Do genetic factors protect for early onset lung cancer? A case control study before the age of 50 years

Global, regional, and national burden and trends of early-onset tracheal, bronchus, and lung cancer from 1990 to 2019

BACKGROUND

Tracheal, bronchus, and lung cancer (TBL) is one of the main cancer health problems worldwide, but data on the burden and trends of early-onset tracheal, bronchus, and lung cancer (EO-TBL) are sparse. The aim of the present study was to provide the latest and the most comprehensive burden estimates of the EO-TBL cancer from 1990 to 2019.

METHODS

Overall, we used data from the Global Burden of Disease (GBD) study in EO-TBL cancer from 1990 to 2019. Evaluation metrics included incidence, mortality, and disability-adjusted life years (DALYs). The joinpoint regression model was used to analyze the temporal trends. Decomposition analysis was employed to analyze the driving factors for EO-TBL cancer burden alterations. Bayesian age-period-cohort (BAPC) analysis was used to estimate trends in the next 20 years.

RESULTS

The global age-standardized incidence rate (ASIR), age-standardized mortality rate (ASMR), and age-standardized DALYs rate (ASDR) for EO-TBL cancer decreased significantly from 3.95 (95% uncertainty interval [UI]: 3.70-4.24), 3.41 (95% UI: 3.19-3.67), 158.68 (95% UI: 148.04-170.92) in 1990 to 2.82 (95% UI: 2.54-3.09), 2.28 (95% UI: 2.07-2.49), 106.47 (95% UI: 96.83-116.51) in 2019 with average annual percent change (AAPC) of -1.14% (95% confidence interval [CI]: -1.32 to -0.95), -1.37% (95% CI: -1.55 to -1.18), and - 1.35% (95% CI: -1.54 to -1.15) separately. The high and high-middle sociodemographic index (SDI) region had a higher burden of EO-TBL cancer but demonstrated a downward trend. The most prominent and significant upward trends were Southeast and South Asia, Africa, and women in the low SDI and low-middle SDI quintiles. At the regional and national level, there were significant positive correlations between ASDR, ASIR, ASMR, and SDI. Decomposition analysis showed that population growth and aging have driven the increase in the number of incidence, mortality, and DALYs in the global population, especially among the middle SDI quintile and the East Asia region. The BAPC results showed that ASDR, ASIR, and ASMR in women would increase but the male population remained relatively flat over the next 20 years.

CONCLUSIONS

Although global efforts have been the most successful and effective in reducing the burden of EO-TBL cancer over the past three decades, there was strong regional and gender heterogeneity. EO-TBL cancer need more medical attention in the lower SDI quintiles and in the female population.

A two-stage genome-wide association study identified four potential early-onset nonsmall cell lung cancer risk loci based on 26,652 participants in Chinese population

Early-onset lung cancer is rare with an increasing incidence rate. Although several genetic variants have been identified for it with candidate gene approaches, no genome-wide association study (GWAS) has been reported. In this study, a two-stage strategy was adopted: firstly we performed a GWAS to identify variants associated with early-onset nonsmall-cell lung cancer (NSCLC) risk using 2556 cases (age ≤ 50 years) and 13,327 controls by logistic regression model. To further discriminate younger cases from older ones, we took a case-case analysis for the promising variants with above early-onset cases and 10,769 cases (age > 50 years) by Cox regression model. After combining these results, we identified four early-onset NSCLC susceptibility loci at 5p15.33 (rs2853677, odds ratio [OR] = 1.48, 95% confidence interval [CI]: 1.36-1.60, Pcase-control  = 3.58 × 10-21 ; hazard ratio [HR] = 1.10, 95% CI: 1.04-1.16, Pcase-case  = 6.77 × 10-4 ), 5p15.1 (rs2055817, OR = 1.24, 95% CI: 1.15-1.35, Pcase-control  = 1.39 × 10-7 ; HR = 1.08, 95% CI: 1.02-1.14, Pcase-case  = 6.90 × 10-3 ), 6q24.2 (rs9403497, OR = 1.24, 95% CI: 1.15-1.35, Pcase-control  = 1.61 × 10-7 ; HR = 1.11, 95% CI: 1.05-1.17, Pcase-case  = 3.60 × 10-4 ) and 12q14.3 (rs4762093, OR = 1.31, 95% CI: 1.18-1.45, Pcase-control  = 1.90 × 10-7 ; HR = 1.10, 95% CI: 1.03-1.18, Pcase-case  = 7.49 × 10-3 ). Except for 5p15.33, other loci were found to be associated with NSCLC risk for the first time. All of them had stronger effects in younger patients than in older ones. These results provide a promising overview for early-onset NSCLC genetics.

The rs1801280 SNP is associated with non-small cell lung carcinoma by exhibiting a highly deleterious effect on N-acetyltransferase 2

PURPOSE

N-acetyltransferase 2 is an enzyme that is involved in the detoxification of carcinogens in the human body, so any damage to this protein may lead to the emergence of several metabolic dysfunctions. This work was conducted to determine the association between NAT2 polymorphism and non-small cell lung carcinoma (NSCLC) that is increasingly reported in the Iraqi population.

METHODS

PCR sequencing was conducted to assess the possible association between genetic variants and NSCLC. Several in silico tools were implemented to investigate the effect of the observed SNPs on the structure, function, and stability of the altered NAT2.

RESULTS

Five SNPS of NAT2 (rs1208, rs1041983, rs1799929, rs1799930, and rs1801280) were identified in high frequencies in the amplified fragment. These SNPs showed variable distributions of haplotypes between cases and controls. No significant association of rs1208, rs1041983, rs1799929, and rs1799930 with NSCLC was shown in the investigated population. In contrast, rs1801280: CC genotype showed a highly significant (P = 0.009) association with the NSCLC, and individuals with this genotype had 2.19 more chances for developing NSCLC (OR 2.19; Cl_95% 1.21-3.94). Association analysis of rs1801280 SNP distribution among the investigated patients showed that patients with CC genotype showed a significant (P = 0.02, OR 2.65) association with family history, which entailed a high hereditary possibility of this genotype among Iraqi patients. It was predicted that this SNP showed high damaging effects on the activity of NAT2 enzyme, with various deleterious outcomes on enzyme structure, function, and stability.

CONCLUSION

Data indicated that rs1801280 SNP exerted a tight association with NSCLC since individuals with CC genotype exhibited the most damaging effects on the NAT2 that may be behind the low acetylation rates of this enzyme in patients with NSCLC.

