Search

Puberty is a time of intense growth and differentiation of breast tissue and a window of susceptibility (WOS) for breast cancer. Although oxidative stress markers have been associated with breast cancer risk, it is unclear whether oxidative stress levels are different during the pubertal WOS, and if so, whether these differences are related to breast cancer susceptibility. We measured urinary biomarkers of whole body oxidative stress (urinary F2-Isoprostanes and 8-oxodeoxyguanosine (8-oxodG)) in 158 girls (ages 6-13 years), 71 with and 87 without a breast cancer family history (BCFH) from a cohort of adolescent girls from the New York site of the LEGACY cohort (Lessons in Epidemiology and Genetics in Adults Cancer from Youth). We compared levels of urinary oxidative stress biomarkers (F2-Isoprostanes and 8-oxodG) across the pubertal window, defined by Tanner Stage (TS) of breast development, both cross-sectionally and longitudinally within girls over an 18-month follow up period. Urinary oxidative stress biomarkers were unrelated to pubertal stages in cross-sectional analyses after considering adjustments for body mass index (BMI) and BCFH. In our longitudinal analysis, we found that urinary 8-oxodG levels, but not F2-Isoprostane levels, increased with age in BCFH + girls ( β  = 6.12, 95% CI = 0.08-12.16) compared to BCFH-girls. Higher BMI was associated with higher level of F2-Isoprostane in both cross-sectional ( β  = 0.02, 95% CI = 0.0004-0.05) and longitudinal analysis ( β  = 0.02, 95% CI = 0.0002-0.05). These findings support that higher BMI increases oxidative stress biomarkers over the pubertal window and that there are changes in 8-oxodG oxidative stress biomarkers in girls with a BCFH compared to girls without a BCFH.

To examine 143 diabetes risk single nucleotide polymorphisms (SNPs), identified from genome-wide association studies, in association with breast cancer (BC) incidence and subsequent mortality. A population-based sample of Caucasian women with first primary invasive BC (n = 817) and controls (n = 1021) were interviewed to assess diabetes status. Using the National Death Index, women with BC were followed for >18 years during which 340 deaths occurred (139 BC deaths). Genotyping was done using DNA extracted from blood samples. We used unconditional logistic regression to estimate age-adjusted odds ratios and 95% confidence intervals (CIs) for BC incidence, and Cox regression to estimate age-adjusted hazard ratios and CIs for all-cause and BC-specific mortality. Twelve SNPs were associated with BC risk in additive genotype models, at α = 0.05. The top three significant SNPs included SLC30A8-rs4876369 (P = 0.0034), HHEX-rs11187146 (P = 0.0086), and CDKN2A/CDKN2B-rs1333049 (P = 0.0094). Diabetes status modified the associations between rs4876369 and rs2241745 and BC incidence, on the multiplicative interaction scale. Six SNPs were associated with all-cause (CDKAL1-rs981042, P = 0.0032; HHEX-rs1111875, P = 0.0361; and INSR-rs919275, P = 0.0488) or BC-specific (CDKN2A/CDKN2B-rs3218020, P = 0.0225; CDKAL1-rs981042, P = 0.0246; and TCF2/HNF1B-rs3094508, P = 0.0344) mortality in additive genotype models, at α = 0.05. Genetic polymorphisms that increase the risk of developing diabetes may also increase the risk of developing and dying from BC., (© 2018 Wiley Periodicals, Inc.)

ELISA is commonly used for the detection of urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), a marker of whole body oxidative stress. However, the method has been criticized for high inter-laboratory variability and poor agreement with chromatographic techniques. We performed an inter-laboratory comparison of 8-oxodG assessed in 30 urine samples and a urine spiked with four different concentrations of 8-oxodG by ELISA using standardized experimental conditions, including: sample pre-treatment with solid-phase extraction (SPE), performing analysis using a commercial kit from a single manufacturer and strict temperature control during the assay. We further compared the ELISA results with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and performed tentative identification of compounds that may contribute to the discrepancy between both methods. For all but one participating laboratory (Data 1) we observed consistent ELISA results lying mostly within 1SD of the mean 8-oxodG concentration. Mean 8-oxodG levels assessed by ELISA correlated with the data obtained by HPLC-MS/MS (R=0.679, p<0.001). The correlation improved when Data 1 were excluded from the analysis (R=0.749, p<0.001). We identified three outlying urine samples; one with an ELISA 8-oxodG concentration lower, and two with 8-oxodG levels higher, than those measured by HPLC-MS/MS. Omitting these samples further improved inter-methodology agreement (R=0.869, p<0.001). In the outliers with high 8-oxodG estimates various aromatic and heterocyclic compounds were tentatively identified using gas chromatography-mass spectrometry (GC-MS). Application of authentic standards revealed the presence of saccharides, including d-glucose and d-galactose as putative interfering substances. In summary, assay standardization improved ELISA inter-laboratory agreement, although some variability is still observed. There are still compounds contributing to overestimation of 8-oxodG by ELISA, but only in some urine samples. Thus, despite significant improvement, ELISA still should not be considered a robust alternative to chromatographic techniques., (Copyright © 2016 Elsevier Inc. All rights reserved.)

