GSTT1, GSTM1 and CYP2E1 genetic polymorphisms in gastric cancer and chronic gastritis in a Brazilian population

MIM:To test the hypothesis that,in the Southeastern Brazilian population,the GSTT1,GSTM1 and CYP2E1 polymorphisms and putative risk factors are associated with an increased risk for gastric cancer.METHODS:We conducted a study on 100 cases of gastric cancer(GC),100 cases of chronic gastritis(CG),and 150 controls(C).Deletion of the GSTT1 and GSTM1 genes was assessed by multiplex PCR.CYP2E1/PsА genotyping was performed using a PCR-RFLP assay.RESULTS:No relationship between GSTT1/GSTM1 deletion and the c1/c2 genotype of CYP2E1 was observed among the three groups.However,a significant difference between CG and C was observde,due to a greater number of GSTT1/GSTM1 positive genotypes in the CG group.The GSTT1 null genotype occurred more frequently in Negroid subjicts,and the GSTM1 null genotype was observed mainly in individuals with chronic gastritis infected with H pylori.CONCLUSION:Our findings indecate that there is no obvious relationship between the GSTT1,GSTM1 and CYP2E1 polymorphisms and gastric cancer.     

Phase Ⅰ／Ⅱ enzyme gene polymorphisms and esophageal cancer risk： A meta-analysis of the literature

AIM: Phase I/II enzymes metabolize environmental carcinogens and several functional polymorphisms have been reported in their encoding genes. Although their significance with regard to esophageal carcinogenicity has been examined epidemiologically, it remains controversial. The present systematic review of the literature was performed to clarify associations. METHODS: Eligible studies were case-control or cohort studies published until September 2004 that were written in any language. From PubMed and a manual review of reference lists in relevant review articles, we obtained 16 studies related to the CYP1A1 Ile-Val substitution in exon 7, CYP1A1 MspI polymorphisms, CYP2E1 Rsal polymorphisms, GSTM1 null type, GSTT1 null type and GSTP1 Ilel04Val. All were of case-control design. Summary statistics were odds ratios (ORs) comparing heterozygous-, homozygous-non-wild type or these two in combination with the homozygous wild type, or the null type with the non-null type for GSTM1 and GSTT1, A random effect model was used to estimate the summary ORs. A meta-regression analysis was applied to explore sources of heterogeneity. RESULTS: Individuals with the Ile-Val substitution in CYP1A1 exon 7 had increased esophageal cancer risk, with ORs (95%CI) compared with lie/lie of 1.37 (1.09-1.71), 2.52 (1.62-3.91) and 1.44 (1.17-1.78) for Ile-Val, Val/Val genotype and the combined group. No significant association was found between esophageal cancer risk and the other genetic parameters. CONCLUSION: A significant association exists between the CYP1A1 Ile-Val polymorphism and risk of esophageal cancer. Polymorphisms that increase the internal exposure to activated carcinogens may increase the risk of esophageal cancer.     

Phase Ⅰ/Ⅱ enzyme gene polymorphisms and esophageal cancer risk: A meta-analysis of the literature

AIM: Phase Ⅰ/Ⅱ enzymes metabolize environmental carcinogens and several functional polymorphisms have been reported in their encoding genes. Although their significance with regard to esophageal carcinogenicity has been examined epidemiologically, it remains controversial. The present systematic review of the literature was performed to clarify associations.METHODS: Eligible studies were case-control or cohort studies published until September 2004 that were written in any language. From PubMed and a manual review of reference lists in relevant review articles, we obtained 16 studies related to the CYP1A1 Ile-Val substitution in exon 7, CYP1A1MspI polymorphisms, CYP2E1 RsaI polymorphisms,GSTM1 null type, GSTT1 null type and GSTP1 Ile104Val.All were of case-control design. Summary statistics were odds ratios (ORs) comparing heterozygous-, homozygousnon-wild type or these two in combination with the homozygous wild type, or the null type with the non-null type for GSTM1 and GSTT1. A random effect model was used to estimate the summary ORs. A meta-regression analysis was applied to explore sources of heterogeneity. RESULTS: Individuals with the Ile-Val substitution in CYP1A1 exon 7 had increased esophageal cancer risk,with ORs (95%CI) compared with Ile/Ile of 1.37 (1.09-1.71),2.52 (1.62-3.91) and 1.44 (1.17-1.78) for Ile-Val, Val/Val genotype and the combined group. No significant association was found between esophageal cancer risk and the other genetic parameters.CONCLUSION: A significant association exists between the CYP1A1 Ile-Val polymorphism and risk of esophageal cancer. Polymorphisms that increase the internal exposure to activated carcinogens may increase the risk of esophageal cancer.     

