CYP1A1, CYP2E1 and GSTM1 genetic polymorphisms. The effect of single and combined genotypes on lung cancer susceptibility in Chilean people.

CYP1A1, CYP2E1 and GSTM1 polymorphisms were evaluated in Chilean healthy controls and lung cancer patients. In the Chilean healthy group, frequencies of CYP1A1 variant alleles for MspI (m2 or CYP1A1*2A) and ile/val (val or CYP1A1*2B) polymorphisms were 0.25 and 0.33, respectively. Frequencies of variant alleles C (CYP2E1*6) and c2 (CYP2E1*5B) for CYP2E1 were 0.21 and 0.16, respectively and frequency for GSTM1(-) was 0.24. The presence of variant alleles for GSTM1, MspI and Ile/val polymorphisms was more frequent in cases than in controls. However, frequencies for the c2 and C alleles were not significantly different in controls and in cases. The estimated relative risk for lung cancer associated to a single mutated allele in CYP1A1, CYP2E1 or GSTM1 was 2.41 for m2, 1.69 for val, 1.16 for C, 0.71 for c2 and 2.46 for GSTM1(-). The estimated relative risk was higher for individuals carrying combined CYP1A1 and GSTM1 mutated alleles (m2/val, OR=6.28; m2/GSTM1(-), OR=3.56) and lower in individuals carrying CYP1A1 and CYP2E1 mutated alleles (m2/C, OR=1.39; m2/c2, OR=2.00; val/C, OR=1.45; val/c2, OR=0.48; not significant). The OR values considering smoking were 4.37 for m2, 4.05 for val, 3.47 for GSTM1(-), 7.38 for m2/val and 3.68 for m2/GSTM1(-), higher values than those observed without any stratification by smoking. Taken together, these findings suggest that Chilean people carrying single or combined GSTM1 and CYP1A1 polymorphisms could be more susceptible to lung cancer induced by environmental pollutants such as polycyclic aromatic hydrocarbons.     

CYP1A1 and CYP1B1 polymorphisms and risk of lung cancer among never smokers: a population-based study

The cytochrome P450 (CYP) superfamily of enzymes catalyse one of the first steps in the metabolism of carcinogens such as polycyclic aromatic hydrocarbons, nitroaromatics and arylamines. Polymorphisms within the CYP1A1 gene have been shown to be associated with lung cancer risk, predominantly among Asian populations. Despite functional evidence of a possible role of CYP1B1 in lung cancer susceptibility, only a few studies have evaluated polymorphisms in this gene in relation to lung cancer susceptibility. This population-based study evaluates polymorphisms in both of these CYP genes within never smokers, most of whom had environmental tobacco smoke (ETS) exposure. Cases (n = 160) were identified through the metropolitan Detroit Surveillance, Epidemiology and End Results program, and age, sex and race-matched population-based controls (n = 181) were identified using random digit dialing. Neither CYP1A1 MspI nor CYP1A1 Ile(462)Val was associated with lung cancer susceptibility among Caucasians or African-Americans. Among Caucasians, however, CYP1B1 Leu(432)Val was significantly associated with lung cancer susceptibility odds ratio (OR) for at least one valine allele = 2.87 [95% confidence interval (CI) 1.63-5.07]. Combinations of this Phase I enzyme polymorphism along with selected Phase II enzyme polymorphisms (GSTM1 null, GSTP1 Ile(105)Val and NQO1 C(609)T) were evaluated. The combination of CYP1B1 Leu(432)Val and NQO1 C(609)T appeared to be associated with the highest risk of lung cancer (OR = 4.14, 95% CI 1.60-10.74), although no combinations differed significantly from the risk associated with CYP1B1 Leu(432)Val alone. When individuals were stratified by household ETS exposure (yes/no), CYP1B1 Leu(432)Val alone and in combination with Phase II enzyme polymorphisms was more strongly associated with increased lung cancer susceptibility among those with at least some household ETS exposure. Additional studies will be required to further validate these findings among never smokers and to evaluate the effects of this polymorphism among smoking populations as well.     