We aimed to investigate oxidative stress biomarkers in a cross-sectional pilot study of 50 participants with sporadic ALS (SALS) compared to 46 control subjects. We measured urinary 8-oxodeoxyguanosine (8-oxodG), urinary 15-F(2t)-isoprostane (IsoP), and plasma protein carbonyl by ELISA methods. We also determined if ELISA measurement of 8-oxodG could be validated against measures from high-pressure liquid chromatography coupled with electrochemical detection, the current standard method. We found that 8-oxodG and IsoP levels adjusted for creatinine were significantly elevated in SALS participants. These differences persisted after age and gender were controlled in regression analyses. These markers are highly and positively correlated with each other. 8-oxodG measured by the two techniques from the same urine sample were positively correlated (p<.0001). Protein carbonyl was not different between SALS participants and controls. In conclusion, using ELISA, we confirmed that certain oxidative stress biomarkers were elevated in SALS participants. ELISA may be reliable and thus useful in epidemiology studies requiring large numbers of samples to determine the significance of increased oxidative stress markers in SALS. Further studies are required.

The association between aflatoxin B1 (AFB1) exposure and oxidative stress was extensively examined in 84 adolescents from an area at high risk for hepatocellular carcinoma in China. Plasma level of aflatoxin B1-albumin adducts (AAAs) was associated with AFB1 excretion in urine (r = 0.394, P < 0.001). Urinary AFB1 was also associated with both the urinary excretion of 8-hydroxydeoxyguanosine (8-OHdG) (r > or = 0.479, P < 0.001) and 8-OHdG and hOGG1 levels in peripheral leukocytes (r > or = 0.308, P < or = 0.005). Similarly, AAA was significantly associated with both the urinary excretion of 8-OHdG (r > or = 0.259, P < or = 0.018) and the 8-OHdG and hOGG1 levels in peripheral leukocytes (r > or = 0.313, P < or = 0.004). In addition, urinary 8-OHdG was correlated with both the level of DNA 8-OHdG (r > or = 0.24, P < or = 0.05) and the expression of hOGG1 in peripheral leukocytes (r > or = 0.429, P < 0.001). Protein carbonyl content (PCC) level was significantly associated with not only the level of DNA 8-OHdG (r > or = 0.366, P < 0.001) and the urinary 8-OHdG (r > or = 0.258, P < or = 0.018) but also the expression of hOGG1 in peripheral leukocytes (r = 0.485, P < 0.001). A significant but weak association was found between high-performance liquid chromatograph-electrochemical detection (HPLC-ECD) and enzyme-linked immunosorbent assay (ELISA) for urinary 8-OHdG (r = 0.334, P = 0.002) and between HPLC-ECD and flow cytometry assays for 8-OHdG in leucocytes (r = 0.395, P < 0.001). Significant associations were observed between AAA and PCC and liver function indices (alanine aminotransferase and aspartate aminotransferase). These findings suggest significant contribution from AFB1 exposure to oxidative stress and subsequent repair among adolescents that may impose substantial risk for hepatocarcinogenesis in adulthood in this region.

Exposure to ambient air pollution is associated with many diseases. Oxidative and nitrosative stress are believed to be two of the major sources of particulate matter (PM)-mediated adverse health effects. PM in ambient air arises from industry, local heating, and vehicle emissions and poses a serious problem mainly in large cities. In the present study we analyzed the level of oxidative and nitrosative stress among 50 bus drivers from Prague, Czech Republic, and 50 matching controls. We assessed simultaneously the levels of 15-F(2t)-isoprostane (15-F(2t)-IsoP) and 8-oxodeoxyguanosine (8-oxodG) in urine and protein carbonyl groups and 3-nitrotyrosine (NT) in blood plasma. For the analysis of all four markers we used ELISA techniques. We observed significantly increased levels of oxidative and nitrosative stress markers in bus drivers. The median levels (min, max) of individual markers in bus drivers versus controls were as follows: 8-oxodG: 7.79 (2.64-12.34)nmol/mmol versus 6.12 (0.70-11.38)nmol/mmol creatinine (p<0.01); 15-F(2t)-IsoP: 0.81 (0.38-1.55)nmol/mmol versus 0.68 (0.39-1.79)nmol/mmol creatinine (p<0.01); carbonyl levels: 14.1 (11.8-19.0)nmol/ml versus 12.9 (9.8-16.6)nmol/ml plasma (p<0.001); NT: 694 (471-3228)nmol/l versus 537 (268-13833)nmol/l plasma (p<0.001). 15-F(2t)-IsoP levels correlated with vitamin E (R=0.23, p<0.05), vitamin C (R=-0.33, p<0.01) and cotinine (R=0.47, p<0.001) levels. Vitamin E levels also positively correlated with 8-oxodG (R=0.27, p=0.01) and protein carbonyl levels (R=0.32, p<0.001). Both oxidative and nitrosative stress markers positively correlated with PM2.5 and PM10 exposure. In conclusion, our study indicates that exposure to PM2.5 and PM10 results in increased oxidative and nitrosative stress.