Genetic polymorphisms in cytochrome P4502E1, alcohol and aldehyde dehydrogenases and the risk of esophageal squamous cell carcinoma in Gansu Chinese males

AIM：To evaluate the association between genetic polymorphisms in CYP2E1, ALDH2 and ADH1B and the risk of esophageal squamous cell carcinoma （ESCC） in a high risk area of Gansu Province, in Chinese males.
METHODS： A case-control study was conducted to investigate the genetic polymorphisms of these enzymes （CYP2E1 ＊c1/＊c2, ALDH2 ＊1/＊2 and ADH1B ＊1/＊1 genotypes）. A total of 80 esophageal cancer cases and 480 controls were recruited.
RESULTS： Compared with controls, cases had a greater prevalence of heavier alcohol consumption （53.8% vs 16.2%） and a higher proportion of alcohol drinkers with 〉 30 drink-years （28.8% vs 13.5%）. Heavier alcohol consumption and alcohol drinking with 〉 30 drink- years increased the risk of ESCC, with ORs （95% CI） of 3.20 （1.32-9.65） and 1.68 （0.96-3.21）. CYP2E1 （＊c1/＊c1）, ALDH2 （＊1/＊2） and ADH1B （＊1/＊1） genotype frequencies were higher among patients with squamous cell carcinomas, at a level close to statistical significance （P = 0.014; P = 0.094; P = 0.0001 respectively）. There were synergistic interactions among alcohol drinking and ALDH2, ADH1B and CYP2E1 genotypes. The risk of the ESCC in moderate-to-heavy drinkers with an inactive ALDH2 encoded by ALDH2 ＊1/＊2 as well as ADH1B encoded by ADH1B ＊1/＊1 and CYP2E1 encoded by CYP2E1 ＊c1/＊c1 was higher than that in the never/rare-to-light drinkers with an active ALDH2 （＊1/＊1 genotype） as well as ADH1B （＊1/＊2 ＋ ＊2/＊2） and CYP2E1 （＊c1/＊c2 ＋ ＊c2/＊c2） genotypes, with a statistically significant difference; ORs （95% CI） of 8.58 （3.28-22.68）, 27.12 （8.52-70.19） and 7.64 （2.82-11.31） respectively. The risk of the ESCC in moderate-to-heavy drinkers with ALDH2 （＊1/＊2） combined the ADH1B （＊1/＊1） genotype or ALDH2 （＊1/＊2） combined the CYP2E1 （＊c1/＊c1） genotype leads to synergistic interactions, higher than drinkers with ALDH2 （＊1/＊1） ＋ ADH1B （＊1/＊2 ＋ ＊2/＊     

Effects of dietary intake and genetic factors on hypermethylation of the hMLH1 gene promoter in gastric cancer

AIM: Hypermethylation of the promoter of the hMLH1 gene, which plays an important role in mismatch repair during DNA replication, occurs in more than 30% of human gastric cancer tissues. The purpose of this study was to investigate the effects of environmental factors, genetic polymorphisms of major metabolic enzymes, and microsatellite instability on hypermethylation of the promoter of the hMLH1 gene in gastric cancer. METHODS: Data were obtained from a hospital-based, case-control study of gastric cancer. One hundred and ten gastric cancer patients and 220 age- and sex-matched control patients completed a structured questionnaire regarding their exposure to environmental risk factors. Hypermethylation of the hMLH1 gene promoter, polymorphisms of the GSTM1, GSTT1, CYP1A1, CYP2E1, ALDH2 and L-myc genes, microsatellite instability and mutations of p53 and Ki-ras genes were investigated. RESULTS: Both smoking and alcohol consumption were associated with a higher risk of gastric cancer with hypermethylation of the hMLH1 gene promoter. High intake of vegetables and low intake of potato were associated with increased likelihood of gastric cancer with hypermethylation of the hMLH1 gene promoter. Genetic polymorphisms of the GSTM1, GSTT1, CYP1A1, CYP2E1, ALDH2, and L-myc genes were not significantly associated with the risk of gastric cancer either with or without hypermethylation in the promoter of the hMLH1 gene. Hypermethylation of the hMLH1 promoter was significantly associated with microsatellite instability (MSI): 10 of the 14 (71.4%) MSI-positive tumors showed hypermethylation, whereas 28 of 94 (29.8%) the MSI-negative tumors were hypermethylated at the hMLH1 promoter region. Hypermethylation of the hMLH1 gene promoter was significantly inversely correlated with mutation of the p53 gene. CONCLUSION: These results suggest that cigarette smoking and alcohol consumption may influence the development of hMLH1-positive gastric cancer. Most dietary factors and polymorphisms of GSTM1, GSTT1, CYP1A1, CYP2E1, ALDH2, and L-myc genes are not independent risk factors for gastric cancer with hypermethylation of the hMLH1 promoter. These data also suggest that there could be two or more different molecular pathways in the development of gastric cancer, perhaps involving tumor suppression mechanisms or DNA mismatch repair.     

