3-Q-1-S-Alb, E2-2,3-Q-4-S-Alb and E2-3,4-Q-2-S-Alb were detected in most of the subjects with median levels at 325, 457, and 592 pmol/g, respectively. We also found a significantly positive relationship between logged levels of E2-2,3-Q-4-S-Alb and those of E2-3,4-Q-2-S-Alb (r = 0.537, p<0.001). We noticed that logged levels of 1,2-NPQ-Alb are positively and significantly associated with increasing logged levels of E2-3,4-Q-2-S-Alb (r = 0.539, p<0.001). This evidence suggests that environmental exposure to PAHs may enhance the production of reactive quinone species of endogenous estrogen in human. Overall, we conclude that the methodology developed in this study may be applied to epidemiological study to serve as biomarkers of environmental exposure to PAHs and other modulators of estrogen homeostasis. (This work was supported by the National Science Council, Taiwan, through grant NSC99-2314-B-005-001-MY3) Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4641. doi:10.1158/1538-7445.AM2011-4641

Spatial distribution of manganese in enamel and coronal dentine of human primary teeth

Emerging evidence indicates that excessive exposure to manganese (Mn) during the prenatal period and early childhood may result in neurodevelopmental deficits. However, accurate exposure biomarkers are not well established, limiting our understanding of exposure–response relationships over these susceptible periods of development. Naturally shed deciduous teeth are potentially a useful biomarker of environmental exposure to Mn. However, the uptake and distribution of Mn in human teeth has not been studied in detail. Mn distribution was measured at high resolution (~ 20 μm) in eight human primary teeth using laser ablation-inductively coupled plasma-mass spectrometry. A bio-imaging methodology was applied to construct detailed elemental maps of three incisors, and bone meal (NIST SRM 1486) was used to validate the analyses. The distribution of Mn in enamel and coronal dentine showed a distinct and reproducible pattern. In enamel, the 55Mn: 43Ca ratio was highest at the outer edge of enamel (range = 0.57 to 4.74) for approximately 20–40 μm but was substantially lower in deeper layers (range = 0.005 to 0.013). The highest levels of Mn were observed in dentine immediately adjacent the pulpal margin ( 55Mn: 43Ca range = 2.27 to 6.95). Importantly, a clearly demarcated high Mn zone was observed in dentine at the incisal end of the teeth. Using confocal laser scanning microscopy to visualize the neonatal line, this region was identified as being in the prenatally formed dentine. The high-resolution map of the spatial distribution of Mn in human primary teeth highlighted specific reproducible patterns of Mn distribution in enamel and coronal dentine.

Creatinine in Spot Urine Samples: Sources of Variation and the Adjustment of Urinary Biomarkers Among Roofers Exposed to Asphalt

PP-30-056 Background/Aims: Urinary biomarkers of environmental exposures and early effects are often reported with respect to levels of urinary creatinine. This study investigates sources of variation of urinary creatinine and the effects of adjustment on urinary 1-hydroxypyrene (1-OHPyr) and 8-hydroxy-2′-deoxyguanosine (8-OHdG). Methods: Urine samples were collected from 19 roofers in South Florida before and after 6 hours of work. 1-OHPyr was analyzed though LC-MS/MS, 8-OHdG was analyzed by enzyme-linked immunosorbent assay, and creatinine was analyzed using a colorimetric kit. Statistical tests were performed after natural logarithmic transformation. Results: When compared to the Hispanics, African American roofers had higher levels of urinary creatinine before (220.3 vs. 78.7 mg/dL, P = 0.06) and after the work (395.0 vs. 123.6 mg/dL, P = 0.01). A negative correlation was observed between creatinine in urine and amount of alcoholic drinks consumed within the last 24 hour (Pearson r = −0.470 and −0.515 for before and after the work, respectively, P < 0.05 for both). In linear regressions models of urinary creatinine, African American race explained 38.2% of the variation before the work, and 44.8% of the variation after the work. Linear regression models of urinary (after work) 8-OHPyr and 1-OHPyr were compared with and without creatinine adjustment. When 8-OHdG levels were adjusted, the model explained 17.2% less of the variation (71.3% vs. 88.5%) and had twice the estimated error variance (0.202 vs. 0.107) than the model without adjustment. When 1-OHPyr levels were adjusted, only levels of 1-OHPyr before work remained in the model explaining 78.4% of the variation. The model without adjustment included other variables (gloves, burn due to work) and explained 82.1% of the variation. Conclusion: Our results show that urinary creatinine levels may vary greatly because of individual factors, such as race and alcohol consumption. Routine adjustments of urinary biomarkers may introduce additional error into analyses.

