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Rifkin SB, Miller AK, Montalvan-Sanchez EE, Norwood DA, Martinez E, Waterboer T, Beasley TM, Dominguez RL, Williams SM, Morgan DR. Wood cookstove use is associated with gastric cancer in Central America and mediated by host genetics. Sci Rep 2023; 13:16515. [PMID: 37783717 PMCID: PMC10545771 DOI: 10.1038/s41598-023-42973-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 09/17/2023] [Indexed: 10/04/2023] Open
Abstract
Biomass cookstove food preparation is linked to aero-digestive cancers, mediated by ingested and inhaled carcinogens (e.g., heterocyclic amines, and polycyclic aromatic hydrocarbons). We investigated the association between gastric adenocarcinoma, wood cookstove use, H. pylori CagA infection and risk modification by variants in genes that metabolize and affect the internal dose of carcinogens. We conducted a population-based, case-control study (814 incident cases, 1049 controls) in rural Honduras, a high-incidence region with a homogeneous diet and endemic H. pylori infection, primarily with the high-risk CagA genotype. We investigated factors including wood cookstove use, H. pylori CagA serostatus, and 15 variants from 7 metabolizing genes, and the interactions between wood stove use and the genetic variants. Male sex (OR 2.0, 1.6-2.6), age (OR 1.04, 1.03-1.05), wood cookstove use (OR 2.3, 1.6-3.3), and CagA serostatus (OR 3.5, 2.4-5.1) and two SNPs in CYP1B1 (rs1800440 and rs1056836) were independently associated with gastric cancer in multivariate analysis. In the final multivariate model, a highly significant interaction (OR 3.1, 1.2-7.8) was noted between wood cookstove use and the rs1800440 metabolizing genotype, highlighting an important gene-environment interaction. Lifetime wood cookstove use associates with gastric cancer risk in the high-incidence regions of Central America, and the association is dependent on the rs1800440 genotype in CYP1B1. H. pylori CagA infection, wood cookstove use and the rs1800440 genotype, all of which are highly prevalent, informs who is at greatest risk from biomass cookstove use.
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Affiliation(s)
- Samara B Rifkin
- Department of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, MI, USA
| | - Anna K Miller
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Eleazar E Montalvan-Sanchez
- Hospital de Occidente, Ministry of Health, Santa Rosa de Copan, Copan, Honduras
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Dalton A Norwood
- Hospital de Occidente, Ministry of Health, Santa Rosa de Copan, Copan, Honduras
- Division of Preventive Medicine, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | | | - Tim Waterboer
- Infections and Cancer Epidemiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - T Mark Beasley
- Department of Biostatistics, School of Public Health, The University of Alabama at Birmingham, Birmingham, AL, USA
- Birmingham/Atlanta Geriatric Research, Education, and Clinical Center, Birmingham Veterans Affairs Medical Center, Birmingham, AL, USA
| | - Ricardo L Dominguez
- Hospital de Occidente, Ministry of Health, Santa Rosa de Copan, Copan, Honduras
| | - Scott M Williams
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA
- Department of Population and Quantitative Health Sciences and Cleveland Institute for Computational Biology, Case Western Reserve University, Cleveland, OH, USA
| | - Douglas R Morgan
- Medicine and Epidemiology, UAB Division of Gastroenterology and Hepatology, The University of Alabama at Birmingham (UAB), Birmingham, AL, 35294, USA.
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Zhang MX, Liu K, Wang FG, Wen XW, Song XL. Association between CYP2E1 polymorphisms and risk of gastric cancer: An updated meta-analysis of 32 case-control studies. Mol Clin Oncol 2016; 4:1031-1038. [PMID: 27284439 DOI: 10.3892/mco.2016.824] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 03/03/2016] [Indexed: 01/01/2023] Open
Abstract
Previous studies suggested that RsaI/PstI and DraI polymorphisms on cytochrome P450 2E1 (CYP2E1) may be associated with susceptibility to gastric cancer (GC). However, this association remains ambiguous. A meta-analysis of previously published studies was performed in an attempt to elucidate this association. The odds ratio and 95% confidence interval were used to assess the strength of the association. In the overall analyses of RsaI/PstI and DraI, no association was identified. In the subgroup analyses, RsaI/PstI was identified to increase the risk of GC in the smoking population. In addition, in the previous studies of interactions with other genes, RsaI/PstI was revealed to be associated with increased GC risks when glutathione S-transferase-µ-1 or glutathione S-transferase θ-1 was null or DraI was homozygous wild-type. However, these stratified analyses were lacking credibility due to the limitation of correlational study numbers. In conclusion, CYP2E1 polymorphisms revealed no association with the risk of GC.
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Affiliation(s)
- Ming-Xing Zhang
- Department of Gastrointestinal Surgery, Shandong Cancer Hospital and Institute, Jinan, Shandong 250117, P.R. China; Department of Gastrointestinal Surgery, Liaocheng People's Hospital, Liaocheng, Shandong 252000, P.R. China
| | - Kai Liu
- Department of Gastrointestinal Surgery, Shandong Cancer Hospital and Institute, Jinan, Shandong 250117, P.R. China
| | - Fu-Gang Wang
- Department of Gastrointestinal Surgery, Shandong Cancer Hospital and Institute, Jinan, Shandong 250117, P.R. China
| | - Xiao-Wen Wen
- Department of Gastrointestinal Surgery, Shandong Cancer Hospital and Institute, Jinan, Shandong 250117, P.R. China
| | - Xi-Lin Song
- Department of Gastrointestinal Surgery, Shandong Cancer Hospital and Institute, Jinan, Shandong 250117, P.R. China
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Abstract
Cytochrome 450 (CYP450) designates a group of enzymes abundant in smooth endoplasmic reticulum of hepatocytes and epithelial cells of small intestines. The main function of CYP450 is oxidative catalysis of various endogenous and exogenous substances. CYP450 are implicated in phase I metabolism of 80% of drugs currently in use, including anticancer drugs. They are also involved in synthesis of various hormones and influence hormone-related cancers. CYP450 genes are highly polymorphic and their variants play an important role in cancer risk and treatment. Association studies and meta-analyses have been performed to decipher the role of CYP450 polymorphisms in cancer susceptibility. Cancer treatment involves multimodal therapies and evaluation of CYP450 polymorphisms is necessary for pharmacogenetic assessment of anticancer therapy outcomes. In addition, CYP450 inhibitors are being evaluated for improved pharmacokinetics and oral formulation of several anticancer drugs.