An Assessment of GPX1 (rs1050450), DIO2 (rs225014) and SEPP1 (rs7579) Gene Polymorphisms in Women with Endometrial Cancer

Background: Numerous studies indicate a relationship between the presence of GPX1 (rs1050450), DIO2 (rs225014) and SEPP1 (rs7579) gene polymorphisms and the development of chronic or neoplastic diseases. However, there are no reports on the influence of these polymorphisms on the development of endometrial cancer. Methods: 543 women participated in the study. The study group consisted of 269 patients with diagnosed endometrial cancer. The control group consisted of 274 healthy women. Blood samples were drawn from all the participants. The PCR-RFLP method was used to determine polymorphisms in the DIO2 (rs225014) and GPX1 (rs1050450) genes. The analysis of polymorphisms in the SEPP1 (rs7579) gene was performed by means of TaqMan probes. Results: There was a 1.99-fold higher risk of developing endometrial cancer in CC homozygotes, DIO2 (rs225014) polymorphism (95% Cl 1.14–3.53, p = 0.017), compared to TT homozygotes. There was no correlation between the occurrence of GPX1 (rs1050450) and SEPP1 (rs7579) polymorphisms and endometrial cancer. Conclusion: Carriers of the DIO2 (rs225014) polymorphism may be predisposed to the development of endometrial cancer. Further research confirming this relationship is recommended.

Molecular properties and survival of lung adenocarcinoma in young patients

OBJECTIVE

This study aims to investigate the molecular properties and factors of lung cancer in young patients aged 18-45 years, affecting survival in patients with pulmonary adenocarcinoma.

METHODS

Patients aged between 18 and 45 years who were diagnosed with lung adenocarcinoma in our hospital between January 2015 and December 2019 and their tumoural mutations were studied and included in this study and then reviewed retrospectively from the hospital records.

RESULTS

At the time of diagnosis, 71 (3.57%) of 1985 primary lung cancer patients were 45 years old, and 42 (59.2%) male and 29 (40.8%) female patients with a mean age of 39.9 were evaluated. Most of the patients were diagnosed with advanced-stage lung cancer, 55 (77.5%) of them were in stage IV. PET CT showed that the standard intake value (SUV) of 11.1 tended to be high. Multiple organ metastases were detected in 57 patients (80.3%). EGFR (epidermal growth factor receptor) mutation was positive in 13 patients (18.3%), ALK (anaplastic lymphoma kinase) mutation was positive in 13 patients (18.3%) and ROS (c-ros) mutation oncogene was positive in 2 (2.8%) patients. Surgical operation was performed in 21 (29.6%), radiotherapy was given to 29 (40.8%), chemotherapy to 48 (67.6%) and targeted therapy to 22 (31.0%) patients. The mean overall survival of the patients was 16 months. Within 1 year, 41 (57.7%) patients died.

CONCLUSION

In our study, significant efficacy of age, gender distribution, smoking, metastasis, ALK positivity, presence of chemotherapy, targeted therapy and surgical treatment was observed in young adenocarcinoma patients. The molecular properties of lung adenocarcinoma in young patients differ from those in the general population, and major driver genes are major factors influencing tumour differentiation and prognosis. In our study, we aimed to explain the molecular properties and results of pulmonary adenocarcinoma. In the future, we will provide constructive recommendations for the prevention and treatment of young patients.

Genetic polymorphisms in the mEH gene in relation to tobacco smoking: role in lung cancer susceptibility and survival in north Indian patients with lung cancer undergoing platinum-based chemotherapy

Aim: Epoxide hydrolase is involved in oxidative defenses and is responsible for the activation of carcinogens. The relationship between EPHX1 polymorphisms (Tyr¹¹³His and His¹³⁹Arg) and overall survival (OS) and lung cancer (LC) risk was investigated. Methods: The study comprised 550 cases and 550 controls. Genotyping and statistical analysis were applied. Results: The variant genotypes of EPHX1 polymorphisms exhibited no association with LC risk. The Tyr¹¹³His polymorphism exhibited twofold increased odds of lymph node invasion (p = 0.04). The Tyr/His genotype is a risk factor for smokers. Subjects carrying the combined genotype for His¹³⁹Arg showed better median survival time (MST) and the heterozygous genotype revealed better MST in the case of small-cell lung cancer (SCLC; 11.30 vs 6.73 months; log-rank test: p = 0.02). The heterozygous genotype (His139Arg) had longer MST in patients receiving cisplatin/carboplatin and irinotecan (11.30 vs 7.23; log-rank test: p = 0.007) Conclusion: The Tyr¹¹³His polymorphism is associated with LC risk in smokers and is a potential prognostic factor for OS in patients with SCLC after irinotecan.

Association of Genetic Polymorphisms in Oxidative Stress and Inflammation Pathways with Glaucoma Risk and Phenotype

Oxidative stress and neuroinflammation are involved in the pathogenesis and progression of glaucoma. Our aim was to evaluate the impact of selected single-nucleotide polymorphisms in inflammation and oxidative stress genes on the risk of glaucoma, the patients’ clinical characteristics and the glaucoma phenotype. In total, 307 patients with primary open-angle glaucoma or ocular hypertension were enrolled. The control group included 339 healthy Slovenian blood donors. DNA was isolated from peripheral blood. Genotyping was performed for SOD2 rs4880, CAT rs1001179, GPX1 rs1050450, GSTP1 rs1695, GSTM1 gene deletion, GSTT1 gene deletion, IL1B rs1143623, IL1B rs16944, IL6 rs1800795 and TNF rs1800629. We found a nominally significant association of GSTM1 gene deletion with decreased risk of ocular hypertension and a protective role of IL1B rs16944 and IL6 rs1800629 in the risk of glaucoma. The CT and TT genotypes of GPX1 rs1050450 were significantly associated with advanced disease, lower intraocular pressure and a larger vertical cup–disc ratio. In conclusion, genetic variability in IL1B and IL6 may be associated with glaucoma risk, while GPX and TNF may be associated with the glaucoma phenotype. In the future, improved knowledge of these pathways has the potential for new strategies and personalised treatment of glaucoma.

The impact of catalase and glutathione peroxidase-1 genetic polymorphisms on their enzyme activities among Egyptian patients with keratoconus

BACKGROUND

Elevated oxidative stress plays a significant role in pathophysiology of keratoconus (KC). Polymorphisms of the antioxidant enzymes as CAT and GPX-1 might alter their antioxidant enzyme capacities leading to increase in the oxidative damage induced KC.

AIM

To analyze the impact of CAT rs7943316 A/T and GPX-1 rs1050450 C/T single nucleotide polymorphisms (SNPs) on the risk and severity of KC among a group of Egyptian population.

SUBJECT & METHODS

CAT rs7943316 and GPX-1 rs1050450 SNPs were examined using polymerase chain reaction-restriction fragment length polymorphism in 100 control subjects and 150 KC patients [50 patients (KC stages 1&2), 50 patients (KC stage 3) and 50 patients (KC stage 4)].

RESULTS

Patients with TT genotype of CAT rs7943316 were at high risk of developing KC. T allele of GPX-1 rs1050450 was significantly associated with KC risk (P ˂0.001). The frequency of CAT TT genotype and T allele was significantly higher among severe stages of KC compared to mild and moderate stages. GPX-1 T allele frequency was significantly higher among severe stages of KC compared to mild and moderate stages. A very significant decrease in the antioxidant enzyme activities was observed in association with these SNPs. Age of the patients, CAT and GPX-1 SNPs as well as their enzyme activities were independent predictors of KC severity.