Effects of dietary intake and genetic factors on hypermethyiation of the hMLH1 gene promoter in gastric cancer

AIM: Hypermethylation of the promoter of the hMLH1 gene, which plays an important role in mismatch repair during DNA replication, occurs in more than 30% of human gastric cancer tissues. The purpose of this study was to investigate the effects of environmental factors, genetic polymorphisms of major metabolic enzymes, and microsatellite instability on hypermethylation of the promoter of the hMLH1 gene in gastric cancer. METHODS: Data were obtained from a hospital-based, case-control study of gastric cancer. One hundred and ten gastric cancer patients and 220 age- and sex-matched control patients completed a structured questionnaire regarding their exposure to environmental risk factors. Hypermethylation of the hMLH1 gene promoter, polymorphisms of the GSTM1, GSTT1, CYP1A1, CYP2E1, ALDH2 and L-myc genes, microsatellite instability and mutations of p53 and Ki-ras genes were investigated. RESULTS: Both smoking and alcohol consumption were associated with a higher risk of gastric cancer with hypermethylation of the hMLH1 gene promoter. High intake of vegetables and low intake of potato were associated with increased likelihood of gastric cancer with hypermethylation of the hMLH1 gene promoter. Genetic polymorphisms of the GSTM1, GSTT1, CYP1A1, CYP2E1, ALDH2, and L-myc genes were not significantly associated with the risk of gastric cancer either with or without hypermethylation in the promoter of the hMLH1 gene. Hypermethylation of the hMLH1 promoter was significantly associated with microsatellite instability (MSI): 10 of the 14 (71.4%) MSI-positive tumors showed hypermethylation, whereas 28 of 94 (29.8%) the MSI-negative tumors were hypermethylated at the hMLH1 promoter region, Hypermethylation of the hMLH1 gene promoter was significantly inversely correlated with mutation of the p53 gene. CONCLUSION: These results suggest that cigarette smoking and alcohol consumption may influence the development of hMLH1-positive gastric cancer. Most dietary factors and polymorphisms of GSTM1, GSTT1, CYP1A1, CYP2E1, ALDH2, and L-myc genes are not independent risk factors for gastric cancer with hypermethylation of the hMLH1 promoter. These data also suggest that there could be two or more different molecular pathways in the development of gastric cancer, perhaps involving tumor suppression mechanisms or DNA mismatch repair.     

GSTM1, GSTT1, GSTP1 and CYPIA1 genetic polymorphisms and susceptibility to esophageal cancer in a French population： Different pattern of squamous cell carcinoma and adenocarcinoma

AIM: To evaluate the association between CYPIA1 and GSTs genetic polymorphisms and susceptibility to esophageal squamous cell carcinoma (SCC) and esophageal adenocarcinorna (ADC) in a high risk area of northwest of France.METHODS: A case-control study was conducted to investigate the genetic polymorphisms of these enzymes (CYPIAI*2C and GSTP1 exon 7 Val alleles, GSTM1 *2/*2 and GSl-l-l*2/*2 null genotypes). A total of 79 esophagealcancer cases and 130 controls were recruited. RESULTS: GSTM2*2/*2 and CYP1A1*1A/*2C genotype frequencies were higher among squamous cell cardnomas at a level close to statistical significance (OR = 1.83, 95% CI0.88-3.83, P= 0.11; OR = 3.03, 95% CI 0.93-9.90, P= 0.07,respectively). For GSTP1 polymorphism, no difference wasfound between controls and cases, whatever their histological status. Lower frequency of GST/-1 deletion was observed in ADC group compared to controls with a statistically significant difference (OR=13.31, 95% CI 1.66-106.92, P<0.01).CONCLUSION: In SCC, our results are consistent with the strong association of this kind of turnout with tobacco exposure. In ADC, our results suggest 3 distinct hypotheses:(1) activation of exogenous procarcinogens, such as small halogenated compounds by GSTTI‘, (2) contribution of GSTT1 to the inflammatory response of esophageal mucosa, which is known to be a strong risk factor for ADC,possibly through leukotriene synthesis; (3) higher sensitivity to the inflammatory process associated with intracellular depletion of glutathione.     