This experiment examined the effects of delays in separation and freezing of whole blood components on analytes of interest in studies of prostate cancer prevention, in order to evaluate the feasibility of centralized processing of blood for the multisite Selenium and Vitamin E Cancer Prevention Trial. Blood from 40 healthy men was subjected to four treatment protocols, allowing the contrast of immediate processing to delays of 32, 72, and 144 hours. At 32 hours, simulating refrigerated storage and overnight shipping, there was a 2.9% decrease (95% confidence interval, 0.7-5.1) in insulin-like growth factor-I (IGF-I) but no significant change in carotenoids, tocopherols, testosterone, 3alpha-androstanediol glucuronide (AAG), sex hormone-binding globulin (SHBG) or insulin-like growth factor binding protein 3 (IGFBP3). A 144-hour processing delay, simulating weekend blood collection or shipping delay, resulted in significant changes in gamma-tocopherol (-1.5%), IGF-I (-5.7%), IGFBP3 (-2.9%), SHBG (-4.0%), testosterone (+4.7%), and AAG (+5.5%). The rank-order and intraclass correlations between analytes from blood processed immediately and those subjected to delayed processing were 0.96 or higher for carotenoids, tocopherols, AAG, and SHBG, and between 0.87 and 0.95 for IGF-I, IGFBP3, and testosterone. A 32-hour delay decreased lymphocyte viability from 82.5% to 75.0% (P = 0.45), but a 72-hour delay decreased viability to 36.8% (P < 0.001). Overnight shipping and centralized processing is an acceptable approach to blood collection in large multisite trials examining the cancer-related measures proposed in the Selenium and Vitamin E Cancer Prevention Trial. Longer processing delays, however, have small but statistically significant effects on many analytes and substantially decrease lymphocyte viability.

BackgroundPolycyclic aromatic hydrocarbon (PAH) exposures from tobacco smoke, automobile exhaust, grilled or smoked meat and other sources are widespread and are a public health concern, as many are classified as probable carcinogens and suspected endocrine-disrupting chemicals. PAH exposures can be quantified using urinary biomarkers.MethodsSeven urinary metabolites of naphthalene, fluorene, phenanthrene, and pyrene were measured in two samples collected from girls aged 6-16 years from the San Francisco Bay Area. We used Spearman correlation coefficients (SCC) to assess correlations among metabolite concentrations (corrected for specific gravity) separately in first (n = 359) and last (N = 349) samples, and to assess consistency of measurements in samples collected up to 72 months apart. Using multivariable linear regression, we assessed variation in mean metabolites across categories of participant characteristics and potential outdoor, indoor, and dietary sources of PAH exposures.ResultsThe detection rate of PAH metabolites was high (4 metabolites in ≥98% of first samples; 5 metabolites in ≥95% of last samples). Correlations were moderate to strong between fluorene, phenanthrene and pyrene metabolites (SCC 0.43-0.82), but weaker between naphthalene and the other metabolites (SCC 0.18-0.36). SCC between metabolites in first and last samples ranged from 0.15 to 0.49. When classifying metabolite concentrations into tertiles based on single samples (first or last samples) vs. the average of the two samples, agreement was moderate to substantial (weighted kappa statistics 0.52-0.65). For specific metabolites, concentrations varied by age, race/ethnicity, and body mass index percentile, as well as by outdoor sources (season of sample collection, street traffic), indoor sources (heating with gas, cigarette smoke), and dietary sources (frequent use of grill, consumption of smoked meat or fish) of PAH exposures.ConclusionsUrinary PAH exposure was widespread in girls aged 6-16 years and associated with several sources of exposure. Tertile classification of a single urine sample provides reliable PAH exposure ranking.

Objective: To determine the associations between plasma creatinine (PCr), plasma uric acid (PUA), and urinary oxidative stress (OS) biomarkers with the ALSFRS-R at baseline and survival in a large epidemiological cohort study (ALS COSMOS) with a well-phenotyped patient population (N = 355).Methods: Fasting plasma and first void urine samples were obtained. PCr, PUA, urinary 8-oxo-deoxy guanosine (8-oxodG), and 15-F2t-isoprostane (IsoP) were analyzed at baseline, near the midpoint of follow-up, and at the final blood draw (before death or withdrawal from study). We estimated associations between these biomarkers and the ALSFRS-R at baseline and survival.Results: At baseline, PCr correlated with ALSFRS-R (Spearman r = 0.30), percent (%) FVC (r = 0.20), PUA (r = 0.37), and 8-oxodG (r = -0.13, all p

Arsenic and polycyclic aromatic hydrocarbons (PAH) are environmental pollutants to which people around the world are exposed through water, food and air. In mouse and in vitro studies of human cells, both of these chemicals have been shown to modulate the immune system. In some experimental studies, a synergistic disruption of immune function was observed by a combined exposure to arsenic and PAH. However, a joint effect of arsenic and PAH on immune function has not been studied in humans. We have conducted an epidemiological investigation to examine effects of chronic arsenic and PAH exposures on immune function. We assessed T-cell proliferation (TCP) and cytokine production of anti-CD3/anti-CD28 stimulated lymphocytes in human peripheral blood mononuclear cells (HPBMC) among 197 healthy men enrolled to the Health Effects of Arsenic Longitudinal (HEALS) cohort in Bangladesh. By design, approximately half were active smokers and the rest were never smokers. Our analyses demonstrated that IL-1b, IL-2, IL-4 and IL-6 were significantly stimulated as a function of urinary arsenic levels in models adjusted for age, body mass index (BMI), smoking status and PAH-DNA adducts. After correcting for false detection rate (FDR), only IL-1b remained statistically significant. We found a U-shaped dose response relationship between urinary arsenic and IL-1b. On the other hand, PAH-DNA adducts were associated with an inhibition of TCP and appeared as an inverted U-shape curve. Dose response curves were non-monotonic for PAH-DNA adduct exposures and suggested that cytokine secretion of IFNg, IL-1b, IL-2, IL-10 and IL17A followed a complex pattern. In the majority of donors, there was a trend towards a decrease in cytokine associated with PAH-DNA adducts. We did not observe any interaction between urinary arsenic and PAH-DNA adducts on immune parameters. Our results indicate that long-term exposures to arsenic and PAH have independent, non-monotonic associations with TCP and cytokine production. [ABSTRACT FROM AUTHOR]