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Malakar M, Devi KR, Phukan RK, Kaur T, Deka M, Puia L, Baruah D, Mahanta J, Narain K. CYP2E1 genetic polymorphism with dietary, tobacco, alcohol habits, H. pylori infection status and susceptibility to stomach cancer in Mizoram, India. Asian Pac J Cancer Prev 2014; 15:8815-22. [PMID: 25374213 DOI: 10.7314/apjcp.2014.15.20.8815] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
BACKGROUND The incidence of stomach cancer in India is highest in the state of Mizoram. In this population based matched case-control study, we evaluated the relationship between CYP450 2E1 RsaI polymorphism and risk of stomach cancer taking into considering various important dietary habits along with tobacco, alcohol consumption and H. pylori infection status. MATERIALS AND METHODS A total of 105 histologically confirmed stomach cancer cases and 210 matched healthy population controls were recruited. CYP2E1 RsaI genotypes were determined by PCR-RFLP and H. pylori infection status by ELISA. Information on various dietary, tobacco and alcohol habits was recorded in a standard questionnaire. RESULTS Our study revealed no significant association between the CYP2E1 RsaI polymorphism and overall risk of stomach cancer in Mizoram. However, we observed a non-significant protective effect of the variant allele (A) of CYP2E1 against stomach cancer. Tobacco smokers carrying C/C genotype have three times more risk of stomach cancer, as compared to non-smokers carrying C/C genotype. Both Meiziol and cigarette current and past smokers who smoked for more than 10 times per day and carrying the (C/C) genotype are more prone to develop stomach cancer. Smoke dried fish and preserved meat (smoked/sun dried) consumers carrying C/C genotype possesses higher risk of stomach cancer. No significant association between H. pylori infection and CYP2E1 RsaI polymorphism in terms of stomach cancer was observed. CONCLUSIONS Although no direct association between the CYP2E1 RsaI polymorphism and stomach cancer was observed, relations with different tobacco and dietary risk habits in terms of developing stomach cancer exist in this high risk population of north-eastern part of India. Further in-depth study recruiting larger population is required to shed more light on this important problem.
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Affiliation(s)
- Mridul Malakar
- Regional Medical Research Centre, NE Region (Indian Council of Medical Research), Dibrugarh, Assam, India E-mail :
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CYP2E1 RsaI/PstI polymorphism and gastric cancer susceptibility: meta-analyses based on 24 case-control studies. PLoS One 2012; 7:e48265. [PMID: 23139769 PMCID: PMC3489680 DOI: 10.1371/journal.pone.0048265] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 09/21/2012] [Indexed: 02/07/2023] Open
Abstract
Background Previous reports implicate CYP2E1 RsaI/PstI polymorphism as a possible risk factor for several cancers. Published studies on the relationship of CYP2E1 RsaI/PstI polymorphisms with the susceptibility to gastric cancer are controversial. This study aimed to determine this relationship accurately. Methods Meta-analyses that assessed the association of CYP2E1 RsaI/PstI variations with gastric cancer were conducted. Subgroup analyses on ethnicity, smoking status, alcohol consumption, and source of controls were also performed. Eligible studies up to Mar 2012 were identified. Results After rigorous searching and screening, 24 case-control studies comprising 3022 cases and 4635 controls were selected for analysis. The overall data failed to indicate the significant associations of CYP2E1 RsaI/PstI polymorphisms with the gastric cancer risk [c2 vs. c1: odds ratio (OR) = 1.06; 95% confidence interval (CI) = 0.88–1.28; c2c2 vs. c1c1: OR = 1.23; 95% CI = 0.78–1.92; c2c2+c1c2 vs. c1c1: OR = 0.93; 95% CI = 0.79–1.10]. Similar results were observed in the subgroup analyses on ethnicity, drinking status, and source of controls. However, in the subgroup analysis on smoking status, a borderline increase in cancer risk was found among long-term smokers (c2c2+c1c2 vs. c1c1: OR = 1.39; 95% CI = 1.00–1.92). Conclusion CYP2E1 RsaI/PstI polymorphisms may modify the susceptibility to gastric cancer among individuals who have a smoking history. Large and well-designed studies are needed to confirm this conclusion.