Polymorphisms of drug-metabolizing enzymes and risk of childhood acute lymphoblastic leukemia

The involvement of phase I and II enzymes is well documented in the metabolism of a wide range of drugs and xenobiotics. Single-nucleotide polymorphisms (SNPs) of these enzymes are also known to alter their protein expression and function. Moreover, genetic susceptibility and environmental exposure have been proposed to be an etiology of cancer. We hypothesized that polymorphisms of these enzymes might affect the risk of childhood acute lymphoblastic leukemia (ALL). CYP 1A1, CYP 3A4*1B, CYP 3A5*3, CYP 3A5*6, GSTM1, and GSTT1 polymorphisms were genotyped by using PCR-RFLP in 107 children with ALL and 320 healthy controls. Allele and genotype frequencies of each of the SNPs were compared between two groups. It was found that the allele frequencies of CYP 1A1*1, *2A, *2B, and *4 were not different between cases and controls. CYP 3A4*1B allele frequency was only 0.8% and 0.9% in ALL and controls, respectively. CYP 3A5*1/*1, *1/*3, and *3/*3 genotype frequencies showed no statistically significant difference between patients and controls. CYP 3A5*6 was not detected in our population. The GSTM1 null genotype was significantly increased in children with ALL (OR 1.7; 95% CI, 1.0, 2.7). In contrast, the GSTT1 null genotype did not show this effect. Our data thus demonstrate that the GSTM1 null genotype might increase the risk of childhood ALL in a Thai population.     

Glutathione-S-transferase （GSTM1, GSTrl） and the risk of gastrointestinal cancer in a Korean population

AIM: To evaluate the association of glutathione S-transferase mu (GSTM1) and glutathione S-transferase theta (GSTT1) null genotypes with the risk of gastric cancer (GC) and colorectal cancer (CRC) in a South Korean population.METHODS: We conducted a population-based, large-scale case-control study including 2213 GCs, 1829 CRCs, and 1699 controls. Null and non-null genotypes of GSTM1 and GSTT1 were determined using real-time PCR.RESULTS: The null genotypes of GSTM1 and GSTT1 were not significantly associated with elevated risk of gastric (OR = 1.070, 95% CI = 0.935-1.224; OR = 1.101, 95% CI = 0.963-1.259, respectively) or colorectal cancer (OR = 1.065, 95% CI = 0.923-1.228; OR = 1.041, 95% CI = 0.903-1.200, respectively). The frequency of the combined null GST genotype was not different between the two cancer groups and controls. Moreover, smoking, drinking, and age did not modify the association between these genotypes and the risk of gastric or colorectal cancer.CONCLUSION: GSTM1 and GSTT1 null genotypes were not associated with increased risk of GC or CRC in Koreans.     

Glutathione-S-transferase (GSTM1, GSTT1) and the risk of gastrointestinal cancer in a Korean population

AIM: To evaluate the association of glutathione S-transferase mu (GSTM1) and glutathione S-transferase theta (GSTT1) null genotypes with the risk of gastric cancer (GC) and colorectal cancer (CRC) in a South Korean population.METHODS: We conducted a population-based, largescale case-control study including 2213 GCs, 1829CRCs, and 1699 controls. Null and non-null genotypes of GSTM1 and GSTT1 were determined using realtime PCR.RESULTS: The null genotypes of GSTM1 and GSTT1 were not significantly associated with elevated risk of gastric (OR = 1.070, 95% CI = 0.935-1.224; OR = 1.101, 95% CI = 0.963-1.259, respectively) or colorectal cancer (OR = 1.065, 95% CI = 0.923-1.228; OR = 1.041, 95% CI = 0.903-1.200, respectively). The frequency of the combined null GST genotype was not different between the two cancer groups and controls.Moreover, smoking, drinking, and age did not modify the association between these genotypes and the risk of gastric or colorectal cancer.CONCLUSION: GSTM1 and GSTT1 null genotypes were not associated with increased risk of GC or CRC in Koreans.     

