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

Dysregulation of immunity by cigarette smoking promotes inflammation and cancer: A review

Smoking is a serious global health issue. Cigarette smoking contains over 7000 different chemicals. The main harmful components include nicotine, acrolein, aromatic hydrocarbons and heavy metals, which play the key role for cigarette-induced inflammation and carcinogenesis. Growing evidences show that cigarette smoking and its components exert a remarkable impact on regulation of immunity and dysregulated immunity promotes inflammation and cancer. Therefore, this comprehensive and up-to-date review covers four interrelated topics, including cigarette smoking, inflammation, cancer and immune system. The known harmful chemicals from cigarette smoking were summarized. Importantly, we discussed in depth the impact of cigarette smoking on the formation of inflammatory or tumor microenvironment, primarily by affecting immune effector cells, such as macrophages, neutrophils, and T lymphocytes. Furthermore, the main molecular mechanisms by which cigarette smoking induces inflammation and cancer, including changes in epigenetics, DNA damage and others were further summarized. This article will contribute to a better understanding of the impact of cigarette smoking on inducing inflammation and cancer.

Saliva as a diagnostic tool to measure polycyclic aromatic hydrocarbon exposure in dental patients exposed to intimate partner violence (IPV)

BACKGROUND

Social habits such as tobacco use, alcohol consumption, and chemically contaminated diet contribute to poor oral health. Intimate Partner Violence (IPV) is a global public health epidemic which can exacerbate the prevalence of health conditions affecting a victim's lifespan. This study investigates using saliva as a biomarker for detecting levels of benzo(a)pyrene [B(a)P]; a toxicant present in cigarette smoke and barbecued meat in a population of IPV + female patients.

METHODS

A cross-sectional IRB-approved study utilized 63 female participants (37 African Americans [AA], and 26 non-African Americans [NAA]), who provided consent for the study. Participants submitted samples of saliva, as well as questionnaires about demographics, health history, and a well-validated (IPV) screen.

RESULTS

The prevalence of IPV was greater in AA compared to NAA. While the concentrations of PAHs/B(a)P detected in saliva of IPV samples in NAA were generally within the range of B(a)P reported for saliva from elsewhere, the concentrations were high in some IPV positive samples. Among the B(a)P metabolites, the concentrations of B(a)P 7,8-diol, B(a)P 3,6- and 6,12-dione metabolites were greater than the other metabolite in both AA and non-AA groups who were positive.

CONCLUSION

Our study supports the use of saliva as a potential "diagnostic rheostat" to identify toxicants that may exacerbate/precipitate systemic disease in female victims of IPV. In addition, our study is the first to report that IPV may precipitate the accumulation of B(a)P in oral cavity that can alter inflammatory cascades and increase risk of poor health outcomes in this population of patients.

Association of cigarette smoking habits with the risk of prostate cancer: a systematic review and meta-analysis

BACKGROUND

Association of cigarette smoking habits with the risk of prostate cancer is still a matter of debate. This systematic review and meta-analysis aimed to assess the association between cigarette smoking and prostate cancer risk.

METHODS

We conducted a systematic search on PubMed, Embase, Cochrane Library, and Web of Science without language or time restrictions on June 11, 2022. Literature search and study screening were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Prospective cohort studies that assessed the association between cigarette smoking habits and the risk of prostate cancer were included. Quality assessment was conducted using the Newcastle-Ottawa Scale. We used random-effects models to obtain pooled estimates and the corresponding 95% confidence intervals.

RESULTS

A total of 7296 publications were screened, of which 44 cohort studies were identified for qualitative analysis; 39 articles comprising 3 296 398 participants and 130 924 cases were selected for further meta-analysis. Current smoking had a significantly reduced risk of prostate cancer (RR, 0.74; 95% CI, 0.68-0.80; P < 0.001), especially in studies completed in the prostate-specific antigen screening era. Compared to former smokers, current smokers had a significant lower risk of PCa (RR, 0.70; 95% CI, 0.65-0.75; P < 0.001). Ever smoking showed no association with prostate cancer risk in overall analyses (RR, 0.96; 95% CI, 0.93-1.00; P = 0.074), but an increased risk of prostate cancer in the pre-prostate-specific antigen screening era (RR, 1.05; 95% CI, 1.00-1.10; P = 0.046) and a lower risk of prostate cancer in the prostate-specific antigen screening era (RR, 0.95; 95% CI, 0.91-0.99; P = 0.011) were observed. Former smoking did not show any association with the risk of prostate cancer.

CONCLUSIONS

The findings suggest that the lower risk of prostate cancer in smokers can probably be attributed to their poor adherence to cancer screening and the occurrence of deadly smoking-related diseases, and we should take measures to help smokers to be more compliant with early cancer screening and to quit smoking.

TRIAL REGISTRATION

This study was registered on PROSPERO (CRD42022326464).

Repurposing antifungal drugs for cancer therapy

BACKGROUND

Repurposing antifungal drugs in cancer therapy has attracted unprecedented attention in both preclinical and clinical research due to specific advantages, such as safety, high-cost effectiveness and time savings compared with cancer drug discovery. The surprising and encouraging efficacy of antifungal drugs in cancer therapy, mechanistically, is attributed to the overlapping targets or molecular pathways between fungal and cancer pathogenesis. Advancements in omics, informatics and analytical technology have led to the discovery of increasing "off-site" targets from antifungal drugs involved in cancerogenesis, such as smoothened (D477G) inhibition from itraconazole in basal cell carcinoma.

AIM OF REVIEW

This review illustrates several antifungal drugs repurposed for cancer therapy and reveals the underlying mechanism based on their original target and "off-site" target. Furthermore, the challenges and perspectives for the future development and clinical applications of antifungal drugs for cancer therapy are also discussed, providing a refresh understanding of drug repurposing.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review may provide a basic understanding of repurposed antifungal drugs for clinical cancer management, thereby helping antifungal drugs broaden new indications and promote clinical translation.

Smoking and Risk of Prostate Cancer and Prostate Cancer Death: A Pooled Study

BACKGROUND

Prospective and detailed investigations of smoking and prostate cancer (PCa) risk and death are lacking.

OBJECTIVE

To investigate prediagnosis smoking habit (status, intensity, duration, and cessation) as a risk factor, on its own and combined with body mass index (BMI), for PCa incidence and death.

DESIGN, SETTING, AND PARTICIPANTS

We included 351448 men with smoking information from five Swedish cohorts.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We used Cox regression to calculate hazard ratios (HRs) and confidence intervals (CIs) for PCa incidence (n = 24731) and death (n = 4322).