CONCLUSION

Our study suggests that CAT (rs7943316) and GPX-1 (rs1050450) SNPs act as independent predictors for different grades of KC and that these SNPs might have a role in the pathogenesis of the disease.

Association of Promoter Region Polymorphisms of IL-10 Gene with Susceptibility to Lung Cancer: Systematic Review and Meta-Analysis

Objective: Epidemiological studies have suggested that the promoter region polymorphisms of interleukin-10 (IL-10) gene may be associated with an increased risk of lung cancer. However, those studies results are controversial. Thus, a comprehensive meta-analysis was performed to evaluate the association of promoter region polymorphisms of IL-10 gene with susceptibility to lung cancer. Methods: a comprehensive search of PubMed, EMBASE, and CNKI databases was performed to find all eligible studies up to September 15, 2018. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of such association. Results: A total number of 19 case-control studies with 4084 cases and 6,131 controls were selected. The overall meta-analysis results showed that the -592A>C polymorphism was significantly associated with lung cancer risk under four genetic models, i.e., allele (CT vs. TT: OR= 1.17, 95% CI 1.01-1.35, p=0.02), homozygote (CC vs. AA: OR= 1.64, 95% CI 1.29-2.02, p≤0.001), heterozygote (CA vs. AA: OR= 1.26, 95% CI 1.06-1.50, p≤0.001), and dominant (CC+CA vs. AA: OR= 1.31, 95% CI 1.11-1.54, p=0.001). However, there was no significant association between -819T>C and -1082A>G polymorphisms of IL-10 and lung cancer risk. Similarly, subgroup analyses by ethnicity detected significant association between IL-10 -592A>C and lung cancer among Asians and Caucasians. Conclusions: Our meta-analysis suggests that the IL-10 -592A>C polymorphism might be risk factor for lung cancer, especially among Asian and Caucasians. In contrast, the IL-10 -819T>C and -1082A>G polymorphisms are not significantly associated with increased risk of lung cancer.

Genetic polymorphism in selenoprotein P modifies the response to selenium-rich foods on blood levels of selenium and selenoprotein P in a randomized dietary intervention study in Danes

Background

Selenium is an essential trace element and is suggested to play a role in the etiology of a number of chronic diseases. Genetic variation in genes encoding selenoproteins, such as selenoprotein P and the glutathione peroxidases, may affect selenium status and, thus, individual susceptibility to some chronic diseases. In the present study, we aimed to (1) investigate the effect of mussel and fish intake on glutathione peroxidase enzyme activity and (2) examine whether single nucleotide polymorphisms in the GPX1, GPX4, and SELENOP genes modify the effect of mussel and fish intake for 26 weeks on whole blood selenium, plasma selenoprotein P concentrations, and erythrocyte GPX enzyme activity in a randomized intervention trial in Denmark.

Results

CC homozygotes of the SELENOP/rs3877899 polymorphism who consumed 1000 g fish and mussels per week for 26 consecutive weeks had higher levels of both selenoprotein P (difference between means - 4.68 ng/mL (95% CI - 8.49, - 0.871)) and whole blood selenium (difference between means - 5.76 (95% CI - 12.5, 1.01)) compared to fish and mussel consuming T-allele carriers although the effect in whole blood selenium concentration was not statistically significant.

Conclusions

Our study indicates that genetically determined variation in SELENOP leads to different responses in expression of selenoproteins following consumption of selenium-rich foods. This study also emphasizes the importance of taking individual aspects such as genotypes into consideration when assessing risk in public health recommendations.

Analysis of the Clinicopathological Characteristics and Risk Factors in Patients with Lung Cancer and Chronic Obstructive Pulmonary Disease

OBJECTIVE

To investigate the clinicopathological characteristics and risk factors in patients with lung cancer and COPD.

MATERIALS AND METHODS

We retrospectively reviewed the clinical data of 282 patients with lung cancer, including 174 and 108 patients with and without COPD, respectively. Information on age, sex, smoking status, and histologic type was obtained from medical records.

RESULTS

Lung cancer patients with COPD and those with the chronic bronchitis (CB) phenotype had higher smoking indices compared to those without COPD (723.95 ± 631.48 and 920.95 ± 712.93 versus 418.40 ± 506.84; P = 0.010; P = 0.001, resp.), and current smokers accounted for significantly higher proportions of lung cancer patients with COPD and the CB phenotype versus without COPD (51.15% and 63.74% versus 35.19%; P = 0.009; P = 0.001, resp.). Adenocarcinoma was significantly more common in lung cancer patients without versus with COPD (48.15% versus 35.63%; P = 0.037), whereas small cell lung cancer was more common in patients with COPD (23.56% versus 13.89%). Among patients with COPD, male sex (odds ratio [OR], 19.946; P < 0.001), current smokers (OR: 6.588; P = 0.001), and age ≥ 75 years (OR: 2.670; P = 0.008) were identified as high-risk factors.

CONCLUSION

The risk factors for COPD among lung cancer patients were age ≥ 75 years, current smokers with the CB phenotype, and male sex.

Association between glutathione peroxidase-1 (GPX1) Rs1050450 polymorphisms and cancer risk

Glutathione peroxidase (GPX), one of the antioxidant enzymes, exerts a vital role in reducing oxidative damage. GPX1 Pro198Leu (rs1050450) polymorphism has been reported in the development of several cancers, while the results were inconsistent. We thus conducted this meta-analysis to identify the association between GPX1 (rs1050450) polymorphism and cancer risk. 52 eligible publications with 60 case-control studies were included, with 21,296 cancer patients and 30,346 controls. The results in total population suggested there was a significant association between GPX1 (rs1050450) polymorphism and cancer susceptibility in part genetic models (TT vs CT+CC: OR = 1.15, 95% CI = 1.01-1.32, P = 0.042; TT vs CC: OR = 1.15, 95% CI = 1.00-1.31, P = 0.044; T vs C: OR = 1.09, 95% CI = 1.01-1.17, P = 0.02). The stratified analysis by cancer types suggested a positive correlation between GPX1 (rs1050450) polymorphism and the development of bladder cancer (TT+CT vs CC: OR = 1.72, 95% CI = 1.09-2.70, P = 0.019; TT vs CT+CC: OR = 3.56, 95% CI = 1.42-8.94, P = 0.007; TT vs CC: OR = 3.75, 95% CI = 1.41-9.94, P = 0.008; T vs C: OR = 1.941, 95% CI = 1.17-3.22, P = 0.01) as well as head and neck cancer (TT vs CT+CC: OR = 2.19, 95% CI = 1.39-3.46, P = 0.001) and brain cancer (TT+CT vs CC: OR = 1.19, 95% CI = 1.03-1.37, P = 0.018). These results support that GPX1 (rs1050450) polymorphism might be a candidate marker for cancer risk with type-specific effects.

