Polymorphisms in GSTM1, CYP1A1, CYP2E1, and CYP2D6 are associated with susceptibility and chemotherapy response in non-small-cell lung cancer patients

Gene regulatory networks reveal sex difference in lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) has been observed to have significant sex differences in incidence, prognosis, and response to therapy. However, the molecular mechanisms responsible for these disparities have not been investigated extensively.

METHODS

Sample-specific gene regulatory network methods were used to analyze RNA sequencing data from non-cancerous human lung samples from The Genotype Tissue Expression Project (GTEx) and lung adenocarcinoma primary tumor samples from The Cancer Genome Atlas (TCGA); results were validated on independent data.

RESULTS

We found that genes associated with key biological pathways including cell proliferation, immune response and drug metabolism are differentially regulated between males and females in both healthy lung tissue and tumor, and that these regulatory differences are further perturbed by tobacco smoking. We also discovered significant sex bias in transcription factor targeting patterns of clinically actionable oncogenes and tumor suppressor genes, including AKT2 and KRAS. Using differentially regulated genes between healthy and tumor samples in conjunction with a drug repurposing tool, we identified several small-molecule drugs that might have sex-biased efficacy as cancer therapeutics and further validated this observation using an independent cell line database.

CONCLUSIONS

These findings underscore the importance of including sex as a biological variable and considering gene regulatory processes in developing strategies for disease prevention and management.

Gene regulatory Networks Reveal Sex Difference in Lung Adenocarcinoma

Lung adenocarcinoma (LUAD) has been observed to have significant sex differences in incidence, prognosis, and response to therapy. However, the molecular mechanisms responsible for these disparities have not been investigated extensively. Sample-specific gene regulatory network methods were used to analyze RNA sequencing data from non-cancerous human lung samples from The Genotype Tissue Expression Project (GTEx) and lung adenocarcinoma primary tumor samples from The Cancer Genome Atlas (TCGA); results were validated on independent data. We observe that genes associated with key biological pathways including cell proliferation, immune response and drug metabolism are differentially regulated between males and females in both healthy lung tissue, as well as in tumor, and that these regulatory differences are further perturbed by tobacco smoking. We also uncovered significant sex bias in transcription factor targeting patterns of clinically actionable oncogenes and tumor suppressor genes, including AKT2 and KRAS. Using differentially regulated genes between healthy and tumor samples in conjunction with a drug repurposing tool, we identified several small-molecule drugs that might have sex-biased efficacy as cancer therapeutics and further validated this observation using an independent cell line database. These findings underscore the importance of including sex as a biological variable and considering gene regulatory processes in developing strategies for disease prevention and management.

Genetic Variations on Redox Control in Cardiometabolic Diseases: The Role of Nrf2

The transcription factor Nrf2 is a master regulator of multiple cytoprotective genes that maintain redox homeostasis and exert anti-inflammatory functions. The Nrf2-Keap1 signaling pathway is a paramount target of many cardioprotective strategies, because redox homeostasis is essential in cardiovascular health. Nrf2 gene variations, including single nucleotide polymorphisms (SNPs), are correlated with cardiometabolic diseases and drug responses. SNPs of Nrf2, KEAP1, and other related genes can impair the transcriptional activation or the activity of the resulting protein, exerting differential susceptibility to cardiometabolic disease progression and prevalence. Further understanding of the implications of Nrf2 polymorphisms on basic cellular processes involved in cardiometabolic diseases progression and prevalence will be helpful to establish more accurate protective strategies. This review provides insight into the association between the polymorphisms of Nrf2-related genes with cardiometabolic diseases. We also briefly describe that SNPs of Nrf2-related genes are potential modifiers of the pharmacokinetics that contribute to the inter-individual variability.

A review of the most important natural antioxidants and effective medicinal plants in traditional medicine on prostate cancer and its disorders

