No association of polymorphisms in the cell polarity gene SCRIB with breast cancer risk.

The human homolog of the Drosophila Scribble (SCRIB) tumor suppressor gene encodes a protein that regulates apical-basolateral polarity in mammalian epithelia and controls cell proliferation. Due to the role of cell polarity proteins in human cancers, we investigated whether genetic variability in SCRIB impacts breast carcinogenesis and tumor pathology. Five genetic variants were analyzed for an association with breast cancer risk and histopathological tumor parameters using a single nucleotide polymorphism (SNP) tagging approach. Genotyping of five tag SNPs was performed by TaqMan allelic discrimination and RFLP-based PCR using the GENICA population-based breast cancer case-control collection including 1,021 cases and 1,015 age-matched controls. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by ordinal logistic regression. None of the tag SNPs was associated with breast cancer risk or tumor characteristics. Our findings suggest that genetic variability in the SCRIB polarity gene does not contribute to breast cancer development.

The earwax-associated SNP c.538G>A (G180R) in ABCC11 is not associated with breast cancer risk in Europeans.

Genetic polymorphisms of human ABC-transporter genes have been suggested to modulate breast cancer risk in the general population. In particular ABCC11 (MRP8), which is highly expressed in breast cancer tissue and involved in the efflux of conjugated estrogen metabolites such as estrone-3-sulfate and estradiol-17beta-glucuronide, has recently been proposed as a potential risk factor for female breast cancer. The wet earwax-associated G-allele of the c.538G>A polymorphism was associated with an increased risk for breast cancer in Japanese women. In contrast, no evidence for such an association could be observed in Caucasian women. We aimed to confirm/refute the association of the c.538G>A variant in ABCC11 with breast cancer risk and/or histo-pathological tumor characteristics in an independent population-based breast cancer case-control study from Germany comprising 1021 cases and 1015 age-matched controls. No association for allele and genotype frequencies of the 538G>A variant in ABCB11 with breast cancer risk was found. Our data suggest that the c.538G>A variation in ABCC11 does not contribute to breast carcinogenesis in women of European descent.

Polymorphisms of the nuclear receptor pregnane X receptor and organic anion transporter polypeptides 1A2, 1B1, 1B3, and 2B1 are not associated with breast cancer risk.

Organic anion transporter polypeptides (OATPs, SLCOs) are involved in the uptake of conjugates steroid hormones such as estrone-3-sulfate. It has been suggested that the expression of OATPs in breast tissues could impact breast carcinogenesis and tumor pathology. The nuclear receptor pregnane X receptor (PXR) is involved in the regulation of SLCO1A2 expression. We investigated 31 variants located in PXR, SLCO1A2, SLCO1B1, SLCO1B3, and SLCO2B1 for an association with breast cancer risk and/or histo-pathological tumor characteristics. Polymorphisms were selected on the basis of a known or potential functional consequence and an allele frequency >2%. Genotyping was performed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry using the GENICA population-based breast cancer case-control collection comprising 1,021 cases and 1,015 age-matched controls. Statistical analysis was performed by SAS, and all tests were two-sided. None of the 31 analyzed transporter and PXR polymorphisms showed an association with breast cancer risk or tumor characteristics. Our data suggest that among the many known transporters common variations of PXR, SLCO1A2, SLCO1B1, SLCO1B3, and SLCO2B1 do not contribute to breast carcinogenesis.

Development of a sandwich ELISA to measure exposure to occupational cow hair allergens.

BACKGROUND: Cow hair and dander are important inducers of occupational allergies in cattle-exposed farmers. To estimate allergen exposure in farming environments, a sensitive enzyme immunoassay was developed to measure cow hair allergens. METHODS: A sandwich ELISA was developed using polyclonal rabbitantibodies against a mixture of hair extracts from different cattle breeds. To assess the specificity of the assay, extracts from other mammalian epithelia, mites, molds and grains were tested. To validate the new assay, cow hair allergens were measured in passive airborne dust samples from the stables and homes of farmers. Dust was collected with electrostatic dust fall collectors (EDCs). RESULTS: The sandwich ELISA was found to be very sensitive (detection limit: 0.1 ng/ml) and highly reproducible, demonstrating intra- and interassay coefficients of variation of 4 and 10%, respectively. The assay showed no reactivity with mites, molds and grains, but some cross-reactivity with other mammalian epithelia, with the strongest reaction with goat. Using EDCs for dust sampling, high concentrations of bovine allergens were measured in cow stables (4,760-559,400 µg/m²). In addition, bovine allergens were detected in all areas of cattle farmer dwellings. A large variation was found between individual samples (0.3-900 µg/m²) and significantly higher values were discovered in changing rooms. CONCLUSION: The ELISA developed for the detection of cow hair proteins is a useful tool for allergen quantification in occupational and home environments. Based on its low detection limit, this test is sensitive enough to detect allergens in passive airborne dust.

