A cross-sectional study of polycyclic aromatic hydrocarbon-DNA adducts and polymorphism of glutathione S-transferases among heavy smokers by race/ethnicity

Plasma levels of polychlorinated biphenyls (PCBs) and breast cancer mortality: The Carolina Breast Cancer Study

BACKGROUND

It is unknown whether carcinogenic and endocrine disrupting polychlorinated biphenyls (PCBs) influence mortality following breast cancer. We examined plasma levels of 17 PCB congeners in association with mortality among women with breast cancer.

METHODS

Participants included 456 white and 292 black women in North Carolina who were diagnosed with primary invasive breast cancer from 1993 to 1996, and who had PCB and lipid measurements from blood samples obtained an average of 4.1 months after diagnosis. Over a median follow-up of 20.6 years, there were 392 deaths (210 from breast cancer). We used Cox regression to estimate covariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and breast cancer-specific 5-year mortality, and 20-year mortality (conditional on 5-year survival) in association with tertiles and continuous ln-transformed lipid-adjusted PCB levels.

RESULTS

The highest (vs. lowest) tertiles of PCB74, PCB99, and PCB118 were associated with 5-year breast cancer-specific mortality HRs of 1.46 (95%CI = 0.86-2.47), 1.57 (95%CI = 0.90-2.73), and 1.86 (95%CI = 1.07-3.23), respectively. Additionally, one-ln unit increases in PCB74, PCB99, PCB118, and total PCBs were each associated with 33-40% increases in 5-year breast cancer-specific mortality rates. The PCBs were not, however, associated with longer-term breast cancer-specific mortality. For all-cause mortality, one-ln unit increases in PCB118, PCB146, PCB153, PCB182, PCB187, and total PCBs were associated with 20-37% increases in 20-year all-cause mortality rates among women who survived at least 5 years.

CONCLUSION

PCBs may increase the risk of short-term breast cancer-specific mortality and long-term all-cause mortality among women with breast cancer.

Idiotypic and anti-idiotypic antibodies against polycyclic aromatic hydrocarbon in human blood serum are new biomarkers of lung cancer

Evaluation of epidemiologic risk factor in relation to lung cancer invoked by polycyclic aromatic hydrocarbons has been inconsistent. To address this issue, we conducted a prospective evaluation of new biomarkers for lung cancer classified according levels of idiotypic and anti-idiotypic antibodies against polycyclic aromatic hydrocarbons in human blood serum. The blood serums of 557 lung cancer patients and 227 healthy donors were analysis of these antibodies by ELISA. Collected data were regrouped and analyzed by gender, smoking, and age as predictors of risk lung cancer factors. Also, the data of lung cancer patients were additionally analyzed by stages and types of lung cancer, surgery, and chemotherapy. It was suggested to use ratio of idiotypic and anti-idiotypic antibodies rather than distinguish level each of them separately. The ratio of levels in healthy people was 3.32 times higher than in lung cancer patients. This approach gave more precisely results and great prognostic value. The logistic regression model (AUC = 0.9) and neural networks (AUC = 0.95) were built to compare lung cancer patients and healthy donors by predictors. The ELISA data of 49 people random sampled from the originally ELISA data and ELISA data of 52 coal miners as a group of lung cancer risk were confirmed logistic regression model. So, suggested idiotypic and anti-idiotypic antibodies against polycyclic aromatic hydrocarbons were not only shown difference between healthy donors and lung cancer patients also elicited group of lung cancer risk among healthy people.