Herbal plants can be used to treat and prevent life-threatening diseases, such as prostate cancer, infections and other diseases. The findings from traditional medicine and the use of medicinal plants can help control and treat most problems due to prostate diseases. The aim of this study was to identify and report the most important medicinal plants that affect prostate disorders. Based on the results of the review of numerous articles indexed in the databases ISI, Scopus, PubMed, Google Scholar, etc., a number of plants have been reported to be used in the treatment and prevention of diseases, inflammation, infection, and cancer of the prostate gland. The plants include Panax ginseng, Arum palaestinum, Melissa officinalis, Syzygium paniculatum, Coptis chinensis, Embelia ribes, Scutellaria baicalensis, Tripterygium wilfordii, Salvia triloba, Ocimum tenuiflorum, Psidium guajava, Ganoderma lucidum, Litchi chinensis, Saussurea costus, Andrographis paniculata, Magnolia officinalis and Prunus africana. Phytochemical investigations have examined the therapeutic effects of medicinal plants effective on prostate cancer and their possible mechanisms of action and clinical effects as well as the use of active flavonoids in production of herbal drugs. Due to the active ingredients and important flavonoids of these plants, they can be used in production of herbal drugs that prevent and treat infections, inflammation and cancer of the prostate gland, and reduce the metastasis of prostate cancer cells, reducing the patients’ suffering and pain.

Combined effects of glutathione S-transferase M1 and T1 polymorphisms on risk of lung cancer: Evidence from a meta-analysis

Many studies have reported an association between the glutathione S-transferase M1 null and T1 null polymorphisms and lung cancer risk. However, the combined effects of GSTM1 null and GSTT1 null polymorphisms have not been reported previously. We, therefore, performed a meta-analysis to investigate the combined effects. 40 publications with 44 case–control studies were selected in the meta-analysis, including 13,706 cases and 13,093 controls. Significant association was observed between the combined effects of GSTM1 and GSTT1 polymorphisms and lung cancer risk when all the eligible studies were pooled into the meta-analysis. When we performed subgroup analysis, significantly increased lung cancer risk was observed in Caucasians (− − vs. + +: OR = 1.23, 95% CI: 1.07 to 1.41), Asians (− − vs.− +: OR = 1.24, 95% CI: 1.10 to 1.41; recessive model: OR = 1.45, 95% CI: 1.19 to 1.77; dominant model: OR = 1.53, 95% CI: 1.24 to 1.90), Indians (− − vs. + +: OR = 2.53, 95% CI: 1.61 to 3.98; recessive model: OR = 1.69, 95% CI: 1.07 to 2.67; dominant model: OR = 2.11, 95% CI: 1.36 to 3.28), hospital-based studies, and population-based studies. In summary, this meta-analysis indicates that the combined effects of the GSTM1 and GSTT1 polymorphisms are associated with increased lung cancer risk in Asians, Caucasians, and Indians.

Ethical Dilemmas in Protecting Susceptible Subpopulations From Environmental Health Risks: Liberty, Utility, Fairness, and Accountability for Reasonableness

Various U.S. laws, such as the Clean Air Act and the Food Quality Protection Act, require additional protections for susceptible subpopulations who face greater environmental health risks. The main ethical rationale for providing these protections is to ensure that environmental health risks are distributed fairly. In this article, we (1) consider how several influential theories of justice deal with issues related to the distribution of environmental health risks; (2) show that these theories often fail to provide specific guidance concerning policy choices; and (3) argue that an approach to public decision making known as accountability for reasonableness can complement theories of justice in establishing acceptable environmental health risks for the general population and susceptible subpopulations. Since accountability for reasonableness focuses on the fairness of the decision-making process, not the outcome, it does not guarantee that susceptible subpopulations will receive a maximum level of protection, regardless of costs or other morally relevant considerations.

Cytochrome P-450 Polymorphisms and Clinical Outcome in Patients with Non-Small Cell Lung Cancer

Lung cancer is an increasing worldwide public health problem. Most patients with lung cancer have non-small cell lung cancer (NSCLC). These patients are mainly treated with standard platinum-based chemotherapy. Poor response and great inter-individual variety in treatment response occurs among these patients. There is accumulating evidence to support the hypothesis that genetic polymorphisms alter the drug response and survival. Cytochrome P450 (CYP) enzymes metabolize antineoplastic drugs and are involved in drug resistance. Polymorphic CYPs have altered enzyme activities and thus they may influence the response to chemotherapy and survival in patients with lung cancer. In the current review, recent findings with respect to the role of mainly CYP1A1, CYP1B1, CYP2D6, CYP2E1 and CYP3A4 gene polymorphisms in response to chemotherapy and survival in patients with NSCLC have been provided, which could be useful for clinicians in the prognosis of these patients who are mainly treated with platinum-based chemotherapy.

Development of diagnostic model of lung cancer based on multiple tumor markers and data mining

Objective

To develop early intelligent discriminative model of lung cancer and evaluate the efficiency of diagnosis value.