Assessment of micronuclei in lymphocytes from workers exposed to vapours and aerosols of bitumen.

We investigated the micronucleus frequencies in peripheral blood lymphocytes of 225 mastic asphalt workers (age 17-62 years) and 69 non-bitumen-exposed road construction workers (age 18-64 years) in Germany before and after the working shift. Median shift exposure to vapours and aerosols of bitumen of exposed workers was 3.0 mg/m³. Micronuclei (MN) were determined with a standard method using cytochalasin B. Median MN frequency was 6.0 (interquartile range (IQR) 4.0-8.5) MN/1,000 binucleated lymphocytes (MN/1,000 BNC) in exposed workers and 6.0 (IQR 4.0-8.3) MN/1,000 BNC in non-exposed workers before shift. After shift, we observed 6.5 (IQR 4.4-9.3) MN/1,000 BNC in exposed workers and 6.5 (IQR 4.0-9.0) MN/1,000 BNC in non-exposed workers. Regression models were applied with the log-transformed MN frequency as the dependent variable in order to estimate the effects of exposure to vapours and aerosols of bitumen and of potential confounders. Age was the strongest predictor of MN formation in both exposed workers and referents. Our data suggest that MN formation was not associated with concentration of vapours and aerosols of bitumen during shift at the individual level. Although similar MN frequencies were observed in both groups, the modelling of factors potentially influencing MN frequency revealed a weak group difference in the post-shift model. We conclude that this small difference cannot be judged to be a relevant mutagenic effect of exposure to vapours and aerosols of bitumen, also with regard to the lack of adjustment for multiple testing and the lack of a group effect in the original data.

Irritative effects of vapours and aerosols of bitumen on the airways assessed by non-invasive methods.

Irritative effects caused by vapours and aerosols of bitumen were assessed by non-invasive methods including spirometry, nasal lavage fluid (NALF) and induced sputum (IS) in a cross-shift study comparing 320 bitumen-exposed workers with 118 road construction workers as the reference group. Lung function parameters, forced vital capacity (FVC) and forced expiratory volume in one second (FEV(1)) were within normal ranges in both the reference and the bitumen-exposed groups pre- and post-shift with marginally lower values in smokers of both groups. During the shift, a slight decline in FEV(1) and FVC was observed in the bitumen-exposed group independent of their smoking habits, whereas in the non-smoking reference group, the decline in FEV(1) was not observed. No significant differences between bitumen-exposed workers and the reference group and no significant shift effect were observed on the upper airways using NALF analysis. The IS concentrations of interleukin (IL)-8, total protein and matrix metalloproteinase-9 were significantly higher in bitumen-exposed workers than in the reference group. However, the concentration of these three biomarkers in the IS samples, which are indicators of inflammatory effects on the lower airways of bitumen-exposed workers, was already higher in exposed workers before shift and did not show an increase during the shift. Therefore, the key finding of this aspect of the Human Bitumen Study is the detection of potentially (sub-) chronic irritative inflammatory effects in the lower airways of bitumen-exposed workers.

Modulation of urinary polycyclic aromatic hydrocarbon metabolites by enzyme polymorphisms in workers of the German Human Bitumen Study.