Placental biomarkers of PAH exposure and glutathione-S-transferase biotransformation enzymes in an obstetric population from Tijuana, Baja California, Mexico

Environmental exposures along the US-Mexico border have the potential to adversely affect the maternal-fetal environment. The purpose of this study was to assess placental biomarkers of environmental exposures in an obstetric population at the California-Baja California border in relation to detoxifying enzymes in the placenta and nutritional status. This study was conducted on consenting, full-term, obstetric patients (n=54), delivering in a hospital in Tijuana, Baja California (BC), Mexico. Placental polyaromatic hydrocarbon (PAH)-DNA adducts were measured in addition to placental glutathione-S-transferase (GST) activity and genotype, maternal serum folate, and maternal and umbilical cord blood lead and cadmium levels. A questionnaire was administered to the mothers to determine maternal occupation in a maquiladora, other exposures, and obstetric indicators. In univariate analysis, maternal serum folate levels were inversely correlated with total PAH-DNA adducts (rho=-0.375, p=0.007); adduct #1 (rho=-0.388, p=0.005); and adduct #3 (rho =-0.430, p=0.002). Maternal lead levels were significantly positively correlated with cord blood lead levels (rho=0.512, p<0.001). Cadmium levels were generally very low but significantly higher in mothers exposed to environmental tobacco smoke (ETS) (either at work or at home, n=10). In multivariate analysis, only maternal serum folate levels remained as a significant negative predictor of total DNA-PAH adducts levels in placenta. These findings affirm that placental tissue is a valuable and readily available source of human tissue for biomonitoring; and indicate that further study of the role of nutrition in detoxification and mitigation of environmental exposures in pregnant women is warranted.

The GSTM1null (deletion) and MGMT84 rs12917 (Phe/Phe) haplotype are associated with bulky DNA adduct levels in human leukocytes

Tobacco smoke and air pollutants contain carcinogens, such as polycyclic aromatic hydrocarbons (PAHs) and tobacco specific nitrosamines (TSNA), that are substrates of metabolizing enzymes generating reactive metabolites that can bind to DNA. Variation in the activity of these enzymes may modify the extent to which these metabolites can interact with DNA. We compared the levels of bulky DNA adducts in blood leukocytes from 93 volunteers living in Mexico City with the presence of 13 single nucleotide polymorphisms (SNPs) in genes related to PAH and TSNA metabolism (AhR rs2044853, CYP1A1 rs1048943, CYP1A1 rs1048943, CYP1A1 rs1799814, EPHX1 rs1051740, EPHX1 rs2234922, GSTM1 null, GSTT1 null and GSTP1 rs947894), DNA repair (XRCC1 rs25487, ERCC2 rs13181 and MGMT rs12917) and cell cycle (TP53 rs1042522). (32)P-postlabeling analysis was used to quantify bulky DNA adduct formation. Genotyping was performed using PCR-RFLP. The mean levels of bulky DNA adducts were 8.51±3.66 adducts/10(8) nucleotides (nt) in smokers and 8.38±3.59 adducts/10(8) nt in non-smokers, being the difference not statistically significant. Without taking into account the smoking status, GSTM1 null individuals had a marginally significant lower adduct levels compared with GSTM1 volunteers (p=0.0433) and individuals heterozygous for MGMT Leu/Phe had a higher level of bulky adducts than those who were homozygous wild type (p=0.0170). A multiple regression analysis model showed a significant association between the GSTM1 (deletion) and MGMT rs12917 (Phe/Phe) haplotype and the formation of DNA adducts in smokers (R(2)=0.2401, p=0.0215). The presence of these variants conferred a greater risk for higher adduct levels in this Mexican population.

The clinically relevant pharmacogenomic changes in acute myelogenous leukemia

Acute myelogenous leukemia (AML) is an extremely heterogeneous neoplasm with several clinical, pathological, genetic and molecular subtypes. Combinations of various doses and schedules of cytarabine and different anthracyclines have been the mainstay of treatment for all forms of AMLs in adult patients. Although this combination, with the addition of an occasional third agent, remains effective for treatment of some young-adult patients with de novo AML, the prognosis of AML secondary to myelodysplastic syndromes or myeloproliferative neoplasms, treatment-related AML, relapsed or refractory AML, and AML that occurs in older populations remains grim. Taken into account the heterogeneity of AML, one size does not and should not be tried to fit all. In this article, the authors review currently understood, applicable and relevant findings related to cytarabine and anthracycline drug-metabolizing enzymes and drug transporters in adult patients with AML. To provide a prime-time example of clinical applicability of pharmacogenomics in distinguishing a subset of patients with AML who might be better responders to farnesyltransferase inhibitors, the authors also reviewed findings related to a two-gene transcript signature consisting of high RASGRP1 and low APTX, the ratio of which appears to positively predict clinical response in AML patients treated with farnesyltransferase inhibitors.