RESULTS AND LIMITATIONS

Smoking was associated with a lower risk of any PCa (HR 0.89, 95% CI 0.86-0.92), which was most pronounced for low-risk PCa (HR 0.74, 95% CI 0.69-0.79) and was restricted to PCa cases diagnosed in the prostate-specific antigen (PSA) era. Smoking was associated with a higher risk of PCa death in the full cohort (HR 1.10, 95% CI 1.02-1.18) and in case-only analysis adjusted for clinical characteristics (HR 1.20, 95% CI 1.11-1.31), which was a consistent finding across case groups (p = 0.8 for heterogeneity). Associations by smoking intensity and, to lesser degree, smoking duration and cessation, supported the associations for smoking status. Smoking in combination with obesity (BMI ≥30 kg/m²) further decreased the risk of low-risk PCa incidence (HR 0.40, 95% CI 0.30-0.53 compared to never smokers with BMI <25 kg/m²) and further increased the risk of PCa death (HR 1.49, 95% CI 1.21-1.84). A limitation of the study is that only a subgroup of men had information on smoking habit around the time of their PCa diagnosis.

CONCLUSIONS

The lower PCa risk for smokers in the PSA era, particularly for low-risk PCa, can probably be attributed to low uptake of PSA testing by smokers. Poor survival for smokers, particularly obese smokers, requires further study to clarify the underlying causes and the preventive potential of smoking intervention for PCa death.

PATIENT SUMMARY

Smokers have a higher risk of dying from prostate cancer, which further increases with obesity.

Cardiac physiology and metabolic gene expression during late organogenesis among F. heteroclitus embryo families from crosses between pollution-sensitive and -resistant parents

BACKGROUND

The teleost fish Fundulus heteroclitus inhabit estuaries heavily polluted with persistent and bioaccumulative chemicals. While embryos of parents from polluted sites are remarkably resistant to toxic sediment and develop normally, embryos of parents from relatively clean estuaries, when treated with polluted sediment extracts, are developmentally delayed, displaying deformities characteristic of pollution-induced embryotoxicity. To gain insight into parental effects on sensitive and resistant phenotypes during late organogenesis, we established sensitive, resistant, and crossed embryo families using five female and five male parents from relatively clean and predominantly PAH-polluted estuaries each, measured heart rates, and quantified individual embryo expression of 179 metabolic genes.

RESULTS

Pollution-induced embryotoxicity manifested as morphological deformities, significant developmental delays, and altered cardiac physiology was evident among sensitive embryos resulting from crosses between females and males from relatively clean estuaries. Significantly different heart rates among several geographically unrelated populations of sensitive, resistant, and crossed embryo families during late organogenesis and pre-hatching suggest site-specific adaptive cardiac physiology phenotypes relative to pollution exposure. Metabolic gene expression patterns (32 genes, 17.9%, at p < 0.05; 11 genes, 6.1%, at p < 0.01) among the embryo families indicate maternal pollutant deposition in the eggs and parental effects on gene expression and metabolic alterations.

CONCLUSION

Heart rate differences among sensitive, resistant, and crossed embryos is a reliable phenotype for further explorations of adaptive mechanisms. While metabolic gene expression patterns among embryo families are suggestive of parental effects on several differentially expressed genes, a definitive adaptive signature and metabolic cost of resistant phenotypes is unclear and shows unexpected sensitive-resistant crossed embryo expression profiles. Our study highlights physiological and metabolic gene expression differences during a critical embryonic stage among pollution sensitive, resistant, and crossed embryo families, which may contribute to underlying resistance mechanisms observed in natural F. heteroclitus populations living in heavily contaminated estuaries.

PAH-pollution effects on sensitive and resistant embryos: Integrating structure and function with gene expression

Polycyclic aromatic hydrocarbons (PAHs) are among the most widespread natural and anthropogenic pollutants, and some PAHs are proven developmental toxicants. We chemically characterized clean and heavily polluted sites and exposed fish embryos to PAH polluted sediment extracts during four critical developmental stages. Embryos were collected from Fundulus heteroclitus populations inhabiting the clean and heavily polluted Superfund estuary. Embryos of parents from the clean sites are sensitive to PAH pollutants while those of parents from the heavily polluted site are resistant. Chemical analysis of embryos suggests PAH accumulation and pollution-induced toxicity among sensitive embryos during development that ultimately kills all sensitive embryos before hatching, while remarkably, the resistant embryos develop normally. The adverse effects on sensitive embryos are manifested as developmental delays, reduced heart rates, and severe heart, liver, and kidney morphological abnormalities. Gene expression analysis of early somitogenesis, heartbeat initiation, late organogenesis, and pre-hatching developmental stages reveals genes whose expression significantly differs between sensitive and resistant embryo populations and helps to explain mechanisms of sensitivity and resistance to polluted environments during vertebrate animal development.

The Multifarious Link between Cytochrome P450s and Cancer

Cancer is a leading cause of death worldwide. Cytochrome P450s (P450s) play an important role in the metabolism of endogenous as well as exogenous substances, especially drugs. Moreover, many P450s can serve as targets for disease therapy. Increasing reports of epidemiological, diagnostic, and clinical research indicate that P450s are enzymes that play a major part in the formation of cancer, prevention, and metastasis. The purposes of this review are to shed light on the current state of knowledge about the cancer molecular mechanism involving P450s and to summarize the link between the cancer effects and the participation of P450s.

Development of a database on key characteristics of human carcinogens

A database on mechanistic characteristics of human carcinogenic agents was developed by collecting mechanistic information on agents identified as human carcinogens (Group 1) by the International Agency for Research on Cancer (IARC) in the IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. A two-phase process is described for the construction of the database according to 24 toxicological endpoints, derived from appropriate test systems that were acquired from data obtained from the mechanisms sections of the IARC Monographs (Section 4) and a supplementary PubMed search. These endpoints were then aligned with 10 key characteristics of human carcinogens that reflect the broader attributes of these agents relating to the development of cancer in humans. The considerations involved in linking of toxicological endpoints to key characteristics are described and specific examples of the determination of key characteristics for six specific agents (tamoxifen, hepatitis B virus, arsenic, ultraviolet and solar radiation, tobacco smoking, and dioxin) are provided. Data for humans and animals were tabulated separately, as were results for in-vivo and for in-vitro sources of information. The database was constructed to support a separate analysis of the expression of these endpoints by 86 Group 1 carcinogens, in-vivo and in-vitro along with an analysis of the key characteristics of these agents.

The role of phase I and II genetic polymorphisms, smoking, alcohol and cancer family history, in the risk of developing testicular cancer

BACKGROUND

Testicular cancer (TCa) is a malignant tumor with highest incidence and mortality rates in Chile. The genes coding for cytochrome P450, glutathione-S-transferases (GSTs), and UDP glucuronyl transferases (UGT) participate in the biotransformation and detoxification of xenobiotics. Mutations in these genes have been associated with a high incidence of various types of cancer and an increased risk of presenting adverse reactions to drugs.

OBJECTIVE

The aim of this study was to relate the presence of genetic polymorphisms in cytochrome P450 1A1 (CYP1A1), CYP3A4, GSTM1, GSTP1, GSTT1, and UGT1A1 genes and nongenetic factors with the risk of developing TCa.