Methods

Based on the genetic polymorphism profile of CYP1A1-rs1048943, GSTM1, mEH-rs1051740, XRCC1-rs1799782 and XRCC1-rs25489 and the methylations of p16 and RASSF1A gene, and the length of telomere in the peripheral blood from 200 lung cancer patients and 200 health persons, the discriminative model was established through decision tree and ANN technique.

Results

ACU of the discriminative model based on multiple tumour markers increased by about 10%; The accuracy rate of decision tree model and ANN model for testing set were 93.00% and 89.62% respectively. The ROC analysis showed the decision tree model’s AUC is 0.929 (0.894∼0.964), the ANN model’s AUC is 0.894 (0.853∼0.935). However, the classify accuracy rate and AUC of Fisher discriminatory analysis model are all about 0.7.

Conclusion

The early intelligent discriminative model of lung cancer based on multiple tumor markers and data mining techniques has a higher accuracy rate and might be useful for early diagnosis of lung cancer.

Genetic Polymorphisms and Platinum-based Chemotherapy Treatment Outcomes in Patients with Non-Small Cell Lung Cancer: A Genetic Epidemiology Study Based Meta-analysis

Data regarding genetic polymorphisms and platinum-based chemotherapy (PBC) treatment outcomes in patients with NSCLC are published at a growing pace, but the results are inconsistent. This meta-analysis integrated eligible candidate genes to better evaluate the pharmacogenetics of PBC in NSCLC patients. Relevant studies were retrieved from PubMed, Chinese National Knowledge Infrastructure and WANFANG databases. A total of 111 articles comprising 18,196 subjects were included for this study. The associations of genetic polymorphisms with treatment outcomes of PBC including overall response rate (ORR), overall survival (OS) and progression-free survival (PFS) were determined by analyzing the relative risk (RR), hazard ration (HR), corresponding 95% confidence interval (CI). Eleven polymorphisms in 9 genes, including ERCC1 rs11615 (OS), rs3212986 (ORR), XPA rs1800975 (ORR), XPD rs1052555 (OS, PFS), rs13181 (OS, PFS), XPG rs2296147 (OS), XRCC1 rs1799782 (ORR), XRCC3 rs861539 (ORR), GSTP1 rs1695 (ORR), MTHFR rs1801133 (ORR) and MDR1 rs1045642 (ORR), were found significantly associated with PBC treatment outcomes. These variants were mainly involved in DNA repair (EXCC1, XPA, XPD, XPG, XRCC1 and XRCC3), drug influx and efflux (MDR1), metabolism and detoxification (GSTP1) and DNA synthesis (MTHFR), and might be considered as potential prognostic biomarkers for assessing objective response and progression risk in NSCLC patients receiving platinum-based regimens.

Xenobiotic/drug metabolizing enzyme and TP53 polymorphisms and clinical outcome in advanced nonsmall cell lung cancer patients

BACKGROUND/AIM

The association between polymorphisms of xenobiotic/drug metabolizing enzymes and TP53 and response to chemotherapy and survival of patients with nonsmall cell lung cancer (NSCLC) are limited and inconclusive. In this study, CYP2E1*5B, CYP2E1*6, CYP2E1*7B, GSTO1 (A140D), and TP53 (Arg72Pro) polymorphisms and response to platinum-based chemotherapy and survival in 137 advanced stage NSCLC patients were investigated.

MATERIALS AND METHODS

Genetic polymorphism analyses were determined by polymerase chain reaction (PCR) coupled with restriction fragment length polymorphism (RFLP).

RESULTS

The patients with TP53 Pro/Pro variant were more likely to be resistant to chemotherapy than those with Arg/Arg variants with marginal significance (P = 0.066). We also analyzed these gene variants in combination with CYP1A1 (Ile462Val), CYP1B1 (Asn453Ser), GSTM1, GSTP1 exon 5 (Ile105Val), and GSTP1 exon 6 (Ala114Val) and GSTT1 polymorphic genes that we have previously genotyped in the same patients (Ada et al., Neoplasma, 57, 512-527, 2010). The multivariate analysis revealed that adjusted hazard ratio (HR) of death of the combined variant genotypes of TP53 (Arg72Pro, Pro72Pro) and CYP1A1 (Ile462Val, Val462Val) increased significantly as compared to wild-type genotypes (HR, 6.03; 95% CI, 1.39-26.04, P = 0.016).