Glutathione-<Emphasis Type="Italic">S</Emphasis>-transferase P1, T1 and M1 genetic polymorphisms in neoadjuvant-treated locally advanced gastric cancer: GSTM1-present genotype is associated with better prognosis in completely resected patients

OBJECTIVE: Neoadjuvant chemotherapy in gastric cancer is now standard in the Western world; however, only 30-40% of the patients respond to induction therapy. Pretherapeutic predictors of response and prognosis would be of utmost interest to individualize treatment. Glutathione-S-transferase enzymes detoxify therapeutic drugs such as platin derivates and may influence outcome of the treated patients. Therefore, glutathione-S-transferase (GST) polymorphisms were assessed as predictive markers in cisplatinum-based neoadjuvant-treated gastric cancer. MATERIALS AND METHODS: DNA was isolated from 139 patients with locally advanced gastric cancer (cT3/4 anyN cM0) before chemotherapy. Multiplex polymerase chain reaction was used for GSTT1 and GSTM1 genes, and allelic discrimination assay with the TaqMan system for the GSTP1 gene. RESULTS: One hundred ten patients could be analyzed for GSTT1 (T-:23; T + 87), 112 for GSTM1 (M-:52; M +:60) and 132 for GSTP1 (Ile/Ile: 55; Ile/Val: 59; Val/Val: 18). There was no significant correlation between any of the GSTT1, GSTM1, or GSTP1 genotypes and patients' characteristics or histopathological data; only the GSTM1+ genotype was associated with the non-intestinal subtype of the Lauren classification (p = 0.045). GSTT1, GSTM1, and GSTP1 genotypes were not correlated with response to chemotherapy (p = 0.57, p = 0.38, p = 0.33). In R0 resected patients, we found an improved survival for patients with the GSTM1-present genotype compared to patients with the GSTM1-null genotype (p = 0.017). Moreover, the GSTM1-present genotype showed a significantly better tumor-related (p = 0.017) and disease-free survival (p = 0.029). CONCLUSION: None of the common GST polymorphisms predicts response in our study, but the GSTM1+ genotype was associated with a better prognosis in completely resected patients. Further investigations on chemotherapy-associated gene polymorphisms are warranted.     

Genetic polymorphisms of cytochrome p450 2E1, glutathione S-transferase M1 and T1, and susceptibility to gastric carcinoma in Taiwan

BACKGROUND AND AIMS: Cytochrome p450 (CYP) and glutathione S-transferase (GST) enzymes are involved in activation and detoxification of many potential carcinogens. Genetic polymorphisms in these enzymes have been found to influence interindividual and interethnic susceptibility to cancer. Although CYP and GST enzymes are involved in the activation and detoxification of N-nitrosamines and related compound, studies on the relationship between genetic polymorphisms of CYP2E1, GSTT1, and GSTM1 and the risk of gastric carcinoma (GC) are few, and the results have been conflicting. PATIENTS AND METHODS: We conducted a hospital-based case-control study to investigate whether such variations affect the risk of developing GC. Subjects included 356 GC patients and 278 unaffected controls. Peripheral white blood cell DNA was obtained from all subjects. Genotyping of CYP2E1 was performed using a PCR-based restriction fragment length polymorphism assay. Deletion of GSTT1 and GSTM1 genes was assessed by multiplex PCR. RESULTS: The distribution of c2/c2 genotype of CYP2E1, detected by PstI or RsaI digestion, differed significantly between GC patients and controls; the odds ratio was 2.9. It remained significant after adjustment with gender, histological subtypes (diffuse, intestinal, mixed), location (cardia, body, antrum/angle), and stage (early, advanced). In contrast, the prevalence of CYP2E1 DraI polymorphism and GSTT1 and GSTM1 null genotype was similar in controls and GC patients. CONCLUSION: Our findings suggest that the CYP2E1 genotype is a determinant of GC risk in Taiwan.     

