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Early natural menopause has been regarded as a biomarker of reproductive and somatic aging. Cigarette smoking is the most harmful factor for lung health and also an established risk factor for early menopause. Understanding the effect of early menopause on health outcomes in middle-aged and older female smokers is important to develop preventive strategies.This study aimed to examine the associations of early menopause with multiple lung health and aging biomarkers, lung cancer risk, and all-cause and cause-specific mortality in postmenopausal women who were moderate or heavy smokers.This study was conducted on postmenopausal women with natural (n=1038) or surgical (n=628) menopause from the Pittsburgh Lung Screening Study. The Pittsburgh Lung Screening Study is a community-based research cohort of current and former smokers, screened with low-dose computed tomography and followed up for lung cancer. Early menopause was defined as occurring before 45 years of age. The analyses were stratified by menopause types because of the different biological and medical causes of natural and surgical menopause. Statistical methods included linear model, generalized linear model, linear mixed-effects model, and time-to-event analysis.The average age of the 1666 female smokers was 59.4±6.7 years, with 1519 (91.2%) of the population as non-Hispanic Whites and 1064 (63.9%) of the population as current smokers at baseline. Overall, 646 (39%) women reported early menopause, including 198 (19.1%) women with natural menopause and 448 (71.3%) women with surgical menopause (P.001). Demographic variables did not differ between early and nonearly menopause groups, regardless of menopause type. Significant associations were identified between early natural menopause and higher risk of wheezing (odds ratio, 1.65; P.01), chronic bronchitis (odds ratio, 1.73; P.01), and radiographic emphysema (odds ratio, 1.70; P.001) and lower baseline lung spirometry in an obstructive pattern (-104.8 mL/s for forced expiratory volume in the first second with P.01, -78.6 mL for forced vital capacity with P=.04, and -2.1% for forced expiratory volume in the first second-to-forced vital capacity ratio with P=.01). In addition, early natural menopause was associated with a more rapid decline of forced expiratory volume in the first second-to-forced vital capacity ratio (-0.16% per year; P=.01) and incident airway obstruction (odds ratio, 2.02; P=.04). Furthermore, women early natural menopause had a 40% increased risk of death (P=.023), which was mainly driven by respiratory diseases (hazard ratio, 2.32; P.001). Mediation analyses further identified that more than 33.3% of the magnitude of the associations between early natural menopause and all-cause and respiratory mortality were explained by baseline forced expiratory volume in the first second. Additional analyses in women with natural menopause identified that the associations between continuous smoking and subsequent lung cancer risk and cancer mortality were moderated by early menopause status, and females with early natural menopause who continued smoking had the worst outcomes (hazard ratio,4.6; P.001). This study did not find associations reported above in female smokers with surgical menopause.Early natural menopause was found to be a risk factor for malignant and nonmalignant lung diseases and mortality in middle-aged and older female smokers. These findings have strong public health relevance as preventive strategies, including smoking cessation and chest computed tomography screening, should target this population (ie, female smokers with early natural menopause) to improve their postmenopausal health and well-being.

Objective Iron and steel industry workers are exposed to high levels of inhalable dust particles that contain various elements, including metals, and cause occupational lung diseases. We aim to assess the relationship between occupational dust exposure, systemic inflammation, and spirometric decline in a cohort of Chinese iron and steel workers. Methods We studied 7513 workers who participated in a Health Surveillance program at Wugang Institute for Occupational Health between 2008 and 2017. Time-weighted exposure intensity (TWEI) of dust was quantified based on self-reported dust exposure history, the experience of occupational hygienists, and historical data of dust exposure for workers with certain job titles. A linear mixed-effects model was used for association analyses. Results The average annual change of lung function was − 50.78 ml/year in forced expiratory volume in 1 s (FEV1) and − 34.36 ml/year in forced vital capacity (FVC) in males, and − 39.06 ml/year in FEV1 and − 26.66 ml/year in FVC in females. Higher TWEI prior to baseline was associated with lower longitudinal measurements of FEV1 and FVC but not with their decline rates. Higher WBC and its differential at baseline were associated with lower longitudinal measurements and a more rapid decline of FEV1 and FVC in a dose-dependent monotonically increasing manner. Moreover, the increase of WBC and its differential post-baseline was also associated with a more rapid decline of FEV1 and FVC. Conclusions Our findings support the important role of systemic inflammation in affecting the temporal change of lung function in iron and steel industry workers.

N,N-Dimethylformamide (DMF) is a widespread contaminant of leather factories and their surrounding environment. There is a lack of direct in vivo evidence supporting CYP2E1 as a primary enzyme responsible for DMF metabolism and hepatotoxicity. In this study, a novel Cyp2e1 knockout (KO) mouse model was generated and used to assess whether DMF metabolism and hepatotoxicity is CYP2E1 dependent using an acute toxicity protocol with a single dose of 1500 mg DMF/kg. An epidemiological study in 698 DMF-exposed workers and 188 non-DMF-exposed controls was conducted to investigate the associations between functional polymorphisms of CYP2E1 (rs6413432/rs2031920) and DMF metabolite (N-methylcarbmoylated-hemoglobin [NMHb]). We successfully established Cyp2e1 KO mice with evidence from DNA sequence analysis, which showed 1-bp insertion at 65 bp (C) site of Cyp2e1 Exon 1. In addition, western blot and in vivo pharmacokinetic study also showed a complete absence of CYP2E1 protein and a 92% and 88% reduction in CYP2E1 activity among males and females, respectively. DMF metabolism as evidenced by increased blood NMHb, and hepatotoxicity as evidenced by elevated liver/body weight ratio, activity of liver enzymes and massive liver necrosis were detected in wild-type (WT) mice but were completely abrogated in KO mice, strongly supporting a CYP2E1-dependent pattern of DMF metabolism and hepatotoxicity. Moreover, variant allele of CYP2E1-rs6413432 was also significantly associated with higher NMHb levels in DMF-exposed workers (P = 0.045). The increase of glucose-regulated protein 94 detected in WT mice but not in KO mice suggested CYP2E1-dependent endoplasmic reticulum stress may be a key mechanism underlying DMF-induced hepatotoxicity.