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Tian Z, Li YL, Zhao L, Zhang CL. CYP2E1 RsaI/PstI Polymorphism and Liver Cancer Risk among East Asians: a Huge Review and Meta-analysis. Asian Pac J Cancer Prev 2012; 13:4915-21. [DOI: 10.7314/apjcp.2012.13.10.4915] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Kang-Sickel JCC, Butler MA, Frame L, Serdar B, Chao YCE, Egeghy P, Rappaport SM, Toennis CA, Li W, Borisova T, French JE, Nylander-French LA. The utility of naphthyl-keratin adducts as biomarkers for jet-fuel exposure. Biomarkers 2011; 16:590-9. [PMID: 21961652 DOI: 10.3109/1354750x.2011.611598] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We investigated the association between biomarkers of dermal exposure, naphthyl-keratin adducts (NKA), and urine naphthalene biomarker levels in 105 workers routinely exposed to jet-fuel. A moderate correlation was observed between NKA and urine naphthalene levels (p = 0.061). The NKA, post-exposure breath naphthalene, and male gender were associated with an increase, while CYP2E1*6 DD and GSTT1-plus (++/+-) genotypes were associated with a decrease in urine naphthalene level (p < 0.0001). The NKA show great promise as biomarkers for dermal exposure to naphthalene. Further studies are warranted to characterize the relationship between NKA, other exposure biomarkers, and/or biomarkers of biological effects due to naphthalene and/or PAH exposure.
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Affiliation(s)
- Juei-Chuan C Kang-Sickel
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, USA
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Webb A, Lind PA, Kalmijn J, Feiler HS, Smith TL, Schuckit MA, Wilhelmsen K. The investigation into CYP2E1 in relation to the level of response to alcohol through a combination of linkage and association analysis. Alcohol Clin Exp Res 2010; 35:10-8. [PMID: 20958328 DOI: 10.1111/j.1530-0277.2010.01317.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND A low level of response to alcohol during an individual's early experience with alcohol is associated with an increase risk of alcoholism. A family-based genome-wide linkage analysis using sibling pairs that underwent an alcohol challenge where the level of response to alcohol was measured with the Subjective High Assessment Scale (SHAS) implicated the 10q terminal (10qter) region. CYP2E1, a gene known for its involvement with ethanol metabolism, maps to this region. METHODS Variance component multipoint linkage analysis was performed on a combined map of single-nucleotide polymorphism (SNP) and microsatellite data. To account for the heterogeneity evident in the dataset, a calculation assuming locus heterogeneity was made using the Heterogeneity Log of Odds (HLOD) score. Association between SNP marker allele counts and copy number and SHAS scores were evaluated using a logistic regression model. RESULTS Linkage analysis detected significant linkage to CYP2E1, which was diminished because of apparent locus heterogeneity traced to a single family with extreme phenotypes. In retrospect, circumstances recorded during testing for this family suggest that their phenotype data are likely to be unreliable. Significant allelic associations were detected for several CYP2E1 polymorphisms and the SHAS score. DNA sequencing from families that contributed the greatest evidence for linkage did not detect any changes directly affecting the primary amino acid sequence. With the removal of a single family, combined evidence from microsatellites and SNPs offers significant linkage between the level of response to alcohol and the region on the end of chromosome 10. CONCLUSION Combined linkage and association indicate that sequence changes in or near CYP2E1 affect the level of response to alcohol providing a predictor of risk of alcoholism. The absence of coding sequence changes indicates that regulatory sequences are responsible. Implicating CYP2E1 in the level of response to alcohol allows inferences to be made about how the brain perceives alcohol.
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Affiliation(s)
- Amy Webb
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, USA
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N-Nitrosamines. ACTA ACUST UNITED AC 2009. [DOI: 10.1201/9781420027983.ch12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Gianfagna F, De Feo E, van Duijn CM, Ricciardi G, Boccia S. A systematic review of meta-analyses on gene polymorphisms and gastric cancer risk. Curr Genomics 2008; 9:361-74. [PMID: 19506726 PMCID: PMC2691668 DOI: 10.2174/138920208785699544] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Revised: 05/15/2008] [Accepted: 05/21/2008] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Individual variations in gastric cancer risk have been associated in the last decade with specific variant alleles of different genes that are present in a significant proportion of the population. Polymorphisms may modify the effects of environmental exposures, and these gene-environment interactions could partly explain the high variation of gastric cancer incidence around the world. The aim of this report is to carry out a systematic review of the published meta-analyses of studies investigating the association between gene polymorphisms and gastric cancer risk, and describe their impact at population level. Priorities on the design of further primary studies are then provided. METHODS A structured bibliographic search on Medline and EMBASE databases has been performed to identify meta-analyses on genetic susceptibility to gastric cancer, without restriction criteria. We report the main results of the meta-analyses and we describe the subgroup analyses performed, focusing on the detection of statistical heterogeneity. We investigated publication bias by pooling the primary studies included in the meta-analyses, and we computed the population attributable risk (PAR) for each polymorphism. RESULTS Twelve meta-analyses and one pooled-analysis of community based genetic association studies were included, focusing on nine genes involved in inflammation (IL-1beta, IL-1RN, IL-8), detoxification of carcinogens (GSTs, CYP2E1), folate metabolism (MTHFR), intercellular adhesion (E-cadherin) and cell cycle regulation (p53). According to their random-Odds Ratios, individuals carrying one of the IL-1RN *2, IL-1beta -511T variant alleles or homozygotes for MTHFR 677T are significantly at higher risk of gastric cancer than those with the wild type homozygote genotypes, showing high PARs. The main sources of heterogeneity in the meta-analyses were ethnicity, quality of the primary study, and selected environmental co-exposures. Effect modification by Helicobacter pylori infection for subjects carrying the unfavourable variant of IL-1 polymorphisms and by low folate intake for individuals homozygotes for MTHFR 677T allele has been reported, while genes involved in the detoxification of carcinogens show synergistic interactions. Publication bias was observed (Egger test, p = 0.03). DISCUSSION The published meta-analyses included in our systematic review focused on polymorphisms having a small effect in increasing gastric cancer risk per se. Nevertheless, the risk increase by interacting with environmental exposures and in combination with additional unfavourable polymorphisms. Unfortunately meta-analyses are underpowered for many subgroup analyses, so additional primary studies performed on larger population and collecting data on environmental and genetic co-exposures are demanded.