Relationship of tobacco smoking CYP1A1 GSTM1 gene polymorphism and esophageal cancer in Xi'an

AIM: To analyze the association of tobacco smoking polymorphism of CYP1A1 (7th exon) and GSTM1 genotype and esophageal cancer(EC) in Xi'an. METHODS: A hospital based case-control study, with molecular epidemiological method, was carried out. Polymorphism of CYP1A1 and GSTM1 of samples from 127 EC cases and 101 controls were detected by PCR method. RESULTS: There were no significant difference of age and gender between cases and controls. Tobacco smoking was the main risk factor OR=1.97;95% CI=1.12-3.48 for EC in Xi'an. The proportions of CYP1A1 Ile/Ile, Ile/Val and Val/Val gene types in cases and controls was 19.7% 45.7% 34.6% and 30.7%,47.5%, 21.8% respectively(P=0.049).Individuals with CYP1A1 Val/Val genotype compared to those with CYP1A1 Ile/Ile genotype had higher risk for EC increased (OR=2.48, 95%CI=1.12-5.54). The proportions of GSTM1 deletion genotype in cases and controls were 58.3% and 43.6%(OR=1.81, 95%CI=1.03-3.18, P=0.028). Analysis of gene-environment interaction showed that tobacco smoking and CYP1A1 Val/Val genotype; tobacco smoking and GSTM1 deletion genotype had synergism interaction respectively. Analysis of gene-gene interaction did not find synergistic interaction between these two genes. But in GSTM1 deletion group there was significant difference of distribution of CYP1A1 genotype between cases and controls (P=0.011). CONCLUSION: CYP1A1 Val/Val and GSTM1 deletion genotypes are genetic susceptibility biomarkers for EC. The risk increases, when person with CYP1A1 Val/Val and/or GSTM1 deletion genotype. And these two-metabolic enzymes seem to have interactions with tobacco smoking, in which the mechanism still needs further study.     

Lung adenocarcinoma and squamous cell carcinoma in association with genetic polymorphisms of GSTs in Slovak population

Slovak Republic belongs to the countries with high incidence of lung cancer. Gene polymorphisms of the glutathione S-transferases (GSTs) may play a role in individual lung cancer susceptibility. In presented case-control study we investigate the incidence of polymorphism of GSTT1, GSTM1, GSTP1 genes and their combinations as possible predictive factors for identification of individuals with increased risk of formation and development of adenocarcinoma (AC) and squamous cell carcinoma (SCC) of lung in Slovak population. The study was conducted on 520 individuals consisting of 118 patients with adenocarcinoma, 112 patients with squamous cell carcinoma and 290 control individuals. GSTT1, GSTM1, GSTP1 gene polymorphisms were assayed by standard PCR and PCR-RFLP technique. The results of this study indicate that the GSTT1null-genotype and combination GSTT1 null and Ile/Val or Val/Val are associated with increased risk of lung adenocarcinoma. A significant association with 2.13 - fold increased risk was observed between lung adenocarcinoma and GSTT1 null genotype (95% CI = 1.29 - 3.51; p= 0.004). Also it was proved 2.83 times statistically higher risk for development of this histological type of lung cancer (95% CI = 1.34 - 6.01; P= 0.005) in combination of GSTT1null and Ile/Val or Val/Val genotypes. GSTT1, GSTM1, GSTP1 polymorphism did not show any significant association with SCC. Our study suggests that genetic make-up in metabolizing genes may increase susceptibility towards lung cancer development.     

Interaction models of CYP1A1, GSTM1 polymorphisms and tobacco smoking in intestinal gastric cancer

AIM: To explore the interaction models of the cytochrome P-450 (CYP) 1A1 Val variant and glutathione S-transferase (GST) M1 null polymorphisms with tobacco smoking in the occurrence of intestinal gastric cancer. METHODS: A community-based case-control study was conducted in Yangzhong. Subjects included 114 intestinal types of gastric cancer with endoscopic and pathological diagnosis during January 1997 and December 1998, and 693 controls selected from their spouse, siblings or siblings-in-law who had no history of digestive system cancer. Logistic regression was used to estimate the interaction models. RESULTS: The frequency of the CYP1A1 Val variant allele in cases did not differ from that in controls. The OR of GSTM1 null genotype was 2.0 (95% confidence interval (95%CI): 1.2-3.1, P<0.01). It showed a significant type 2 form of interaction model when both CYP1A1 Val variant allele and former tobacco smoking existed (i.e., among the multiplicative effects, the disease risk is increased by the tobacco exposure alone but not by the CYP1A1 variant alone). The interaction index gamma was 2.8, and OR(eg) (95%CI) was 5.0 (1.9-13.4). GSTM1 null genotype and former tobacco smoking were significant in a type 4 interaction model (i.e., the disease risk is increased by GSTM1 null genotype or tobacco exposure alone among the multiplicative effects). The interaction index gamma and OR(eg) (95%CI) were 3.4 and 8.4 (3.4-20.9), respectively. CONCLUSION: Different interaction models of CYP1A1 Val variant allele and GSTM1 null genotype with tobacco smoking will contribute to understanding carcinogenic mechanism, but there is a need to further investigate in larger scale studies.     