BACKGROUND: Phthalates, known endocrine disruptors, may play a role in breast carcinogenesis. Few studies have examined phthalates in relation to breast cancer (BC), and, to our knowledge, none have considered survival following BC. OBJECTIVES: We examined 11 urinary phthalate metabolites, individually and as molar sum groupings, in association with BC incidence and subsequent survival. METHODS: Our study includes 710 women diagnosed with first primary BC in 1996-1997 and 598 women without BC from Long Island, New York. Within 3 mo of diagnosis, participants provided spot urine samples. Nine phthalate metabolites were measured in all women; two [monocarboxyoctyl phthalate (MCOP) and monocarboxy-isononyl phthalate (MCNP)] were measured in 320 women with and 205 without BC. Women with BC were followed since diagnosis using the National Death Index; during follow-up (median=17:6 y), we identified 271 deaths (98 BC related). We examined creatinine-corrected metabolite concentrations in association with: BC, using logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) and all-cause/BC-specific mortality, using Cox regression to estimate hazard ratios (HRs) and 95% CIs. We also examined effect modification by body mass index (BMI) and estrogen receptor (ER) status. RESULTS: The highest (vs. lowest) quintiles of mono(3-carboxypropyl) phthalate (MCPP), monobenzyl phthalate (MBzP), MCNP, and MCOP were associated with BC ORs ranging from 0.71-0.73. The highest (vs. lowest) quintiles of mono(2-ethylhexyl) phthalate (MEHP) and MCOP were associated with BC-specific mortality HRs of 0.54 (95% CI: 0.28, 1.04) and 0.55 (95% CI: 0.23, 1.35), respectively. For BC-specific mortality, interactions were significant between BMI and mono(2-ethyl-5-oxyhexyl) phthalate (MEOHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), with positive associations among women with BMI<25 and inverse associations among women with BMI≥25:0 kg=m2. CONCLUSIONS: Consistent with laboratory evidence, we observed inverse associations between urinary concentrations of several phthalate metabolites and BC and subsequent survival; however, these results should be interpreted with caution given that biospecimen collection among women with BC occurred after diagnosis, which may be of particular concern for our case-control findings. [ABSTRACT FROM AUTHOR]

Global decreases in DNA methylation, particularly in repetitive elements, have been associated with genomic instability and human cancer. Emerging, though limited, data suggest that in white blood cell (WBC) DNA levels of methylation, overall or in repetitive elements, may be associated with cancer risk. We measured methylation levels of three repetitive elements [Satellite 2 (Sat2)], long interspersed nuclear element-1 (LINE-1) and Alu) by MethyLight, and LINE-1 by pyrosequencing in a total of 282 breast cancer cases and 347 unaffected sisters from the New York site of the Breast Cancer Family Registry (BCFR) using DNA from both granulocytes and total WBC. We found that methylation levels in all markers were correlated between sisters (Spearman correlation coefficients ranged from 0.17 to 0.55). Sat2 methylation was statistically significantly associated with increased breast cancer risk [odds ratio (OR) = 2.09, 95% confidence interval (CI) = 1.09–4.03; for each unit decrease in the natural log of the methylation level, OR = 2.12, 95% CI = 0.88–5.11 for the lowest quartile compared with the highest quartile]. These associations were only observed in total WBC but not granulocyte DNA. There was no association between breast cancer and LINE-1 and Alu methylation. If replicated in larger prospective studies, these findings support that selected markers of epigenetic changes measured in WBC, such as Sat2, may be potential biomarkers of breast cancer risk. [ABSTRACT FROM PUBLISHER]

Global DNA hypomethylation is associated with genomic instability and human cancer and blood DNAs collected at the time of cancer diagnosis have been used to examine the relationship between global methylation and cancer risk. To test the hypothesis that global hypomethylation is associated with increased risk of hepatocellular carcinoma (HCC), we conducted a prospective case–control study nested within a community-based cohort with 16 years of follow-up. We measured methylation levels in Satellite 2 (Sat2) by MethyLight and LINE-1 by pyrosequencing using baseline white blood cell DNA from 305 HCC cases and 1254 matched controls. We found that Sat2 hypomethylation was associated with HCC risk [odds ratio (OR) per unit decrease in natural log Sat2 methylation = 1.77, 95% confidence interval (CI) = 1.06–2.95]. The association was significant among individuals diagnosed with HCC before age 62 (OR per unit decrease in natural log Sat2 methylation = 2.47, 95% CI = 1.06–5.73) but not after (OR = 1.67, 95% CI = 0.84–3.32). We did not observe an association of LINE-1 with HCC overall risk by age at diagnosis. Among carriers of hepatitis B virus surface antigen (HBsAg), with each 1U decrease in natural log Sat2 methylation level, the OR for HCC increased by 2.19 (95% CI = 1.00–4.89). LINE-1 hypomethylation was associated with about a 2-fold increased risk of HCC, with ORs (95% CI) of 2.39 (1.06–5.39), 2.09 (0.91–4.77) and 2.28 (0.95–5.51, Ptrend = 0.14) for HBsAg carriers in the third, second and lowest quartile of LINE-1 methylation, respectively compared with carriers in the fourth. These results suggest that global hypomethylation may be a useful biomarker of HCC susceptibility. [ABSTRACT FROM AUTHOR]