Data concerning the influence of sequence variants of metabolizing enzymes on the effect modulation of current exposure to vapors and aerosols of bitumen in humans are limited. To assess the influence of 18 single-nucleotide polymorphisms (SNP) in genes coding for enzymes involved in polycyclic aromatic hydrocarbon (PAH) and amine metabolism regarding their impact on urinary markers 1-hydroxpyrene (1-OHP) and the sum of 1-, 2+9-, 3-, 4-hydroxyphenanthrene (OHPHE). Based on personal ambient monitoring data for bitumen emissions, 218 German workers exposed to vapors and aerosols of bitumen during a shift and 96 German roadside construction workers without exposure to bitumen but with similar working tasks were studied. SNP determination based on DNA aliquots isolated from blood samples by real-time PCR or direct sequencing. The impact of sequence variants on the urinary levels of 1-OHP and sum of OHPHE was estimated with mixed linear models, adjusted for age, creatinine, exposure, smoking, SNP, and time of measurement. In the mixed linear model, an increasing metabolite level of OHPHE was only slightly modulated by the CC variant of the cytochrome P450 SNP CYP1A1 3801T>C (rs4646903; P = 0.051). In contrast, GSTM1 carriers showed a significant (P= 0.046) and double-mutated variants of three NAT2-specific SNP (NAT2*341CC, P = 0.06; NAT2*481TT, P = 0.06; NAT2*803GG, P = 0.042) displayed a decreasing influence on OHPHE levels. None of the SNP studied showed a significant effect on 1-OHP. The modulating SNP effects on OHPHE in the adjusted model were less pronounced when compared with the effects observed in a recent study with 170 workers occupationally exposed to PAH in German industries. This may be due to the much lower PAH exposure in the Human Bitumen Study.

Urinary metabolites of polycyclic aromatic hydrocarbons in workers exposed to vapours and aerosols of bitumen.

Urinary hydroxylated metabolites of polycyclic aromatic hydrocarbons (PAH) were investigated as potential biomarkers of bitumen exposure in a cross-shift study in 317 exposed and 117 non-exposed workers. Personal measurements of the airborne concentration of vapours and aerosols of bitumen during a working shift were weakly associated with post-shift concentrations of 1-hydroxypyrene (1-OHP) and 1-, 2+9-, 3- and 4-hydroxyphenanthrenes (further referred to their sum as OHPHE), but not 1- and 2-hydroxynaphthalene (OHNA). Smoking showed a strong influence on the metabolite concentrations, in particular on OHNA. Pre-shift concentrations of 1-OHP and OHPHE did not differ between the study groups (P = 0.16 and P = 0.89, respectively). During shift, PAH metabolite concentrations increased in exposed workers and non-exposed smokers. Statistical modelling of post-shift concentrations revealed a small increase in 1-OHP by a factor of 1.02 per 1 mg/m(3) bitumen (P = 0.02) and 1.04 for OHPHE (P < 0.001). A group difference was observed that was diminished in non-smokers. Exposed non-smokers had a median post-shift 1-OHP concentration of 0.42 µg/l, and non-smoking referents 0.13 µg/l. Although post-shift concentrations of 1-OHP and OHPHE were slightly higher than those in the general population, they were much lower than in coke-oven workers. The small content of PAHs in vapours and aerosols of bitumen, the increasing use of additives to asphalt mixtures, the strong impact of smoking and their weak association with airborne bitumen limit the use of PAH metabolites as specific biomarkers of bitumen exposure.

Bitumen workers handling mastic versus rolled asphalt in a tunnel: assessment of exposure and biomarkers of irritation and genotoxicity.