CONCLUSION

These results show that combined variant genotypes of TP53 (Arg72Pro, Pro72Pro) and CYP1A1 (Ile/Val, Val/Val) are associated with worsening of survival in NSCLC patients.

Deletion of GSTM1 and GSTT1 genes and lung cancer survival: a systematic review

PURPOSE

The mechanisms of lung carcinogenesis are not fully understood. Not all smokers develop lung cancer, indicating that genetic variations and other environmental factors may play an important role in its development. The human glutathione S-transferases (GSTs) have been associated with an increased risk of lung cancer. Glutathione S-transferases are phase II biotransformation enzymes that play a role in detoxifying a wide range of exogenous agents including carcinogens but also anticarcinogenic drugs.

METHODS

We assessed the effect of allelic deletions in the GSTM1 and GSTT1 genotypes on lung cancer overall survival through a systematic review of the scientific literature after applying predefined inclusion and exclusion criteria.

RESULTS

Most of the included studies found no effect or a tendency to worse survival for individuals with deletion of GSTs.

CONCLUSIONS

Further studies are necessary to understand the magnitude of the effect of the deletion of both genes on lung cancer survival.

Association between the TP53 and CYP2E1*5B gene polymorphisms and non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the most common form of lung cancer. Genetic polymorphisms in tumour suppressor genes and genes encoding xenobiotic metabolising enzymes alter the activity of their corresponding enzymes and are important individual susceptibility factors for NSCLC. Because of the lack of information in literature, the aim of our study was to investigate the role of the tumour suppressor gene TP53 (Arg72Pro) and the xenobiotic metabolising CYP2E1*5B gene polymorphisms on the risk of NSCLC development. The study population consisted of 172 patients and 172 controls (156 men and 16 women in each group). Genetic polymorphisms were determined with real-time polymerase chain reaction (PCR) and PCR restriction fragment length polymorphism (PCR-RFLP). Multivariate analysis showed a significant association with NSCLC for the combination between the TP53 codon72 Arg/Pro and the Pro/Pro genotypes (OR 2.21, 95 % CI 1.390-3.51; p=0.001). We also analysed whether combinations of these gene variants with GSTM1, GSTT1, GSTP1 exon 5 (Ile105Val), and GSTP1 exon 6 (Ala114Val) gene polymorphisms were associated with the NSCLC risk. A significant increase in the risk was observed for the following combinations: TP53 codon72 variant with GSTM1 null (OR 2.22, 95 % CI 1.23-4.04; p=0.009), GSTT1 null (OR 2.98, 95 % CI 1.49-5.94; p=0.002), and GSTP1 (Ala114Val) variant genotypes (OR 3.38, 95 % CI 1.54-7.41; p=0.002). Further studies with larger samples are needed to verify these findings.

Pharmacogenomics of platinum-based chemotherapy sensitivity in NSCLC: toward precision medicine

Lung cancer is one of the leading causes of cancer-related death in the world. Platinum-based chemotherapy is the first-line treatment for non-small-cell lung cancer (NSCLC), however, the therapeutic efficiency varies remarkably among individuals. A large number of pharmacogenomics studies aimed to identify genetic variations which can be used to predict platinum response. Those studies are leading NSCLC treatment to the new era of precision medicine. In the current review, we provided a comprehensive update on the main recent findings of genetic variations which can be used to predict platinum sensitivity in the NSCLC patients.

The interaction between smoking and CYP1A1 MspI polymorphism on lung cancer: a meta-analysis in the Chinese population

Many studies have examined the interaction between CYP1A1 MspI gene polymorphism and smoking for the risk of lung cancer risk in Chinese, but their results have been inconsistent. Therefore, a meta-analysis was performed to ascertain this issue. PubMed, Springer Link, Ovid and other Chinese databases were searched to include all the relevant studies. Smoking status was categorised as 'smokers' and 'non-smokers.' The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using fixed or random effect model. Subgroup analyses according to ethnicity, source of control and geographical location were also conducted. This meta-analysis identified 13 studies containing 2248 lung cases and 3079 controls. Overall, a significant association between lung cancer and the variants of CYP1A1 MspI was found among smokers (type B and type C combined vs. type A: OR = 1.89, 95% CI = 1.15-3.11, P = 0.000 for heterogeneity), whereas not found among non-smokers. Similar to the overall results, stratified analyses showed that the increased risk of lung cancer was observed in population-based studies and north China among smokers (OR = 1.65, 95%CI = 1.03-2.66; OR = 2.00, 95% CI = 1.14-3.53). Our meta-analysis showed that there was an interaction between the CYP1A1 MspI and smoking on the risk of lung cancer in the Chinese population.