DNA and protein adducts in human tissues resulting from exposure to tobacco smoke

Tobacco smoke contains a variety of genotoxic carcinogens that form adducts with DNA and protein in the tissues of smokers. Not only are these biochemical events relevant to the carcinogenic process, but the detection of adducts provides a means of monitoring exposure to tobacco smoke. Characterization of smoking-related adducts has shed light on the mechanisms of smoking-related diseases and many different types of smoking-derived DNA and protein adducts have been identified. Such approaches also reveal the potential harm of environmental tobacco smoke (ETS) to nonsmokers, infants and children. Because the majority of tobacco-smoke carcinogens are not exclusive to this source of exposure, studies comparing smokers and nonsmokers may be confounded by other environmental sources. Nevertheless, certain DNA and protein adducts have been validated as biomarkers of exposure to tobacco smoke, with continuing applications in the study of ETS exposures, cancer prevention and tobacco product legislation. Our article is a review of the literature on smoking-related adducts in human tissues published since 2002.

Elevated polycyclic aromatic hydrocarbon-DNA adducts in benign prostate and risk of prostate cancer in African Americans

Carcinogen-DNA adducts, a marker of DNA damage, are capable of inducing mutations in oncogenes and tumor suppressor genes, resulting in carcinogenesis. We have shown previously that polycyclic aromatic hydrocarbon (PAH)-DNA adduct levels in prostate cancer cases vary by cellular histology and that higher adduct levels are associated with biochemical recurrence. A nested case-control study was conducted in a historical cohort of 6692 men with histopathologically benign prostate specimens. PAH-DNA adduct levels were determined by immunohistochemistry in benign prostate specimens from 536 prostate cancer case-control pairs (59% White and 41% African American). We estimated the overall and race-stratified risk of subsequent prostate cancer associated with higher adduct levels. Prostate cancer risk for men with elevated adduct levels (defined as greater than control group median) was slightly increased [odds ratio (OR) = 1.28, 95% confidence interval (CI) = 0.98-1.67, P = 0.07]. After race stratification, elevated adduct levels were significantly associated with increased risk in African American men (OR = 1.56, CI = 1.00-2.44, *P = 0.05) but not White men (OR = 1.14, CI = 0.82-1.59, P = 0.45). Elevated PAH-DNA adduct levels were significantly associated with 60% increased risk of prostate cancer among cases diagnosed 1-4 years after cohort entry (OR = 1.60, CI = 1.07-2.41) with a greater risk observed in African Americans within the first 4 years of follow-up (OR = 4.71, CI = 1.97-11.26, ***P = 0.0005). Analyses stratified by age or tumor grade revealed no additional significant heterogeneity in risk. Increased prostate cancer risk associated with high PAH-DNA adduct levels in benign prostate was found only in African Americans; risk was greatest within 4 years of follow-up, possibly reflecting a carcinogenic process not yet histologically detectable.

A review of cancer in U.S. Hispanic populations

There are compelling reasons to conduct studies of cancer in Hispanics, the fastest growing major demographic group in the United States (from 15% to 30% of the U.S. population by 2050). The genetically admixed Hispanic population coupled with secular trends in environmental exposures and lifestyle/behavioral practices that are associated with immigration and acculturation offer opportunities for elucidating the effects of genetics, environment, and lifestyle on cancer risk and identifying novel risk factors. For example, traditional breast cancer risk factors explain less of the breast cancer risk in Hispanics than in non-Hispanic whites (NHW), and there is a substantially greater proportion of never-smokers with lung cancer in Hispanics than in NHW. Hispanics have higher incidence rates for cancers of the cervix, stomach, liver, and gall bladder than NHW. With respect to these cancers, there are intriguing patterns that warrant study (e.g., depending on country of origin, the five-fold difference in gastric cancer rates for Hispanic men but not Hispanic women). Also, despite a substantially higher incidence rate and increasing secular trend for liver cancer in Hispanics, there have been no studies of Hispanics reported to date. We review the literature and discuss study design options and features that should be considered in future studies.