METHODS

A total of 276 volunteers from the Chilean general population and 251 Chilean TCa patients were recruited for the study. Genotypic analyses were performed using qPCR and PCR-RFLP.

RESULTS

Variant alleles found to increase the risk of developing TCa were CYP1A1*2C (rs1048943), GSTP1 (rs1695), and GSTT1null, especially when in conjunction with a cancer family history and/or a smoking habit. The results of the multivariate analysis showed that the presence of variant alleles of GSTP1 (rs1695) together with a smoking habit and a family history of cancer accounted for a 15.9% risk of developing TCa in the Chilean population. CYP1A1*2C, GSTM1null, GSTT1null, and GSTP1 (rs1695) are statistically related to the risk of appearance of TCa, alone or associated with nongenetic factors.

CONCLUSION

Therefore, phase I and II variant alleles might be useful in evaluating susceptibility to TCa in the studied population.

Dietary Carcinogens and DNA Adducts in Prostate Cancer

Prostate cancer (PC) is the most commonly diagnosed non-cutaneous cancer and the second leading cause of cancer-related to death in men. The major risk factors for PC are age, family history, and African American ethnicity. Epidemiological studies have reported large geographical variations in PC incidence and mortality, and thus lifestyle and dietary factors influence PC risk. High fat diet, dairy products, alcohol and red meats, are considered as risk factors for PC. This book chapter provides a comprehensive, literature-based review on dietary factors and their molecular mechanisms of prostate carcinogenesis. A large portion of our knowledge is based on epidemiological studies where dietary factors such as cancer promoting agents, including high-fat, dairy products, alcohol, and cancer-initiating genotoxicants formed in cooked meats have been evaluated for PC risk. However, the precise mechanisms in the etiology of PC development remain uncertain. Additional animal and human cell-based studies are required to further our understandings of risk factors involved in PC etiology. Specific biomarkers of chemical exposures and DNA damage in the prostate can provide evidence of cancer-causing agents in the prostate. Collectively, these studies can improve public health research, nutritional education and chemoprevention strategies.

Influence of lifestyle choices on risks of CYP1B1 polymorphisms for prostate cancer

Cytochrome P450 1B1 (CYP1B1) converts xenobiotics to carcinogens and how lifestyle choices may interact with CYP1B1 polymorphisms and affect prostate cancer risk was assessed. Blood genomic DNA from a Caucasian population was analysed at polymorphic sites of the 5' untranslated region of CYP1B1 using TaqMan genotyping assays. Overall, drinker status and minor alleles at rs2551188, rs2567206 and rs10175368 were associated with prostate cancer. Linkage was observed between rs2551188, rs2567206, rs2567207 and rs10175368, and the G-C-T-G haplotype (major allele at respective sites) was decreased in cancer. Interestingly when classified by lifestyle factors, no associations of genotypes were found for non-smokers and non-drinkers, whereas on the contrary, minor type at rs2567206 and rs10175368 increased and major G-C-T-G decreased risk for cancer among smokers and drinkers. Interestingly, rs2551188, rs2567206 and rs10175368 minor genotypes correlated with increased tissue CYP1B1 as determined by immunohistochemistry. Further, rs10175368 enhanced luciferase activity and mobility shift show stronger binding of nuclear factor for the minor allele. These results demonstrate smoking and alcohol consumption to modify the risks of CYP1B1 polymorphisms for prostate cancer which may be through rs10175368, and this is of importance in understanding their role in the pathogenesis and as a biomarker for this disease.

Complete charge separation provoked by full cation encapsulation in the radical mono- and di-anions of 5,6:11,12-di-o-phenylene-tetracene

Herein, we report the synthesis and molecular structure of the mono- and dianionic aromatic molecules [(B15C5-κ5O)2K+](LDOPT˙-) (1) and [(B15C5-κ5O)2K+]2(LDOPT2-)THFsolv (2) derived from the parent aromatic polyhydrocarbon 5,6:11,12-di-o-phenylenetetracene (DOPT, LDOPT) by a controlled stepwise one and two electron chemical reduction. The effect of single and double electron charge transfer to a polycondensed aromatic hydrocarbon (PAH) without any disturbing influence of an associated metal cation has been demonstrated. This was achieved by fully sandwiching the cationic K+ counterions between two benzo-15-crown-5-ether (B15C5) ligands resulting in a fully encapsulating (κ10O) geometry which ensures a complete separation of the K+ counterions and the bare anionic PAH species [LDOPT˙-] and [LDOPT2-]. The structural changes accompanied by the stepwise reduction from LDOPT to [LDOPT˙-] to [LDOPT2-] are discussed and compared to earlier predictions based on density functional theory (DFT) as well as the results of previous studies of alkaline metal cationic PAH anion interactions of DOPT in which only a partial metal cation encapsulation has been achieved so far.

Association between cadmium and androgen receptor protein expression differs in prostate tumors of African American and European American men

Cadmium is a known carcinogen that has been implicated in prostate cancer, but how it affects prostate carcinogenesis in humans remains unclear. Evidence from basic science suggests that cadmium can bind to the androgen receptor causing endocrine disruption. The androgen receptor is required for normal prostate development and is the key driver of prostate cancer progression. In this study, we examined the association between cadmium content and androgen receptor protein expression in prostate cancer tissue of African American (N = 22) and European American (N = 30) men. Although neither overall tumor cadmium content (log transformed) nor androgen receptor protein expression level differed by race, we observed a race-cadmium interaction with regard to androgen receptor expression (P = 0.003) even after accounting for age at prostatectomy, smoking history, and Gleason score. African American men had a significant positive correlation between tumor tissue cadmium content and androgen receptor expression (Pearson correlation = 0.52, P = 0.013), while European Americans showed a non-significant negative correlation between the two (Pearson correlation = -0.19, P = 0.31). These results were unchanged after further accounting for tissue zinc content or dietary zinc or selenium intake. African American cases with high-cadmium content (>median) in tumor tissue had more than double the androgen receptor expression (0.021 vs. 0.008, P = 0.014) of African American men with low-cadmium level. No difference in androgen receptor expression was observed in European Americans by cadmium level (high 0.015 vs. low 0.011, P = 0.30). Larger studies are needed to confirm these results and if upheld, determine the biologic mechanism by which cadmium increases androgen receptor protein expression in a race-dependent manner. Our results suggest that cadmium may play a role in race disparities observed in prostate cancer.

Latest Evidence on the Impact of Smoking, Sports, and Sexual Activity as Modifiable Lifestyle Risk Factors for Prostate Cancer Incidence, Recurrence, and Progression: A Systematic Review of the Literature by the European Association of Urology Section of Oncological Urology (ESOU)

CONTEXT

Smoking, sexual activity, and physical activity (PA) are discussed as modifiable lifestyle factors associated with prostate cancer (PCa) development and progression.