Pathway-Based Kernel Boosting for the Analysis of Genome-Wide Association Studies

The analysis of genome-wide association studies (GWAS) benefits from the investigation of biologically meaningful gene sets, such as gene-interaction networks (pathways). We propose an extension to a successful kernel-based pathway analysis approach by integrating kernel functions into a powerful algorithmic framework for variable selection, to enable investigation of multiple pathways simultaneously. We employ genetic similarity kernels from the logistic kernel machine test (LKMT) as base-learners in a boosting algorithm. A model to explain case-control status is created iteratively by selecting pathways that improve its prediction ability. We evaluated our method in simulation studies adopting 50 pathways for different sample sizes and genetic effect strengths. Additionally, we included an exemplary application of kernel boosting to a rheumatoid arthritis and a lung cancer dataset. Simulations indicate that kernel boosting outperforms the LKMT in certain genetic scenarios. Applications to GWAS data on rheumatoid arthritis and lung cancer resulted in sparse models which were based on pathways interpretable in a clinical sense. Kernel boosting is highly flexible in terms of considered variables and overcomes the problem of multiple testing. Additionally, it enables the prediction of clinical outcomes. Thus, kernel boosting constitutes a new, powerful tool in the analysis of GWAS data and towards the understanding of biological processes involved in disease susceptibility.

Association of Catalase and Glutathione Peroxidase 1 Polymorphisms with Chronic Hepatitis C Outcome

The hepatic damage caused by hepatitis C virus (HCV) infection is associated with the host immune response and viral regulatory factors. Catalase (CAT) and glutathione peroxidase 1 (GPX1) are antioxidant enzymes located in the peroxisomes and mitochondria, respectively, and are responsible for the control of intracellular hydrogen peroxide levels. Polymorphisms in CAT (C-262T) and GPX1 (Pro198Leu) are correlated with serum levels and enzyme activity. This study aimed to investigate the association of genetic polymorphisms of CAT C-262T (rs1001179) and GPX1 Pro198Leu (rs1050450) with different stages of liver fibrosis and development of hepatocellular carcinoma (HCC). This study included 445 patients with chronic hepatitis C, of whom 139 patients had mild fibrosis (F0-F1), 200 had moderate/severe fibrosis (F2-F4), and 106 had HCC. Genotyping of SNPs was performed by real-time PCR using TaqMan probes. The Pro/Pro genotype of GPX1 was significantly associated with fibrosis severity, HCC, Child Pugh score, and BCLC staging. Additionally, patients carrying both CT+TT genotypes in the CAT gene and the Pro/Pro genotype in the GPX1 gene had higher risk for developing moderate/severe fibrosis or HCC (p = 0.009, OR 2.40 and p = 0.002, OR 3.56, respectively). CAT and GPX1 polymorphisms may be implicated in the severity of liver fibrosis and HCC caused by HCV.

Interplay between Superoxide Dismutase, Glutathione Peroxidase, and Peroxisome Proliferator Activated Receptor Gamma Polymorphisms on the Risk of End-Stage Renal Disease among Han Chinese Patients

Background. Single nucleotide polymorphisms (SNPs) of antioxidants, including superoxide dismutase 2 (SOD2) and glutathione peroxidase 1 (GPX1), play an important role in the risk for cancer and metabolic disorders. However, little is known regarding the effect of antioxidant SNPs on renal events. Methods. We prospectively enrolled multicenter patients with end-stage renal disease (ESRD) and those without chronic kidney disease (CKD) of Han Chinese origin, with SOD2 (Val16Ala), GPX1 (Pro197Leu), and PPAR-γ (Pro12Ala, C161T) genotyped. Multiple regression analyses were conducted to evaluate the significant risk determinants for ESRD. Results. Compared to ESRD patients, non-CKD subjects were more likely to have T allele at SOD2 Val16Ala (p = 0.036) and CC genotype at PPAR-γ Pro12Ala (p = 0.028). Regression analysis showed that TT genotype of SOD2 Val16Ala conferred significantly lower ESRD risk among patients without diabetes (odds ratio 0.699; p = 0.018). GPX1 SNP alone did not alter the risk. We detected significant interactions between SNPs including PPAR-γ Pro12Ala, C161T, and GPX1 regarding the risk of ESRD. Conclusion. This is the first and largest study on the association between adverse renal outcomes and antioxidant SNPs among Han Chinese population. Determination of SOD2 and PPAR-γ SNPs status might assist in ESRD risk estimation.

The relationship between COPD and lung cancer

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COPD is a risk factor for lung cancer beyond their shared aetiology.

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Both are driven by oxidative stress.

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Both are linked to cellular aging, senescence and telomere shortening.

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Both have been linked to genetic predisposition.

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Both show altered epigenetic regulation of gene expression.

Both COPD and lung cancer are major worldwide health concerns owing to cigarette smoking, and represent a huge, worldwide, preventable disease burden. Whilst the majority of smokers will not develop either COPD or lung cancer, they are closely related diseases, occurring as co-morbidities at a higher rate than if they were independently triggered by smoking.

Lung cancer and COPD may be different aspects of the same disease, with the same underlying predispositions, whether this is an underlying genetic predisposition, telomere shortening, mitochondrial dysfunction or premature aging. In the majority of smokers, the burden of smoking may be dealt with by the body’s defense mechanisms: anti-oxidants such as superoxide dismutases, anti-proteases and DNA repair mechanisms. However, in the case of both diseases these fail, leading to cancer if mutations occur or COPD if damage to the cell and proteins becomes too great.

Alternatively COPD could be a driving factor in lung cancer, by increasing oxidative stress and the resulting DNA damage, chronic exposure to pro-inflammatory cytokines, repression of the DNA repair mechanisms and increased cellular proliferation. Understanding the mechanisms that drive these processes in primary cells from patients with these diseases along with better disease models is essential for the development of new treatments.

Selenium and chronic diseases: a nutritional genomics perspective

Mechanistic data have revealed a key role for selenium (Se) and selenoproteins in biological pathways known to be altered in multifactorial diseases, such as cellular maintenance, response to oxidative stress and correct protein folding. Although epidemiological studies indicate that low Se intake is linked to increased risk for various chronic diseases, supplementation trials have given confusing outcomes, suggesting that additional genetic factors could affect the relationship between Se and health. Genetic data support this hypothesis, as risk for several chronic diseases, in particular cancer, was linked to a number of single nucleotide polymorphisms (SNP) altering Se metabolism, selenoprotein synthesis or activity. Interactions between SNPs in selenoprotein genes, SNPs in related molecular pathways and biomarkers of Se status were found to further modulate the genetic risk carried by the SNPs. Taken together, nutritional genomics approaches uncovered the potential implication of some selenoproteins as well as the influence of complex interactions between genetic variants and Se status in the aetiology of several chronic diseases. This review discusses the results from these genetic associations in the context of selenoprotein functions and epidemiological investigations and emphasises the need to assess in future studies the combined contribution of Se status, environmental stress, and multiple or individual SNPs to disease risk.