Susceptibility to hepatocellular carcinoma associated with null genotypes of GSTM1 and GSTT1

ALM In order to study the association between the null genotypes of GSTM1 and GSTT1 and the genetic susceptibility to hepatocellular carcinoma (HCC). METHODS The genotypes of GSTM1 and GSTT1 of 63 cases of HCC and 88 controls were detected with the multiple PCR technique. RESULTS The frequency of GSTM1 null genotype was 57.1% among the cases, and 42.0% among the controls, the difference being statistically significant (x2 = 3.35, P = 0.067),but X2 value approaching the significance level.The odds ratio was 1.84 (95% Cl=0.91 - 3.37).The frequency of GSTT1 non-null genotype was 87.3% among the cases and 62.5% among the controls, the difference being statistically significant (X2=11.42, P=0.0007274). The odds ratio was 4.13 (95% Cl = 1.64 - 10.70).According to the cross analysis, the GSTT1 nonnull genotype was more closely associated with HCC than GSTM1 null genotype, and these two factors play an approximate addlitive interaction in the occurrence of HCC. CONCLUSION The persons with GSTM1 nullgenotype and GSTT1 non-null genotype have the increased risk to HCC.     

Polymorphism in alcohol-metabolizing enzymes, glutathione S-transferases and apolipoprotein E and susceptibility to alcohol-induced cirrhosis and chronic pancreatitis

BACKGROUND AND AIM: Susceptibility to organ damage induced by alcohol may be due to inherited variation (polymorphism) in ethanol-metabolizing enzymes, or to polymorphisms affecting free radical or lipid metabolism mediated by enzymes such as glutathione S-transferases and apolipoprotein E. The aim was to compare the genotype frequencies of alcohol dehydrogenase-2 (ADH2), ADH3, aldehyde dehydrogenase-2 (ALDH2), cytochrome P450-2E1 (CYP2E1), glutathione S-transferase-M1 (GSTM1), GSTT1, and apolipoprotein E in patients with alcoholic cirrhosis and alcoholic chronic pancreatitis to those in control groups. PATIENTS AND METHODS: The case-control study was restricted to Caucasian adults: 57 with alcoholic cirrhosis, 71 with alcoholic chronic pancreatitis, 57 alcoholics without apparent organ damage and 200 healthy blood donors. Genotypes were determined by restriction fragment length polymorphism after amplification of genomic DNA by polymerase chain reaction. RESULTS: The genotype ADH3*2/*2 was more frequent in patients with cirrhosis (40%) than blood donors (12%; OR 4.92, 95% CI 2.36-10.31) and patients with chronic pancreatitis (8%; OR 7.33, 95% CI 2.54-23.78) but was not significantly different from alcoholic controls (23%; OR 2.27, 95% CI 0.95-5.66). Patients with cirrhosis also had a higher frequency (P < 0.05) of ADH2*1/*1 (100%) than blood donors (92%) and those with chronic pancreatitis (93%). The frequencies of genotypes of ALDH2, CYP2E1, GSTM1, GSTT1 and apolipoprotein E were similar in all groups. CONCLUSION: Alcoholic cirrhosis but not alcoholic chronic pancreatitis is associated with ADH3*2/*2 and perhaps with ADH2*1/*1. Both genes encode less active alcohol-metabolizing enzymes that may be associated with cirrhosis because of delayed formation of acetaldehyde (with higher intakes of alcohol), or diversion of alcohol metabolism through pathways other than ADH.     