Emission levels of vapours and aerosols of bitumen are different when processing rolled asphalt compared to mastic asphalt, with working temperatures up to 180 and 250°C, respectively. During the Human Bitumen Study, we examined six workers handling rolled asphalt and mastic asphalt in two consecutive weeks at the same construction site in a tunnel. In addition to the determination of exposure to bitumen and polycyclic aromatic hydrocarbons (PAH) during shift, we examined urinary PAH metabolites, irritative and genotoxic effects before and after shift. Median personal shift concentration of vapours and aerosols of bitumen was 1.8 (range 0.9-2.4) mg/m(3) during the application of rolled asphalt and 7.9 (range 4.9-11.9) mg/m(3) when mastic asphalt was applied. Area measurement of vapours and aerosols of bitumen revealed higher concentrations than the personal measurements for mastic asphalt (mastic asphalt: 34.9 mg/m(3); rolled asphalt: 1.8 mg/m(3)). Processing mastic asphalt was associated also with higher PAH concentrations. Urinary 1-hydroxypyrene and the sum of 1-, 2+ 9-, 3- and 4-hydroxyphenanthrene increased slightly during shift without clear difference between mastic and rolled asphalt application. However, the post-shift urinary PAH-metabolite concentrations did not reflect the different PAH exposure during mastic and rolled asphalt application. Individual workers could be identified by their spirometry results indicating that these data reflect more chronic than acute effects. In most cases, an increase of 8-oxodGuo adducts was observed during shift that was independent of the asphalt application. 8-oxodGuo and (+)-anti-BPDE-DNA adducts were higher than in exposed workers of the Human Bitumen Study independent of the asphalt application. The DNA-strand breaks were considerably higher pre-shift and decreased during shift. In this study, mastic asphalt application led to significantly higher exposure to vapours and aerosols of bitumen, as well as to airborne PAH, compared to rolled asphalt application. Nevertheless, no differences in the excretion of urinary PAH metabolites, lung function impairment and genotoxic markers were detected. However, higher levels of genotoxicity markers on both examination days compared with the results of the Human Bitumen Study may indicate a possible influence of the specific tunnel setting.

DNA adducts and strand breaks in workers exposed to vapours and aerosols of bitumen: associations between exposure and effect.

To study the associations between exposure to vapours and aerosols of bitumen and genotoxic effects, a cross-sectional and cross-shift study was conducted in 320 exposed workers and 118 non-exposed construction workers. Ambient air measurements were carried out to assess external exposure to vapours and aerosols of bitumen. Hydroxylated metabolites of naphthalene, phenanthrene and pyrene were measured in urine, whereas (+)-anti-benzo[a]pyrene-7,8-diol-9,10-epoxide ((+)-anti-BPDE), 8-oxo-7,8-dihydro-2'-deoxyguanosine (8oxodGuo) and DNA strand breaks were determined in blood. Significantly higher levels of 8-oxodGuo adducts and DNA strand breaks were found in both pre- and post-shift blood samples of exposed workers compared to those of the referents. No differences between exposed workers and referents were observed for (+)-anti-BPDE. Moreover, no positive associations between DNA damage and magnitude of airborne exposure to vapours and aerosols of bitumen could be observed in our study. Additionally, no relevant association between the urinary metabolites of PAH and the DNA damage in blood was observed. Overall, our results indicate increased oxidative DNA damage in workers exposed to vapours and aerosols of bitumen compared to non-exposed referents at the group level. However, increased DNA strand breaks in bitumen workers were still within the range of those found in non-exposed and healthy persons as reported earlier. Due to the lack of an association between oxidative DNA damage and exposure levels at the workplaces under study, the observed increase in genotoxic effects in bitumen workers cannot be attributed to vapours and aerosols of bitumen.

Levels and determinants of exposure to vapours and aerosols of bitumen.

Bitumen (referred to as asphalt in the United States) is a widely used construction material, and emissions from hot bitumen applications have been a long-standing health concern. One objective of the Human Bitumen Study was to identify potential determinants of the exposure to bitumen. The study population analysed comprised 259 male mastic asphalt workers recruited between 2003 and 2008. Personal air sampling in the workers' breathing zone was carried out during the shift to measure exposure to vapours and aerosols of bitumen. The majority of workers were engaged in building construction, where exposure levels were lower than in tunnels but higher than at road construction sites. At building construction sites, exposure levels were influenced by the room size, the processing temperature of the mastic asphalt and the job task. The results show that protective measures should include a reduction in the processing temperature.

Air sampling and determination of vapours and aerosols of bitumen and polycyclic aromatic hydrocarbons in the Human Bitumen Study.