OBJECTIVE

To evaluate the available evidence concerning the association of smoking, sexual activity, and sports and exercise on PCa risk, treatment outcome, progression, and cancer-specific mortality.

EVIDENCE ACQUISITION

A systematic review of studies published between 2007 and 2017 using MEDLINE (via PubMed), Cochrane Central Register of Controlled Trials, and Web of Science databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement criteria was conducted.

EVIDENCE SYNTHESIS

While data concerning the impact of smoking on PCa development remain conflicting, there is robust evidence that smoking is associated with aggressive tumor features and worse cancer-related outcome, which seems to be maintained for 10 yr after smoking cessation. Less convincing and limited evidence exists for the association of sexual activity with PCa risk. The findings related to PA and PCa support the inference that exercise might be a useful factor in the prevention of PCa and tumor progression, while it is not finally proved under which specific conditions PA might be protective against disease development.

CONCLUSIONS

Smoking is associated with aggressive tumor features and worse cancer-related prognosis; as this negative impact seems to be maintained for 10yr after smoking cessation, urologists should advise men to quit smoking latest at PCa diagnosis to improve their prognosis. As several studies indicate a positive impact of exercise on tumor development, progression, and treatment outcome, it is certainly reasonable to advocate an active lifestyle. Least convincing evidence is available for the interaction of sexual activity and PCa, and well-conducted and longitudinal studies are clearly necessary to evaluate whether the suggested associations between PCa risk and sexual behavior are real or spurious.

PATIENT SUMMARY

In this systematic review, we looked at the impact of smoking, sexual activity, and sports and exercise on prostate cancer risk and outcome after treatment. While the evidence for sexual activity is not overall clear, we found that smoking might lead to more aggressive cancers and result in worse treatment outcome. Physical activity might prevent prostate cancer and improve cancer-related outcomes as well. Hence, it is certainly reasonable to advocate an active lifestyle and advise men to quit smoking.

Cytochrome P-450 1B1 Leu432Val Polymorphism Does Not Show Association With Breast Cancer in Northern Iranian Women With a History of Infertility

The Cytochrome P-4501B1 (CYP1B1) Leu432Val polymorphism has been previously shown to be associated with some types of cancer and affects CYP1B1-mediated metabolism of various infertility drugs. To establish the frequency of CYP1B1 Leu432Val polymorphism among women with a history of infertility drug use, we studied the genotypes of 147 patients with breast cancer with a history of infertility and 150 cancer-free, infertile women (control group) in Northern Iran. A polymerase chain reaction-based restriction fragment length polymorphism assay was used to detect GG (Val/Val), CG (Leu/Val), and CC (Leu/Leu) genotype frequencies, which did not vary significantly between the 2 patient groups (P = .847). We established for the first time that the incidence of CYP1B1 Leu432Val polymorphism is 46.6% among women with infertility history and breast cancer in Northern Iran. Finally, our results do not show any significant association between CYP1B1 Leu432Val polymorphism and breast cancer in infertile women in this region, who have also received infertility treatment.

Macular Pigment Optical Density and Measures of Macular Function: Test-Retest Variability, Cross-Sectional Correlations, and Findings from the Zeaxanthin Pilot Study of Response to Supplementation (ZEASTRESS-Pilot)

We report on the short-term test-retest baseline variability in macular function tests in ZEASTRESS-Pilot participants (n = 18), on their cross-sectional correlation with macular pigment optical density (MPOD), and on the effects of four months (FUV4) of 20 mg/day zeaxanthin (ZX), followed by a four-month washout (FUV8; n = 24, age 50–81 years old). Outcomes included: MPOD at 0.5 and 2.0 deg eccentricity (MPOD-0.5 and -2.0); contrast sensitivity (CS); pattern-reversal electroretinogram (PERG) amplitude; dark-adapted 650 nm foveal cone sensitivity (DA650-FCS); and 500 mn parafoveal rod sensitivity (DA500-PFRS). All measures of macular function showed close test-retest correlation (Pearson’s r range: 0.744–0.946) and low coefficients of variation (CV range: 1.13%–4.00%). MPOD correlated in a complex fashion with macular function. Following supplementation, MPOD-0.5 and MPOD-2.0 increased at both FUV4 and FUV8 (p ≤ 0.0001 for all measures). Continued, delayed MPOD increase and a small, but significant (p = 0.012), CS increase was seen at FUV8 only in females. PERGs increased significantly at FUV4 (p = 0.0006), followed by a partial decline at FUV8. In conclusion, following ZX supplementation, MPOD increased significantly. There was no effect on DA-650 FCS or DA-500 PFRS. Both CS and PERG amplitudes increased following supplementation, but the effect varied between males and females. Additional studies appear warranted to confirm and characterize further these inter-gender differences.

Evaluation of Oxidative Stress Response Related Genetic Variants, Pro-oxidants, Antioxidants and Prostate Cancer

Background

Oxidative stress and detoxification mechanisms have been commonly studied in Prostate Cancer (PCa) due to their function in the detoxification of potentially damaging reactive oxygen species (ROS) and carcinogens. However, findings have been either inconsistent or inconclusive. These mixed findings may, in part, relate to failure to consider interactions among oxidative stress response related genetic variants along with pro- and antioxidant factors.

Methods

We examined the effects of 33 genetic and 26 environmental oxidative stress and defense factors on PCa risk and disease aggressiveness among 2,286 men from the Cancer Genetic Markers of Susceptibility project (1,175 cases, 1,111 controls). Single and joint effects were analyzed using a comprehensive statistical approach involving logistic regression, multi-dimensionality reduction, and entropy graphs.

Results

Inheritance of one CYP2C8 rs7909236 T or two SOD2 rs2758331 A alleles was linked to a 1.3- and 1.4-fold increase in risk of developing PCa, respectively (p-value = 0.006–0.013). Carriers of CYP1B1 rs1800440GG, CYP2C8 rs1058932TC and, NAT2 (rs1208GG, rs1390358CC, rs7832071TT) genotypes were associated with a 1.3 to 2.2-fold increase in aggressive PCa [p-value = 0.04–0.001, FDR 0.088–0.939]. We observed a 23% reduction in aggressive disease linked to inheritance of one or more NAT2 rs4646247 A alleles (p = 0.04, FDR = 0.405). Only three NAT2 sequence variants remained significant after adjusting for multiple hypotheses testing, namely NAT2 rs1208, rs1390358, and rs7832071. Lastly, there were no significant gene-environment or gene-gene interactions associated with PCa outcomes.

Conclusions

Variations in genes involved in oxidative stress and defense pathways may modify PCa. Our findings do not firmly support the role of oxidative stress genetic variants combined with lifestyle/environmental factors as modifiers of PCa and disease progression. However, additional multi-center studies poised to pool genetic and environmental data are needed to make strong conclusions.