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Affiliation(s)
| | - Emma De Feo
- Institute of Hygiene, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Cornelia M van Duijn
- Department of Epidemiology & Biostatistics, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Stefania Boccia
- Institute of Hygiene, Università Cattolica del Sacro Cuore, Rome, Italy
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Gao CM, Takezaki T, Wu JZ, Chen MB, Liu YT, Ding JH, Sugimura H, Cao J, Hamajima N, Tajima K. CYP2E1 Rsa I polymorphism impacts on risk of colorectal cancer association with smoking and alcohol drinking. World J Gastroenterol 2007; 13:5725-30. [PMID: 17963298 PMCID: PMC4171258 DOI: 10.3748/wjg.v13.i43.5725] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate associations between the Rsa I polymorphism of CYP2E1 and risk of colorectal cancer.
METHODS: A case-control study was conducted with 315 colorectal cancer cases (105 colon, 210 rectal) and 439 population-based controls in Jiangsu Province of China. Genomic DNA samples were assayed for restriction fragment length polymorphisms in CYP2E1 by PCR amplification followed by digestion with Rsa I. Information on smoking and alcohol drinking was collected using a questionnaire. Odds ratios (ORs) were estimated with an unconditional logistic model.
RESULTS: The proportional distribution of the CYP2E1 Rsa I c1/c1, c1/c2 and c2/c2 genotypes were 61.4%, 35.6% and 3.0% in controls, 60.6%, 33.7% and 5.8% in colon cancer cases, and 58.4%, 34.0% and 7.7% in rectal cancer cases, respectively. A significant difference was noted between controls and rectal cancer cases (P = 0.029), the c2/c2 genotype being associated with elevated OR (adjusted age, sex and status of the smoking and alcohol drinking) for rectal cancer (1.64, 95% CI, 1.12-2.41, vs c1 allele carriers), but not for colon cancer. In interaction analysis between the CYP2E1 Rsa I genotype and smoking and drinking habits, we found a significant cooperative action between the c2/c2 genotype and alcohol drinking in the sex-, age-adjusted ORs for both colon (4.74, 95% CI, 1.10-20.40) and rectal (5.75, 95% CI, 1.65-20.05) cancers. Among non-smokers, the CYP2E1 Rsa I c2/c2 genotype was also associated with elevated ORs in the two sites (1.95, 95% CI, 0.99-3.86 and 2.30, 95% CI, 1.32-3.99).
CONCLUSION: The results of the present study suggest that the CYP2E1 c2/c2 genotype increases susceptibility to rectal cancer and the gene-environmental interactions between the CYP2E1 polymorphism and smoking or alcohol drinking exist for colorectal neoplasia in general.
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Masuda G, Tokunaga A, Shirakawa T, Togashi A, Kiyama T, Kato S, Matsukura N, Bou H, Watanabe M, Tajiri T. Helicobacter pylori infection, but not genetic polymorphism of CYP2E1, is highly prevalent in gastric cancer patients younger than 40 years. Gastric Cancer 2007; 10:98-103. [PMID: 17577619 DOI: 10.1007/s10120-007-0414-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2006] [Accepted: 02/25/2007] [Indexed: 02/07/2023]
Abstract
BACKGROUND Gastric cancers in young adults are thought to be associated with risk factors that include Helicobacter pylori infection and genetic polymorphism. The objective of this study was to elucidate the roles of these risk factors in patients younger than 40 years by analyzing clinicopathological data and H. pylori infection, and using molecular epidemiologic techniques. METHODS Clinicopathological features, the presence of H. pylori infection, endoscopic characteristics of gastritis, genetic polymorphism of P4502E1 (CYP2E1), and family history of cancer in patients with gastric cancer treated surgically at Nippon Medical School Hospital from 1991 to 2004 were analyzed, based on our medical database. RESULTS Gastric cancer in those younger than 40 years was characterized by a predominance of female patients with poorly differentiated adenocarcinoma who had undergone total gastrectomy with extended lymphadenectomy. H. pylori infection had a higher prevalence in patients with gastric cancer than in patients with normal endoscopic results or chronic gastritis, especially in those younger than 40 years (odds ratio, 13.7). Atrophic gastritis, nodular gastritis, and rugal hyperplastic gastritis were observed by endoscopy as H. pylori-associated gastritis. No difference in the incidence of either CYP2E1 genetic polymorphism or a family history of cancer was observed among different age groups. CONCLUSION Gastric cancer in patients younger than 40 years is closely associated with H. pylori infection, but not with genetic characteristics. Eradication therapy for H. pylori and endoscopic examination of H. pylori-positive young adults may be anticipated to be adopted as a strategy for the prevention and/or early detection of cancer.