Impact of CYP1A1 Polymorphisms on Susceptibility to Chronic Obstructive Pulmonary Disease: A Meta-Analysis

Objective. Several studies have evaluated the association between CYP1A1 polymorphisms and the susceptibility of chronic obstructive pulmonary disease (COPD) with inconclusive results. We performed the first comprehensive meta-analysis to summarize the association between CYP1A1 polymorphisms and COPD risk. Method. A systematic literature search was conducted (up to April 2015) in five online databases: PubMed, EMBASE, China National Knowledge Infrastructure (CNKI), WeiPu, and WanFang databases. The strength of association was calculated by odds ratio (OR) and corresponding 95% confidence interval (CI). Results. Seven case-control studies with 1050 cases and 1202 controls were included. Our study suggested a significant association between the MspI polymorphism and COPD risk (CC versus TC + TT: OR = 1.57, CI: 1.09–2.26, P = 0.02; CC versus TT: OR = 1.73, CI: 1.18–2.55, P = 0.005). For the Ile/Val polymorphism, a significant association with COPD risk was observed (GG versus AG + AA: OR = 2.75, CI: 1.29–5.84, P = 0.009; GG versus AA: OR = 3.23, CI: 1.50–6.93, P = 0.003; AG versus AA: OR = 1.39, CI: 1.01–1.90, P = 0.04). Subgroup analysis indicated a significant association between the MspI variation and COPD risk among Asians (CC versus TC + TT: OR = 1.70, CI: 1.06–2.71, P = 0.03; CC versus TT: OR = 1.84, CI: 1.11–3.06, P = 0.02). Conclusion. The MspI and Ile/Val polymorphisms might alter the susceptibility of COPD, and MspI polymorphism might play a role in COPD risk among Asian population.

CYP2E1 Rsa Ι/Pst Ι polymorphism and lung cancer susceptibility: a meta-analysis involving 10,947 subjects

Many studies have examined the association between the CYP2E1 Rsa Ι/Pst Ι (rs3813867) polymorphism gene polymorphisms and lung cancer risk in various populations, but their results have been inconsistent. The PubMed and CNKI database was searched for case–control studies published up to October 2013. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. In this meta-analysis, we assessed 23 published studies involving comprising 4727 lung cancer cases and 6220 controls of the association between CYP2E1 Rsa Ι/Pst Ι polymorphism and lung cancer risk. For the homozygote c2/c2 and c2 allele carriers (c1/c2 + c2/c2), the pooled ORs for all studies were 0.73(95% CI = 0.62–0.84; P = 0.005 for heterogeneity) and 0.84 (95% CI = 0.77–0.92; P = 0.001 for heterogeneity) when compared with the homozygous wild-type genotype (c1/c1). In the stratified analysis by ethnicity, the same significantly risks were found among Asians and mixed population for both the c2 allele carriers and homozygote c2/c2. However, no significant associations were found in Caucasian population all genetic models. This updated meta-analysis suggests that CYP2E1 Rsa Ι/Pst Ι c2 allele is a decreased risk factor for the developing lung cancer among Asians and mixed population.

Updated meta-analysis of the association between CYP2E1 RsaI/PstI polymorphisms and lung cancer risk in Chinese population

BACKGROUND

A number of studies have reported relationships of CYP2E1 RsaI/PstI polymorphisms with susceptibility to lung cancer in Chinese population. However, the epidemiologic results have been conflictive rather than conclusive. The purpose of this study was to address the associations of CYP2E1 RsaI/PstI polymorphisms with lung cancer risk in Chinese population comprehensively.

MATERIALS AND METHODS

Systematic searches were conducted in the PubMed, Science Direct, Elsevier, CNKI and Chinese Biomedical Literature Databases. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of association.

RESULTS

Overall, we observed a decreased lung cancer risk among subjects carrying CYP2E1 RsaI/PstI c1/ c2 and c1/c2+c2/c2 genotypes (OR=0.76, 95%CI: 0.64-0.90 and OR=0.78, 95%CI: 0.66-0.93, respectively), as compared with subjects carrying the c1/c1 genotype. In subgroup analysis, we observed a decreased lung cancer risk among c1/c2 carriers in hospital-based studies (OR=0.81, 95%CI: 0.68-0.98) and among carriers with c1/ c2 and c1/c2+c2/c2 genotypes in population-based studies(OR=0.57, 95%CI: 0.42-0.79 and OR=0.58, 95%CI: 0.43-0.79, respectively), as compared with subjects carrying the c1/c1 genotype. Limiting the analysis to studies with controls in Hardy-Weinberg equilibrium (HWE), we similarly observed a decreased lung cancer risk among c1/c2 and c1/c2+c2/c2 carriers (OR=0.73, 95%CI: 0.60-0.88 and OR=0.73, 95%CI: 0.60-0.88, respectively), as compared with c1/c1.