Tobacco smoking, polymorphisms in carcinogen metabolism enzyme genes, and risk of localized and advanced prostate cancer: results from the California Collaborative Prostate Cancer Study

The relationship between tobacco smoking and prostate cancer (PCa) remains inconclusive. This study examined the association between tobacco smoking and PCa risk taking into account polymorphisms in carcinogen metabolism enzyme genes as possible effect modifiers (9 polymorphisms and 1 predicted phenotype from metabolism enzyme genes). The study included cases (n = 761 localized; n = 1199 advanced) and controls (n = 1139) from the multiethnic California Collaborative Case-Control Study of Prostate Cancer. Multivariable conditional logistic regression was performed to evaluate the association between tobacco smoking variables and risk of localized and advanced PCa risk. Being a former smoker, regardless of time of quit smoking, was associated with an increased risk of localized PCa (odds ratio [OR] = 1.3; 95% confidence interval [CI] = 1.0-1.6). Among non-Hispanic Whites, ever smoking was associated with an increased risk of localized PCa (OR = 1.5; 95% CI = 1.1-2.1), whereas current smoking was associated with risk of advanced PCa (OR = 1.4; 95% CI = 1.0-1.9). However, no associations were observed between smoking intensity, duration or pack-year variables, and advanced PCa. No statistically significant trends were seen among Hispanics or African-Americans. The relationship between smoking status and PCa risk was modified by the CYP1A2 rs7662551 polymorphism (P-interaction = 0.008). In conclusion, tobacco smoking was associated with risk of PCa, primarily localized disease among non-Hispanic Whites. This association was modified by a genetic variant in CYP1A2, thus supporting a role for tobacco carcinogens in PCa risk.

The role of epoxide hydrolases in health and disease

Epoxide hydrolases (EH) are ubiquitously expressed in all living organisms and in almost all organs and tissues. They are mainly subdivided into microsomal and soluble EH and catalyze the hydration of epoxides, three-membered-cyclic ethers, to their corresponding dihydrodiols. Owning to the high chemical reactivity of xenobiotic epoxides, microsomal EH is considered protective enzyme against mutagenic and carcinogenic initiation. Nevertheless, several endogenously produced epoxides of fatty acids function as important regulatory mediators. By mediating the formation of cytotoxic dihydrodiol fatty acids on the expense of cytoprotective epoxides of fatty acids, soluble EH is considered to have cytotoxic activity. Indeed, the attenuation of microsomal EH, achieved by chemical inhibitors or preexists due to specific genetic polymorphisms, is linked to the aggravation of the toxicity of xenobiotics, as well as the risk of cancer and inflammatory diseases, whereas soluble EH inhibition has been emerged as a promising intervention against several diseases, most importantly cardiovascular, lung and metabolic diseases. However, there is reportedly a significant overlap in substrate selectivity between microsomal and soluble EH. In addition, microsomal and soluble EH were found to have the same catalytic triad and identical molecular mechanism. Consequently, the physiological functions of microsomal and soluble EH are also overlapped. Thus, studying the biological effects of microsomal or soluble EH alterations needs to include the effects on both the metabolism of reactive metabolites, as well as epoxides of fatty acids. This review focuses on the multifaceted role of EH in the metabolism of xenobiotic and endogenous epoxides and the impact of EH modulations.

Minireview: the molecular and genomic basis for prostate cancer health disparities

Despite more aggressive screening across all demographics and gradual declines in mortality related to prostate cancer (PCa) in the United States, race disparities persist. For African American men (AAM), PCa is more often an aggressive disease showing increased metastases and greater PCa-related mortality compared with European American men. The earliest research points to how distinctions are likely the result of a combination of factors, including ancestry genetics and lifestyle variables. More recent research considers that cancer, although influenced by external forces, is ultimately a disease primarily driven by aberrations observed in the molecular genetics of the tumor. Research studying PCa predominantly from European American men shows that indolent and advanced or metastatic prostate tumors have distinguishing molecular genomic make-ups. Early yet increasing evidence suggests that clinically distinct PCa from AAM also display molecular distinctions. It is reasonable to predict that further study will reveal molecular subtypes and various frequencies for PCa subtypes among diverse patient groups, thereby providing insight as to the genomic lesions and gene signatures that are functionally implicated in carcinogenesis or aggressive PCa in AAM. That knowledge will prove useful in developing strategies to predict who will develop advanced PCa among AAM and will provide the rationale to develop effective individualized treatment strategies to overcome disparities.

Association of GSTT1 gene polymorphisms with the risk of prostate cancer: an updating meta-analysis

It has been demonstrated that the glutathione S-transferase (GST) superfamily helps remove carcinogens from the body and thus might be associated with prostate cancer risk. In recent years, GSTT1 polymorphism has been extensively studied as a potential prostate cancer risk factor; however, the results are inconsistent. To investigate the association between GSTT1 and prostate cancer, we conducted a meta-analysis of 33 studies with 6,697 prostate patients and 7,643 controls. For GSTM1 null versus present genotype, the random effects odds ratio was 0.98 (95 % confidence interval (CI) 0.83-1.16) based on a wide population. Subgroup analyses in the different ethnic groups and different controls were performed. The OR was 1.01 (95 % CI 0.86-1.19) in Caucasians, 1.01 (95 % CI 0.70-1.47) in Asians, and 0.77 (95 % CI 0.42-1.42) in Africans. The OR was 0.98 (95 % CI 0.82-1.16) in non-benign prostate hyperplasia (BPH) controls and 1.09 (95 % CI 0.66-1.79) in BPH controls. In conclusion, our present meta-analysis demonstrates that there is no association between GSTT1 polymorphism and prostate cancer, even in the sub-analysis concerning different races and control sources. The direction of further research should focus not only on the simple relationship of GSTT1 and prostate cancer but also on gene-environment interaction and distinctions of different GSTs.

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.

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.

Neighborhood socioeconomic status modifies the association between individual smoking status and PAH-DNA adduct levels in prostate tissue

Interactions between smoking and neighborhood-level socioeconomic status (SES) as risk factors for higher polycyclic aromatic hydrocarbon (PAH) DNA adduct levels in prostate tissue were investigated. PAH-DNA adducts were measured by immunohistochemistry with staining intensity measured in optical density units by semiquantitative absorbance image analysis in tumor adjacent tissue from 400 prostatectomy specimens from the Henry Ford Health System in Detroit. For each subject, their U.S. Census tract of residence was classified as being of higher or lower SES using the median value of the distribution of the proportion of tract residents with a high-school education. Generalized estimating equation models were used to assess interactions between neighborhood-level SES and smoking status, adjusting for race, age, education level, tumor volume, primary Gleason grade and prostate specific antigen (PSA) at diagnosis. There was a statistical interaction (P = 0.004) between tract-level SES and smoking status. In lower SES tracts smoking status was not associated with adduct staining, but in higher SES tracts adduct staining intensity was 13% (P = 0.01) higher in ever-smokers as compared to never-smokers. Among never-smokers, living in a lower SES tract was associated with a 25% higher mean staining intensity (P < 0.001). Neighborhood SES modifies the association between individual smoking status and PAH-DNA adduct levels in prostate tissue.