Rationale: Gene promoter hypermethylation detected in sputum assesses the extent of field cancerization and predicts lung cancer (LC) risk in ever-smokers. A rapid decline of FEV(1) is a major driver for development of airway obstruction. Objectives: To assess the effects of methylation of 12 genes on FEV(1) decline and of FEV(1) decline on subsequent LC incidence using two independent, longitudinal cohorts (i.e., LSC [Lovelace Smokers Cohort] and PLuSS [Pittsburgh Lung Screening Study]). Methods: Gene methylation was measured in sputum using two-stage nested methylation-specific PCR. The linear mixed effects model was used to assess the effects of studied variables on FEV(1) decline. Measurements and Main Results: A dose-dependent relationship between number of genes methylated and FEV(1) decline was identified, with smokers with three or more methylated genes having 27.8% and 10.3% faster FEV(1) decline than smokers with zero to two methylated genes in the LSC and PLuSS cohort, respectively (all P

Diesel exhaust (DE) as the major source of vehicle-emitted particle matter in ambient air impairs lung function. The objectives were to assess the contribution of local (eg, the fraction of exhaled nitric oxide [FeNO] and serum Club cell secretory protein [CC16]) and systemic (eg, serum C-reaction protein [CRP] and interleukin-6 [IL-6]) inflammation to DE-induced lung function impairment using a unique cohort of diesel engine testers (DETs, n = 137) and non-DETs (n = 127), made up of current and noncurrent smokers. Urinary metabolites, FeNO, serum markers, and spirometry were assessed. A 19% reduction in CC16 and a 94% increase in CRP were identified in DETs compared with non-DETs (all p values

Detection of methylated genes in exfoliated cells from the lungs of smokers provides an assessment of the extent of field cancerization, is a validated biomarker for predicting lung cancer, and provides some discrimination when interrogated in blood. The potential utility of this 8-gene methylation panel for predicting tumor recurrence has not been assessed. The Eastern Cooperative Oncology Group initiated a prevention trial (ECOG-ACRIN5597) that enrolled resected stage I non–small cell lung cancer patients who were randomized 2:1 to receive selenized yeast versus placebo for 4 years. We conducted a correlative biomarker study to assess prevalence for methylation of the 8-gene panel in longitudinally collected sputum and blood after tumor resection to determine whether selenium alters their methylation profile and whether this panel predicts local and/or distant recurrence. Patients (N = 1,561) were enrolled into the prevention trial; 565 participated in the biomarker study with 122 recurrences among that group. Assessing the association between recurrence and risk of gene methylation longitudinally for up to 48 months showed a 1.4-fold increase in OR for methylation in sputum in the placebo group independent of location (local or distant). Kaplan–Meier curves evaluating the association between number of methylated genes and time to recurrence showed no increased risk in sputum, while a significant HR of 1.5 was seen in plasma. Methylation detection in sputum and blood is associated with risk for recurrence. Cancer Prev Res; 10(11); 635–40. ©2017 AACR.

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality worldwide(1). We performed a genetic association study in 15,256 cases and 47,936 controls, with replication of select top results (P

Prenatal nicotinic exposure (PNE) reportedly sensitizes bronchopulmonary C-fibers (PCFs) and prolongs PCF-mediated apnea in rat pups, contributing to the pathogenesis of sudden infant death syndrome. Serotonin, or 5-hydroxytryptamine (5-HT), induces apnea via acting on 5-HT receptor 3 (5-HT(3)R) in PCFs, and among the 5-HT(3)R subunits, 5-HT(3B) is responsible for shortening the decay time of 5-HT(3)R–mediated currents. We examined whether PNE would promote pulmonary 5-HT secretion and prolong the apnea mediated by 5-HT(3)Rs in PCFs via affecting the 5-HT(3B) subunit. To this end, the following variables were compared between the control and PNE rat pups: 1) the 5-HT content in bronchoalveolar lavage fluid, 2) the apneic response to the right atrial bolus injection of phenylbiguanide (a 5-HT(3)R agonist) before and after PCF inactivation, 3) 5-HT(3)R currents and the stimulus threshold of the action currents of vagal pulmonary C-neurons, and 4) the immunoreactivity (IR) and mRNA expression of 5-HT(3A) and 5-HT(3B) in these neurons. Our results showed that PNE up-regulated the pulmonary 5-HT concentration and strengthened the PCF 5-HT(3)R–mediated apnea. PNE significantly facilitated neural excitability by shortening the decay time of 5-HT(3)R currents, lowering the stimulus threshold, and increasing 5-HT(3B) IR. In summary, PNE prolongs the apnea mediated by 5-HT(3)Rs in PCFs, likely by increasing 5-HT(3B) subunits to enhance the excitability of 5-HT(3) channels.—Zhao, L., Gao, X., Zhuang, J., Wallen, M., Leng, S., Xu, F. Prolongation of bronchopulmonary C-fiber–mediated apnea by prenatal nicotinic exposure in rat pups: role of 5-HT(3) receptors.

BackgroundChina has been facing nationwide air pollution at unprecedented high levels primarily from fossil–fuel combustion in the past decade. However, few studies have been conducted on the adverse effect of severe air pollution on lung development in school-age children.MethodsUsing wellness check and air pollution data from 2014 to 2017, we conducted a retrospective analysis of lung development in 21 616 school-age children from Shijiazhuang and Qingdao from North China with severe vs mild air pollution. Linear mixed effects model was performed to assess the effect of air pollution on forced vital capacity (FVC) growth.ResultsExposure to severe air pollution was associated with a dramatic reduction in annual FVC growth rate (−71.3 mL, p3 increase in annual PM2.5 level was associated with a reduction of annual FVC growth by 12.2 mL ( pConclusionOur study raised serious alarm over the threat of severe air pollution to lung development in school-age children. Sex discrepancy in lung development was reduced dramatically in heavily polluted area.

Rationale: Genome-wide association studies (GWAS) of chronic obstructive pulmonary disease (COPD) have identified disease-susceptibility loci, mostly in subjects of European descent.Objectives: We hypothesized that by studying Hispanic populations we would be able to identify unique loci that contribute to COPD pathogenesis in Hispanics but remain undetected in GWAS of non-Hispanic populations.Methods: We conducted a metaanalysis of two GWAS of COPD in independent cohorts of Hispanics in Costa Rica and the United States (Multi-Ethnic Study of Atherosclerosis [MESA]). We performed a replication study of the top single-nucleotide polymorphisms in an independent Hispanic cohort in New Mexico (the Lovelace Smokers Cohort). We also attempted to replicate prior findings from genome-wide studies in non-Hispanic populations in Hispanic cohorts.Measurements and Main Results: We found no genomewide significant association with COPD in our metaanalysis of Costa Rica and MESA. After combining the top results from this metaanalysis with those from our replication study in the Lovelace Smokers Cohort, we identified two single-nucleotide polymorphisms approaching genome-wide significance for an association with COPD. The first (rs858249, combined P value = 6.1 X 10(-8)) is near the genes KLHL7 and NUPL2 on chromosome 7. The second (rs286499, combined P value = 8.4 X 10(-8)) is located in an intron of DLG2. The two most significant single-nucleotide polymorphisms in FAM13A from a previous genome-wide study in non-Hispanics were associated with COPD in Hispanics.Conclusions: We have identified two novel loci (in or near the genes KLHL7/NUPL2 and DLG2) that may play a role in COPD pathogenesis in Hispanic populations.