CONCLUSIONS

Our results suggested that CYP2E1 RsaI/PstI c1/c2 and c1/c2+c2/c2 variants might be a protective factor for developing lung cancer in Chinese population. Further well-designed studies with larger sample size are required to verify our findings.

The association of GSTM1 deletion polymorphism with lung cancer risk in Chinese population: evidence from an updated meta-analysis

Previous studies have reported the association of glutathione S-transferase M1 (GSTM1) deletion polymorphism with genetic susceptibility of lung cancer in Chinese population. However, the results remained controversial. The aim of this study was to clarify the association of GSTM1 deletion polymorphism with lung cancer risk in Chinese population. Systematic searches were performed through the search engines of Medline/Pubmed, Web of Science, EMBASE, CNKI and Wanfang Medical Online. The pooled effects were calculated by STATA 10.0 software package and Review Manager 5.0.24. Overall, we observed an association of GSTM1 deletion polymorphism with increased lung cancer risk in Chinese population (odds ratio (OR) = 1.46, 95% confidence interval (95%CI): 1.32-1.66 for null genotype vs. present genotype) based on 53 studies including 7,833 cases and 10,353 controls. We also observed an increased risk of GSTM1 null genotype for lung cancer in stratified analyses by source of control, smoking status and histological type. The findings suggest that GSTM1 deletion polymorphism may contribute to lung cancer risk in Chinese population. Further, well-designed studies with larger sample sizes are required to verify the results.

The polymorphism of CYP2E1 Rsa I/Pst I gene and susceptibility to respiratory system cancer: a systematic review and meta-analysis of 34 studies

The purpose of this articles is to determine whether the cytochrome P450 2E1 (CYP2E1) Rsa I/Pst I gene polymorphism is correlated with respiratory system cancers. Respiratory system cancers included lung cancer, laryngeal cancer, nasopharyngeal cancer, and cancers of other respiratory organs, which are the most common malignant tumors worldwide; the significant relationship between CYP2E1 Rsa I/Pst I gene polymorphism and some respiratory system cancer have been reported, but results of some other studies are controversial. The pooled odds ratio (OR) with 95% confidence interval (CI) was calculated to assess the association. PubMed, EMBASE, Cochrane Library Databases, China National Knowledge Infrastructure, and Wanfang Database (up to July 20, 2014) were searched for all case-control studies those mainly studied the relationship between CYP2E1 Rsa I/Pst I gene polymorphism and the susceptibility of respiratory system cancer. A total of 332 articles were collected, among which 34 studies that involved 7028 cases and 9822 controls fulfilled the inclusion criteria after being assessed by 2 reviewers. When stratified by cancer site, the C2/C2 polymorphism could increase the risk of nasopharyngeal cancer under the homozygote model (C2C2 vs C1C1: OR = 1.85, 95% CI = 1.20-2.85, P = 0.005) and recessive model (C2C2 vs C1C2/C1C1: OR = 1.89, 95% CI = 1.23-2.89, P = 0.003). Protection effect was found in lung cancer in heterozygote model (C1C2 vs C1C1: OR = 0.82, 95% CI = 0.74-0.91, P < 0.001), dominant model (C1C2/C2C2 vs C1C1: OR = 0.83, 95% CI = 0.76-0.90, P < 0.001), and allele contrast model (C2 vs C1: OR = 0.85, 95% CI = 0.73-1.00, P = 0.045). With regard to ethnicity subgroup analysis, there was significant association in Asian population in heterozygote model (C1C2 vs C1C1: OR = 0.85, 95% CI = 0.78-0.94, P = 0.001), dominant model (C1C2/C2C2 vs C1C1: OR = 0.88, 95% CI = 0.81-0.95, P = 0.001), and recessive model (C2C2 vs C1C2/C1C1: OR = 1.25, 95% CI = 1.01-1.53, P = 0.036). CYP2E1 Rsa I/Pst I gene polymorphism may reduce the risk of respiratory system cancer. Furthermore, significant association was also found in Asian populations.