Clinical trials have suggested a protective effect of selenium supplementation on the risk of esophageal cancer, which may be mediated through the antioxidant activity of selenoenzymes. We investigated whether serum selenium concentrations, selenoenzyme activity, oxidative stress and genetic variation in selenoenzymes were associated with the risk of neoplastic progression to esophageal adenocarcinoma (EA) and two intermediate endpoints, aneuploidy and tetraploidy. In this prospective cohort study, during an average follow-up of 7.3 years, 47 EA cases, 41 aneuploidy cases and 51 tetraploidy cases accrued among 361 participants from the Seattle Barrett's Esophagus Research Study who were free of EA at the time of blood draw and had at least one follow-up visit. Development to EA was assessed histologically and aneuploidy and tetraploidy by DNA content flow cytometry. Serum selenium concentrations were measured using atomic absorption spectrometry, activity of glutathione peroxidase (GPX) 1 and GPX3 by substrate-specific coupled test procedures, selenoprotein P (SEPP1) concentrations and protein carbonyl content by ELISA method and malondialdehyde concentrations by HPLC. Genetic variants in GPX1-4 and SEPP1 were genotyped. Serum selenium was not associated with the risk of neoplastic progression to EA, aneuploidy or tetraploidy (P for trend = 0.25 to 0.85). SEPP1 concentrations were positively associated with the risk of EA [hazard ratio (HR) = 3.95, 95% confidence intervals (CI) = 1.42-10.97 comparing the third tertile with the first] and with aneuploidy (HR = 6.53, 95% CI = 1.31-32.58), but not selenoenzyme activity or oxidative stress markers. No genetic variants, overall, were associated with the risk of neoplastic progression to EA (global p = 0.12-0.69). Our results do not support a protective effect of selenium on risk of neoplastic progression to EA. Our study is the first to report positive associations of plasma SEPP1 concentrations with the risk of EA and aneuploidy, which warrants further investigation. [ABSTRACT FROM AUTHOR]

Our purpose was to identify epigenetic markers of breast cancer risk, which can be reliably measured in peripheral blood and are amenable for large population screening. We used 2 independent assays, luminometric methylation assay (LUMA) and long interspersed elements-1 (LINE-1) to measure "global methylation content" in peripheral blood DNA from a well-characterized population-based case-control study. We examined associations between methylation levels and breast cancer risk among 1055 cases and 1101 controls and potential influences of 1-carbon metabolism on global methylation. Compared with women in the lowest quintile of LUMA methylation, those in the highest quintile had a 2.41-fold increased risk of breast cancer (95% confidence interval: 1.83-3.16; P, trend<0.0001). The association did not vary by other key tumor characteristics and lifestyle risk factors. Consistent with LUMA findings, genome-wide methylation profiling of a subset of samples revealed greater promoter hypermethylation in breast cancer case participants (P 0.04); higher LUMA was associated with higher promoter methylation in the controls (P 0.05). LUMA levels were also associated with functional sodium nitroprusside in key 1-carbon metabolizing genes, MTHFR C677T (P 0.001) and MTRR A66G (P 0.018). LINE-1 methylation was associated with neither breast cancer risk nor 1-carbon metabolism. Our results show that global promoter hypermethylation measured in peripheral blood was associated with breast cancer risk. [ABSTRACT FROM AUTHOR]

DNA methylation, a widely used epigenetic mark, has been associated with many tumors. However, few studies have addressed the role of cell-free plasma DNA methylation in discriminating aggressive prostate cancer (PCa) from indolent cases. We conducted a case series and a case-control study among histologically confirmed stage II/III cases and matched controls recruited at Columbia University Medical Center. The aim of this study was to investigate whether plasma DNA methylation levels are appropriate surrogate biomarker of PCa tumor tissue levels and whether these markers are associated with worse clinicopathological tumor characteristics, which correlate with poorer prognosis. Quantitative pyrosequencing was used to detect methylation levels of p16 ( CDKN4A), APC, GSTP1, and LINE-1 in 24 pairs of prostate tumor and adjacent tissues, as well as 27 plasma samples of PCa patients and 24 of controls. DNA methylation levels were significantly higher in tumor tissue than in adjacent nontumor tissue for p16 ( CDKN4A), GSTP1, and APC; GSTP1 had a higher average percentage methylation in tumor tissue (38.9%) compared with p16 ( CDKN4A) (5.9%) and APC (14.5%). GSTP1, p16 ( CDKN4A), and APC methylation in tumor tissue was statistically significantly higher for cases with Gleason score ≥7 compared with those with Gleason score <7 [49.0% vs. 21.9% ( p=0.01), 6.6% vs. 4.5% ( p=0.04), and 19.1% vs. 7.4% ( p=0.02), respectively]. Plasma LINE-1 methylation levels were higher in those with higher Gleason (67.6%) than in those with Gleason's below 7 (64.6%, p=0.03). Significant plasma-tissue correlations were observed for GSTP1 and LINE-1 methylation. These data, although preliminary, suggest that aberrant methylation may be a useful marker to identify PCa patients with clinically aggressive disease. [ABSTRACT FROM AUTHOR]