In-vitro oxidation of bisphenol A: Is bisphenol A catechol a suitable biomarker for human exposure to bisphenol A?

The extensive use of bisphenol A (BPA) in the manufacture of consumer products results in widespread human exposure to the chemical. In the body, BPA undergoes first-pass metabolism to form BPA glucuronide, considered to be a major BPA byproduct. Concentrations of total (free plus conjugated) urinary species of BPA are used to assess human exposure to BPA. However, because BPA can be present in numerous consumer and household products, potential contamination with parent BPA during collection and handling may pose a challenge when measuring BPA in such biological samples as blood or urine. In this study we investigated the in-vitro phase I metabolism of BPA in rat and human liver microsomes by using on-line solid-phase extraction-high-performance liquid chromatography-tandem mass spectrometry to identify phase I metabolites (e.g., BPA oxidation products) that could be used as potential alternative biomarkers of BPA exposure. We unambiguously identified 5-hydroxy BPA (BPA catechol) as an in-vitro oxidative metabolite of BPA, but human microsomes oxidized only about 10% of BPA to BPA catechol. We evaluated the usefulness of BPA catechol as a potential biomarker of human exposure to BPA by measuring total concentrations of BPA catechol and BPA in 20 urine samples. We detected BPA catechol at much lower concentrations and frequency than those of BPA. Furthermore, we found that free BPA catechol was rather unstable in urine, which highlights the importance of sampling techniques to adequate interpretation of biomonitoring data. Together, these findings suggest that BPA catechol may not be a suitable biomarker of environmental exposure to BPA, but could be used to confirm BPA exposure in special populations or in situations when urine specimens were potentially contaminated with BPA.

Urinary BTEX, MTBE and naphthalene as biomarkers to gain environmental exposure profiles of the general population

The aim of this work was to evaluate urinary benzene, toluene, ethylbenzene, m+p-xylene, o-xylene (BTEX), methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and naphthalene (NAP) as biomarkers of exposure to environmental pollutants. Personal air and urine samples from 108 subjects belonging to the Italian general population were compared. Urinary profiles were obtained by headspace gas chromatography–mass spectrometry. BTEX, MTBE, ETBE and NAP median airborne exposures during a 5-h sampling were 4.0, 25.3, 3.8, 9.3, 3.4, 3.4, < 0.8, and 3.4 µg/m 3, respectively. Meanwhile, median urinary levels, as geometric means of three determinations were: 122, 397, 74, 127, 43, 49, < 15, and 46 ng/L, respectively. Urinary benzene and toluene concentrations were 4.6- and 1.2-fold higher in smokers than in non-smokers. For most chemicals, significant positive correlations between airborne exposure (log-transformed) and the corresponding biological marker (log-transformed) were found, with Pearson's r values for correlation, ranging from 0.228 to 0.396. Multiple linear regression analysis showed that the urinary level of these chemicals was influenced by personal airborne exposure, urinary creatinine, and urinary cotinine, with R 2 0.733 for benzene. Urinary chemicals are useful biomarkers of environmental exposure. Given the ease of rapidly obtaining urine samples, they represent a non-invasive alternative to blood chemical analysis. The possibility of obtaining urinary exposure profiles makes this method an appealing tool for environmental epidemiology.

Hepatic gene expression in flounder chronically exposed to multiply polluted estuarine sediment: Absence of classical exposure ‘biomarker’ signals and induction of inflammatory, innate immune and apoptotic pathways