Effect of smoking on survival from non-small cell lung cancer: a retrospective Veterans' Affairs Central Cancer Registry (VACCR) cohort analysis

Although a well-established risk factor for lung cancer, the impact of smoking on the survival of non-small cell lung cancer (NSCLC) is not well known. We performed a retrospective analysis of the Veteran's Affairs Comprehensive Cancer Registry of NSCLC patients. Smoking status was categorized as never smoker, past smoker and current smoker based on self-reported history. Multivariate analysis was performed to evaluate the impact of smoking on overall survival (OS) from NSCLC. The study population (n = 61,440) comprised predominantly of males (98 %) and Caucasians (81 %). The median age at diagnosis was 68 years (range 22-108 years). Current smokers were diagnosed with NSCLC at a younger age (65 years) compared to never smokers (71 years) and past smokers (72 years) (p < 0.001). On multivariate analysis, current smokers (n = 34,613) [Hazard ratio (HR) 1.059; 95 % confidence interval (CI) 1.012-1.108], but not past smokers (n = 23,864) (HR 1.008; 95 % CI 0.962-1.056), had worse OS for Stage III and IV NSCLC, compared to never smokers (n = 2,963). Smoking status was not prognostic in stages I and II NSCLC. Current smokers were diagnosed with NSCLC at a younger age than never smokers. Although current smoking was associated with worse prognosis, especially in stages III and IV, the impact of smoking status on OS was modest.

Quantitative assessment of the influence of EPHX1 gene polymorphisms and cancer risk: a meta-analysis with 94,213 subjects

Purpose

Previous studies investigating the association between EPHX1 polymorphisms (Tyr113His and His139Arg) and cancer risk have yielded inconsistent results. This meta-analysis was performed to derive a more precise estimation of relationship between two EPHX1 polymorphisms and risk of different types of cancer.

Methods

Data were extracted from relevant studies detected by a systematic literature search. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the strength of the association between EPHX1 polymorphisms and cancer risk.

Results

This meta-analysis carefully collected 99 studies on these two polymorphisms and cancer risk published up to March 2014, consisting of 45 studies (20,091 cases and 27,396 controls) for Tyr113His and 54 studies (19,437 cases and 27,289 controls) for His139Arg. The results in overall population did not show any significant association between these two polymorphisms and cancer risk for all genetic models. However, EPHX1 Tyr113His homozygote individuals have a significantly increased risk of cancer among Asians (homozygote model: OR =1.46, 95% CI=1.05–2.03; recessive model: OR =1.39, 95% CI =1.10–1.76) and mixed population (homozygote model: OR =1.17, 95% CI =1.02–1.34; recessive model: OR =1.17, 95% CI =1.02–1.33), but not Caucasians.

Conclusion

His/His genotype of EPHX1 Tyr113His polymorphism is a risk factor for developing caner for Asian and mixed population, while no evidence was found for the association between the EPHX1 His139Arg polymorphism and increased cancer risk.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-014-0082-9) contains supplementary material, which is available to authorized users.

Effect of Cigarette Smoking on the Clinical Outcomes of ACL Reconstruction

BACKGROUND

We compared the clinical outcomes of nonsmokers, current smokers, and former smokers following reconstruction of the anterior cruciate ligament (ACL) and investigated the association between the amount of smoking and outcomes following ACL reconstruction.

METHODS

We retrospectively reviewed the records of 251 patients who underwent unilateral ACL reconstruction with use of bone-patellar tendon-bone autograft between January 2002 and August 2009. Patients were divided into three groups according to smoking history: Group 1, nonsmokers; Group 2, current smokers; and Group 3, former smokers. Preoperative values and twenty-four-month postoperative findings were compared among the groups. The stability of the ACL was evaluated with use of the Lachman test and the pivot-shift test, and anterior translation was tested with a KT2000 arthrometer. Functional outcomes were assessed on the basis of the Lysholm score and the International Knee Documentation Committee (IKDC) subjective score and objective grade.

RESULTS

The three groups differed significantly in terms of postoperative knee translation, Lysholm score, and IKDC subjective score. The mean side-to-side difference in anterior translation (and standard deviation) was 2.08 ± 1.08 mm in Group 1 (nonsmokers), 2.65 ± 1.31 mm in Group 2 (smokers), and 2.15 ± 1.05 mm in Group 3 (former smokers) (p = 0.003). The mean Lysholm score was 90.5 ± 6.5 in Group 1, 86.0 ± 7.1 in Group 2, and 89.8 ± 6.3 in Group 3 (p < 0.001). The mean IKDC subjective score was 89.3 ± 5.1 in Group 1, 84.9 ± 7.5 in Group 2, and 88.5 ± 4.2 in Group 3 (p < 0.001). However, the difference in the IKDC subjective score among the three groups did not demonstrate a minimal clinically important difference. A dose-dependent association was noted between pack-years of exposure and postoperative anterior translation (estimate, 0.039; p = 0.015) and IKDC objective grade (odds ratio, 1.083; p = 0.002). A comparison of the three subgroups of smokers showed a significant difference in anterior translation (a mean side-to-side difference in anterior translation of 2.31 ± 1.17 mm for the light smokers, 2.60 ± 1.14 mm for the moderate smokers, and 3.29 ± 1.55 mm for the heavy smokers; p = 0.038). The three subgroups also differed significantly in terms of the proportion of cases by IKDC objective grade; among the light smokers, thirteen (42%) were grade A, fifteen (48%) were grade B, two (7%) were grade C, and one (3%) was grade D; among the moderate smokers, seven (35%) were grade A, eight (40%) were grade B, four (20%) were grade C, and one (5%) was grade D; and among the heavy smokers, one (6%) was grade A, eight (44%) were grade B, eight (44%) were grade C, and one (6%) was grade D (p = 0.013).

CONCLUSIONS

Cigarette smoking appeared to have a negative effect on subjective and objective outcomes of ACL reconstruction, and heavy smokers showed greater knee instability. Patients who had stopped smoking at least one month prior to ACL reconstruction had no significant difference in outcomes compared with patients who had never smoked.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Research status and funding trends of lung cancer biomarkers

Lung cancer is one of malignant tumors with the highest morbidity and mortality in the world. At present, research of early diagnosis, treatment, prognosis, and metastasis associated biomarkers is most active. This article reviewed the research status of lung cancer biomarkers and analyzed the funding situation in the field of lung cancer markers in recent 10 years in China and abroad, to provide a reference for the future basic and clinical translational research of lung cancer biomarkers.

eNOSI4 and EPHX1 polymorphisms affect maternal susceptibility to preeclampsia: analysis of five polymorphisms predisposing to cardiovascular disease in 279 Caucasian and 241 African women

PURPOSE

The aim of this study was to evaluate possible associations of genetic polymorphisms predisposing to cardiovascular disease with the development and/or the severity of preeclampsia.