The chemical complexity of emissions from bitumen applications is a challenge in the assessment of exposure. Personal sampling of vapours and aerosols of bitumen was organized in 320 bitumen-exposed workers and 69 non-exposed construction workers during 2001-2008. Area sampling was conducted at 44 construction sites. Area and personal sampling of vapours and aerosols of bitumen showed similar concentrations between 5 and 10 mg/m(3), while area sampling yielded higher concentrations above the former occupational exposure limit (OEL) of 10 mg/m(3). The median concentration of personal bitumen exposure was 3.46 mg/m(3) (inter-quartile range 1.80-5.90 mg/m(3)). Only few workers were exposed above the former OEL. The specificity of the method measuring C-H stretch vibration is limited. This accounts for a median background level of 0.20 mg/m³ in non-exposed workers which is likely due to ubiquitous aliphatic hydrocarbons. Further, area measurements of polycyclic aromatic hydrocarbons (PAHs) were taken at 25 construction sites. U.S. EPA PAHs were determined with GC/MS, with the result of a median concentration of 2.47 µg/m(3) at 15 mastic asphalt worksites associated with vapours and aerosols of bitumen, with a Spearman correlation coefficient of 0.45 (95% CI -0.13 to 0.78). PAH exposure at mastic-asphalt works was higher than at reference worksites (median 0.21 µg/m(3)), but about one order of magnitude lower compared to coke-oven works. For a comparison of concentrations of vapours and aerosols of bitumen and PAHs in asphalt works, differences in sampling and analytical methods must to be taken into account.

No evidence for glutathione S-transferases GSTA2, GSTM2, GSTO1, GSTO2, and GSTZ1 in breast cancer risk.

Breast cancer is a complex disease and in recent years a number of breast cancer susceptibility genes have been identified, but the role of low penetrance susceptibility genes has not been completely resolved. Glutathione S-transferases (GSTs) are phase II xenobiotic metabolizing enzymes involved in the detoxification of chemical carcinogens and environmental pollutants and play an important role in cell defense mechanisms against oxidative stress. They have been in the spot light for the investigation of a potential association with breast cancer risk but so far, sparse or even no data for a potential contribution of GSTA2, GSTM2, GSTO, and GSTZ to breast cancer risk are available. We genotyped GSTA2_448_C > G (rs2180314), GSTA2_742_A > C (rs6577), GSTM2_-832_T > C (rs638820), GSTO1_-1242_G > A (rs2164624), GSTO1_419_A > C (rs4925), GSTO2_-183_A > G (rs2297235), GSTO2_342_A > G (rs156697), GSTZ1_-4378_A > G (rs1046428), and GSTZ1_94_G > A (rs3177427) by MALDI-TOF MS in the German GENICA breast cancer case-control collection of 1021 cases and 1015 controls and performed breast cancer risk association in general and with respect to the stratifications: menopausal status, family history of breast or ovarian cancer, use of oral contraceptives, use of hormone therapy, body mass index, and smoking as well as histopathological tumor characteristics including hormone receptor status, grade, histology, and node status. We did not observe any breast cancer risk associations and conclude that it is unlikely that glutathione S-transferases GSTA2, GSTM2, GSTO1, GSTO2, and GSTZ1 participate in breast cancer susceptibility.

Polymorphisms in the UBC9 and PIAS3 genes of the SUMO-conjugating system and breast cancer risk.

SUMOylation consists in the covalent conjugation of small ubiquitin-related modifiers to target proteins. SUMOylation participates in processes that are tightly linked to tumorigenesis, and genetic variability in the SUMO-conjugating system may influence the development of breast cancer. We recently reported that variation in the UBC9 gene encoding the SUMO-conjugating enzyme may affect the grade of breast tumors. Following comprehensive in silico analyses for detection of putative functional polymorphisms in 14 genes of the SUMO system, we selected one coding SNP in PIAS3 and seven tag SNPs in UBC9 for association analyses. Results were based on 1,021 cases, and 1,015 matched controls from the population-based GENICA study. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by conditional logistic regression. To explore the association with polymorphisms closely linked to the genotyped variants, multiple imputation based on HapMap data was applied. The study revealed associations of four UBC9 polymorphisms with risk of grade 1 tumors. Comparison of genotype and haplotype models indicated that the best representation of risk solely relied on rs7187167 under dominant penetrance. Women carrying the rare allele showed an increased risk of grade 1 tumors compared with common homozygotes (OR 1.87, 95% CI 1.18-2.95). This effect appeared to be stronger in women with a family history of breast or ovarian cancer. Imputation of polymorphisms in a 300-kb region around the genotyped polymorphisms identified no variants with stronger associations. Our findings suggest that genetic variation in UBC9 may affect the risk of grade 1 breast tumors.

Polymorphic loci of E2F2, CCND1 and CCND3 are associated with HER2 status of breast tumors.