The effects of chronic long-term exposure to multiply polluted environments on fish are not well understood, but environmental surveys suggest that such exposure may cause a variety of pathologies, including cancers. Transcriptomic profiling has recently been used to assess gene expression in European flounder ( Platichthys flesus) living in several polluted and clean estuaries. However, the gene expression changes detected were not unequivocally elicited by pollution, most likely due to the confounding effects of natural estuarine ecosystem variables. In this study flounder from an uncontaminated estuary were held on clean or polluted sediments in mesocosms, allowing control of variables such as salinity, temperature, and diet. After 7 months flounder were removed from each mesocosm and hepatocytes prepared from fish exposed to clean or polluted sediments. The hepatocytes were treated with benzo(a)pyrene (BAP), estradiol (E2), copper, a mixture of these three, or with the vehicle DMSO. A flounder cDNA microarray was then used to measure hepatocyte transcript abundance after each treatment. The results show that long-term chronic exposure to a multiply polluted sediment causes increases in the expression of mRNAs coding for proteins of the endogenous apoptotic programme, of innate immunity and inflammation. Contrary to expectation, the expression of mRNAs which are commonly used as biomarkers of environmental exposure to particular contaminants were not changed, or were changed contrary to expectation. However, acute treatment of hepatocytes from flounder from both clean and polluted sediments with BAP or E2 caused the expected changes in the expression of these biomarkers. Thus transcriptomic analysis of flounder exposed long-term to chronic pollution causes a different pattern of gene expression than in fish acutely treated with single chemicals, and reveals novel potential biomarkers of environmental contaminant exposure. These novel biomarkers include Diablo, a gene involved in apoptotic pathways and highly differentially regulated by both chronic and acute exposure to multiple pollutants.

Joint Effects of BMI, Diet, and Urinary Biomarkers of Environmental Exposures in Relation to Female Pubertal Maturation

ISEE-0327 Background: Environmental exposures may alter timing of puberty, a factor related to later reproductive function, breast cancer, and other chronic diseases. The Breast Cancer and Environment Research Centers (BCERCs) are investigating environmental exposures and puberty in females. We hypothesize that hormonally active exposures because of their weak biologic activity may alter age at pubertal onset, although their effects may be modified by adiposity (the major source of prepubertal estrogen). Methods: A multi-ethnic cohort of 6-8 year old girls was established at three national BCERC sites. At baseline, urine specimens from 1151 girls were analyzed for biomarker panels of hormonally active chemicals (9 phthalate, 8 phenol, and 3 phytoestrogen metabolites). Breast development stages from physical examination, and covariate information including body mass index (BMI), diet, and selected characteristics were collected. We calculated multivariate adjusted prevalence ratios (aPR) for the association of baseline biomarker measurements with breast stage (stage B2+ [any] vs. B1 [none]) at first annual follow-up (N = 948). Results: Breast development (B2+) was present in 25% of girls. Three biomarkers had small but significant effects on breast stage in BMI-biomarker interaction models. For example, the likelihood of being B2+ decreased monotonically across quintiles of enterolactone (aPR = 0.92 [0.83-0.98] vs 1st [reference]) among girls with BMI-percentile ≥ median. BP-3 showed an inverse association and 2,5-dichlorophenol a positive association among high BMI-percentile girls; there was no association in low-BMI girls. Modification of the biomarker-B2+ association was observed with selected dietary factors that may be related to hormonal mechanism of the exposures. Conclusion: Preliminary results from this longitudinal study suggest that environmental exposures may be associated with pubertal developmental if considered jointly with body size distribution or dietary factors. Longer follow-up may provide further insight on effects of weak hormonal agents in relation to female puberty.

The Relationship among Maternal Fish Consumption, Mercury Level, and Health Effects from Fetus to Infant Using a Structural Equation Model: Mothers and Childrenʼs Environmental Health (MOCEH)

ISEE-0647 Background and Objective: Prenatal exposure to high levels of mercury have been associated with adverse reproductive outcomes. We examined the relationship among maternal fish consumption, mercury level, and health effects from fetus to infant using a structural equation model. Methods: The collaborating multi-centers for a prospective cohort study of Mothers and Children's Environmental Health (MOCEH) have been built up in 2006 and we enrolled 1,286 women before the second trimester of their pregnancy and their spouses between 2006–2009. A trained nurse interviewed participants to record general information on demographic and socioeconomic factors, health behaviors, and environmental factors. We collected blood and urine samples to measure biomarkers for environmental exposures including heavy metals. We measured the mercury level in blood using atomic absorption spectrophotometry. A structural equation model was used to describe the sequential relationships between environmental factors, mercury level and health effects from fetus to infant. We used AMOS 6.0 (SPSS Inc.) for the structural equation model analysis. Results: Overall, pre-pregnant fish consumption was associated with birth weight and the weight of infants at 6 months of age. Amongst women who consumed blue-backed fish, Trichiurus lepturus and bluefin tuna, the weight of the fetus and the infant was lower in the group with a greater than 50 percentile level of mercury in blood and having higher fish consumption comparted to those fetus’ and infants whose mothers were in the lower 50 percentile for mercury blood level and having lower levels of fish consumption. The path in the model showed that mercury levels in blood directly affected birth weight. After considering environmental factors, we considered that fish consumption might cause increased levels of mercury in blood. Birth weight was indirectly decreased by fish consumption through blood mercury level. Conclusion: More detailed evaluation of the potential adverse effects of pre-pregnant fish consumption may be warranted. Pregnant woman should be cautious of consuming some types of fish due to potential mercury contamination.