Widespread contamination of N,N-dimethylformamide (DMF) has been identified in the environment of leather industries and their surrounding residential areas. Few studies have assessed the dose-response relationships between internal exposure biomarkers and liver injury in DMF exposed populations. We assessed urinary N-methylformamide (NMF) and N-acetyl-S-(N-methylcarbamoyl) cysteine (AMCC) and blood N-methylcarbmoylated hemoglobin (NMHb) levels in 698 Chinese DMF-exposed workers and 188 nonDMF- exposed workers using ultraperformance liquid-chromatography tandem mass-spectrometry. Liver injury was defined as having abnormal serum activities of any of the 3 liver enzymes, including alanine aminotransferase, aspartate aminotransferase, and γ-glutamyl transpeptidase. Higher liver injury rates were identified in DMF-exposed workers versus nonDMF-exposed workers (9.17% vs 4.26%, P = .029) and in male versus female workers (11.4% vs 3.2%, P < .001). Positive correlations between environmental exposure categories and internal biomarker levels were identified with all 3 biomarkers undetectable in nonDMF-exposed workers. Lower confidence limit of benchmark dose (BMDL) was estimated using the benchmark dose (BMD) method. Within all study subjects, BMDLs of 14.0 mg/l for NMF, 155 mg/l for AMCC, and 93.3 nmol/g for NMHb were estimated based on dose-response relationships between internal levels and liver injury rates. Among male workers, BMDLs of 10.9 mg/l for NMF, 119 mg/l for AMCC, and 97.0 nmol/g for NMHb were estimated. In conclusion, NMF, AMCC, and NMHb are specific and reliable biomarkers and correlate well with DMF-induced hepatotoxicity. NMF correlates the best with liver injury, while NMHb may be the most stable indicator. Males have a greater risk of liver injury than females upon DMF exposure.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Epidemiological studies of underground miners suggest that occupational exposure to radon causes lung cancer with squamous cell carcinoma (SCC) as the predominant histological type. However, the genetic determinants for susceptibility of radon-induced SCC in miners are unclear. Double-strand breaks (DSBs) induced by radioactive radon daughters are repaired primarily by non-homologous end joining (NHEJ) that is accompanied by the dynamic changes in surrounding chromatin, including nucleosome repositioning and histone modifications. Thus, a molecular epidemiological study was conducted to assess whether genetic variation in 16 genes involved in NHEJ and related histone modification affected susceptibility for SCC in radon-exposed former miners (267 SCC cases and 383 controls) from the Colorado plateau. A global association between genetic variation in the haplotype block where SIRT1 resides and the risk for SCC in miners (P=0.003) was identified. Haplotype alleles tagged by the A allele of SIRT1 rs7097008 were associated with increased risk for SCC (Odds Ratio = 1.69, P = 8.2×10−5) and greater survival in SCC cases (Hazard Ratio = 0.79, P = 0.03) in miners. Functional validation of rs7097008 demonstrated that the A allele was associated with reduced gene expression in bronchial epithelial cells and compromised DNA repair capacity in peripheral lymphocytes. Together, these findings substantiate genetic variation in SIRT1 as a risk modifier for developing SCC in miners and suggested that SIRT1 may also play a tumor suppressor role in radon-induced cancer in miners. Citation Format: Shuguang Leng, Maria A. Picchi, Yushi Liu, Yong Lin, Christine A. Stidley, Frank D. Gilliland, Marty R. Jacobson, Steven A. Belinsky. Genetic variation in SIRT1 affects susceptibility of lung squamous cell carcinomas in former uranium miners from the Colorado plateau. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3624. doi:10.1158/1538-7445.AM2013-3624

Background Chronic obstructive pulmonary disease (COPD) is characterized by an irreversible airflow limitation in response to inhalation of noxious stimuli, such as cigarette smoke. However, only 15–20 % smokers manifest COPD, suggesting a role for genetic predisposition. Although genome-wide association studies have identified common genetic variants that are associated with susceptibility to COPD, effect sizes of the identified variants are modest, as is the total heritability accounted for by these variants. In this study, an extreme phenotype exome sequencing study was combined with in vitro modeling to identify COPD candidate genes. Results We performed whole exome sequencing of 62 highly susceptible smokers and 30 exceptionally resistant smokers to identify rare variants that may contribute to disease risk or resistance to COPD. This was a cross-sectional case-control study without therapeutic intervention or longitudinal follow-up information. We identified candidate genes based on rare variant analyses and evaluated exonic variants to pinpoint individual genes whose function was computationally established to be significantly different between susceptible and resistant smokers. Top scoring candidate genes from these analyses were further filtered by requiring that each gene be expressed in human bronchial epithelial cells (HBECs). A total of 81 candidate genes were thus selected for in vitro functional testing in cigarette smoke extract (CSE)-exposed HBECs. Using small interfering RNA (siRNA)-mediated gene silencing experiments, we showed that silencing of several candidate genes augmented CSE-induced cytotoxicity in vitro. Conclusions Our integrative analysis through both genetic and functional approaches identified two candidate genes (TACC2 and MYO1E) that augment cigarette smoke (CS)-induced cytotoxicity and, potentially, COPD susceptibility.

One promising approach for early detection of lung cancer is by monitoring gene promoter hypermethylation events in sputum. Epidemiologic studies suggest that dietary fruits and vegetables and the micronutrients they contain may reduce risk of lung cancer. In this study, we evaluated whether diet and multivitamin use influenced the prevalence of gene promoter methylation in cells exfoliated from the aerodigestive tract of current and former smokers. Members (N = 1,101) of the Lovelace Smokers Cohort completed the Harvard Food Frequency Questionnaire and provided a sputum sample that was assessed for promoter methylation of eight genes commonly silenced in lung cancer and associated with risk for this disease. Methylation status was categorized as low (fewer than two genes methylated) or high (two or more genes methylated). Logistic regression models were used to identify associations between methylation status and 21 dietary variables hypothesized to affect the acquisition of gene methylation. Significant protection against methylation was observed for leafy green vegetables [odds ratio (OR) = 0.83 per 12 monthly servings; 95% confidence interval (95% CI), 0.74–0.93] and folate (OR, 0.84 per 750 μg/d; 95% CI, 0.72–0.99). Protection against gene methylation was also seen with current use of multivitamins (OR, 0.57; 95% CI, 0.40–0.83). This is the first cohort-based study to identify dietary factors associated with reduced promoter methylation in cells exfoliated from the airway epithelium of smokers. Novel interventions to prevent lung cancer should be developed based on the ability of diet and dietary supplements to affect reprogramming of the epigenome. Cancer Res; 70(2); 568–74

Coke oven workers are regularly exposed to polycyclic aromatic hydrocarbons (PAHs) and have a high risk for lung cancer. Limited evidence has demonstrated a direct link between exposure to PAHs and early genetic damage in exposed workers. The cytokinesis-block micronucleus (CBMN) cytome assay is a comprehensive system for measuring DNA damage and cytotoxicity. In the current study, we investigated different chromosomal damage endpoints including micronuclei (MN), nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs), in 141 PAH-exposed subjects and 66 unexposed controls. The frequencies of MN, NPBs and NBUDs were all significantly higher in PAH-exposed workers than in controls (2.4-, 5-, and 3-fold, respectively). We further classified the PAH-exposed workers into different PAHs exposure groups based on their work positions on the oven and their urinary 1-hydroxypyrene and found that the frequencies of NPBs and NBUDs increased with the increasing level of both external and internal PAHs exposure levels. Similar trend was not found for MN due to the reduced MN frequency in the highest PAHs exposure group compared with the second highest PAHs exposure group. Using principal component analysis, we confirmed that the frequencies of NPBs and NBUDs are more sensitive to reflect the external or internal levels of PAHs exposure. In PAH-exposed subjects, NPB and NBUD frequencies were influenced by gender and females have lower frequencies of NPB and NBUD. Taken together, our observations indicate that NPBs and NBUDs are more sensitive and reliable biomarkers for genetic damages induced by PAHs and could potentially be used for the biomonitoring of genotoxin-exposed populations.