Meat-cooking mutagens and risk of renal cell carcinoma

BACKGROUND

High-temperature cooked meat contains two families of carcinogens, heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). Given the kidneys' role in metabolism and urinary excretion of these compounds, we investigated meat-derived mutagens, as well as meat intake and cooking methods, in a population-based case-control study conducted in metropolitan Detroit and Chicago.

METHODS

Newly diagnosed, histologically confirmed adenocarcinoma of the renal parenchyma (renal cell carcinoma (RCC)) cases (n=1192) were frequency matched on age, sex, and race to controls (n=1175). The interviewer-administered Diet History Questionnaire (DHQ) included queries for meat-cooking methods and doneness with photographic aids. Levels of meat mutagens were estimated using the DHQ in conjunction with the CHARRED database.

RESULTS

The risk of RCC increased with intake of barbecued meat (P(trend)=0.04) and the PAH, benzo(a)pyrene (BaP) (multivariable-adjusted odds ratio and 95% confidence interval, highest vs lowest quartile: 1.50 (1.14, 1.95), P(trend)=0.001). With increasing BaP intake, the risk of RCC was more than twofold in African Americans and current smokers (P(interaction)<0.05). We found no association for HCAs or overall meat intake.

CONCLUSION

BaP intake, a PAH in barbecued meat, was positively associated with RCC. These biologically plausible findings advocate further epidemiological investigation into dietary intake of BaP and risk of RCC.

Multi-institutional prostate cancer study of genetic susceptibility in populations of African descent

Prostate cancer disparities have been reported in men of African descent who show the highest incidence, mortality, compared with other ethnic groups. Few studies have explored the genetic and environmental factors for prostate cancer in men of African ancestry. The glutathione-S-transferases family conjugates carcinogens before their excretion and is expressed in prostate tissue. This study addressed the role of GSTM1 and GSTT1 deletions on prostate cancer risk in populations of African descent. This multi-institutional case-control study gathered data from the Genetic Susceptibility to Environmental Carcinogens (GSEC) database, the African-Caribbean Cancer Consortium (AC3) and Men of African Descent and Carcinoma of the Prostate Consortium (MADCaP). The analysis included 10 studies (1715 cases and 2363 controls), five in African-Americans, three in African-Caribbean and two in African men. Both the GSTM1 and the GSTT1 deletions showed significant inverse associations with prostate cancer [odds ratio (OR): 0.90, 95% confidence interval (CI) 0.83-0.97 and OR 0.88, 95% CI: 0.82-0.96, respectively]. The association was restricted to Caribbean and African populations. A significant positive association was observed between GSTM1 deletion and prostate cancer in smokers in African-American studies (OR: 1.28, 95% CI: 1.01-1.56), whereas a reduced risk was observed in never-smokers (OR: 0.66, 95% CI: 0.46-0.95). The risk of prostate cancer increased across quartiles of pack-years among subjects carrying the deletion of GSTM1 but not among subjects carrying a functional GSTM1. Gene-environment interaction between smoking and GSTM1 may be involved in the etiology of prostate cancer in populations of African descent.

Polymorphisms in glutathione S-transferase genes increase risk of prostate cancer biochemical recurrence differentially by ethnicity and disease severity

Objective

Genetic polymorphisms that modify the detoxifying activity of glutathione S-transferases (GSTs) can affect the level of carcinogenic metabolites created by endogenous steroid hormones and exogenous chemical substances. Although the GSTM1 null genotype has been shown to increase prostate cancer mortality in Caucasians, potential associations between GST polymorphisms and prostate cancer biochemical recurrence (BCR) have not been well studied, particularly in African-Americans.

Methods

We examined potential associations between the GSTM1 null, GSTT1 null and GSTP1 Ile105Val polymorphisms and BCR, after prostatectomy, in 168 African-American and 226 Caucasian patients treated at Henry Ford Hospital in Detroit, Michigan using Cox proportional hazards modeling.

Results

We found that African-Americans with the GSTT1 null genotype had increased BCR risk compared to those having GSTT1 present (hazard ratio (HR) = 2.30; 95% CI = 1.01–5.18; p = 0.04); and African-Americans with the GSTT1 null genotype and high grade tumors had an even greater risk (HR = 7.82; 95% CI = 2.49–24.50; p < 0.001). In Caucasians, an increased risk was observed in those patients with high grade tumors and the GSTM1 null genotype (HR = 2.88; 95% CI = 1.16–7.14; p = 0.02). Similar associations were observed for advanced stage and more aggressive (high grade or advanced stage) disease.

Conclusion

Our results suggest GSTs may hold promise as therapeutic targets in more advanced prostate cancers, particularly, in African-Americans.

GSTP1 mRNA expression in human circulating blood leukocytes is associated with GSTP1 genetic polymorphism

OBJECTIVES

We explored association between GSTP1 Ile(105)Val (rs1695) polymorphism and GSTP1 mRNA expression in circulating blood leukocytes.

DESIGN AND METHODS

GSTP1 transcripts level and polymorphism were determined by Real-Time PCR in 51 bladder cancer and 90 healthy men.

RESULTS

Individuals with at least one GSTP1 Val(105) variant allele possessed higher GSTP1 mRNA level in blood leukocytes compared to GSTP1 Ile(105)Ile carriers.

CONCLUSIONS

GSTP1 Ile(105)Val gene polymorphism influences its expression in blood, regardless of cancer disease.

Smoking, the xenobiotic pathway, and clubfoot

BACKGROUND

Isolated clubfoot is a common orthopedic birth defect that affects approximately 135,000 newborns worldwide. It is characterized by ankle equinus, hindfoot varus, and forefoot adductus. Although numerous studies suggest a multifactorial etiology, the specific genetic and environmental components have yet to be delineated. Maternal smoking during pregnancy is the only common environmental factor consistently shown to increase the risk for clubfoot. Moreover, a positive family history of clubfoot, in conjunction with maternal smoking, increases the risk 20-fold. These findings suggest that genetic variation in smoking metabolism (xenobiotic) genes may increase susceptibility to clubfoot. Based on this reasoning, we interrogated eight candidate genes from the xenobiotic metabolism.

METHODS

Twenty-two single-nucleotide polymorphisms and two null alleles in these genes (CYP1A1, CYP1A2, CYP1B1, CYP2A6, EPHX1, NAT2, GSTM1, and GSTT1) were genotyped in a dataset composed of non-Hispanic white and Hispanic multiplex and simplex families.