CYP1A1 and GSTM1 polymorphisms and lung cancer risk in Chinese populations: a meta-analysis

Genetic polymorphisms of cytochrome p450 (CYP1A1) and glutathione S-transferase M1 (GSTM1) genes are thought to have significant effects on the metabolism of environmental carcinogens and thus on cancer risk, but the reported results are not always consistent. In this meta-analysis, we assessed reported studies of associations between polymorphisms of these two genes and risk of lung cancer in Chinese populations. Through a systematic literature search for publications between 1989 and 2006, we summarized the data from 46 studies on polymorphisms of MspI and exon7-Val of CYP1A1 and GSTM1 and lung cancer risk in Chinese populations, and found that compared with the wild-type homozygous genotype (type A), lung cancer risk for the combined variant genotypes (types B and C) was 1.34-fold (95% confidence interval [CI]=1.08-1.67) (Z=2.64, P=0.008); the risk for the combined variant genotypes (Ile/Val and Val/Val) of CYP1A1 exon7 was 1.61-fold (95% CI=1.24-2.08) (Z=3.62, P<0.001), compared with the Ile/Ile genotype; and that the risk for the GSTM1 null genotype was 1.54-fold (95% CI=1.31-1.80) (Z=5.32, P<0.001), compared with the GSTM1 present genotype. Therefore, in 46 published studies in Chinese populations, we found evidence of an association between the CYP1A1 variant and GSTM1 null genotypes and increased risk of lung cancer.     

GSTM1, GSTP1, CYP1A1 and CYP2D6 polymorphisms in lung cancer patients from an environmentally polluted region of Poland: correlation with lung DNA adduct levels.

The CYP and GST genetic polymorphisms, controlling metabolism of xenobiotics, are considered to influence an individual's susceptibility to environmental and occupational carcinogens and predisposition to cancer. In the study, the effect of the GSTM1, GSTP1, CYP1A1 and CYP2D6 polymorphisms was investigated in relation to PAH-DNA adduct levels in non-tumourous lung tissue from non-small cell lung cancer (NSCLC) patients living in the industrialized region of Upper Silesia, Poland. The level of adducts among smokers was significantly elevated when compared to non-smokers (P = 0.0005). Adduct levels correlated inversely with age of patients (P = 0.00001). The GSTP1 and CYP2D6 polymorphisms had no influence on DNA adduct levels. There was a significant relationship between high adduct levels and the combined GSTM1 (null)/CYP1A1-Ile/Val genotype in the squamous cell carcinoma group (P = 0.028). An elevated number of adducts was found in patients with the GSTM1 (null)/CYP1Al-Ile/Val genotype compared to the GSTM1 (null)/CYP1A1-Ile/Ile carriers (P = 0.043). A higher frequency of the CYP1A1-Ile/Val and GSTM1 (null)/CYP1A1-Ile/Val genotypes was observed in patients with high adduct levels (P = 0.05 and P = 0.009, respectively). A significant prevalence of the GSTM1(null)/CYP1A1-Ile/Val carriers in the adenocarcinoma group was found (P = 0.003). Thus, our findings imply that the GSTMI and CYP1A1 exon 7 polymorphisms may influence PAH-DNA adduct levels in target tissue from NSCLC patients, especially in the squamous cell carcinoma group. Moreover, individuals carrying the GSTM1(null)/CYP1A1-Ile/Val genotype might exhibit a greater predisposition to a peripheral type of lung cancer.     

p53 mutations of lung cancer are not significantly affected by CYP1A1 or GSTM1 polymorphisms

Cytochrome p4501A1 gene (CYP1A1) and glutathione S-transferase mu gene (GSTM1) are involved in the metabolic activation or detoxification of environmental carcinogens including benzo[a]pyrene in tobacco smoke. Individuals with both Val/Val and C type of CYP1A1 (CYP1A1; Val/Val and CYP1A1; C) or homozygous null (-/-) genotype of GSTM1 gene (GSTM1; -/-) show increased susceptibility to lung cancer. The incidence of p53 gene mutations are related to the smoking index of the lung cancer patients. Therefore we determined genotypes of these enzymes and screened p53 gene mutations in 123 non-small cell lung cancer (NSCLC) patients. p53 gene mutations were found in 35% (43/123) of the patients. The incidence of p53 gene mutation CYP1A1; Val/Val (60.0%), CYP1A1; C (50.0%) tended to be higher than those of CYPIAI; Ile/Ile and Ile/Val (40.4%) or CYP1A1; A and B (40.5%). We conclude that the incidence of the p53 mutations does not seem to be significantly affected by only CYP1A1 or GSTM1 polymorphisms in lung cancer patients.     