Objective: The aim of this study was to explore the relationship between UGTIA7 gene polymorphisms and susceptibility to chromosomal damage among polycyclic aromatic hydrocarbons (PAH)-exposed workers. Methods: Blood and urine samples of 140 PAH-exposed workers and 66 non―PAH-exposed workers were collected. The polymorphisms of UGTIA7, cytokinesisblock micronucleus (CBMN) and 1-hydroxypyrene were analyzed. Results: UGTIA7 codon 208 Arg carriers exhibited significantly higher CBMN frequencies than did the Trp/Trp (P < 0.05). Stratification analysis revealed that the significant association between CBMN frequencies and the polymorphisms of UGTIA7 Asn129Lys, Arg131Lys, and Trp208Arg was most pronounced. Moreover, higher CBMN frequencies were found among subjects with * 3 allele than those with * 1 allele (P = 0.008) in younger PAH-exposed workers. Conclusion: Polymorphisms of UGTIA7 gene may alter the severity of PAH-induced chromosomal damage among the exposed workers.

Lung cancer is the leading cause of cancer deaths worldwide, yet few genetic markers of lung cancer risk useful for screening exist. The let-7 family-of-microRNAs (miRNA) are global genetic regulators important in controlling lung cancer oncogene expression by binding to the 3′ untranslated regions of their target mRNAs. The purpose of this study was to identify single nucleotide polymorphisms (SNP) that could modify let-7 binding and to assess the effect of such SNPs on target gene regulation and risk for non–small cell lung cancer (NSCLC). let-7 complementary sites (LCS) were sequenced in the KRAS 3′ untranslated region from 74 NSCLC cases to identify mutations and SNPs that correlated with NSCLC. The allele frequency of a previously unidentified SNP at LCS6 was characterized in 2,433 people (representing 46 human populations). The frequency of the variant allele is 18.1% to 20.3% in NSCLC patients and 5.8% in world populations. The association between the SNP and the risk for NSCLC was defined in two independent case-control studies. A case-control study of lung cancer from New Mexico showed a 2.3-fold increased risk (confidence interval, 1.1–4.6; P = 0.02) for NSCLC cancer in patients who smoked

Background Trichloroethylene (TCE) is used extensively as an industrial solvent and has been recognized as one of the major environmental pollutants. To date, > 200 cases of TCE-induced hypersensitivity dermatitis among exposed workers have been reported worldwide, and TCE exposure has become one of the critical occupational health issues in Asia. Objectives The study aimed to identify genetic susceptible biomarkers associated with the TCE-induced hypersensitivity dermatitis in genes located in the human leukocyte antigen (HLA) region. Methods From 1998 to 2006, 121 cases with TCE-induced hypersensitivity dermatitis and 142 tolerant controls were recruited into the population-based case–control study. We determined HLA alleles B, DRB1, DQA1, and DQB1, by sequence-based typing. p-Values were corrected for comparisons of multiple HLA alleles. In addition, we compared and analyzed the structure character of amino acid residues of HLA molecules found in participants. Results We obtained complete genotyping data of 113 cases and 142 controls. The allele HLA-B*1301 was present in 83 (73.5%) of 113 patients compared with 13 (9.2%) of 142 tolerant workers (odds ratio = 27.5; 95% confidence interval, 13.5–55.7; corrected p = 1.48 × 10−21). In addition, the HLA-B*44 alleles were present in 6.2% (7/113) of patients, but were absent in TCE-tolerant workers. Residue 95 shared by HLA-B*1301 and HLA-B*44 molecules formed a different pocket F than other residues. Conclusions The allele HLA-B*1301 is strongly associated with TCE-induced hypersensitivity dermatitis among exposed workers and might be used as a biomarker to predict high risk individuals to TCE.

O6-Methylguanine-DNA methyltransferase (MGMT) is a DNA repair enzyme that protects cells from carcinogenic effects of alkylating agents; however, MGMT is silenced by promoter hypermethylation during carcinogenesis. A single-nucleotide polymorphism (SNP) in an enhancer in the MGMT promoter was previously identified to be highly significantly associated with risk for MGMT methylation in lung cancer and sputum from smokers. To further genetic investigations, a genome-wide association and replication study was conducted in two smoker cohorts to identify novel loci for MGMT methylation in sputum that were independent of the MGMT enhancer polymorphism. Two novel trans-acting loci (15q15.2 and 17q24.3) that were identified acted together with the enhancer SNP to empower risk prediction for MGMT methylation. We found that the predisposition to MGMT methylation arising from the 15q15.2 locus involved regulation of the ubiquitin protein ligase E3 component UBR1. UBR1 attenuation reduced turnover of MGMT protein and increased repair of O6-methylguanine in nitrosomethylurea-treated human bronchial epithelial cells, while also reducing MGMT promoter activity and abolishing MGMT induction. Overall, our results substantiate reduced gene transcription as a major mechanism for predisposition to MGMT methylation in the lungs of smokers, and support the importance of UBR1 in regulating MGMT homeostasis and DNA repair of alkylated DNA adducts in cells. Cancer Res; 75(15); 3108–17. ©2015 AACR.

Theoretically, a haplotype has a higher level of heterozygosity than individual single nucleotide polymorphism (SNP) and the association study based on the haplotype may have an increased power for detecting disease associations compared with SNP-based analysis. In this study, we investigated the effects of four haplotype-tagging SNPs (htSNP) and the inferred haplotype pairs of the X-ray cross-complementing group 1 (XRCC1) gene on chromosome damage detected by the cytokinesis-block micronucleus assay. The study included 141 coke-oven workers with exposure to a high level of polycyclic aromatic hydrocarbons and 66 nonexposed controls. The frequencies of total MN and MNed cells were borderline associated with the Arg194Trp polymorphism (P = 0.053 and P = 0.050, respectively) but not associated with the Arg280His, Arg399Gln and Gln632Gln polymorphisms among coke-oven workers. Five haplotypes, including CGGG, TGGG, CAGG, CGAG, and CGGA, were inferred based on the four htSNPs of XRCC1 gene. The haplotype CGGG was associated with the decreased frequencies of total MN and MNed cells, and the haplotypes TGGG and CGAG were associated with the increased frequencies of total MN and MNed cells with adjustment for covariates among coke-oven workers. This study showed that the haplotypes derived from htSNPs in the XRCC1 gene were more likely than single SNPs to correlate with the polycyclic aromatic hydrocarbon–induced chromosome damage among coke-oven workers.