Overexpression of the human epidermal growth factor receptor 2 (HER2) in breast tumors is associated with bad prognosis. Therefore, it is highly relevant to further improve understanding of the regulatory mechanisms of HER2 expression. In addition to gene amplification, transcriptional regulation plays a crucial role in HER2 overexpression. In this study, we analyzed 3 polymorphisms E2F2_-5368_A>G, CCND1_870_A>G and CCND3_-677_C>T located in genes involved in cell cycle regulation in the GENICA population-based and age-matched breast cancer case-control study from Germany. We genotyped 1,021 cases and 1,015 controls by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Statistical analyses were performed by conditional logistic regression. We observed no differences in genotype frequencies between breast cancer cases and controls. Subgroup analysis showed associations between carriers of the E2F2_-5368_G allele (OR: 0.60, 95% CI: 0.42-0.85), carriers of the CCND1_870_G allele (OR: 0.66, 95% CI: 0.45-0.96) and carriers of the CCND3_-677_T allele (OR: 1.72, 95% CI: 1.20-2.49) and HER2 expression in breast tumors. This finding points to an association of an increased expression of these cell cycle regulators with lower expression of HER2. An explanation for this observation might be that low expression of E2F2, CCND1 and CCND3 decrease levels of factors down-regulating HER2. We conclude that the analyzed polymorphisms located in E2F2, CCND1 and CCND3 are potential markers for HER2 status of breast tumors.

Common variants in the UBC9 gene encoding the SUMO-conjugating enzyme are associated with breast tumor grade.

UBC9 encodes a protein that conjugates small ubiquitin-related modifier (SUMO) to target proteins resulting in a change of their localization, activity or stability. Genetic variability may affect expression and activity of UBC9 and may have an impact on breast tumor progression. We investigated associations between UBC9 genotypes and histopathological parameters in 1,021 breast cancer cases of the GENICA collection using a single nucleotide polymorphism (SNP) tagging approach. Genotyping analyses were performed by TaqMan(R) allelic discrimination. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by ordinal logistic regression. Multiple imputation based on HapMap data was applied to boost the power of the study. The study revealed significant associations of three UBC9 SNPs with histological grade (rs7187167, p(trend) = 0.001; rs11248866, p(trend) = 0.009; rs8052688, p(trend) = 0.008). Model selection identified a recessive penetrance model for rs7187167 as the best representation of tumor grade (global p = 0.001). This model did not improve by inclusion of additional SNPs in linkage disequilibrium. Imputation of SNPs in a 300 kb region around the genotyped SNPs supported rs7187167 as a major contributor to tumor grade. Compared with common allele carriers, rare homozygotes presented less frequently with high grade tumors (G3 vs. G1: OR 0.26, 95% CI 0.11-0.62; G3 vs. G2: OR 0.45, 95% CI 0.23-0.86). In addition to tumor size, nodal status and estrogen receptor status, multivariate analyses confirmed an independent role of rs7187167 as predictor of tumor grade (p = 0.0003). The present results underline the value of genetic variation in UBC9 for breast cancer prognosis.

CYP2C19*17 is associated with decreased breast cancer risk.

Cytochrome P450 2C19 (CYP2C19) plays an important role in the metabolism of xenobiotics and drugs and contributes to the catabolism of endogenous substrates like estradiol. Genetic variability impacts expression and activity of CYP2C19 and therefore can influence catabolism of estrogens. In the present study we analyzed the association of three polymorphisms of CYP2C19 namely CYP2C19*2 (CYP2C19_681_G>A, rs4244285), CYP2C19*3 (CYP2C19_636_G>A, rs57081121) and CYP2C19*17 (CYP2C19_-806_C>T, rs12248560), with breast cancer susceptibility. We genotyped 1,015 breast cancer cases and 1,021 age-matched, population-based controls of the German GENICA study by matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Risk estimates were calculated by logistic regression. All tests were two-sided. We observed a decreased breast cancer risk for carriers of the CYP2C19*17 allele (OR 0.77, 95% CI: 0.65-0.93; P = 0.005). In subgroup analysis we observed a significant decreased breast cancer risk for women using hormone therapy for ten years or longer who were carriers of the CYP2C19*17 allele (OR 0.57, 95% CI: 0.39-0.83; P = 0.003). Since CYP2C19*17 defines an ultra rapid metabolizer phenotype we suggest that an increased catabolism of estrogens by CYP2C19 may lead to decreased estrogen levels and therefore reduces breast cancer risk. This protective effect seems to be stronger in combination with long-term intake of supplemental estrogens during hormone therapy.