p53 is an important tumour suppressor gene that encodes p53 protein, a molecule involved in cell cycle regulation and has been inconsistently linked to breast cancer survival. Using archived tumour tissue from a population-based sample of 859 women diagnosed with breast cancer between 1996 and 1997, we determined p53 mutations in exons 5–8 and p53 protein overexpression. We examined the association of p53 mutations with overexpression and selected tumour clinical parameters. We assessed whether either p53 marker was associated with survival through 2002, adjusting for other tumour markers and prognostic factors. The prevalence of protein overexpression in the tumour was 36% (307/859) and of any p53 mutation was 15% (128/859). p53 overexpression was positively associated with the presence of any p53 mutation (odds ratio [OR]= 2.2, 95% confidence interval [CI]= 1.5–3.2), particularly missense mutations (ER = 7.0, 95% CI = 3.6–13.7). Negative oestrogen and progesterone receptor (ER/PR) status was positively associated with both p53 protein overexpression (= 2.6, 95% CI = 1.7–4.0) and p53 mutation (OR = 3.9, 95% CI = 2.4–6.5). Any p53 mutation and missense mutations, but not p53 protein overexpression, were associated with breast cancer-specific mortality (hazard ratio [HR]= 1.7, 95% CI = 1.0–2.8; HR = 2.0, 95% CI = 1.1–3.6, respectively) and all-cause mortality (HR = 1.5, 95% CI = 1.0–2.4; HR = 2.0, 95% CI = 1.2–3.4, respectively); nonsense mutations were associated only with breast cancer-specific mortality (HR = 3.0, 95% CI = 1.1–8.1). These associations however did not remain after adjusting for ER/PR status. Thus, in this population-based cohort of women with breast cancer, although p53 protein overexpression and p53 mutations were associated with each other, neither independently impacted breast cancer-specific or all-causing mortality, after considering ER/PR status. [ABSTRACT FROM AUTHOR]

We have recently suggested that polymorphisms in metabolism and repair pathways may play a role in modulating the effects of exposure to the carcinogen vinyl chloride in the production of biomarkers of its mutagenic damage. The aim of the present study was to extend these observations by examining gene-environment interactions between several common polymorphisms in the DNA repair genes XRCC1 and ERCC2/XPD and vinyl chloride exposure on the production of vinyl chloride-induced biomarkers of mutation. A cohort of 546 French vinyl chloride workers were genotyped for the XRCC1 codon 194 (Arg>Trp; rs1799782), 280 (Arg>His; rs25489) and 399 (Arg>Gln; rs25487) polymorphisms and the ERCC2/XPD codon 312 (Asp>Asn; rs1799793) and 751 (Lys>Gln; rs13181) polymorphisms. The results demonstrated a statistically significant allele dosage effect of the XRCC1 399 variant on the production of the vinyl chloride-induced mutant p53 biomarker, even after controlling for confounders including cumulative vinyl chloride exposure (p = 0.03), with a potentially supramultiplicative gene-environment interaction. In addition, the results demonstrate statistically significant allele dosage effects of the ERCC2/XPD 312 and 751 variants on the production of the vinyl chloride-induced mutant ras-p21 biomarker, even after controlling for confounders including cumulative vinyl chloride exposure (p < 0.0001 and p = 0.0006, respectively), with a potentially supramultiplicative gene-environment interaction for the codon 751 allele. Finally, the results suggest potential supramultiplicative gene-gene interactions between CYP2E1 (c2 allele; rs3813867) and ERCC2/XPD polymorphisms that are consistent with the proposed carcinogenic pathway for vinyl chloride, which requires metabolic activation by CYP2E1 to reactive intermediates that form DNA adducts that, if not removed by DNA repair mechanisms, result in oncogenic mutations. [ABSTRACT FROM AUTHOR]

Telomere shortening limits the proliferative capacity of human cells, restrains the regenerative capacity of organ systems during chronic diseases and aging and also induces chromosomal instability as well as initiation of cancer. Previous studies demonstrated that telomeres are often significantly shorter in tumor tissue, including hepatocellular carcinoma (HCC), compared to the surrounding tissue, but telomere length in HCC tissues was not correlated with several clinical parameters, such as age, sex, HBV or HCV infections and tumor size. In the present study, the telomere length ratio of 36 paired HCC, and their adjacent non-tumor tissues was measured by quantitative PCR (Q-PCR). The mean telomere lengths (SD) for HCC and adjacent non-tumor tissues were 0.26 (0.10) and 0.47 (0.20) respectively (t = 6.22, P < 0.0001). There was a large difference in the distribution of subjects based on telomere length in tumor and adjacent non-tumor tissues. The number of tumors with telomere length shorter than 0.50 was much higher than that of adjacent non-tumor tissues; more than 90% of the tissues with telomere length ≥ 0.50 were adjacent non-tumor tissues. The correlations between telomere length and aflatoxin B1- and polycyclic aromatic hydrocarbon-DNA adducts level, p53 mutations and p16 hypermethylation status were also tested, but no significant associations were found. The relationship between telomere length shortening, chemical carcinogen exposure, and genetic and epigenetic changes in hepatocarcinogenesis needs further investigation. [ABSTRACT FROM AUTHOR]