Meta-analysis of GSTM1 null genotype and lung cancer risk in Asians

BACKGROUND

Several molecular epidemiological studies have been conducted to examine the association between glutathione S-transferase M 1 (GSTM1) null genotype and lung cancer in Asians; however, the conclusions remained controversial. We therefore performed an extensive meta-analysis on 31 published case-control studies with a total of 5347 lung cancer cases and 6072 controls.

MATERIAL/METHODS

PubMed and EMBASE were searched to identify case-control studies investigating the associations of GSTM1 null genotype with risk of lung cancer in Asians. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association between lung cancer risk and polymorphism of GSTM1.

RESULTS

GSTM1 null genotype was significantly associated with lung cancer risk (OR=1.43; 95% CI, 1.30-1.58). This result remained statistically significant when the adjusted ORs were combined (OR=1.38; 95% CI, 1.23-1.54). In the subgroup analysis by sex, there were significant associations in women and men. When stratifying for histology, this genotype showed increased adenocarcinoma risk and squamous cell carcinoma risk. In the subgroup analysis stratified by smoking status, lung cancer risk was increased in both smokers and non-smokers.

CONCLUSIONS

This study suggests that GSTM1 null genotype is a risk factor for lung cancer in Asians.

The associations between two vital GSTs genetic polymorphisms and lung cancer risk in the Chinese population: evidence from 71 studies

BACKGROUND

The genetic polymorphisms of glutathione S-transferase (GSTs) have been suspected to be related to the development of lung cancer while the current results are conflicting, especially in the Chinese population.

METHODS

Data on genetic polymorphisms of glutathione S-transferase Mu 1 (GSTM1) from 68 studies, glutathione S-transferase theta 1 (GSTT1) from 17 studies and GSTM1-GSTT1 from 8 studies in the Chinese population were reanalyzed on their association with lung cancer risk. Odds ratios (OR) were pooled using forest plots. 9 subgroups were all or partly performed in the subgroup analyses. The Galbraith plot was used to identify the heterogeneous records. Potential publication biases were detected by Begg's and Egger's tests.

RESULTS

71 eligible studies were identified after screening of 1608 articles. The increased association between two vital GSTs genetic polymorphisms and lung cancer risk was detected by random-effects model based on a comparable heterogeneity. Subgroup analysis showed a significant relationship between squamous carcinoma (SC), adenocarcinoma (AC) or small cell lung carcinoma (SCLC) and GSTM1 null genotype, as well as SC or AC and GSTT1 null genotype. Additionally, smokers with GSTM1 null genotype had a higher lung cancer risk than non-smokers. Our cumulative meta-analysis demonstrated a stable and reliable result of the relationship between GSTM1 null genotype and lung cancer risk. After the possible heterogeneous articles were omitted, the adjusted risk of GSTs and lung cancer susceptibility increased (fixed-effects model: ORGSTM1 = 1.23, 95% CI: 1.19 to 1.27, P<0.001; ORGSTT1 = 1.18, 95% CI: 1.10 to 1.26, P<0.001; ORGSTM1-GSTT1 = 1.33, 95% CI: 1.10 to 1.61, P = 0.004).

CONCLUSIONS

An increased risk of lung cancer with GSTM1 and GSTT1 null genotype, especially with dual null genotype, was found in the Chinese population. In addition, special histopathological classification of lung cancers and a wide range of gene-environment and gene-gene interaction analysis should be taken into consideration in future studies.

Combined effects of CYP1A1 MspI and GSTM1 genetic polymorphisms on risk of lung cancer: an updated meta-analysis