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Affiliation(s)
- Gotaro Masuda
- Surgery for Organ and Biological Regulation, First Department of Surgery, Nippon Medical School, Tokyo, Japan
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Atsuta Y, Kawase H, Hamajima N, Nishio K, Niwa Y, Tanaka D, Yamamoto K, Tamakoshi A. Use of duplex PCR-CTPP methods for CYP2E1RsaI/IL-2 T-330G and IL-1B C-31T/TNF-A T-1031C polymorphisms. ACTA ACUST UNITED AC 2005; 9:89-94. [PMID: 16137184 DOI: 10.1007/bf03260076] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Two duplex polymerase chain reaction (PCR) with confronting two-pair primer (PCR-CTPP) methods were designed for cytochrome P450 (CYP) 2E1 RsaI and interleukin (IL-2) T-330G, and for IL-1B C-31T and tumor necrosis factor-alpha (TNF-A) T-1031C. The four polymorphisms are considered to be functional, and the three cytokines reportedly inhibit CYP2E1 expression. Many studies have reported associations between the above polymorphisms and risk of diseases including cancers and inflammatory diseases. AIM The main objective of this study was to examine the applicability of the established PCR conditions to a real situation. PARTICIPANTS Participants were female examinees aged from 35 to 85 years who attended health checks run by a local government in Japan. RESULTS The allele frequencies among 325 female health check examinees were 0.804 for CYP2E1 c1 allele, 0.668 for IL-2-330T allele, 0.554 for IL-1B-31T allele, and 0.822 for TNF-A-1031T allele. p-Values from a Hardy-Weinberg equilibrium test were 0.658, 0.955, 0.062, and 0.806, respectively. DISCUSSION Clear DNA bands observed with electrophoresis allowed us to genotype the four polymorphisms. The genotype frequencies were within the Hardy-Weinberg equilibrium test proportions, though the p-value for IL-1B C-31T was marginal. CONCLUSIONS Both duplex PCR-CTPP methods may be useful tools for studies on the association between these polymorphisms and disease risk.
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Affiliation(s)
- Yoshiko Atsuta
- Department of Preventive Medicine/Biostatistics and Medical Decision Making, Nagoya University Graduate School of Medicine, Nagoya City, Japan.
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Kim SY, Choi JK, Cho YH, Chung EJ, Paek D, Chung HW. Chromosomal aberrations in workers exposed to low levels of benzene: association with genetic polymorphisms. ACTA ACUST UNITED AC 2005; 14:453-63. [PMID: 15226677 DOI: 10.1097/01.fpc.0000114751.08559.7b] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Benzene and its metabolites damage human lymphocytes, resulting in chromosomal aberrations and aneuploidy. Polymorphisms in the genes for benzene-metabolizing enzymes have been implicated in benzene-associated haematotoxicity. In this study, we examined the specificity of benzene-induced aneuploidy and the influence of genetic polymorphisms (GSTM1, GSTT1, GSTP1, NAT2, NQO1 and CYP2E1) on chromosomal aberrations. In total, 82 benzene-exposed workers from a coke oven plant and 76 matched controls were examined. The benzene concentration in the work-place air ranged from 0.014-0.743 p.p.m. (geometric mean 0.557 p.p.m.). Benzene exposure was associated with significant increases in both monosomy and trisomy of chromosomes 8 and 21. Translocations between chromosomes 8 and 21 [t(8:21)] were eight-fold more frequent in the high-level exposure group compared to the control group. Multiple regression analysis indicated that the frequencies of chromosome aberrations were significantly associated with benzene exposure and polymorphisms in the metabolic enzyme genes. A particular subset of genotypes, which included the GSTM1-null and GSTT1-null genotypes, the slow acetylator type of NAT2, a variant of the NQO1 genotype and the CYP2E1 DraI and RsaI genotypes, were either separately, or in combination, associated with increased frequencies of aneuploidy among the benzene-exposed individuals after adjustments for age, alcohol consumption and smoking. These results suggest that polymorphisms in the genes for benzene-metabolizing enzymes influence the susceptibility of individuals to chromosomal aberrations in relation to benzene exposure.
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Affiliation(s)
- Su Young Kim
- School of Public Health and Institute of Health and Environmental Sciences, Seoul National University, Seoul, Korea
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Atsuta Y, Kawase H, Hamajima N, Nishio K, Niwa Y, Tanaka D, Yamamoto K, Tamakoshi A. Use of Duplex PCR-CTPP Methods for CYP2E1Rsa I/IL-2 T???330G and IL-1B C???31T/TNF-A T???1031C Polymorphisms. ACTA ACUST UNITED AC 2005. [DOI: 10.2165/00066982-200509020-00005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Neuhaus T, Ko YD, Lorenzen K, Fronhoffs S, Harth V, Bröde P, Vetter H, Bolt HM, Pesch B, Brüning T. Association of cytochrome P450 2E1 polymorphisms and head and neck squamous cell cancer. Toxicol Lett 2004; 151:273-82. [PMID: 15177663 DOI: 10.1016/j.toxlet.2003.09.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2003] [Revised: 09/02/2003] [Accepted: 09/02/2003] [Indexed: 10/26/2022]
Abstract
The development of head and neck squamous cell cancer (HNSCC) is known to be strongly associated with tobacco use. One of the main enzymes for bioactivation of tobacco-related substances is the cytochrome 450 (CYP)2E1, of which different genetic variants are described. Analyzing a correlation between certain neoplasia and alteration of the CYP2E1 gene, most studies focus on the polymorphisms -1053C>T and 7632T>A, but recently another polymorphism, named -71G>T, with enhanced transcriptional activity, has been identified. In the current case-control study we investigate the putative association of the mentioned CYP2E1 polymorphisms on the risk of HNSCC. Comparing 312 German individuals with HNSCC to 299 controls we found a significantly enhanced risk for the development of that neoplasia in smoking carriers of -71G>T heterozygosity, while in -1053C>T and 7632T>A polymorphisms a corresponding correlation was absent. Since a coincidence of an aberrant p53 gene and CYP2E1 mutations has been described, we choose a subgroup of 140 patients with HNSCC for analyzing an association of mutations in these two genes. However, no such association could be found in either of the mentioned polymorphisms. Further studies have to focus on the -71G>T polymorphism and its possible linkage to cancers, in which smoking is a known risk-factor, as well as its functional relevance concerning the bioactivation of tobacco-related substances.