White blood cell DNA adducts in a cohort of asthmatic children exposed to environmental tobacco smoke

Purpose

Exposure to environmental tobacco smoke (ETS) leads to molecular damage in the form of DNA adducts. While lung cancer risk is higher among African Americans compared to White Americans, a few studies have tested for racial differences in DNA adducts among children exposed to ETS. The purpose of this study was to test whether African American children have higher DNA adducts levels compared to White children adjusted for ETS exposure.

Methods

Data and biologic specimens were drawn from an existing cohort of 212 asthmatic children. These subjects participated in a 12-month ETS-reduction trial that employed HEPA air cleaners with active filter cartridges and sham filter cartridges. White blood cell (WBC) DNA was analyzed for DNA adducts using ³²P-postlabeling. We assessed ETS exposure using a validated air nicotine dosimeter. We determined the independent relationship between African American race and DNA adduct levels adjusted for ETS exposure and air cleaner use.

Results

The mean age of the subjects was 8.4 years; 55% were African American. There was no difference in DNA adduct levels between African American and White children (11.8 vs. 11.2 adducts per 10⁹ nucleotides, p = 0.86), despite slightly higher levels of air nicotine exposure (3.4 vs. 2.2 μg/m³, p = 0.14). African American children used their air cleaners less often than White children. We found that the best predictor of DNA adduct levels was the duration of air cleaner use (r = −0.133, p = 0.056). This association was independent of cartridge type.

Conclusions

We did not see differences in adduct levels by race even after accounting for the level of ETS exposure. However, there was a marginal inverse association between air cleaner use and adducts. Additional research is required to understand this phenomenon.

PAH-DNA adducts, cigarette smoking, GST polymorphisms, and breast cancer risk

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) may increase breast cancer risk, and the association may be modified by inherited differences in deactivation of PAH intermediates by glutathione S-transferases (GSTs). Few breast cancer studies have investigated the joint effects of multiple GSTs and a PAH biomarker.

OBJECTIVE

We estimated the breast cancer risk associated with multiple polymorphisms in the GST gene (GSTA1, GSTM1, GSTP1, and GSTT1) and the interaction with PAH-DNA adducts and cigarette smoking.

METHODS

We conducted unconditional logistic regression using data from a population-based sample of women (cases/controls, respectively): GST polymorphisms were genotyped using polymerase chain reaction and matrix-assisted laser desorption/ionization time-of-flight assays (n = 926 of 916), PAH-DNA adduct blood levels were measured by competitive enzyme-linked immunosorbent assay (n = 873 of 941), and smoking status was assessed by in-person questionnaires (n = 943 of 973).

RESULTS

Odds ratios for joint effects on breast cancer risk among women with at least three variant alleles were 1.56 [95% confidence interval (CI), 1.13-2.16] for detectable PAH-DNA adducts and 0.93 (95% CI, 0.56-1.56) for no detectable adducts; corresponding odds ratios for three or more variants were 1.18 (95% CI, 0.82-1.69) for ever smokers and 1.44 (95% CI, 0.97-2.14) for never smokers. Neither interaction was statistically significant (p = 0.43 and 0.62, respectively).

CONCLUSION

We found little statistical evidence that PAHs interacted with GSTT1, GSTM1, GSTP1, and GSTA1 polymorphisms to further increase breast cancer risk.