BACKGROUND: Epidemiologic studies of cardiovascular disease risk factors and appropriate biomarkers in populations exposed to a wide range of arsenic levels are a public health research priority. OBJECTIVE: We investigated the relationship between inorganic arsenic exposure from drinking water and plasma levels of soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular adhesion molecule-1 (sVCAM-1), both markers of endothelial dysfunction and vascular inflammation, in an arsenic-exposed population in Araihazar, Bangladesh. METHODS: The study participants included 115 individuals with arsenic-related skin lesions participating in a 2 × 2 randomized, placebo-controlled, double-blind trial of vitamin E and selenium supplementation. Arsenic exposure status and plasma levels of sICAM-1 and sVCAM-1 were assessed at baseline and after 6 months of follow-up. RESULTS: Baseline well arsenic, a long-term measure of arsenic exposure, was positively associated with baseline levels of both sICAM-1 and sVCAM-1 and with changes in the two markers over time. At baseline, for every 1-μg/L increase in well arsenic there was an increase of 0.10 ng/mL [95% confidence interval (CI), 0.00-0.20] and 0.33 ng/mL (95% CI, 0.15-0.51) in plasma sICAM-1 and sVCAM-1, respectively. Every 1-μg/L increase in well arsenic was associated with a rise of 0.11 ng/mL (95% CI, 0.01-0.22) and 0.17 ng/mL (95% CI, 0.00-0.35) in sICAM-1 and sVCAM-1 from baseline to follow-up, respectively, in spite of recent changes in urinary arsenic as well as vitamin E and selenium supplementation during the study period. CONCLUSIONS: The findings indicate an effect of chronic arsenic exposure from drinking water on vascular inflammation that persists over time and also suggest a potential mechanism underlying the association between arsenic exposure and cardiovascular disease. [ABSTRACT FROM AUTHOR]

The authors briefly review the current potential and limitations of molecular epidemiology. This approach uses biomarkers to measure the internal and bioeffective dose of toxicants, early biologic effects likely to be predictive of cancer, and variations in individual susceptibility. The most frequent application of biomarkers has been in assessment of exposure/dose and susceptibility due to genetic and nongenetic factors. More research is needed to establish the predictive significance of biomarkers in terms of disease risk. To illustrate that molecular epidemiology has potential in identifying etiologic factors in disease, this article presents data from a recent study of the developmental effects of fetal exposure to polycyclic aromatic hydrocarbons (PAH) via ambient pollution. The study was carried out in an industrialized area of Poland with relatively high levels of PAH pollution from coal burning. PAH-DNA adducts in leukocytes and plasma cotinine were measured in umbilical cord blood as dosimeters of transplacental PAH and cigarette smoke, respectively. The study subjects were 70 newborns from the industrialized city of Krakow and 90 newborns from Limanowa, a rural town with far greater use of coal for home heating. Neworns whose levels of PAH-DNA adducts were above the median (3. 85/108 nucleotides) had a significantly decreased birth length, weight, and head circumference. Cotinine was significantly inversely associated with birth weight and length. Although preliminary, these results provide a new molecular link between PAH exposure and developmental effects, generating initial data and hypotheses for further study. Am J Epidemiol 1998; 147: 309–14. [ABSTRACT FROM AUTHOR]