RESULTS

Only rs1048943/CYP1A1 had significantly altered transmission in the aggregate and multiplex non-Hispanic white datasets (p = 0.003 and p = 0.009, respectively). Perturbation of CYP1A1 can cause an increase in harmful, adduct-forming metabolic intermediates. A significant interaction between EPHX1 and NAT2 was also found (p = 0.007). Importantly, for CYP1A2, significant maternal (p = 0.03; relative risk [RR] = 1.24; 95% confidence interval [CI], 1.04-1.44) and fetal (p = 0.01; RR = 1.33; 95% CI, 1.13-1.54) genotypic effects were identified, suggesting that both maternal and fetal genotypes can negatively impact limb development. No association was found between maternal smoking status and variation in xenobiotic metabolism genes.

CONCLUSION

Together, these results suggest that xenobiotic metabolism genes are unlikely to play a major role in clubfoot; however, perturbation of this pathway may still play a contributory role.

Constitutive expression of bioactivating enzymes in normal human prostate suggests a capability to activate pro-carcinogens to DNA-damaging metabolites

BACKGROUND

The constitutive bioactivating capacity of human prostate may play a role in determining risk of adenocarcinoma developing in this tissue. Expression of candidate enzymes that convert exogenous and/or endogenous agents into reactive DNA-damaging species would suggest the potential to generate initiating events in prostate cancer (CaP).

METHODS

Normal prostate tissues from UK-resident Caucasians (n = 10) were collected following either radical retropubic prostatectomy (RRP) or cystaprostatectomy (CyP). An analysis of gene and protein expression of candidate metabolizing enzymes, including cytochrome P450 (CYP)1A1, CYP1A2, CYP1B1, N-acetyltransferase 1 (NAT1), sulfotransferase (SULT)1A1, SULT1A3, NAD(P)H:quinone oxidoreductase (NQO1), prostaglandin H synthase 1 (cyclooxygenase 1; COX1), and CYP oxidoreductase (POR) was carried out. Quantitative real-time reverse transcriptase polymerase chain reaction, Western blot, and immunohistochemical analysis were conducted.

RESULTS

Except for CYP1A1 and CYP1A2, the metabolizing enzymes examined appeared to be expressed with minimal inter-individual variation (in general, approximately two- to fivefold) in the expression levels. Enzymes such as CYP1B1 and NQO1 that are capable of bioactivating pro-carcinogens to reactive metabolites were readily identifiable in human prostate. Immunohistochemical analysis showed that although some expression is located in the stroma, the majority is localized to epithelial cells lining the glandular elements of the tissue; these are the cells from which CaP might arise.

CONCLUSION

Constitutive expression of bioactivating enzymes confers the potential to convert a range of exogenous and/or endogenous agents to reactive species capable of inducing DNA damaging events. These findings suggest an organ capability for pro-carcinogen activation that could play an important role in the etiology of human CaP.

Association of CYP1B1 Polymorphisms with Breast Cancer: A Case-Control Study in the Han Population in Ningxia Hui Autonomous Region, P. R. China

Studies investigating possible associations between cytochrome P4501B1 (CYP1B1) polymorphisms and breast cancer risk have been inconsistent. We set out to ascertain whether there might be an association between polymorphisms in exon 2 (codon 119, G→T) and exon 3 (codon 432, G→C) of CYP1B1 and breast cancer in a Chinese Han population in the rural region of Ningxia. Using an allele-specific polymerase chain reaction method and direct DNA sequencing, the presence or absence of the two CYP1B1 polymorphisms was investigated. Genotype and allele frequencies were analyzed in breast cancer cases (n = 152) and healthy age-matched controls (n = 156). The odds ratio (OR) of 119G→T or 432G→C in breast cancer cases and controls was 3.3 (95% CI: 1.28 to 8.28) and 2.8 (95% CI: 1.04 to 7.51), respectively. In addition, the OR for people with both polymorphisms (119T and 432C) was 4.69 (95% CI: 1.97 to 11.19). Our results suggest that certain polymorphisms in the CYP1B1 gene might increase risk for breast cancer among Han Chinese, perhaps because they influence the efficiency of CYP1B1 bio-transformation of oestrogens or pro-carcinogens into DNA-reactive electrophiles that may act as cancer-initiating agents.

African American-preponderant single nucleotide polymorphisms (SNPs) and risk of breast cancer

BACKGROUND

African American women more often present with more aggressive types of breast cancer than Caucasian women, but little is known whether genetic polymorphisms specific to or disproportionate in African Americans are associated with their risk of breast cancer.

METHODS

A population-based case-control study was conducted including 194 cases identified through the Metropolitan Detroit Cancer Surveillance System and 189 controls recruited through random digit dialing to examine polymorphisms in genes involved in estrogen metabolism and action.

RESULTS

The African American-specific CYP1A1 5639C allele was associated with an increased risk of breast cancer (odds ratio (OR)=2.34, 95% confidence interval (CI) 1.23-4.44) and this association with the CYP1A1 5639 locus was dependent on another polymorphism in the CYP3A4 gene (P=0.043 for the interaction). In addition, African American-predominant CYP1B1 432 Val allele was significantly more often found in the cases than in the controls overall and the HSD17B1 312 Gly allele was specifically associated with premenopausal breast cancer risk (OR=3.00, 95%CI 1.29-6.99).

CONCLUSION

These observations need to be confirmed in larger studies due to the limited statistical power of the study based on a small number of cases.

An updating meta-analysis of the GSTM1, GSTT1, and GSTP1 polymorphisms and prostate cancer: a HuGE review

It has been postulated that individuals with GSTM1, GSTT1 deficiency and, GSTP1 (105Ile/Val transition) have increased susceptibility to carcinogens and are more likely to develop prostate cancer. In recent years, GST status has been extensively studied as a prostate cancer risk factor; however, the results are inconsistent. To re-examine this controversy, we have undertaken an updating meta-analysis of 29 studies with GSTM1 genotyping (4,564 prostate cancer cases and 5,464 controls), 22 studies with GSTT1 genotyping (3,837 cases and 4,552 controls), and 24 studies with GSTP1 genotyping (5,301 cases and 5,621 controls). The random effects odds ratio was 1.33 [95% confidence interval (95% CI): 1.15, 1.55; I(2) = 68.9%, P for heterogeneity = 0.00] for the GSTM1 null versus present genotype and 1.05 (95% CI: 0.86, 1.27; I(2) = 68.2%, P for heterogeneity = 0.00) for the GSTT1 null versus present genotype, and 1.06 (95% CI: 0.91, 1.24; I(2) = 71.5%, P for heterogeneity = 0.00) for the GSTP1-Val versus GSTP1-Ile allele. For GSTM1 polymorphism, similar results reached in Caucasians and Asians, with exception for Africans. No association between GSTT1 or GSTP1 polymorphisms and prostate cancer risk was detected in different racial. In conclusion, the major finding of our study suggested that GSTM1 polymorphism conferred an increasing risk of prostate cancer on a wide population basis, however, no relationship was found between GSTT1 and GSTP1 status and the risk of prostate cancer.