The role of african american ethnicity and metabolism in sentinel polychlorinated biphenyl congener serum levels

Polychlorinated biphenyls (PCBs) are environmental contaminants found in the serum of human populations across the globe. A small set of sentinel PCB congeners (IUPAC# 101, 118, 138, 153, and 180) commonly sought in human serum are often used as markers of exposure. The Chicago Great Lakes cohort of pregnant African American women was developed to study organochlorine exposure through Great Lakes resources in a pregnant African American population and their children. Comparison of PCB serum concentrations in women reporting mixed race/ethnicity within the cohort shows significant elevations of serum PCB 101 and 118 in women reporting exclusive African American ancestry.Incubations were performed using pooled human liver microsomes followed by individual recombinant human CYP isoform microsomes to identify whether the other sentinel congeners are metabolized by human CYP 450. In human liver microsome metabolism experiments with the sentinel PCB congeners (IUPAC# 101, 118, 138, 153, and 180), only PCB 101 metabolism produced an identifiable metabolite. However, a significant loss of parent compound was observed for PCB 118 incubations with human liver microsomes. The loss of PCB 101 and PCB 118 in microsome experiments indicates they are likely metabolized in human liver. Therefore, CYP 450 mediated metabolic differences may contribute to differences in serum concentrations by race/ethnicity.PCB metabolism has an important impact on toxicity. PCB metabolites have been shown to differ significantly in toxicity profiles relative to parent compounds. Biomonitoring studies of PCB serum levels have correlated with toxicity for the metabolizeable congeners such as PCB 101 and PCB 118. However, measureable amounts of metabolizeable parent congeners such as PCB 101 may not be detectable in the serum of study participants. Because PCB 118 is metabolized, but is also readily found in human serum, it may be a better marker of metabolism related PCB toxicity. Human specific PCB metabolism is difficult to characterize but has important pathophysiological ramifications and deserves further study.

Meta-analysis and pooled analysis of GSTM1 and CYP1A1 polymorphisms and oral and pharyngeal cancers: a HuGE-GSEC review

The association of GSTM1 and CYP1A1 polymorphisms and oral and pharyngeal cancers was assessed through a meta-analysis of published case-control studies and a pooled analysis of both published and unpublished case-control studies from the Genetic Susceptibility to Environmental Carcinogens database (http://www.upci.upmc.edu/research/ccps/ccontrol/index.html ). Thirty publications used in the meta-analysis included a total of 7783 subjects (3177 cases and 4606 controls); 21 datasets, 9397 subjects (3130 cases and 6267 controls) were included in the pooled analysis. The GSTM1 deletion was 2-fold more likely to occur in African American and African cases than controls (odds ratio: 1.7, 95% confidence interval: 0.9-3.3), although this was not observed among whites (odds ratio: 1.0, 95% confidence interval: 0.9-1.1). The meta-analysis and pooled analysis showed a significant association between oral and pharyngeal cancer and the CYP1A1 MspI homozygous variant (meta-ORm2/m2: 1.9, 95% confidence interval: 1.4-2.7; Pooled ORm2m2: 2.0, 95% confidence interval: 1.3-3.1; ORm1m2 or [infi]m2m2: 1.3, 95% confidence interval: 1.1-1.6). The association was present for the CYP1A1 (exon 7) polymorphism (ORVal/Val: 2.2, 95% confidence interval: 1.1-4.5) in ever smokers. A joint effect was observed for GSTM1 homozygous deletion and the CYP1A1 m1m2 variant on cancer risk. Our findings suggest that tobacco use and genetic factors play a significant role in oral and pharyngeal cancer.

Polycyclic aromatic hydrocarbon--DNA adducts in prostate and biochemical recurrence after prostatectomy

PURPOSE

DNA adduct levels may be influenced by metabolic activity, DNA repair capabilities, and genomic integrity, all of which play a role in cancer progression.