Exploring the associations between genetic polymorphisms of metabolic enzymes and susceptibility to polycyclic aromatic hydrocarbon (PAH)-induced chromosomal damage is of great significance for understanding PAH carcinogenesis. Cytochrome P450, glutathione S-transferase, microsomal epoxide hydrolase, NAD(P)H:quinone oxidoreductase, and N-acetyltransferase are PAH-metabolizing enzymes. In this study, we genotyped for the polymorphisms of these genes and assessed their effects on cytokinesis-block micronucleus (CBMN) frequencies in peripheral blood lymphocytes among 141 coke-oven workers and 66 non-coke-oven worker controls. The geometric means of urinary 1-hydroxypyrene levels in coke-oven workers and the controls were 12.0 and 0.7 micromol/mol creatinine, respectively (P0.01). The CBMN frequency (number of micronuclei per 1,000 binucleated lymphocytes) was significantly higher in coke-oven workers (9.5 +/- 6.6 per thousand) than in the controls (4.0 +/- 3.6 per thousand; P0.01). Among the coke-oven workers, age was positively associated with CBMN frequency; the mEH His113 variant genotype exhibited significantly lower CBMN frequency (8.5 +/- 6.5 per thousand) than did the Tyr113/Tyr113 genotype (11.3 +/- 6.4 per thousand; P0.01); the low mEH activity phenotype exhibited a lower CBMN frequency (8.6 +/- 6.8 per thousand) than did the high mEH activity phenotype (13.2 +/- 6.7 per thousand; P = 0.01); the GSTP1 Val105/Val105 genotype exhibited a higher CBMN frequency (15.0 +/- 5.8 per thousand) than did the GSTP1 Ile105/Ile105 or Ile105/Val105 genotypes (9.3 +/- 6.5 per thousand; P0.01); the joint effect of high mEH activity phenotype and GSTM1 null genotype on CBMN frequencies was also found. Gene-environment interactions between occupational PAH exposure and polymorphisms of mEH and/or GSTM1 were also evident. These results indicate that the mEH, GSTP1, and GSTM1 polymorphisms may play a role in sensitivity or genetic susceptibility to the genotoxic effects of PAH exposure in the coke-oven workers.

A wide variety of base damages and single-strand breaks formed by reactive oxygen species during metabolic activation of polycyclic aromatic hydrocarbons (PAHs) have been recognized to be involved in PAH carcinogenesis. In this study, alkaline comet assay was used to detect the DNA damage in peripheral blood lymphocytes among 143 coke-oven workers and 50 non-coke-oven workers, and the effects of genetic polymorphisms of XRCC1 and ERCC2 genes on DNA damage were evaluated. The olive tail moment was significantly higher in coke-oven workers than in non-coke-oven workers (2.6, 95% CI=2.1-3.3 versus 1.0, 95% CI=0.8-1.2, p0.01), and significant correlation between ln-transformed urinary 1-OHP and ln-transformed olive tail moment was found in total population (n=193, Pearson's r=0.393, p0.001) and in coke-oven workers (n=143, Pearson's r=0.224, p=0.007). The olive tail moment was significantly higher in coke-oven workers with GA genotype of G27466A polymorphism of XRCC1 than those with GG genotype (4.6, 95% CI=2.5-8.7 versus 2.4, 95% CI=1.9-2.9, p0.01 with adjustment for covariates). No significant associations between C26304T, G28152A and G36189A polymorphisms of XRCC1 and G23591A and A35931C polymorphisms of ERCC2 and olive tail moment were found in both groups. The study showed that the alkaline comet assay is a suitable biomarker in the detection of DNA damage among coke-oven workers and it suggested that the A allele of G27466A polymorphism of XRCC1 may be associated with decreased DNA repair capacity toward PAH-induced base damage and strand breaks.

Trichloroethylene (TCE)-induced severe generalized dermatitis (SGD) is considered to be a contact allergic disease and is dependent on a cell-mediated immune response. Little is known about its pathogenesis. Several lines of evidence suggest that tumour necrosis factor (TNF) and interleukin 4 (IL-4) are involved in the immunological and inflammatory reactions. To investigate the relation between polymorphisms of TNF and the IL-4 gene and the risk of TCE-induced SGD, a case-control study was conducted consisting of 111 patients diagnosed with SGD and 152 TCE-exposed workers without SGD. Polymerase chain reaction-restriction fragment length polymorphism was used to detect the polymorphisms of TNF-alpha (G-238A, G-308A), TNF-beta (intron 1) and IL-4 (C-590T). Logistic regression was applied to calculate the odds ratios (OR) and 95% confidence intervals. The results reveal that the frequency of TNF alpha-308 wild allele in cases was significantly higher than that in control subjects (p=0.049). Individuals with a heterozygous genotype of TNF alpha-308 were associated with the decreased risk of TCE-induced SGD relative to the homozygous genotype (OR=0.398, 95% CI=0.164-0.967). No significant differences in the allele and genotype frequencies could be demonstrated at any other polymorphic loci among both groups. The finding of a possible contribution of a TNF-alpha genetic polymorphism is a primary result because the pathogenesis of TCE-induced SGD is complex and likely to involve the interaction of a number of genes. A further study should be conducted to illustrate the influence of a link between certain relevant alleles in the assessment of genetic susceptibility

Background: High radon exposure is a risk factor for squamous cell carcinoma, a major lung cancer histology observed in former uranium miners. Radon exposure can cause oxidative stress, leading to pulmonary inflammation. Interleukin-6 (IL-6) is a pro-carcinogenic inflammatory cytokine that plays a pivotal role in lung cancer development. Objectives: We assessed whether single nucleotide polymorphisms (SNPs) in the IL6 promoter are associated with lung cancer in former uranium miners with high occupational exposure to radon gas. Methods: Genetic associations were assessed in a case–control study of former uranium miners (242 cases and 336 controls). A replication study was performed using data from the Gene Environment Association Studies (GENEVA) Genome Wide Association Study (GWAS) of Lung Cancer and Smoking. Functional relevance of the SNPs was characterized using in vitro approaches. Results: We found that rs1800797 was associated with squamous cell carcinoma in miners and with a shorter time between the midpoint of the period of substantial exposure and diagnosis among the cases. Furthermore, rs1800797 was also associated with lung cancer among never smokers in the GENEVA dataset. Functional studies identified that the risk allele was associated with increased basal IL-6 mRNA level and greater promoter activity. Furthermore, fibroblasts with the risk allele showed greater induction of IL-6 secretion by hydrogen peroxide or benzo[a]pyrene diolepoxide treatments. Conclusions: An IL6 promoter variant was associated with lung cancer in uranium miners and never smokers in two external study populations. The associations are strongly supported by the functional relevance that the IL6 promoter SNP affects basal expression and carcinogen-induced IL-6 secretion. Citation: Leng S, Thomas CL, Snider AM, Picchi MA, Chen W, Willis DG, Carr TG, Krzeminski J, Desai D, Shantu A, Lin Y, Jacobson MR, Belinsky SA. 2016. Radon exposure, IL-6 promoter variants, and lung squamous cell carcinoma in former uranium miners. Environ Health Perspect 124:445–451; http://dx.doi.org/10.1289/ehp.1409437