METHODS

A two hospital-based prospective case-control study was performed in Germany and Ghana. 470 blood samples of 250 Caucasian and 220 black African have been genotyped by pyrosequencing and fragment length analysis. We evaluated the distribution of the epoxide hydrolase 1 (EPHX1) polymorphism on exon 3, the endothelial nitric oxide synthase (eNOS) polymorphisms on exon 7 and on intron 4, the angiotensinogen polymorphism on exon 2 and the estrogen receptor 1 polymorphism in intron 1.

RESULTS

74 Caucasian and 84 African were classified as preeclampsia with 27 Caucasian developing a hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome and 17 African women experiencing eclampsia. Multivariate logistic regression analysis adjusting for ethnicity, age and parity revealed for carriers of eNOSI4 VNTR4a a 1.7-fold increased (95% CI 1.10-2.711, p = 0.016) risk to develop preeclampsia and a 3.6-fold increase for carriers of the EPHX1 113Tyr (95% CI 1.366-8.750, p = 0.009) to develop severest preeclampsia.

CONCLUSION

Our finding of eNOSI4 polymorphism predisposing to preeclampsia independently of ethnicity, age and parity supports the concept of NO being involved in the endothelial disorder preeclampsia. Since EPHX1 is highly expressed in the liver, can interact with various signaling pathways and is involved in central nervous system disorders, the association of EPHX1 polymorphism with the HELLP syndrome and eclampsia may hint to EPHX being a further key player in the pathogenesis of preeclampsia.

The rs1050450 C > T polymorphism of GPX1 is associated with the risk of bladder but not prostate cancer: evidence from a meta-analysis

Glutathione peroxidase (GPX) is an endogenous antioxidant enzyme counteracting oxidative stress. Accumulating evidence has demonstrated that the GPX1 rs1050450 C > T polymorphism may modulate cancer risk, but the association of GPX1 rs1050450 polymorphism with bladder cancer (BC) and prostate cancer (PCa) is still inconclusive. This meta-analysis was designed to determine the exact association of GPX1 rs1050450 C > T polymorphism with the risk of bladder cancer and prostate cancer. Odds ratios (ORs) and 95% confidence intervals (CI) were calculated to estimate the association strength. Databases of PubMed, EMBASE, and China National Knowledge Infrastructure were searched to retrieve eligible studies. In total, ten eligible studies with 6,194 participants were included. By pooling all eligible studies, we found that carriers of the variant T allele were associated with a significantly increased risk of urinary tract cancer (T vs. C: OR = 1.459 and 95% CI, 1.086-1.962; CT/TT vs. CC: OR = 1.411 and 95 % CI, 1.053-1.891). In stratified analysis, we observed that the rs1050450 C > T polymorphism was significantly associated with an increased risk of BC (T vs. C: OR = 2.111 and 95% CI, 1.020-4.368; CT/TT vs. CC: OR = 1.876 and 95% CI, 1.011-3.480), while the association was not significant for PCa. Egger's test and Begg's test revealed no publication bias. The present meta-analysis provides evidence that the GPX1 rs1050450 C > T polymorphism leads to an increased risk of BC but not the risk of PCa.

A low selenium level is associated with lung and laryngeal cancers

Purpose

It has been suggested that selenium deficiency is a risk factor for several cancer types. We conducted a case-control study in Szczecin, a region of northwestern Poland, on 95 cases of lung cancer, 113 cases of laryngeal cancer and corresponding healthy controls.

Methods

We measured the serum level of selenium and established genotypes for four variants in four selenoprotein genes (GPX1, GPX4, TXNRD2 and SEP15). Selenium levels in the cases were measured after diagnosis but before treatment. We calculated the odds of being diagnosed with lung or laryngeal cancer, conditional on selenium level and genotype.

Results

Among lung cancer cases, the mean selenium level was 63.2 µg/l, compared to a mean level of 74.6 µg/l for their matched controls (p<0.0001). Among laryngeal cancer cases, the mean selenium level was 64.8 µg/l, compared to a mean level of 77.1 µg/l for their matched controls (p<0.0001). Compared to a serum selenium value below 60 µg/l, a selenium level above 80 µg/l was associated with an odds ratio of 0.10 (95% CI 0.03 to 0.34; p = 0.0002) for lung cancer and 0.23 (95% CI 0. 09 to 0.56; p = 0.001) for laryngeal cancer. In analysis of four selenoprotein genes we found a modest evidence of association of genetic variant in GPX1 with the risk of lung and laryngeal cancers.

Conclusion

A selenium level below 60 µg/l is associated with a high risk of both lung and laryngeal cancer.

Association between microsomal epoxide hydrolase 1 T113C polymorphism and susceptibility to lung cancer

Previous case-control studies assessing the association between microsomal epoxide hydrolase 1 (EPHX1) T113C and susceptibility to lung cancer reported conflicting results. Thus, a systemic review and meta-analysis of published studies were performed to assess the possible association. PubMed and Embase databases were searched for all eligible studies. The strength of the association between EPHX1 T113C polymorphism and lung cancer risk was estimated by the pooled odds ratios (ORs) with its 95 % confidence interval. Twenty-four individual case-control studies involving a total of 4,970 lung cancer cases and 8,917 controls were finally included into the meta-analysis. When all 24 studies were included into the meta-analysis, the pooled results suggested that there was no association between EPHX1 T113C polymorphism and lung cancer risk under all four comparison models, and all P values for the pooled ORs were more than 0.05. In the subgroup analysis of Caucasians, the pooled results suggested that EPHX1 T113C polymorphism was associated with decreased risk of lung cancer under all four comparison models, and all P values for the pooled ORs were less than 0.05. However, in the subgroup analysis of Asians, the pooled results suggested that EPHX1 T113C polymorphism was associated with increased risk of lung cancer under three comparison models, and all P values for the pooled ORs were less than 0.05. There was no risk of publication bias. This current meta-analysis suggests that EPHX1 T113C polymorphism is associated with lung cancer risk, and there is an obvious race-specific effect in the association.