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Affiliation(s)
- Thomas Neuhaus
- Medizinische Universitäts-Poliklinik Bonn, Universität Bonn, Wilhelmstr. 35-37, D-53111 Bonn, Germany
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17
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Balakin KV, Ekins S, Bugrim A, Ivanenkov YA, Korolev D, Nikolsky YV, Ivashchenko AA, Savchuk NP, Nikolskaya T. QUANTITATIVE STRUCTURE-METABOLISM RELATIONSHIP MODELING OF METABOLICN-DEALKYLATION REACTION RATES. Drug Metab Dispos 2004; 32:1111-20. [PMID: 15269187 DOI: 10.1124/dmd.104.000364] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
It is widely recognized that preclinical drug discovery can be improved via the parallel assessment of bioactivity, absorption, distribution, metabolism, excretion, and toxicity properties of molecules. High-throughput computational methods may enable such assessment at the earliest, least expensive discovery stages, such as during screening compound libraries and the hit-to-lead process. As an attempt to predict drug metabolism and toxicity, we have developed an approach for evaluation of the rate of N-dealkylation mediated by two of the most important human cytochrome P450s (P450), namely CYP3A4 and CYP2D6. We have taken a novel approach by using descriptors generated for the whole molecule, the reaction centroid, and the leaving group, and then applying neural network computations and sensitivity analysis to generate quantitative structure-metabolism relationship models. The quality of these models was assessed by using the cross-validated correlation coefficients of 0.82 for CYP3A4 and 0.79 for CYP2D6 as well as external test molecules for each enzyme. The relative performance of different neural networks was also compared, and modular neural networks with two hidden layers provided the best predictive ability. Functional dependencies between the neural network input and output variables, generalization ability, and limitations of the described approach are also discussed. These models represent an initial approach to predicting the rate of P450-mediated metabolism and may be applied and integrated with other models for P450 binding to produce a systems-based approach for predicting drug metabolism.
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18
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Abstract
The human cytochrome P450 (CYP) complement of heme-thiolate enzymes is reviewed. Of the 57 individual P450s characterized in Homo sapiens thus far, it is apparent that approximately one-half are associated with the metabolism of drugs and other xenobiotics, whereas the other half have endogenous functions in steroid, prostanoid, eicosanoid and fatty acid metabolism. This review covers the extent of enzyme functionality for the known human P450s, focusing primarily on their role in the Phase I metabolism of foreign compounds, which involves the CYP1, CYP2 and CYP3 families.
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Affiliation(s)
- David F V Lewis
- School of Biomedical and Molecular Sciences, University of Surrey, UK.
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19
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Bugrim A, Nikolskaya T, Nikolsky Y. Early prediction of drug metabolism and toxicity: systems biology approach and modeling. Drug Discov Today 2004; 9:127-35. [PMID: 14960390 DOI: 10.1016/s1359-6446(03)02971-4] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Many of the drug candidates that fail in clinical trials are withdrawn because of unforeseen effects of human metabolism, such as toxicity and unfavorable pharmacokinetic profiles. Early pre-clinical elimination of such compounds is important but not yet possible. An ideal system would enable researchers to make a confident elimination decision based purely on the structure of a new compound, and incorporate and use multiple pre-clinical experimental data to support such a decision. Currently available resources can be split into three categories: (i). structure-activity relationships (SAR) computational models based on compound structure; (ii). 'pattern' databases of tissue or organ response to drugs, compiled from high-throughput experiments; and (iii). 'systems biology' databases of metabolic pathways, genes and regulatory networks. In this review, we outline the advantages and drawbacks of each of these systems and suggest directions for their integration.
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Affiliation(s)
- Andrej Bugrim
- GeneGo, 500 Renaissance Drive, Suite 106, St Joseph, MI 49085, USA.
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20
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Korolev D, Balakin KV, Nikolsky Y, Kirillov E, Ivanenkov YA, Savchuk NP, Ivashchenko AA, Nikolskaya T. Modeling of human cytochrome p450-mediated drug metabolism using unsupervised machine learning approach. J Med Chem 2003; 46:3631-43. [PMID: 12904067 DOI: 10.1021/jm030102a] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We developed a computational algorithm for evaluating the possibility of cytochrome P450-mediated metabolic transformations that xenobiotics molecules undergo in the human body. First, we compiled a database of known human cytochrome P-450 substrates, products, and nonsubstrates for 38 enzyme-specific groups (total of 2200 compounds). Second, we determined the cytochrome-mediated metabolic reactions most typical for each group and examined the substrates and products of these reactions. To assess the probability of P450 transformations of novel compounds, we built a nonlinear quantitative structure-metabolism relationships (QSMR) model based on Kohonen self-organizing maps (SOM). This neural network QSMR model incorporated a predefined set of physicochemical descriptors encoding the key molecular properties that define the metabolic fate of individual molecules. Isozyme-specific groups of substrate molecules were visualized, thus facilitating prediction of tissue-specific metabolism. The developed algorithm can be used in early stages of drug discovery as an efficient tool for the assessment of human metabolism and toxicity of novel compounds in designing discovery libraries and in lead optimization.