Identification and Application of Biomarkers in Molecular and Genomic Epidemiologic Research

Biomarkers are characteristic biological properties that can be detected and measured in a variety of biological matrices in the human body, including the blood and tissue, to give an indication of whether there is a threat of disease, if a disease already exists, or how such a disease may develop in an individual case. Along the continuum from exposure to clinical disease and progression, exposure, internal dose, biologically effective dose, early biological effect, altered structure and/or function, clinical disease, and disease progression can potentially be observed and quantified using biomarkers. While the traditional discovery of biomarkers has been a slow process, the advent of molecular and genomic medicine has resulted in explosive growth in the discovery of new biomarkers. In this review, issues in evaluating biomarkers will be discussed and the biomarkers of environmental exposure, early biologic effect, and susceptibility identified and validated in epidemiological studies will be summarized. The spectrum of genomic approaches currently used to identify and apply biomarkers and strategies to validate genomic biomarkers will also be discussed.

Fast purification of trace vitellogenin from Chinese rare minnow using protein A-immobilized antibody

Vitellogenin (Vtg) is a highly responsive biomarker for environmental exposure to various estrogenically active compounds. Here we present a simple, fast, mild, and stable immobilization of anti-Vtg antibody, and demonstrate its powerful applications for preconcentration and purification of fish Vtg proteins, allowing for the monitoring and screening of environmental exposure to estrogenically active compounds. In this immobilization method, rabbit antiserum containing a specific polyclonal antibody against Vtg was directly immobilized on an antibody-binding Staphylococcal protein A matrix (SpA) without the need for prior purification. Under the unique elution conditions, the Vtg protein can be eluted out alone without any leaked specific antibody. The developed method was further used to purify Vtg from whole-body homogenate of Chinese rare minnow. Compared with previous purification methods, the isolated Vtg fraction by this method displays higher purity and well-preserved structure integrity. Moreover, our method is eight times faster. The simple one-step protein A-based specific antibody immobilization and its associated elution strategy may be extended to a number of antibodies for various application purposes, highlighting the paramount advantages over traditional immunoprecipitation and covalent immobilization of antibodies, and suggesting a wide range of promising applications in environmental monitoring and proteome analysis.

Biological transformation, kinetics and dose-response assessments of bound musk ketone hemoglobin adducts in rainbow trout as biomarkers of environmental exposure

Low levels (ng/g) of musk ketone (MK), used as a fragrance additive in the formulation of personal care products, are frequently detected in the water and other environment. Thus, aquatic organisms can be continuously exposed to MK. In this study, kinetics and dose-response assessments of 2-amino-MK (AMK) metabolite, bound to cysteine-hemoglobin (Hb) in rainbow trout, formed by enzymatic nitro-reduction of MK have been demonstrated. Trout were exposed to a single exposure of 0.010, 0.030, 0.10, and 0.30 mg MK/g fish. Twenty-seven Hb samples were collected from exposed- and control fish subsequent to exposure intervals of 1 d (24 h), 3 d (72 h), and 7 d (168 h). Basic hydrolysis released bound AMK metabolite was extracted into n-hexane and then concentrated and analyzed by gas chromatography (GC) electron capture negative ion chemical ionization (NICI) mass spectrometry (MS) using selected ion monitoring (SIM). The presence of the AMK metabolite in Hb extracts was confirmed by agreement of similar mass spectral features and retention time with a standard. In the dose-response study, maximum adduct formation was obtained at the 0.10 mg/g dose with an average AMK metabolite concentration of 2.2 ng/g. For kinetics, the highest concentration of the AMK metabolite was found to be 32.0 ng/g at 0.030 mg/g dose in 3-d sample. Further elimination of the metabolite showed kinetics with a half-life estimated to be 2 d, assuming first-order kinetics. The metabolite was not detected in the control samples, non-hydrolyzed Hb, and reagent blank extracts. The detection limit for AMK in the Hb was approximately 0.30 ng/g, based on a signal to noise ratio of 3 (S/N = 3).