GPX1 gene Pro200Leu polymorphism, erythrocyte GPX activity, and cancer risk

A meta-analysis was conducted to assess the effect of glutathione peroxidase1 (GPX1) gene Pro200Leu (rs1050450) polymorphism on cancer risk. A comprehensive search was performed to identify all studies on the association of GPX1 gene Pro200Leu polymorphism with cancer risk. The fixed or random effect pooled measure was selected based on homogeneity test among studies. Heterogeneity among studies was evaluated using the I (2). Potential sources of between-study heterogeneity were explored by meta-regression and the sensitivity analysis. Publication bias was estimated using Egger's linear regression test. 35 published articles with 36 results were identified involving 16,920 cases and 19,946 controls. Results from the articles that both obeyed Hardy-Weinberg equilibrium in controls and met high quality design, showed no significant association of GPX1 gene Pro200Leu polymorphism with cancer risk in any of dominant (OR = 1.05, 95 %CI = 0.98-1.12), recessive (OR = 1.04 (0.95-1.13), and TT versus CC (OR = 1.05, 95 %CI = 0.97-1.15) models, and the findings were consistent considering the stratified analysis by cancer type. However, multivariate-adjusted ORs from articles that both obeyed Hardy-Weinberg equilibrium in controls and met high quality design, showed a significant association considering dominant (OR = 1.22, 95 %CI = 1.06-1.41), TT versus CC (OR = 1.16, 95 %CI = 1.02-1.32) models, and a marginally significant association was found considering TC versus CC (OR = 1.11, 95 %CI = 0.99-1.25) model. And compared with the CC genotype, the erythrocyte GPX activity was significantly lower for TT genotype: the standardized mean difference (SMD) = -0.37, 95 %CI = (-0.624, -0.118), and CT genotype: SMD = -0.19, 95 %CI = (-0.37, -0.002). The association of GPX1 gene Pro200Leu polymorphism with cancer risk might be influenced by confounders.

Drug Resistance Mechanisms in Non-Small Cell Lung Carcinoma

Lung cancer is the most commonly diagnosed cancer in the world. “Driver” and “passenger” mutations identified in lung cancer indicate that genetics play a major role in the development of the disease, progression, metastasis and response to therapy. Survival rates for lung cancer treatment have remained stagnant at ~15% over the past 40 years in patients with disseminated disease despite advances in surgical techniques, radiotherapy and chemotherapy. Resistance to therapy; either intrinsic or acquired has been a major hindrance to treatment leading to great interest in studies seeking to understand and overcome resistance. Genetic information gained from molecular analyses has been critical in identifying druggable targets and tumor profiles that may be predictors of therapeutic response and mediators of resistance. Mutated or overexpressed epidermal growth factor receptor (EGFR) and translocations in the echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) genes (EML4-ALK) are examples of genetic aberrations resulting in targeted therapies for both localized and metastatic disease. Positive clinical responses have been noted in patients harboring these genetic mutations when treated with targeted therapies compared to patients lacking these mutations. Resistance is nonetheless a major factor contributing to the failure of targeted agents and standard cytotoxic agents. In this review, we examine molecular mechanisms that are potential drivers of resistance in non-small cell lung carcinoma, the most frequently diagnosed form of lung cancer. The mechanisms addressed include resistance to molecular targeted therapies as well as conventional chemotherapeutics through the activity of multidrug resistance proteins.

Selenoproteins and Cancer Prevention

The discovery of multiple selenoproteins has raised tantalizing questions about their role in maintaining normal cellular function. Unfortunately, many of these remain inadequately investigated. While they have a role in maintaining redox balance, other functions are becoming increasingly recognized. As the roles of these selenoproteins are further characterized, a better understanding of the true physiological significance of this trace element will arise. This knowledge will be essential in defining optimum intakes to achieve cellular homeostasis in order to optimize health, including a reduction in cancer, for diverse populations. Human variation in the response to selenium likely reflects significant interactions between the type and amounts of selenium consumed with the genome and a host of environmental factors including the totality of the diet, as discussed in this review.

Relationships between single nucleotide polymorphisms of antioxidant enzymes and disease

The presence and progression of numerous diseases have been linked to deficiencies in antioxidant systems. The relationships between single nucleotide polymorphisms (SNPs) arising from specific antioxidant enzymes and diseases associated with elevated oxidative stress have been studied with the rationale that they may be useful in screening for diseases. The purpose of this narrative review is to analyse evidence from these studies. The antioxidant enzyme SNPs selected for analysis are based on those most frequently investigated in relation to diseases in humans: superoxide dismutase (SOD2) Ala16Val (80 studies), glutathione peroxidise (GPx1) Pro197Leu (24 studies) and catalase C-262T (22 studies). Although the majority of evidence supports associations between the SOD2 Ala16Val SNP and diseases such as breast, prostate and lung cancers, diabetes and cardiovascular disease, the presence of the SOD2 Ala16Val SNP confers only a small, clinically insignificant reduction (if any) in the risk of these diseases. Other diseases such as bladder cancer, liver disease, nervous system pathologies and asthma have not been consistently related to this SOD SNP genotype. The GPx1 Pro197Leu and catalase C-262T SNP genotypes have been associated with breast cancer, but only in a small number of studies. Thus, currently available evidence suggests antioxidant enzyme SNP genotypes are not useful for screening for diseases in humans.

Heritability of radiation response in lung cancer families

Radiation sensitivity is assumed to be a cancer susceptibility factor due to impaired DNA damage signalling and repair. Relevant genetic factors may also determine the observed familial aggregation of early onset lung cancer. We investigated the heritability of radiation sensitivity in families of 177 Caucasian cases of early onset lung cancer. In total 798 individuals were characterized for their radiation-induced DNA damage response. DNA damage analysis was performed by alkaline comet assay before and after in vitro irradiation of isolated lymphocytes. The cells were exposed to a dose of 4 Gy and allowed to repair induced DNA-damage up to 60 minutes. The primary outcome parameter Olive Tail Moment was the basis for heritability estimates. Heritability was highest for basal damage (without irradiation) 70% (95%-CI: 51%-88%) and initial damage (directly after irradiation) 65% (95%-CI: 47%-83%) and decreased to 20%-48% for the residual damage after different repair times. Hence our study supports the hypothesis that genomic instability represented by the basal DNA damage as well as radiation induced and repaired damage is highly heritable. Genes influencing genome instability and DNA repair are therefore of major interest for the etiology of lung cancer in the young. The comet assay represents a proper tool to investigate heritability of the radiation sensitive phenotype. Our results are in good agreement with other mutagen sensitivity assays.

GPx-1 polymorphism (rs1050450) contributes to tumor susceptibility: evidence from meta-analysis

PURPOSE

Accumulating evidences implicate the selenium-containing cytosolic glutathione peroxidase, GPx-1, as a determinant of cancer risk and a mediator of the chemopreventive properties of selenium. Since the identification of a well-characterized functional polymorphism named Pro198Leu (rs1050450 C>T) in GPx-1, abundant studies have evaluated the association between Pro198Leu polymorphism and tumor risk in diverse population. But, the available results are conflicting.

METHODS

To derive a more precise estimation, we performed a meta-analysis based on 14,372 cases with different tumor types and 18,081 controls from 31 published case-control studies. Published literature from PubMed was retrieved. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of the association.

RESULTS

Overall, the results indicated that individuals who carried variant Leu allele (Pro/Leu and Leu/Leu) were associated with an increased cancer risk [odds ratio (OR) = 1.12, 95% confidence interval (CI) = 1.02-1.23] in a dominant genetic model. In further subgroup analyses, the increased risk of cancer was observed in subgroup of Asians and sample size more than 500 subjects.

CONCLUSION

These results suggest that the GPx-1 Pro198Leo polymorphism contributes to cancer susceptibility through a disturbed antioxidant balance.