CYP1A1, GST gene polymorphisms and risk of chronic myeloid leukemia

PRINCIPLES: Associations between polymorphisms for genes encoding enzymes involved in biotransformation of xenobiotics and susceptibility to several cancers have been shown in several studies. The aim of the present study is to investigate the influence of cytochromes P450 (CYP450) 1A1*2C and Glutathione S-transferases (GSTs) (T1 and M1) gene polymorphisms in susceptibility to chronic myeloid leukaemia (CML). METHODS: The frequency of CYP1A1 Ile/Val alleles and of GSTT1 and GSTM1 homozygous deletions was examined in 107 patients with CML and 132 healthy controls by PCR and/or PCRRFLP methods using blood samples. RESULTS: The frequency of CYP1A1 Val allele was found to be 19.2% in CML patients and 4.4% for controls, indicating that persons carrying this allele had an increased risk of CML (OR = 5.10, 95% CI: 2.60-9.97). The frequency of individuals carrying the GSTT1 null genotype was higher among CML patients (40.2%) compared to controls (19.2%) (OR = 2.82, 95% CI: 1.58-5.05; p <0.001). Therefore, GSTT1 present genotype may be a protective factor for CML. Although GSTM1 null genotype frequency was slightly higher in the patient group (44.9%) than in the controls (42.3%), this difference was not statistically significant (OR = 1.11, 95% CI: 0.66-1.86; p = 0.693). Individuals with GSTM1 null genotypes without the T allele have a 5.981 higher risk for CML than those who have the T allele. CONCLUSIONS: This data suggests that polymorphic CYP1A1 and GSTT1 genes appear to affect susceptibility to CML.     

基因多态性及常见危险因素与胃癌易患性的研究

目的探讨中国汉族人群细胞色素P450(CYP)1A1基因型、谷胱甘肽巯基转移酶(GST) M1基因型及常见危险因素与胃癌易患性的关系,为胃癌高危人群的确定和胃癌的一级预防提供分子生物学手段。方法所有研究对象经胃镜和病理检查分为胃癌(GC,仅包括胃腺癌)组102例、慢性萎缩性胃炎(CAG)组110例、慢性浅表性胃炎(CSG)组110例、胃溃疡(GU)组62例、十二指肠溃疡(DU)组62例及正常对照组62例。采用统一的调查表对每个研究对象进行调查,调查项目包括年龄、性别、学历、职业、吸炯史、饮酒史、饮食习惯、肿瘤家族史等。采用序列特异性引物的聚合酶链反应(PCR-SSP)方法检测CYP1A1基因型及GSTM1基因型测定组的基因型频率,ELISA法测定幽门螺杆菌(Hp)感染,病例对照研究方法进行流行病学分析。结果单因素分析显示与胃癌有关联的危险因素为年龄、性别、文化程度、职业、Hp感染、吸烟、CYP1A1 G/G基因型、GSTM1空白基因型,其中大蒜为保护性因素;多因素分析显示与胃癌有关联的危险因素分别为Hp感染、CYP1A1 G/G基因型、GSTM1空白基因型,大蒜仍为保护性因素。CYP1A1 G／G基因型及GSTM1空白基因型对胃癌的发生具有协同作用。Hp感染与CYP1A1 G／G基因型、GSTM1空白基因型对胃癌的发生存在协同作用;吸烟与CYP1A1 G/G基因型、GSTM1空白基因型存在协同作用。结论具有CYP1A1 G/G或GSTM1基因型的个体发生胃癌的危险性增加,而同时有两种基因型的个体发生胃癌的危险性更高,这两种基因型可以认为是胃癌易患性的标志。     

Glutathione S-transferase genotype and risk of systemic lupus erythematosus in Koreans

Oxidative stress caused by poor detoxification efficiency of reactive oxygen species (ROS) may play a role in the development of systemic lupus erythematosus (SLE). Glutathione S-transferase (GST) is involved in the detoxification of ROS and genetic polymorphisms of GSTM1, GSTT1 and GSTP1 are associated with altered enzyme activity. The aim of this study was to determine whether GSTMI (deletion), GSTT1 (deletion) and GSTP1 (Ile(105)-->Val(105)) polymorphisms are associated with susceptibility to SLE or frequency of clinical manifestations according to the ACR diagnostic criteria. DNA was isolated from blood samples collected from 330 patients with SLE and 270 age- and sex-matched controls. GST genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. No associations were observed between GSTM1, GSTT1, and GSTP1 genotypes and risk of SLE. Among SLE patients, the GSTM1 null genotype was associated with a lower frequency of hematological disorders (P = 0.012), and a higher SSA(+)/SSB(-) autoantibody profile (P = 0.042). Compared to SLE patients with the GSTT1 non-null genotype, those with the GSTT1 null genotype had a lower frequency of discoid rash (P = 0.018), and nephritis (P = 0.033). Our findings suggest that genetic polymorphisms of GSTM1, GSTT1, and GSTP1 do not influence the risk of SLE, but a deletion of either GSTM1 or GSTT1 may influence certain clinical manifestations of the disease.