Gene promoter methylation detected in sputum predicts lung cancer risk in smokers. Compared with non-Hispanic whites (NHW), Hispanics have a lower age-standardized incidence for lung cancer.This study compared the methylation prevalence in sputum of NHWs with Hispanics using the Lovelace Smokers cohort (n = 1998) and evaluated the effect of Native American ancestry (NAA) and diet on biomarkers for lung cancer risk.Genetic ancestry was estimated using 48 ancestry markers. Diet was assessed by the Harvard University Dietary Assessment questionnaire. Methylation of 12 genes was measured in sputum using methylation-specific polymerase chain reaction. The association between NAA and risk for methylation was assessed using generalized estimating equations. The ethnic difference in the association between pack-years and risk for lung cancer was assessed in the New Mexico lung cancer study.Overall Hispanics had a significantly increased risk for methylation across the 12 genes analyzed (odds ratio, 1.18; P = 0.007). However, the risk was reduced by 32% (P = 0.032) in Hispanics with high versus low NAA. In the New Mexico lung cancer study, Hispanic non-small cell lung cancer cases have significantly lower pack-years than NHW counterparts (P = 0.007). Furthermore, compared with NHW smokers, Hispanic smokers had a more rapidly increasing risk for lung cancer as a function of pack-years (P = 0.058).NAA may be an important risk modifier for methylation in Hispanic smokers. Smoking intensity may have a greater impact on risk for lung cancer in Hispanics compared with NHWs.

Many people frequently tan indoors despite being aware of the increased risk of melanoma. Ultraviolet radiation is hypothesized to modify biological reward pathways, for example, through the dopamine neurotransmitter system, to reinforce tanning behaviour. In this pilot study, we relied on questionnaire and DNA data from a recently completed case–control study to examine 67 single-nucleotide polymorphisms (SNPs) and related haplotypes in five dopamine receptor and drug metabolism genes in relation to indoor tanning among controls. We also examined the association between individual SNPS and likelihood of melanoma, adjusting for or stratifying on indoor tanning status. In candidate and haplotype gene analyses, variants only in the DRD2 dopamine receptor and ANKK1 signalling genes were positively associated with indoor tanning use among controls; only associations for ANKK1 remained statistically significant (P < 0.05) after adjustment. Several SNPs in ANKK1 and DRD2 associated with indoor tanning among controls were also found to be associated with increased risk of melanoma. Upon stratifying for indoor tanning status, one ANKK1 SNP was positively associated with melanoma among non-tanners, while three DRD2 SNPS were positively associated with melanoma among tanners or non-tanners, depending on the SNP. These alleles represent important genomic regions to further explore addictive tanning behaviour.

Purpose: To evaluate the methylation state of 31 genes in sputum as biomarkers in an expanded nested, case–control study from the Colorado cohort, and to assess the replication of results from the most promising genes in an independent case–control study of asymptomatic patients with stage I lung cancer from New Mexico. Experimental Design: Cases and controls from Colorado and New Mexico were interrogated for methylation of up to 31 genes using nested, methylation-specific PCR. Individual genes and methylation indices were used to assess the association between methylation and lung cancer with logistic regression modeling. Results: Seventeen genes with ORs of 1.4 to 3.6 were identified and selected for replication in the New Mexico study. Overall, the direction of effects seen in New Mexico was similar to Colorado with the largest increase in case discrimination (ORs, 3.2–4.2) seen for the PAX5α, GATA5, and SULF2 genes. Receiver operating characteristic (ROC) curves generated from seven-gene panels from Colorado and New Mexico studies showed prediction accuracy of 71% and 77%, respectively. A 22-fold increase in lung cancer risk was seen for a subset of New Mexico cases with five or more genes methylated. Sequence variants associated with lung cancer did not improve the accuracy of this gene methylation panel. Conclusions: These studies have identified and replicated a panel of methylated genes whose integration with other promising biomarkers could initially identify the highest risk smokers for computed tomographic screening for early detection of lung cancer. Clin Cancer Res; 18(12); 3387–95. ©2012 AACR.

Gene promoter hypermethylation is now regarded as a promising biomarker for the risk and progression of lung cancer. The one-carbon metabolism pathway is postulated to affect deoxyribonucleic acid (DNA) methylation because it is responsible for the generation of S-adenosylmethionine (SAM), the methyl donor for cellular methylation reactions. This study investigated the association of single nucleotide polymorphisms (SNPs) in six one-carbon metabolism-related genes with promoter hypermethylation in sputum DNA from non-Hispanic white smokers in the Lovelace Smokers Cohort (LSC) (n = 907). Logistic regression was used to assess the association of SNPs with hypermethylation using a high/low methylation cutoff. SNPs in the cystathionine beta synthase (CBS) and 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR) genes were significantly associated with high methylation in males [CBS rs2850146 (-8283G > C), OR = 4.9; 95% CI: 1.98, 12.2, P = 0.0006] and low methylation in females [MTRR rs3776467 (7068A > G), OR = 0.57, 95% CI: 0.42, 0.77, P = 0.0003]. The variant allele of rs2850146 was associated with reduced gene expression and increased plasma homocysteine (Hcy) concentrations. Three plasma metabolites, Hcy, methionine and dimethylglycine, were associated with increased risk for gene methylation. These studies suggest that SNPs in CBS and MTRR have sex-specific associations with aberrant methylation in the lung epithelium of smokers that could be mediated by the affected one-carbon metabolism and transsulfuration in the cells. Abbreviations: CBS cystathionine beta synthase DNA deoxyribonucleic acid HBEC human bronchial epithelial cell Hcy homocysteine LD, linkage disequilibrium; LSC lovelace Smokers Cohort MAF minor allele frequency MTHFR methylenetetrahydrofolate reductase MTRR methyltransferase reductase SNP single nucleotide polymorphisms SAH S-adenosylhomocysteine SAM S-adenosylmethionine

Aberrant cytosine methylation affects regulation of hundreds of genes during cancer development. In this study, a novel aberrantly hypermethylated CpG island in cancer was discovered within the TOX2 promoter. TOX2 was unmethylated in normal cells but 28% lung (n = 190) and 23% breast (n = 80) tumors were methylated. Expression of two novel TOX2 transcripts identified was significantly reduced in primary lung tumors than distant normal lung (p

The detection of tumor suppressor gene promoter methylation in sputum-derived exfoliated cells predicts early lung cancer. Here, we identified genetic determinants for this epigenetic process and examined their biologic effects on gene regulation. A two-stage approach involving discovery and replication was used to assess the association between promoter hypermethylation of a 12-gene panel and common variation in 40 genes involved in carcinogen metabolism, regulation of methylation, and DNA damage response in members of the Lovelace Smokers Cohort (N = 1,434). Molecular validation of three identified variants was conducted using primary bronchial epithelial cells. Association of study-wide significance (P < 8.2 × 10−5) was identified for rs1641511, rs3730859, and rs1883264 in TP53, LIG1, and BIK, respectively. These single-nucleotide polymorphisms (SNP) were significantly associated with altered expression of the corresponding genes in primary bronchial epithelial cells. In addition, rs3730859 in LIG1 was also moderately associated with increased risk for lung cancer among Caucasian smokers. Together, our findings suggest that genetic variation in DNA replication and apoptosis pathways impacts the propensity for gene promoter hypermethylation in the aerodigestive tract of smokers. The incorporation of genetic biomarkers for gene promoter hypermethylation with clinical and somatic markers may improve risk assessment models for lung cancer. Cancer Res; 72(3); 707–15. ©2011 AACR.