EXPERIMENTAL DESIGN

To determine if elevated DNA adducts are a marker for prostate cancer progression, we measured polycyclic aromatic hydrocarbon-DNA adducts by immunohistochemistry in prostate cells of 368 surgical prostate cancer patients treated at the Henry Ford Hospital in Detroit, Michigan, between September 1999 and July 2004. Patients were followed up to 5 years after surgery with relative risk for biochemical recurrence (BCR) estimated with a Cox proportional hazards model that adjusted for standard clinical risk factors.

RESULTS

At 1 year of follow-up, patients with adduct levels above the median in tumor cells [hazard ratio (HR), 2.40; 95% confidence interval (95% CI), 1.10-5.27] and nontumor cells (HR, 3.22; 95% CI, 1.40-7.39) had significant increased risk of BCR, but these HRs decreased to 1.12 (95% CI, 0.68-1.83) and 1.46 (95% CI, 0.89-2.41) in tumor and nontumor cells at 5 years postsurgery. When we restricted our analysis to patients with advanced-stage (III+) disease, those with high adduct levels in either tumor (53.5% versus 30.2%; P = 0.07) or nontumor (55.2% versus 28.6%; P = 0.02) cells had BCR rates almost 2-fold higher. In race-stratified analyses, the greatest risk of BCR associated with high adduct levels (in nontumor cells) was for African American patients younger than 60 years old (HR, 3.79; 95% CI, 1.01-14.30).

CONCLUSIONS

High polycyclic aromatic hydrocarbon-DNA adduct levels in nontumor prostate cells are most strongly associated with BCR between 1 and 2 years after surgery and in patient subsets defined by younger age, advanced tumor stage, and African American race.

GSTM1 and GSTT1 polymorphism influences protection against induced oxidative DNA damage by quercetin and ascorbic acid in human lymphocytes in vitro

Antioxidants are of major importance in the protection against cellular oxidative damage caused by endogenous as well as exogenous free radicals. This study aims to establish the impact of genetic polymorphisms in GSTM1 and GSTT1, which encode for enzymatic antioxidative defence, on H(2)O(2)-induced oxidative DNA damage and on the effectiveness of quercetin and ascorbic acid in preventing this induced damage in human lymphocytes. Lymphocytes from 12 healthy volunteers were pre-incubated either with 10 microM of quercetin or with 10 microM of ascorbic acid, and exposed to 25 microM H(2)O(2) for 1h. The induction of oxidative DNA damage was quantified using the Comet assay. Genotyping of these 12 subjects showed that six individuals were GSTM1+ and six were GSTM1-; eight were GSTT1+ and four GSTT1-.

RESULTS

Baseline levels of oxidative DNA damage did not differ between GSTM1 or GSTT1 variants and their respective wild types. Also with respect to ex vivo induced levels of oxidative DNA damage, no significant difference was seen between variants and wild types of both genotypes. The protection against H(2)O(2)-induced oxidative DNA damage by quercetin was significantly higher in GSTT1 wild types than in GSTT1 variants (57% and 9% decrease, respectively; p=0.01); furthermore, GSTT1 wild types were protected against induced oxidative DNA damage by ascorbic acid pre-incubation while GSTT1 variants showed an increase of damage (16% decrease vs. 91% increase; p=0.01). For GSTM1 variants and wild types, observed differences in protective effects of quercetin or ascorbic acid were not statistically significant. Overall, quercetin proves to be better in protecting human lymphocytes in vitro against oxidative DNA damage upon H(2)O(2) challenge than ascorbic acid.