New biomarkers of occupational exposure to polycyclic aromatic hydrocarbons.

Polycyclic aromatic hydrocarbons (PAH) are metabolized in a complex manner. Although biological activity is associated with diol-epoxide formation, phenolic metabolites have predominantly been used in human biomonitoring. In this study monohydroxylated and new metabolites were characterized as biomarkers for occupational PAH exposure. In 97 male workers, personal exposure to 16 airborne PAH compounds was measured during shift. In postshift urine, 1-hydroxypyrene and 1,6- and 1,8-dihydroxypyrene (1-OHP, DiOHP) were determined as metabolites of pyrene (P), and the sum of 1-, 2-, 3-, 4-, and 9-hydroxyphenanthrenes (OHPHE), and PHE-dihydrodiols (PHED) as metabolites of phenanthrene (PHE). The referent group comprised 21 nonsmoking construction workers. Median (interquartile range) shift concentrations of airborne P and PHE were 1.46 (0.62-4.05 microg/m(3)) and 10.9 (3.69-23.77 microg/m(3)), respectively. The corresponding parameters were 3.86 (2.08-7.44) microg/g creatinine (crn) for 1-OHP, 0.66 (0.17-1.65) microg/g crn for DiOHP, 11.44 (5.21-34.76) microg/g crn for OHPHE, and 12.28 (3.3-97.76) microg/g crn for PHED in PAH-exposed workers. The median levels of 1-OHP and OHPHE were 0.09 (0.08-0.17 microg/m(3)) and 0.59 (0.45-1.39 microg/m(3)), respectively, in the referents. PHE correlated significantly with OHPHE and PHED, and P with 1-OHP but not with DiOHP. Under a doubling of PHE, OHPHE increased by a factor of 1.56 and PHED by 1.57. With a doubling of P, 1-OHP rose by 1.31 and DiOHP by 1.27. P is predominantly metabolized into 1-OHP, whereas PHE is metabolized equally into OHPHE and PHED. Thus metabolites of PHE were found as reliable biomarkers for PAH exposure.

Biological monitoring as a useful tool for the detection of a coal-tar contamination in bitumen-exposed workers.

In our research project entitled "Chemical irritative and/or genotoxic effect of fumes of bitumen under high processing temperatures on the airways," 73 mastic asphalt workers exposed to fumes of bitumen and 49 construction nonexposed workers were analyzed and compared with respect to polycyclic aromatic hydrocarbons (PAHs) exposure and exposure-related health effects. In order to assess the internal exposure the monohydroxylated metabolites of pyrene, 1- hydroxypyrene (1-OHP), and phenanthrene, 1-, 2- and 9-, and 3- and 4-hydroxyphenanthrene (OHPH) were determined in pre- and post-shift urinary samples. Significantly higher concentrations 1-OHP and OHPH were detected in the post-shift urine samples of 7 mastic asphalt workers working on the same construction site compared to the reference workers and all other 66 mastic asphalt workers. The adjusted mean OHPH in the reference, 66 mastic worker, and 7 worker subgroups was 1022, 1544, and 12919 ng/g creatinine (crn) respectively, indicating a marked rise in the 7 worker subgroup. In addition, there was a more than 12-fold increase of PAH metabolites from pre- to post-shift in these 7 workers, whereas in the other mastic asphalt workers there was only a twofold rise in PAH-metabolite concentration between pre- and post-shift values. The analysis of a drilling core from the construction site of the seven workers led to the detection of the source for this marked PAH exposure during the working shift as being coal tar plates, which were, without knowledge of the workers and coordinators, the underground material of the mastic asphalt layer. The evaluation of the stationary workplace concentration showed enhanced levels of phenanthrene, pyrene, fluorene, anthracene, and acenaphthene during working shifts at the construction site of these seven workers. Our study shows that biological monitoring is also a useful tool for the detection of unrecognized sources with high PAH concentrations.