Genetic polymorphisms of cytochrome P450 1A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) genes might contribute to the variability in individual susceptibility to lung cancer, but the reported results from individual studies are not always consistent. We therefore conducted a meta-analysis to systematically estimate the associations between polymorphisms of these two genes and risk of lung cancer. Twenty-one studies with 8,926 subjects were finally enrolled into this study. Meta-analysis was performed by RevMan 5.2. Odds ratio (OR) and its 95 % confidence interval (CI) were calculated to evaluate the susceptibility to lung cancer. Compared with the wild-type homozygous genotype, significantly elevated risk of lung cancer were associated with variant CYP1A1 MspI (m1/m2 + m2/m2 vs. m1/m1: OR = 1.27, 95 % CI = 1.12-1.43, P < 0.001) and deletion of GSTM1 (null vs. present: OR = 1.26, 95 % CI = 1.13-1.40, P < 0.001). Both the two genetic polymorphisms were independently associated with the risk of lung cancer. The pooled OR of lung cancer for population with both CYP1A1 MspI and GSTM1 mutations (MspI m1/m2 or m2/m2 and GSTM1 null) was 1.62 (95 % CI 1.27-2.07, P < 0.001) when compared with those without any of the above mutations, which is higher than single genetic polymorphism. In the stratified analysis, significantly higher risks of lung cancer associated with above genetic polymorphisms were found only in Asian population. This meta-analysis suggests that the CYP1A1 MspI and GSTM1 polymorphisms correlate with increased lung cancer susceptibility independently, and that there is an interaction between the two genes. However, the associations vary in different ethnic populations.

New molecular insights in tobacco-induced lung cancer

We know that cigarette smoking is a leading preventable cause of carcinogenesis in lung cancer. Cigarette smoke is a mixture of more than 5000 chemical compounds, among which more than 60 are recognized to have a specific carcinogenic potential. Carcinogens and their metabolites (i.e., N-nitrosamines and polycyclic aromatic hydrocarbons) can activate multiple pathways, contributing to lung cell transformation in different ways. Nicotine, originally thought only to be responsible for tobacco addiction, is also involved in tumor promotion and progression with antiapoptotic and indirect mitogenic properties. Lung nodules are frequent in smokers and can be transformed into malignant tumors depending on persistant smoking status. Even if detailed mechanisms underlying tobacco-induced cancerogenesis are not completely elucitated, this report collects the emergent body of knowledge in order to simplify the extremely complex framework that links smoking exposure to lung cancer.

Induction of antioxidative Nrf2 gene transcription by coffee in humans: depending on genotype?

The Nrf2/ARE pathway is a major cellular defense mechanism that prevents damage by reactive oxygen species through induction of antioxidative phase II enzymes. However, the activity of the Nrf2/ARE system is not uniform with variability in response presumed to be dependent on the Nrf2 genotype. We recently completed a pilot human coffee intervention trial with healthy humans, where large interindividual differences in the antioxidative response to the study coffee were examined. Here, we address the question whether differences in the modulation of Nrf2 gene transcription, assessed as an induction of Nrf2 gene transcription by Q-PCR, might be correlated with specific Nrf2 genotypes. To date, nine single nucleotide polymorphisms (SNPs) have been identified in the Nrf2 (NFE2L2) gene. Two of these, the -617C/A and -651G/A SNPs are located within the promoter region and have previously been reported to influence the activity of the Nrf2/ARE pathway by reducing Nrf2 transcriptional activity. Sequencing of the critical Nrf2 gene promoter region not only confirmed the existence of these SNPs within the participants of the trial at the expected frequency (33% carrying the -617C/A, 17% the -651G/A and 56% the -653A/G SNP) but also indicated reduced Nrf2 gene transcription associated with a normal diet if the SNPs at position -617, -651 or -653 were present. Of note, the data also indicated the study coffee increased Nrf2 gene transcription even in SNP carriers. This further highlights the relevance of genotype-dependent induction of Nrf2 gene transcription that appears to be largely influenced by dietary factors.

Meta-analysis on pharmacogenetics of platinum-based chemotherapy in non small cell lung cancer (NSCLC) patients

AIM

To determine the pharmacogenetics of platinum-based chemotherapy in Non Small Cell Lung Cancer (NSCLC) patients.

METHODS

Publications were selected from PubMed, Cochrane Library and ISI Web of Knowledge. A meta-analysis was conducted to determine the association between genetic polymorphisms and platinum-based chemotherapy by checking odds ratio (OR) and 95% confidence interval (CI).

RESULTS

Data were extracted from 24 publications, which included 11 polymorphisms in 8 genes for meta-analysis. MDR1 C3435T (OR = 1.97, 95% CI: 1.11-3.50, P = 0.02), G2677A/T (OR = 2.61, 95% CI: 1.44-4.74, P = 0.002) and GSTP1 A313G (OR = 0.32, 95% CI: 0.17-0.58, P = 0.0002) were significantly correlated with platinum-based chemotherapy in Asian NSCLC patients.

CONCLUSION

Attention should be paid to MDR1 C3435T, G2677A/T and GSTP1 A313G for personalized chemotherapy treatment for NSCLC patients in Asian population in the future.