Associations between smoking, polymorphisms in polycyclic aromatic hydrocarbon (PAH) metabolism and conjugation genes and PAH-DNA adducts in prostate tumors differ by race

Polycyclic aromatic hydrocarbon (PAH)-DNA adducts may induce mutations that contribute to carcinogenesis. We evaluated potential associations between smoking and polymorphisms in PAH metabolism [CYP1A1 Ile 462Val, CYP1B1 Ala 119Ser and Leu 432Val, microsomal epoxide hydrolase (mEH) Tyr 113His and His139Arg, CYP3A4 A(-392)G] and conjugation [glutathione S-transferase (GST) M1 null deletion, GSTP1 Ile 105Val] genes and PAH-DNA adduct levels (measured by immunohistochemistry) in tumor and nontumor prostate cells in 400 prostate cancer cases. Although no statistically significant associations were observed in the total sample, stratification by ethnicity revealed that Caucasian ever smokers compared with nonsmokers had higher adduct levels in tumor cells (mean staining intensity in absorbance units +/- SE, 0.1748 +/- 0.0052 versus 0.1507 +/- 0.0070; P = 0.006), and Caucasians carrying two mEH 139Arg compared with two 139His alleles had lower adducts in tumor (0.1320 +/- 0.0129 versus 0.1714 +/- 0.0059; P = 0.006) and nontumor (0.1856 +/- 0.0184 versus 0.2291 +/- 0.0085; P = 0.03) cells. African Americans with two CYP1B1 432Val compared with two 432Ile alleles had lower adducts in tumor cells (0.1600 +/- 0.0060 versus 0.1970 +/- 0.0153; P = 0.03). After adjusting for smoking status, carrying the putative "high-risk" genotype combination, the faster metabolism of PAH-epoxides to PAH-diol-epoxides (CYP1B1 432Val/Val and mEH 139Arg/Arg) with lower PAH-diol-epoxide conjugation (GSTP1 (105)Ile/Ile), was associated with increased adducts only in Caucasian nontumor cells (0.2363 +/- 0.0132 versus 0.1920 +/- 0.0157; P= 0.05). We present evidence, for the first time in human prostate that the association between smoking and PAH-DNA adducts differs by race and is modified by common genetic variants.

Genetic analysis of CC16, OGG1 and GCLC polymorphisms and susceptibility to COPD

BACKGROUND AND OBJECTIVES

The importance of genetic susceptibility in COPD has not been determined. The aim of this study was to investigate the association between susceptibility to COPD and polymorphisms in the Clara cell 16 kDa secretory protein (CC16), 8-hydroxy-guanine glycosylase (OGG1) and glutamatecysteine ligase catalytic subunit (GCLC) genes in a southern Chinese population of Han nationality.

METHODS

A case-control study was performed on 166 paired subjects with or without COPD, who were randomly selected from a pool of 310 paired subjects. These subjects were selected from epidemiological survey participants, with matched-pairs being strictly localized in the Guangzhou urban and Shaoguan rural areas. The following polymorphisms were genotyped by PCR-single strand conformation polymorphism analysis: 38 A/G in exon 1 of the CC16 gene, 1245C/G in exon 7 of the OGG1 gene and -129C/T in the GCLC gene. Genotype frequencies and allelic frequencies were analysed.

RESULTS

There were no significant differences in the distribution of genotype frequencies for CC16 38 A/G, OGG1 1245C/G or GCLC -129C/T between the COPD and non-COPD subjects. The distribution of the allelic frequencies of these three genes also showed no significant difference between the two groups.

CONCLUSIONS

The genetic polymorphisms in CC16 38 A/G, OGG1 1245C/G and GCLC -129C/T are not associated with susceptibility to COPD in a southern Chinese population of Han nationality.

Genetic polymorphisms of glutathione S-transferases and the risk of adult brain tumors: a meta-analysis

BACKGROUND

Studies investigating the association between genetic polymorphisms of glutathione S-transferases (GST) and risk of adult brain tumors have reported conflicting results. The rationale of this meta-analysis was to determine whether GST variants increase the susceptibility of adult brain tumors by pooling data.

METHODS

Two investigators independently searched the HuGENet database, MEDLINE, EMBASE, conference articles, and manually reviewed bibliographies of retrieved articles. Papers were included if they were observational studies investigating the influence of GSTM1, GSTT1, GSTP1 I105V, or GSTP1 A114V on the development of adult brain cancers. Potential sources of heterogeneity between studies were explored in a meta-regression.