Glutathione peroxidase-1 in health and disease: from molecular mechanisms to therapeutic opportunities

Reactive oxygen species, such as superoxide and hydrogen peroxide, are generated in all cells by mitochondrial and enzymatic sources. Left unchecked, these reactive species can cause oxidative damage to DNA, proteins, and membrane lipids. Glutathione peroxidase-1 (GPx-1) is an intracellular antioxidant enzyme that enzymatically reduces hydrogen peroxide to water to limit its harmful effects. Certain reactive oxygen species, such as hydrogen peroxide, are also essential for growth factor-mediated signal transduction, mitochondrial function, and maintenance of normal thiol redox-balance. Thus, by limiting hydrogen peroxide accumulation, GPx-1 also modulates these processes. This review explores the molecular mechanisms involved in regulating the expression and function of GPx-1, with an emphasis on the role of GPx-1 in modulating cellular oxidant stress and redox-mediated responses. As a selenocysteine-containing enzyme, GPx-1 expression is subject to unique forms of regulation involving the trace mineral selenium and selenocysteine incorporation during translation. In addition, GPx-1 has been implicated in the development and prevention of many common and complex diseases, including cancer and cardiovascular disease. This review discusses the role of GPx-1 in these diseases and speculates on potential future therapies to harness the beneficial effects of this ubiquitous antioxidant enzyme.

Genetically lowered microsomal epoxide hydrolase activity and tobacco-related cancer in 47,000 individuals

BACKGROUND

Two functional polymorphisms of the microsomal epoxide hydrolase (mEH) gene (EPHX1), Tyr113His (rs1051740) and His139Arg (rs2234922), have variably been found to influence susceptibility to various cancer forms. We tested whether genetically lowered mEH activity affects risk of developing cancer in the general population.

METHODS

We genotyped 47,089 individuals from the Danish general population for the Tyr113His and His139Arg polymorphisms in the EPHX1 gene and divided them into groups with predicted fast, intermediate, and slow mEH activity. Using Cox proportional hazards models, we calculated HRs for 26 individual cancer diagnoses and for groups of any cancer, tobacco-related cancers, estrogen-related female cancers, and other cancers.

RESULTS

Of the 47,089 individuals, 7,590 experienced a cancer event, and of these, 1,466 were tobacco-related. After multifactorial adjustment, the HRs (95% CI) for tobacco-related cancer were 1.1 (0.8-1.5) and 1.5 (1.1-2.0) in individuals with intermediate and slow mEH activity versus individuals with the fast phenotype (P(trend) = 0.003). The corresponding HRs among ever-smokers were 1.1 (0.8-1.5) and 1.5 (1.1-2.0; P(trend) = 0.003), whereas HRs among never-smokers did not differ from 1.0.

CONCLUSIONS

Our results indicate that genetically lowered mEH activity is associated with increased risk of developing tobacco-related cancer among smokers in the general population; however, additional studies are needed to confirm our findings.

IMPACT

To our knowledge, this is the largest study to investigate the association of mEH phenotype and genotype with tobacco-related cancers combined in the general population.

Putative EPHX1 enzyme activity is related with risk of lung and upper aerodigestive tract cancers: a comprehensive meta-analysis

Background

EPHX1 is a key enzyme in metabolizing some exogenous carcinogens such as products of cigarette-smoking. Two functional polymorphisms in the EPHX1 gene, Tyr113His and His139Arg can alter the enzyme activity, suggesting their possible association with carcinogenesis risk, particularly of some tobacco-related cancers.

Methodology/Principal Findings

A comprehensive systematic review and meta-analysis was performed of available studies on these two polymorphisms and cancer risk published up to November 2010, consisting of 84 studies (31144 cases and 42439 controls) for Tyr113His and 77 studies (28496 cases and 38506 controls) for His139Arg primarily focused on lung cancer, upper aerodigestive tract (UADT) cancers (including oral, pharynx, larynx and esophagus cancers), colorectal cancer or adenoma, bladder cancer and breast cancer. Results showed that Y113H low activity allele (H) was significantly associated with decreased risk of lung cancer (OR = 0.88, 95%CI = 0.80–0.96) and UADT cancers (OR = 0.86, 95%CI = 0.77–0.97) and H139R high activity allele (R) with increased risk of lung cancer (OR = 1.18, 95%CI = 1.04–1.33) but not of UADT cancers (OR = 1.05, 95%CI = 0.93–1.17). Pooled analysis of lung and UADT cancers revealed that low EPHX1 enzyme activity, predicted by the combination of Y113H and H139R showed decreased risk of these cancers (OR = 0.83, 95%CI = 0.75–0.93) whereas high EPHX1 activity increased risk of the cancers (OR = 1.20, 95%CI = 0.98–1.46). Furthermore, modest difference for the risk of lung and UADT cancers was found between cigarette smokers and nonsmokers both in single SNP analyses (low activity allele H: OR = 0.77/0.85 for smokers/nonsmokers; high activity allele R: OR = 1.20/1.09 for smokers/nonsmokers) and in combined double SNP analyses (putative low activity: OR = 0.73/0.88 for smokers/nonsmokers; putative high activity: OR = 1.02/0.93 for smokers/ nonsmokers).

Conclusions/Significance

Putative low EPHX1 enzyme activity may have a potential protective effect on tobacco-related carcinogenesis of lung and UADT cancers, whereas putative high EPHX1 activity may have a harmful effect. Moreover, cigarette-smoking status may influence the association of EPHX1 enzyme activity and the related cancer risk.

Age specific responses to acute inhalation of diffusion flame soot particles: cellular injury and the airway antioxidant response

Current studies of particulate matter (PM) are confounded by the fact that PM is a complex mixture of primary (crustal material, soot, metals) and secondary (nitrates, sulfates, and organics formed in the atmosphere) compounds with considerable variance in composition by sources and location. We have developed a laboratory-based PM that is replicable, does not contain dust or metals and that can be used to study specific health effects of PM composition in animal models. We exposed both neonatal (7 days of age) and adult rats to a single 6-h exposure of laboratory generated fine diffusion flame particles (DFP; 170 µg/m(3)), or filtered air. Pulmonary gene and protein expression as well as indicators of cytotoxicity were evaluated 24 h after exposure. Although DFP exposure did not alter airway epithelial cell composition in either neonates or adults, increased lactate dehydrogenase activity was found in the bronchoalveolar lavage fluid of neonates indicating an age-specific increase in susceptibility. In adults, 16 genes were differentially expressed as a result of DFP exposure whereas only 6 genes were altered in the airways of neonates. Glutamate cysteine ligase protein was increased in abundance in both DFP exposed neonates and adults indicating an initiation of antioxidant responses involving the synthesis of glutathione. DFP significantly decreased catalase gene expression in adult airways, although catalase protein expression was increased by DFP in both neonates and adults. We conclude that key airway antioxidant enzymes undergo changes in expression in response to a moderate PM exposure that does not cause frank epithelial injury and that neonates have a different response pattern than adults.