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Affiliation(s)
- Dmitry Korolev
- GeneGo, Inc., 227 South Berrien Street, New Buffalo, MI 49117, USA
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21
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Konishi T, Calvillo M, Leng AS, Feng J, Lee T, Lee H, Smith JL, Sial SH, Berman N, French S, Eysselein V, Lin KM, Wan YJY. The ADH3*2 and CYP2E1 c2 alleles increase the risk of alcoholism in Mexican American men. Exp Mol Pathol 2003; 74:183-9. [PMID: 12710951 DOI: 10.1016/s0014-4800(03)00006-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To identify the association between the polymorphisms of genes encoding alcohol metabolizing enzymes and alcoholism, the alcohol dehydrogenase 2 (ADH2), alcohol dehydrogenase 3 (ADH3), aldehyde dehydrogenase 2 (ALDH2), and cytochrome P450 2E1 (CYP2E1) genes were studied in 101 male Mexican American alcoholics. One hundred and four Mexican American nonalcoholic males served as controls. The allele frequency of ADH2*2 (4.3%) and ALDH2*2 (0%), which are considered as protective alleles against alcohol drinking, is very low in Mexican Americans and no association is found between these alleles and alcohol dependence. A strong association was found between ADH3 genotype and alcoholism; the percentage of subjects who carry the ADH3*2 allele was significantly higher in alcoholics (64.4%) than controls (50%). Association was also found between the CYP2E1 RsaI c2 allele and alcohol dependence; the percentage of subjects who carry the RsaI c2 allele was significantly higher in alcoholics (34.7%) than in nonalcoholics (22.1%). The subjects whose alcohol drinking onset age is younger than 25 have much higher CYP2E1 c2 allele frequency than those whose alcohol drinking onset age is older than 25 (22.1% vs 15.7%). Among 101 alcoholics, only 18 subjects carry neither ADH3*2 nor CYP2E1 c2 alleles. For those subjects who have an ADH*1/*1 background, a strong association is found between CYP2E1 RsaI/DraI genotype and alcoholism; the CYP2E1 RsaI c2 and DraI C allele frequencies are much higher in alcoholics than in nonalcoholics (26.4% vs 9.6% for c2 and 27.8% vs 13.5% for C allele). Taken together, ADH3*2 and CYP2E1 c2/C alleles might independently contribute to the development of alcoholism in Mexican American men.
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Affiliation(s)
- Tamiko Konishi
- Department of Pathology, Harbor-UCLA Research and Education Institute, Torrance, CA 90509, USA
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22
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Abstract
The aim of the present paper is to review and evaluate, in a comprehensive manner, the most recent published evidence on the contribution of genetic susceptibility to gastric cancer risk in humans. We have identified all studies available in MEDLINE published up to October 2001. Only studies carried out in humans and comparing gastric cancer cases with at least 1 standard control group were included in the analysis. We were able to find 31 articles based on 25 case-control studies carried out in Caucasian, Asian and African populations. Most of the studies assess the effect of genes involved in detoxifying pathways (n = 12) and inflammatory responses (n = 7). The most widely studied is the GSTM1 null polymorphism. Only a very few studies have evaluated the risk of gastric cancer associated with genes acting on mucosa protection, oxidative damage and DNA repair. The most consistent results are the increased gastric cancer risk associated with IL1B and NAT1 variants, which may account for up to 48% of attributable risk of gastric cancer. Only polymorphisms at HLA-DQ, TNF and CYP2E genes may confer some protective effect against gastric cancer. The most important limitations that preclude definitive conclusions are (i) the lack of appropriate control of potential sources of bias (only 5 population-based studies have been published so far); (ii) the low number of cases analyzed (14 studies included fewer than 99 cases); and (iii) the low number of studies (n = 3) offering concomitant analysis of genetic susceptibility and exposure to relevant cofactors (Helicobacter pylori infection, diet and smoking). We conclude that the scientific data on the role of genetic factors in gastric cancer risk are promising. The lack of association reported so far should be considered with caution due to significant limitations in study design. Cohort studies taking into account simultaneously the different genetic and environmental factors potentially involved in gastric tumorigenesis are needed to ascertain not only the relative contribution of these factors to tumor development but also the contribution of their putative interactions.
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Affiliation(s)
- Carlos A González
- Epidemiology and Cancer Registry Unit, Catalan Institute of Oncology, Barcelona, Spain.
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23
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Shen H, Xu Y, Qian Y, Yu R, Qin Y, Zhou L, Wang X, Spitz MR, Wei Q. Polymorphisms of the DNA repair gene XRCC1 and risk of gastric cancer in a Chinese population. Int J Cancer 2000; 88:601-6. [PMID: 11058877 DOI: 10.1002/1097-0215(20001115)88:4<601::aid-ijc13>3.0.co;2-c] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Gastric cancer remains the leading cause of cancer death in China and other countries in eastern Asia. Studies of gastric cancer have revealed that it is a disease of complex etiology involving dietary, infectious, environmental, occupational and genetic factors. DNA repair capacity has been suggested as a genetic factor contributing to variation in susceptibility to cancer. In the present study, we described an association between 2 polymorphisms of the DNA repair gene XRCC1 and risk of gastric cancer in a Chinese population. We used a polymerase chain reaction-based assay to detect Pvu II and Nci I restriction fragment length polymorphisms (XRCC1 26304 C-->T and XRCC1 28152 G-->A, respectively) in 188 patients with gastric cancer and 166 healthy controls. The XRCC1 26304 T allele (194Trp) frequency (34.6%) was higher and the XRCC1 28152 A allele (399Gln) frequency (25.6%) was lower in healthy Chinese controls than previously reported healthy U.S. Caucasian controls (7.2% and 34.1%, respectively). Multivariate logistic regression analysis revealed that the putative high-risk genotypes XRCC1 26304 CC and XRCC1 28152 GA/AA were associated with a non-significant increased risk for gastric cancer (adjusted odds ratio [OR]=1.45, 95% confidence interval [CI]= 0.93-2.25 and OR=1.53, 95% CI= 0.98-2.39, respectively) compared with other genotypes. However, the XRCC1 26304 CC genotype was associated with a significantly increased risk for gastric cardia cancer (adjusted OR=1.86, 95% CI=1.09-3.20). Individuals with both putative high-risk genotypes (CC and GA/AA) had a significantly higher risk (adjusted OR=1.73, 95% CI=1.12-2.69), particularly for gastric cardia cancer (adjusted OR=2.18, 95% CI=1.21-3.94) than individuals with other genotypes. These findings support the hypothesis that these 2 XRCC1 variants may contribute to the risk of developing gastric cancer, particularly gastric cardia cancer.