Biomarkers of Environmental Exposures in a Multi-Site Study of Young Girls

P-484 Introduction: A study of determinants of puberty in girls is being conducted within the Breast Cancer and the Environment Research Centers because of concerns about younger age at pubertal onset and the association of early menarche with increased risk of breast cancer. For environmental exposures, we are focusing mainly on hormonally relevant agents that might affect the critical endocrine control of reproductive maturation, which may also represent a window of susceptibility for later disease. Because of the paucity of information on many of these chemicals, we conducted a pilot study to determine the degree of detectable concentrations and within- and across geographic site variability of various chemical families. Methods: Girls 6-to-8 years old are being recruited for a 5-year study to follow onset and progression of breast and pubic hair development, as well as menarche, at three sites across the United States (in New York, California and Ohio). Urine samples from 30 girls at each site, and serum samples from two sites, were assayed for bisphenol A (BPA) and other phenols, phthalates, phytoestrogens, polycyclic aromatic hydrocarbons, non-persistent pesticides, perfluorinated chemicals (PFCs) such as perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), and other organohalogenated chemicals. Results: Of ten phthalate metabolites measured, nine were detected in ≥90% of samples (limits of detection (LODs): 0.1–1 ng/ml). Median urinary concentrations ranged from 5–155 ug/g creatinine, with monoethyl phthalate detected at the highest levels, and Californians generally having lower levels than others. BPA and two other phenols were frequently detected (≥90%; LODs ∼0.1–0.5 ng/ml). Median BPA levels were consistent across the three sites at 2.5–3.1 ug/g creatinine, but other phenols showed more variation. Four of seven PFCs were detected in all samples (LODs: 0.05–0.2 ng/ml) and the median serum concentrations were highest for PFOS. The six phytoestrogens were highly detectable and levels varied by site. Discussion: Our results show that many of these potentially hormonally active agents, some of which have been little studied previously in children, were detectable in a large proportion of young girls. Concentrations of several varied by geographic location. Our levels of the common phthalate metabolites were similar to a national sample of children, but some of the phenols and phytoestrogens had higher median concentrations. Median PFC concentrations were consistent with one previous study in the United States. Data on the other biomarkers will be presented and site differences examined by age, race, and body size.

Association between biomarkers of environmental exposure and increased risk of breast cancer

Association between biomarkers of environmental exposure and increased risk of breast cancer

Association between biomarkers of environmental exposure and increased risk of breast cancer.

* University of Pittsburgh Cancer Institute, Center for Environmental Oncology, 5150 Centre Avenue, Suite 435, Pittsburgh, Pennsylvania, 15232, USA. University of Pittsburgh Graduate School of Public Health. Department of Epidemiology, Department of Environmental and Occupational Health, Pittsburgh, Pennsylvania, USA. International Agency for Research on Cancer and Institut National de la Sante et de la Recherche Medicale, Lyon, France, now with University of Bordeaux, Department of Preventive Medicine, France. Correspondence to D.L.D. e-mail: davisdl@upmc.edu

Aflatoxin B1 and polycyclic aromatic hydrocarbon adducts, p53 mutations and p16 methylation in liver tissue and plasma of hepatocellular carcinoma patients

Elevated aflatoxin B(1)-albumin adducts (AFB(1)-Alb) have been associated with an increased risk for HCC development. However, there are no studies in humans, correlating albumin adducts in blood with liver DNA adducts. Forty frozen tumor tissues and 39 paired plasma samples from HCC patients were collected in Taiwan, to determine the relationship between albumin adducts in blood and DNA adducts in liver tissue as well as mutations in p53 and methylation of p16. AFB(1)- and polycyclic aromatic hydrocarbon (PAH)-DNA adducts in tissue and albumin adducts in plasma were determined by immunohistochemistry and competitive ELISA, respectively. Plasma AFB(1)-Alb adducts in subjects with low, medium and high levels of AFB(1)-DNA adducts in tumor tissues were 51.0 +/- 36.5, 70.5 +/- 48.1 and 84.9 +/- 48.2 fmol/mg, respectively (p(trend) = 0.05). No significant correlation was found for PAH. Fourteen of 40 (36%) tissues were positive for mutant p53 protein by immunohistochemistry; 11 of 40 tissue DNA samples (28%) were positive for p53 mutations, but not their corresponding plasma DNAs. p16 was methylated in 24 of 40 (62%) tissues and 12 of 39 (32%) plasma DNAs. Significant correlations were observed between AFB(1)-Alb adducts and p53 mutations and p16 methylation. These data suggest that genetic, epigenetic and environmental exposure biomarkers in plasma may help in estimating the risk for the development of HCC.