RESULTS

We identified eight eligible studies, which included 1,630 cases of glioma, 245 cases of meningioma, and 7,151 controls. Using the random effects model, there was no association between any of the GST variants and the risk of glioma [overall odds ratio (OR), 1.08; 95% confidence interval (95% CI), 0.95-1.22]. Subgroup analyses also showed no relationship between GST variants and histopathologic groups; the overall ORs were 1.13 (95% CI, 0.88-1.43) for high-grade glioma and 1.08 (95% CI, 0.76-1.55) for low-grade glioma. A random effects meta-regression suggested that the use of in-hospital controls produced larger effect estimates in glioma than the use of population controls (overall OR, 1.30; 95% CI, 1.03-1.65). The T1 null genotype was significantly associated with a risk of meningioma (OR, 1.95; 95% CI, 1.02-3.76), but the M1 variant was not.

CONCLUSION

This study did not suggest any relationship between GST variants and risks of glioma; the T1 null genotype may influence the susceptibility of meningioma, but larger studies are needed to substantiate this relationship.

Racial differences in exposure and glucuronidation of the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)

BACKGROUND

In the United States, Blacks who smoke cigarettes have a higher mean blood concentration of the nicotine metabolite cotinine than White smokers. It has not been determined whether there are racial differences in the exposure to the cigarette smoke carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and in the detoxification of NNK metabolites.

METHODS

A community-based cross-sectional survey of 69 Black and 93 White smokers was conducted in lower Westchester County, New York. Information on smoking and lifestyle habits was collected and urinary concentrations of several tobacco smoke biomarkers were compared, including the NNK metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronide (NNAL-Gluc). A frequency histogram and probit plot of NNAL-Gluc:NNAL ratios were constructed to determine slow and rapid glucuronidation phenotypes.

RESULTS

The mean concentrations of total NNAL, urinary cotinine, plasma cotinine, and thiocyanate were significantly higher in Black men than in White men for each cigarette smoked. In women, the only biomarker that was significantly elevated in Blacks was plasma cotinine. A higher proportion of White versus Black women was categorized as "rapid" glucuronidators (two-tailed exact test, P = 0.03). In men, there were no significant differences in NNAL-Gluc:NNAL phenotypes.

CONCLUSIONS

The higher rates of lung carcinoma in black men may be due in part to a higher level of exposure to tobacco smoke carcinogens.

Expression of heat stress protein 70 mRNA in patients with chronic obstructive pulmonary disease and its significance

The effects of cigarette smoke extract (CSE) on the expression of heat stress protein 70 (Hsp70) in human bronchi smooth muscle cells were investigated in vitro, and the changes in Hsp70 mRNA in the patients with chronic obstructive pulmonary disease and their significance were explored. Human bronchi smooth muscle cells were cultured with CSE at the different concentrations. The expression of Hsp70 mRNA and Hsp70 was detected by reverse translation-polymerase chain reaction (RT-PCR) and Western blotting respectively. Levels of Hsp70 mRNA and Hsp70 in lymphocytes from 20 patients with COPD and 20 healthy smoking control subjects were measured by RT-PCR and Western blotting. The results showed the expression of both Hsp70 mRNA and Hsp70 was decreased conformably in human bronchi smooth muscle cells treated with CSE at certain concentration in vitro. The A values of the Hsp70 mRNA expression were 0.24 +/- 0.11 and 0. 42 +/- 0.13 respectively in COPD patients and healthy smoking controls with the difference being significant (P < 0.01). There was also significant difference in the A values of the Hsp70 expression between COPD patients and healthy smoking controls (20.9 +/- 9.9 vs 44.8 +/- 15.3, P < 0.01). The levels of Hsp70 mRNA had strongly positive correlation with Hsp70 protein (r = 0.85, P < 0.01). It was suggested that the expression of Hsp70 mRNA was in concordance with the expression of Hsp70, which could provide a basis on the study of Hsp70 gene regulation and Hsp70 gene in the development of COPD.