Biomarkers such as DNA adducts have significant potential to improvequantitative risk assessment by characterizing individual differences in metabolism of genotoxins and DNA repair and accounting for some of the factors that could affect interindividual variation in cancer risk. Inherent uncertainty in laboratory measurements and within-person variability of DNA adduct levels over time are putatively unrelated to cancer risk and should be subtracted from observed variation to better estimate interindividual variability of response to carcinogenexposure. A total of 41 volunteers, both smokers and nonsmokers, were asked to provide a peripheral blood sample every 3 weeks for several months in order to specifically assess intraindividual variability of polycyclic aromatic hydrocarbon (PAH)DNA adduct levels. The intraindividual variance in PAH-DNA adduct levels, together with measurement uncertainty (laboratory variability and unaccounted for differencesin exposure), constituted roughly 30% of the overall variance. An estimated 70% of the total variance was contributed by interindividual variability and is probably representative of the true biologic variability of response to carcinogenic exposure in lymphocytes. The estimated interindividual variability in DNA damage after subtracting intraindividual variability and measurement uncertainty was 24-fold. Inter-individual variance was higher (52-fold) in persons who constitutively lack the Glutathione S-Transferase M1 (GSTM1) gene which is important in the detoxification pathway of PAR Risk assessment models thatdo not consider the variability of susceptibility to DNA damage following carcinogen exposure may underestimate risks to the general population, especially for those people who are most vulnerable. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbon (PAH) exposures from tobacco smoke, automobile exhaust, grilled or smoked meat and other sources are widespread and are a public health concern, as many are classified as probable carcinogens and suspected endocrine-disrupting chemicals. PAH exposures can be quantified using urinary biomarkers. Seven urinary metabolites of naphthalene, fluorene, phenanthrene, and pyrene were measured in two samples collected from girls aged 6–16 years from the San Francisco Bay Area. We used Spearman correlation coefficients (SCC) to assess correlations among metabolite concentrations (corrected for specific gravity) separately in first (n = 359) and last (N = 349) samples, and to assess consistency of measurements in samples collected up to 72 months apart. Using multivariable linear regression, we assessed variation in mean metabolites across categories of participant characteristics and potential outdoor, indoor, and dietary sources of PAH exposures. The detection rate of PAH metabolites was high (4 metabolites in ≥98% of first samples; 5 metabolites in ≥95% of last samples). Correlations were moderate to strong between fluorene, phenanthrene and pyrene metabolites (SCC 0.43–0.82), but weaker between naphthalene and the other metabolites (SCC 0.18–0.36). SCC between metabolites in first and last samples ranged from 0.15 to 0.49. When classifying metabolite concentrations into tertiles based on single samples (first or last samples) vs. the average of the two samples, agreement was moderate to substantial (weighted kappa statistics 0.52–0.65). For specific metabolites, concentrations varied by age, race/ethnicity, and body mass index percentile, as well as by outdoor sources (season of sample collection, street traffic), indoor sources (heating with gas, cigarette smoke), and dietary sources (frequent use of grill, consumption of smoked meat or fish) of PAH exposures. Urinary PAH exposure was widespread in girls aged 6–16 years and associated with several sources of exposure. Tertile classification of a single urine sample provides reliable PAH exposure ranking. • Urinary PAH metabolites were present in nearly all girls aged 6-16 years • Tertile classification of a single urine sample provided reliable exposure ranking • Metabolites were associated with outdoor and indoor PAH exposure sources • Some of the PAH exposures are modifiable in the home environment [ABSTRACT FROM AUTHOR]

Abstract: A prior study in New York City observed that airborne concentrations of three metals found in steel – iron, manganese, and chromium – are more than 100 times higher in the subway system than in aboveground air. To investigate the potential for health effects of exposure at these levels, we conducted a pilot study of subway workers comparing personal exposures to steel dust with biomarkers of metal exposure, oxidative stress, and DNA damage in blood and urine samples. Workers wore a personal air sampler operating at 4L/m for one to three work shifts with blood and urine samples collected at the end of the final shift. We found that PM2.5 exposures varied among subway workers on the basis of job title and job activity. The subway workers’ mean time-weighted PM2.5 exposure was 52μg/m3, with a median of 27μg/m3, and a range of 6–469μg/m3. The observed concentrations of PM2.5, iron, manganese, and chromium fell well below occupational standards. Biomarker concentrations among the 39 subway workers were compared with a group of 11 bus drivers, and a group of 25 suburban office workers. Concentrations of DNA–protein crosslinks and chromium in plasma were significantly higher in subway workers than in bus drivers, but no significant difference was observed for these biomarkers between subway workers and office workers. Urinary isoprostane concentrations were significantly correlated with the number of years working in the subway system, and were detected at higher, though not significantly higher, concentrations in subway workers than in bus drivers or office workers. At the group level, there was no consistent pattern of biomarker concentrations among subway workers significantly exceeding those of the bus drivers and office workers. At the individual level, steel dust exposure was not correlated with any of the biomarkers measured. [Copyright &y& Elsevier]

7,8-Dihydro-8-oxodeoxyguanosine (8-oxo-dG) is a typical modification of DNA caused by oxygen free radicals and can be an useful biomarker for pollutants inducing oxidative stress. An immunoperoxidase method using monoclonal antibody 1F7 toward 8-oxo-dG was applied to tissues and smeared cells of marine organisms for detection and quantification of oxidative DNA damage in such models. The assay, previously employed on human cells, was assessed for the first time on Mediterranean mussels (Mytilus galloprovincialis) and European eels (Anguilla anguilla), exposed to model pro-oxidant chemicals, namely benzo[a]pyrene (B[a]P) and copper. Quantification of 8-oxo-dG was microscopically carried out and expressed as relative nuclear staining intensity. Higher levels of oxidative DNA damage were detected in the digestive glands of treated mussels compared to controls, while the effect was less pronounced in haemocytes, characterized by more elevated basal levels of 8-oxo-dG. The assay was suitable for detection of 8-oxo-dG also in fish liver sections indicating consistent damage after B[a]P exposure. The main advantage of the immunohistochemical approach is the elimination of DNA extraction which considerably reduces the processing of biological samples. In addition, the assay requires small amounts of frozen tissues or fixed cells for detection of 8-oxo-dG and is potentially able to discriminate variable susceptibility to oxidative stress in different cell types. Although further investigations are required for the improvement and the validation of the assay in field conditions, laboratory exposures provided useful indications on the consistency of the approach and the efficacy of antibody 1F7 in marine organisms for a rapid assessment of pollutant-induced oxidative DNA damage. [Copyright &y& Elsevier]