Purpose: To address the association between sequence variants within the MGMT (O6-methylguanine-DNA methyltransferase) promoter–enhancer region and methylation of MGMT in premalignant lesions from smokers and lung adenocarcinomas, their biological effects on gene regulation, and targeting MGMT for therapy. Experimental Design: Single nucleotide polymorphisms (SNP) identified through sequencing a 1.9 kb fragment 5′ of MGMT were examined in relation to MGMT methylation in 169 lung adenocarcinomas and 1,731 sputum samples from smokers. The effect of promoter haplotypes on MGMT expression was tested using a luciferase reporter assay and cDNA expression analysis along with allele-specific sequencing for methylation. The response of MGMT methylated lung cancer cell lines to the alkylating agent temozolomide (TMZ) was assessed. Results: The A allele of rs16906252 and the haplotype containing this SNP were strongly associated with increased risk for MGMT methylation in adenocarcinomas (ORs ≥ 94). This association was observed to a lesser extent in sputum samples in both smoker cohorts. The A allele was selectively methylated in primary lung tumors and cell lines heterozygous for rs16906252. With the most common haplotype as the reference, a 20 to 41% reduction in promoter activity was seen for the haplotype carrying the A allele that correlated with lower MGMT expression. The sensitivity of lung cancer cell lines to TMZ was strongly correlated with levels of MGMT methylation and expression. Conclusions: These studies provide strong evidence that the A allele of a MGMT promoter–enhancer SNP is a key determinant for MGMT methylation in lung carcinogenesis. Moreover, TMZ treatment may benefit a subset of lung cancer patients methylated for MGMT. Clin Cancer Res; 17(7); 2014–23. ©2011 AACR.

The hypersensitivity dermatitis induced by trichloroethylene (TCE) exposure was influenced by individual genetic susceptibility factors. In this paper, a case-control study was conducted to investigate effects of various genotypes and phenotypes of N-Acetyltransferases (NATs) on individual susceptibility to the disease. The study consists of 111 patients with hypersensitivity dermatitis and 154 healthy TCE-exposed workers. Polymerase chain reaction-restriction fragment length polymorphism was used to detect the polymorphic sites of NAT1 at nt 1095 and 1088 and the sites of NAT2 at nt 481, 590, and 857. Logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (95%CI). The results reveal that subjects with intermediate or slow acetylators of NAT2 have a 2.01 fold (95%CI=1.14-3.54) higher risk for the disease than subjects with the fast acetylators. When non-fast NAT2 phenotype (intermediate and slow acetylators) and a slow NAT1 phenotype were combined, the risk for the disease was significantly increased (OR=2.71, 95%CI 1.29-5.70) to the level higher than that observed for NAT2 non-fast acetylators phenotype alone. These findings suggest that slow metabolic phenotype of NAT2 maybe one of risk factor for TCE-induced hypersensitivity dermatitis and combined slow acetylator phenotypes of NAT1 and NAT2 further increase such risk.

DNA and chromosome damages in peripheral blood lymphocytes were evaluated in 151 workers occupationally exposed to formaldehyde (FA) and 112 non-FA exposed controls. The effects of polymorphisms in three glutathione-S-transferase (GSTs) genes on the DNA and chromosome damages were assessed as well. Alkaline comet assay and cytokinesis-block micronucleus (CBMN) assay were used to determine DNA and chromosome damages, respectively. The genotypes of GSTP1 (Ile105Val), GSTT1, and GSTM1 were assayed. The mean 8-h time-weighted average (TWA) concentrations of FA in two plywood factories were 0.83ppm (range: 0.08-6.30ppm). FA-exposed workers had higher olive tail moment (TM) and CBMN frequency compared with controls (Olive TM, 3.54, 95%CI=3.19-3.93 vs. 0.93, 95%CI=0.78-1.10, P0.01; CBMN frequency, 5.51+/-3.37 vs. 2.67+/-1.32, P0.01). Olive TM and the CBMN frequency also had a dose-dependent relation with the personal FA exposure. Significant association between FA exposure history and olive TM and CBMN frequency were also identified. The level of olive TM was slightly higher in FA-exposed workers with GSTM1 null genotype than those with non-null genotype (3.86, 95%CI=3.31-4.50 vs. 3.27, 95%CI=2.83-3.78, P=0.07) with adjustment of covariates. We also found that FA-exposed workers carrying GSTP1 Val allele had a slightly higher CBMN frequency compared with workers carrying only the wild-type allele (6.32+/-3.78 vs. 5.01+/-2.98, P=0.05). Our results suggest that the FA exposure in this occupational population increased DNA and chromosome damages and polymorphisms in GSTs genes may modulate the genotoxic effects of FA exposure.

DNA repair is an essential mechanism for cells to maintain their genomic integrity under endogenous or exogenous assault. Reduced DNA repair capacity (DRC) is associated with increased risk for several environmentally related cancers. The micronucleus in peripheral lymphocytes has been validated as a biomarker of chromosomal damage, increasing cancer risk in human populations. We hypothesized that suboptimal DRC is associated with the increase in chromosomal damage among 94 coke-oven workers and 64 noncoke-oven controls. DRC was evaluated in isolated lymphocytes by comet assay. Chromosomal damage in peripheral lymphocytes was detected by cytokinesis-block micronucleus assay. Four common coding single nucleotide polymorphisms in the XRCC1 gene were genotyped. Coke-oven workers have significantly increased urinary 1-hydroxypyrene (9.0; 6.8-11.7 μg/L versus 1.5, 1.3-1.7 μg/L; P < 0.01) and micronucleus frequency (7.4‰ ± 4.3‰ versus 3.0‰ ± 3.0‰; P < 0.01), and decreased DRC (55.9% ± 16.4% versus 63.6% ± 18.5%; P < 0.01) compared with controls. Significant correlations between DRC and micronucleus frequency were found in coke-oven workers (r = −0.32; P < 0.01; n = 94) and all study subjects (r = −0.32; P < 0.001; n = 158) but not in controls (r = −0.21; P = 0.11; n = 64). Variants of the Arg399Gln polymorphism were associated with a decreased DRC in both coke-oven workers (51.6% ± 16.1% versus 60.6% ± 15.7%; P < 0.01) and controls (59.1% ± 18.5% versus 68.4% ± 17.5%; P = 0.04). The complicated interrelationship of these multiple biomarkers was also identified by path analysis. These findings should facilitate developing a biomarker-based risk assessment model for lung cancer in this occupational population. (Cancer Epidemiol Biomarkers Prev 2009;18(3):987–93)