Quantification of phase I/II metabolizing enzyme gene expression and polycyclic aromatic hydrocarbon-DNA adduct levels in human prostate

BACKGROUND

Studies of migrant populations suggest that dietary and/or environmental factors play a crucial role in the etiology of prostatic adenocarcinoma (CaP). The human prostate consists of the peripheral zone (PZ), transition zone (TZ), and central zone (CZ); CaP occurs most often in the PZ.

METHODS

To investigate the notion that an underlying differential expression of phase I/II genes, and/or the presence of polycyclic aromatic hydrocarbon (PAH)-DNA adducts might explain the elevated PZ susceptibility, we examined prostate tissues (matched tissue sets consisting of PZ and TZ) from men undergoing radical retropubic prostatectomy for CaP (n = 26) or cystoprostatectomy (n = 1). Quantitative gene expression analysis was employed for cytochrome P450 (CYP) isoforms CYP1A1, CYP1B1, and CYP1A2, as well as N-acetyltransferase 1 and 2 (NAT1 and NAT2) and catechol-O-methyl transferase (COMT).

RESULTS

CYP1B1, NAT1, and COMT were expressed in all tissue sets; levels of CYP1B1 and NAT1 were consistently higher in the PZ compared to TZ. Immunohistochemistry confirmed the presence of CYP1B1 (nuclear-associated and primarily in basal epithelial cells) and NAT1. Normal tissue from 23 of these aforementioned 27 matched tissue sets was analyzed for PAH-DNA adduct levels using antiserum elicited against DNA modified with r7,t8-dihydroxy-t-9,10-oxy-7,8,9,10-tetrahydro-benzo[a]pyrene (BPDE). PAH-DNA adduct levels were highest in glandular epithelial cells, but a comparison of PZ and TZ showed no significant differences.

CONCLUSION

Although expression of activating and/or detoxifying enzymes may be higher in the PZ, PAH-DNA adduct levels appear to be similar in both zones. Therefore, factors other than PAH-DNA adducts may be responsible for promotion of tumor formation in the human prostate.

The Val432Leu polymorphism of the CYP1B1 gene is associated with differences in estrogen metabolism and bone density

Polymorphisms of the CYP450 genes that encode for the enzymes that metabolize estrogen are linked to hormone-related cancers. We investigated the impact of two polymorphisms of the CYP1B1 gene previously reported to be associated with hormone-related disorders on estrogen metabolism and bone mineral density (BMD), another hormone-dependent condition, in women from different ethnic backgrounds. Four hundred sixty-eight postmenopausal Caucasian women, 220 from St. Louis, MO, USA (mean age=63.5+/-0.53 years) and 248 from Palermo, Italy (mean age=72.9+/-0.44 years) participated in the study. Measurements of urinary estrogen metabolites by enzyme-linked immunoassay, serum estradiol by ultrasensitive radioimmnunoassay, and serum sex hormone-binding globulin by immunoradiometric assay were performed only in the American women, while BMD by dual energy X-ray absorptiometry and genotyping by pyrosequencing were performed in both American and Italian women. Differences in the levels of metabolites, free estradiol index and BMD were analyzed by analysis of covariance. Analysis among the American participants for the Valine432Leucine polymorphism showed that, compared to women with the Val/Val genotype, women with the Leu allele (Val/Leu and Leu/Leu) had significantly higher log-transformed values of total urinary estrogen metabolite (ng/mg-creatinine) levels (1.23+/-0.04, 1.35+/-0.02, and 1.34+/-0.03; p=0.03), and significantly lower BMD (gm/cm(2)) in the lumbar spine (1.009+/-0.02, 0.955+/-0.01 and 0.931+/-0.02; p=0.03) and the femoral neck (0.748+/-0.02, 0.717+/-0.01 and 0.693+/-001, p=0.03) for the Val/Val, Val/Leu and Leu/Leu genotypes respectively. There were no significant differences in the urinary metabolites and BMD in the different genotypes for the Alanine119Serine polymorphism among the American women. Meanwhile, a separate analysis among the Italian women revealed no significant differences in BMD among the different genotypes for the two polymorphisms investigated. In conclusion, women with the Leu allele for the CYP1B1 Val432polymorphism have increased estrogen catabolism, as indicated by higher urinary estrogen metabolites, compared to those with Val/Val genotype. This may lead to relative hypoestrogenism and lower BMD in the lumbar spine and femoral neck in these women. Our data suggest that through its effect on the rate of estrogen catabolism, the Val432Leu polymorphism of the CYP1B1 gene may represent as a possible genetic risk factor for osteoporosis in American women.

Gene-environment interaction in tobacco-related cancers

This review summarizes the carcinogenic effects of tobacco smoke and the basis for interaction between tobacco smoke and genetic factors. Examples of published papers on gene-tobacco interaction and cancer risk are presented. The assessment of gene-environment interaction in tobacco-related cancers has been more complex than originally expected for several reasons, including the multiplicity of genes involved in tobacco metabolism, the numerous substrates metabolized by the relevant genes and the interaction of smoking with other metabolic pathways. Future studies on gene-environment interaction and cancer risk should include biomarkers of smoking dose, along with markers of quantitative historical exposure to tobacco. Epigenetic studies should be added to classic genetic analyses, in order to better understand gene-environmental interaction and individual susceptibility. Other metabolic pathways in competition with tobacco genetic metabolism/repair should be incorporated in epidemiological studies to generate a more complete picture of individual cancer risk associated with environmental exposure to carcinogens.

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.

Meat and meat mutagens and risk of prostate cancer in the Agricultural Health Study

Meats cooked at high temperatures, such as pan-frying or grilling, are a source of carcinogenic heterocyclic amines and polycyclic aromatic hydrocarbons. We prospectively examined the association between meat types, meat cooking methods, meat doneness, and meat mutagens and the risk for prostate cancer in the Agricultural Health Study. We estimated relative risks and 95% confidence intervals (95% CI) for prostate cancer using Cox proportional hazards regression using age as the underlying time metric and adjusting for state of residence, race, smoking status, and family history of prostate cancer. During 197,017 person-years of follow-up, we observed 668 incident prostate cancer cases (613 of these were diagnosed after the first year of follow-up and 140 were advanced cases) among 23,080 men with complete dietary data. We found no association between meat type or specific cooking method and prostate cancer risk. However, intake of well or very well done total meat was associated with a 1.26-fold increased risk of incident prostate cancer (95% CI, 1.02-1.54) and a 1.97-fold increased risk of advanced disease (95% CI, 1.26-3.08) when the highest tertile was compared with the lowest. Risks for the two heterocyclic amines 2-amino-3,4,8-trimethylimidazo-[4,5-f]quinoxaline and 2-amino-3,8-dimethylimidazo-[4,5-b]quinoxaline were of borderline significance for incident disease [1.24 (95% CI, 0.96-1.59) and 1.20 (95% CI, 0.93-1.55), respectively] when the highest quintile was compared with the lowest. In conclusion, well and very well done meat was associated with an increased risk for prostate cancer in this cohort.