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Affiliation(s)
- H Shen
- Department of Epidemiology and Statistics, School of Public Health, Nanjing Medical University, Nanjing, China
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24
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Smith G, Stubbins MJ, Harries LW, Wolf CR. Molecular genetics of the human cytochrome P450 monooxygenase superfamily. Xenobiotica 1998; 28:1129-65. [PMID: 9890157 DOI: 10.1080/004982598238868] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- G Smith
- Biomedical Research Centre, Ninewells Hospital and Medical School, Dundee, UK
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25
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Conforti-Froes N, el-Zein R, Au W. Genetic polymorphism and their contribution to cancer susceptibility. CAD SAUDE PUBLICA 1998; 14 Suppl 3:7-13. [PMID: 9819460 DOI: 10.1590/s0102-311x1998000700002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Since the majority of chemical carcinogens are not capable of causing hazardous effects per se, the metabolism of these compounds is a crucial part of the initial host response to the environmental exposure. Disturbances in the balance between activation and detoxification may thus explain the individual variations in responses to exposures to carcinogens. The amount of the ultimate carcinogen produced depends on the action of competing activation and detoxification pathways involving cytochrome P450 and glutathione-S-transferases enzymes.
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Affiliation(s)
- N Conforti-Froes
- Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista. Cristóvão Colombo 2265, São José do Rio Preto, São Paulo, SP 15054-000, Brasil
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26
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Agúndez J, Ladero J, Díaz-Rubio M, Benítez J. Rsa I polymorphism at the cytochrome P4502E1 locus is not related to the risk of alcohol-related severe liver disease. LIVER 1996; 16:380-3. [PMID: 9021717 DOI: 10.1111/j.1600-0676.1996.tb00766.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Ethanol-inducible cytochrome P4502E1 is the main pathway in the non-alcohol dehydrogenase oxidation of ethanol. Its coding gene, CYP2E1, is polymorphic at the Rsa I restriction site in the 5'-flanking region. The mutant genotype c2c2 has a higher transcriptional activity than the genotype c1c1 or c1c2. Heavy drinkers carrying the c2 allele might be at a higher risk of alcoholic cirrhosis since they might synthesize greater amounts of acetaldehyde, the compound believed responsible for hepatotoxicity of ethanol. With the aim of establishing if the c2 allele increases the risk of cirrhosis in heavy drinkers, we studied 58 (6 female) chronic heavy drinkers with liver cirrhosis and 137 healthy normal controls of the same ethnic (white Spaniards) origin. After extraction of DNA from white blood cells, alleles c1 and c2 of CYP2E1 were identified by restriction fragment length polymorphism (RFLP) with endonuclease Rsa I. Fifty-six patients and 130 controls were classified as homozygous c1c1 and two and seven, respectively, as heterozygous c1c2. No homozygous c2c2 were detected. The c2 allele frequencies were 0.017 in patients and 0.026 in controls (non-significant differences). We conclude that the Rsa I RFLP polymorphism is probably not related to the risk of cirrhosis in Spanish heavy drinkers.
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Affiliation(s)
- J Agúndez
- Department of Pharmacology, Medical School, University of Extremadura, Badioz, Spain
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27
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Kim RB, O'Shea D. Interindividual variability of chlorzoxazone 6-hydroxylation in men and women and its relationship to CYP2E1 genetic polymorphisms. Clin Pharmacol Ther 1995; 57:645-55. [PMID: 7781264 DOI: 10.1016/0009-9236(95)90227-9] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Chlorzoxazone 6-hydroxylation is mediated by CYP2E1, and its measurement provides an in vivo probe of the enzyme's activity. To determine the population distribution of such activity, the disposition of chlorzoxazone and its 6-hydroxy metabolite was determined after oral administration to 70 white subjects (40 men and 30 women) residing in middle Tennessee. Both oral (330 +/- 111 ml.min-1, mean +/- SD) and fractional (213 +/- 86 ml.min-1) clearances varied fourfold to fivefold within the population and were unimodally distributed in a visually normal fashion. Clearance values were one-third greater in men than in women, but such differences were less striking after normalization according to body weight. Attempts to develop a single-time-point measure of 6-hydroxylating ability on the basis of plasma levels or urinary excretion of chlorzoxazone or its metabolite were unsuccessful. Genetic polymorphisms (Pst I and Rsa I restriction fragment length polymorphisms) in the 5'-flanking region of CYP2E1 deoxyribonucleic acid obtained from peripheral leukocytes were not associated with differences in the disposition of chlorzoxazone. Similarly, no major effects on 6-hydroxylation were associated with mutations in intron 6 associated with a Dra I restriction fragment length polymorphism. The interindividual variability in CYP2E1 activity as measured in vivo in healthy subjects appears to be considerably less than that expected based on in vitro studies. Whether such variability is associated with individual susceptibility to CYP2E1-mediated toxicity remains to be determined.
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Affiliation(s)
- R B Kim
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232-6600, USA
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