The mutagen sensitivity assay is an in vitro measure of DNA repair capacity used to evaluate intrinsic susceptibility for cancer. The high heritability of mutagen sensitivity to different mutagens validates the use of this phenotype to predict cancer susceptibility. However, genetic determinants of mutagen sensitivity have not been fully characterized. Recently, several studies found that three major cytosine DNA methyltransferases (DNMTs), especially DNMT1, have a direct role in the DNA damage response, independent of their methyltransferase activity. This study evaluated the hypothesis that sequence variants in DNMT1, DNMT3A and DNMT3B are associated with mutagen sensitivity induced by the tobacco carcinogen benzo[a]pyrene diol epoxide (BPDE) in 278 cancer-free smokers. Single-nucleotide polymorphisms (n = 134) dispersed over the entire gene and regulatory regions of these DNMTs were genotyped by the Illumina Golden Gate Assay. DNA sequence variation in the DNMT1 and DNMT3B loci was globally associated with breaks per cell (P < 0.04 for both). No global association between DNMT3A and breaks per cell was seen (P = 0.09). Two haplotypes in block1 of DNMT1 (H284) and 3B (H70) were associated with 16 and 24% increase in breaks per cell, respectively. Subjects with three or four adverse haplotypes of both DNMT1 and 3B had a 50% elevation in mean level of breaks per cell compared with persons without adverse alleles (P = 0.004). The association between sequence variants of DNMT1 and 3B and mutagen sensitivity induced by BPDE supports the involvement of these DNMTs in protecting the cell from DNA damage.

To investigate the association of single nucleotide polymorphisms (SNPs) or haplotypes of aryl hydrocarbon receptor (AHR) gene and chromosomal damage in peripheral blood lymphocytes among coke-oven workers.Eighty-nine coke-oven workers exposed to a high level of polycyclic aromatic hydrocarbons (PAHs) and sixty non-exposed workers were selected as the study subjects. Urinary 1-hydroxypyrene (1-OHPyr) levels were measured as the internal dose of PAHs exposure. The chromosomal damage in peripheral lymphocyte was measured by the cytokinesis-block micronucleus (CBMN) assay. Two SNPs in AHR gene, including rs6960165, rs2282885 were detected by PCR-RFLP. The AHR haplotypes were estimated by Bayesian statistical method with the software of PHASE Version 2.1. The associations between SNPs or haplotypes pairs and CBMN were assessed by analysis of covariance in the coke-oven workers and non-exposed workers.The level of 1-OHPyr among coke-oven workers was significantly higher than that among non-exposed workers (P0.01). The CBMN among coke-oven workers was significantly higher than that among non-exposed workers (P0.01). After adjusting the age and the level of 1-OHPyr, the different SNPs of AHR gene rs6960165 in coke-oven workers were related to the CBMN frequencies (P = 0.014), but no association between the different SNPs of AHR gene rs2282885 and the rates of CBMN was observed in coke-oven workers (P = 0.586), either in the controls (P = 0.308 and P = 0.415, respectively), the haplotypes in coke-oven workers were significantly related to the rates of CBMN (P = 0.007), while there was no significant association in non-exposed workers (P = 0.768).Our results suggested that SNPs rs6960165 or haplotypes of AHR were associated with the CBMN frequencies in coke-oven workers.

Many host factors or biomarkers are involved in the process of early DNA damage induced by occupational exposure to polycyclic aromatic hydrocarbons (PAH) as seen in coke-oven workers. This paper aimed to identify complicated causal interrelationship of various biomarkers using the path analysis. In this analysis, we included 235 subjects (166 coke-oven workers and 69 nonexposed controls) whose data on the comet assay (e.g., Olive tail moment) and cytogenetic analysis of peripheral blood lymphocytes as well as urinary 1-hydroxypyrene (1-OHP) were available. The path analysis showed that coke-oven exposure and tobacco smoke were both significant predictors of the concentrations of urinary 1-OHP (P < 0.05), with a coefficient of determination of 0.75. The factors having significant influence on the Olive tail moment were in the following order: urinary 1-OHP > XRCC1-exon 9 variant genotype > ERCC2-exon 10 variant genotype > XRCC1-exon 6 variant genotype, with a coefficient of determination of 0.22. The variables of relative importance in influencing on cytokinesis-block micronucleus frequencies were in the following order: coke-oven exposure > urinary 1-OHP > age > mEH3 variant genotype > ERCC2-exon 10 variant genotype > XRCC1-exon 6 variant genotype, with a coefficient of determination of 0.27. These results indicated that exogenous agents, especially the coke-oven exposure, played a more important role than the genotypes in the induction of early genetic damage. In conclusion, the path analysis seemed to be an alternative statistical approach for the ascertainment of complicated association among related biomarkers for the assessment of occupational exposure. (Cancer Epidemiol Biomarkers Prev 2007;16(6):1193–9)

The associations of the Bsm1 polymorphism of vitamin D receptor gene and blood lead, zinc protoporphyrin and physical development in 476 environmental lead-exposed children were studied. After blood lead level, age, sex and education level of the patients were adjusted by analysis of covariance, the children with B allele had larger head circumference than those with bb genotype(P = 0.02). While the subjects were stratified by blood lead level and sex, the statistically significant difference in head circumference between different Bsm1 genotypes was found only in high-blood-lead subgroup and in male subgroup. No significant influence of Bsm1 polymorphism on blood lead level, zinc protoporphyrin, height and weight was found, suggesting that the Bsm1 polymorphism of VDR gene may modify the effect of lead on the skull development of children highly exposed to lead.

The relationship between polymorphisms of ALAD and VDR genes and individual susceptibility of lead poisoning was investigated in children highly-exposed to lead.Four hundred and sixty-nine children were recruited into this study and the blood lead, ZPP, hemoglobin as well as three physical developmental indexes (head circumference, height and weight) were measured. VDR and ALAD gene polymorphisms were analyzed by the methods of PCR-RFLP.The subjects with ALAD2 allele had higher ZPP level (10.12 micro mol/L vs 12.87 micro mol/L) (P = 0.017). The subjects with B allele has larger head circumference than only with b allele (51.19 cm vs 50.75 cm) (P = 0.028).It was suggested that the ALAD gene polymorphism modified the relationship between blood lead and ZPP and the VDR gene variants influenced the skull development in children living under lead-polluted environment. The polymorphism of ALAD and VDR genes might serve as the molecular inherited factors modifying the susceptibility of lead poisoning.