CYP1A1 and GSTM1 genetic polymorphisms and lung cancer risk in Caucasian non-smokers: a pooled analysis

Polymorphisms for genes encoding the metabolic enzymes cytochrome P450 1A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) might contribute to the variability in individual susceptibility to lung cancer. The role of CYP1A1 and GSTM1 in lung carcinogenesis might be more important at low levels of exposure to carcinogens. Non-smokers represent a population at low exposure, however, they are often overlooked because of the small number of cases. We therefore conducted a pooled analysis of 14 case-control studies on lung cancer in Caucasian non-smokers with comparable information on genetic polymorphisms included in the International Collaborative Study on Genetic Susceptibility to Environmental Carcinogens. We pooled the raw data from a total of 302 cases and 1631 controls with random effects models. We also evaluated the possibility of inclusion bias and conducted influence analyses. The odds ratio (OR) of lung cancer for the variant CYP1A1 Ile(462)Val polymorphism (Ile/Val, Val/Val) was 2.99 [95% confidence interval (95%CI) 1.51-5.91]; this effect was stronger on lung adenocarcinoma (OR 4.85, 95%CI 2.03-11.6). After excluding outlying or imprecise studies, we did not observe a significant effect of the CYP1A1 MspI (T(3801)C) polymorphism or GSTM1 null genotype (OR 1.20, 95%CI 0.89-1.63). Furthermore, our analyses suggested a combined effect of the CYP1A1 Ile(462)Val polymorphism and GSTM1 null genotype. The OR for the combination of the CYP1A1 Ile(462)Val variant and GSTM1 null genotype was 4.67 (95%CI 2.00-10.9) compared with the concurrent presence of the CYP1A1 wild-type and GSTM1 non-null genotype. We did not observe a modification of the effect of the GSTM1 null genotype according to exposure to environmental tobacco smoke and urban/rural residence. Our study therefore suggests that the CYP1A1 Ile(462)Val variant allele might play a role in lung carcinogenesis among non-smokers, possibly in combination with the GSTM1 null genotype.     

Association of GSTM1, CYP1A1 and CYP2E1 genetic polymorphisms with susceptibility to lung adenocarcinoma: a case-control study in Chinese population

A case-control study of 164 lung adenocarcinoma (AC) patients with 181 age- and gender-matched healthy controls was conducted in order to assess any associations between glutathione- S -transferase M1 (GSTM1), cytochrome P4501A1 (CYP1A1) and cyto-chrome P4502E1 (CYP2E1) polymorphisms and susceptibility to lung AC in Chinese. The presence of CYP2E1 variant allele was significantly less frequent in cases than in controls, while the distribution of GSTM1 null genotype and variant CYP1A1 Msp 1 allele did not vary between cases and controls. After adjustment for age, gender, smoking and all other genotypes, the CYP2E1 Rsa1 variant allele was significantly associated with decreased risk of lung AC [odds ratio 0.534 (95% confidence interval, 0.340–0.837)]. Furthermore, 3.0-fold increased risk was found in individuals with combined GSTM1 null genotype and CYP2E1 Rsa 1 wild type versus those with combined GSTM1 non-null type and CYP2E1 variant allele. Our results suggest that CYP2E1 Rsa 1 variant allele is associated with a decreased risk of lung AC, and combined GSTM1 null genotype and CYP2E1 Rsa1 wild type has a promoting effect on susceptibility to lung AC. (Cancer Sci 2003; 94: 448–452)     

四川人群中CYP1A1基因Ile-Val和Msp1位点多态性与肺癌易感性的研究

目的　探讨细胞色素P45 0 (CYP1A1)基因异亮氨酸 (Ile) 缬氨酸 (Val)位点和Msp1位点多态性和肺癌易感性的相关关系。方法　以病例对照的研究方法 ,采用PCR RFLP和ASA PCR技术检测 82例原发性肺癌和 91例对照的CYP1A1基因Ile Val位点和Msp1位点多态性。 结果　Ile Val三种多态基因型在肺癌组和对照组分布差异有显著性 (P <0 .0 5 ) ,Ile/Val、Val/Val基因型在肺癌组的分布频率明显高于对照组 ;logistic回归分析结果显示Ile/Val、Val/Val基因型患肺癌的危险分别是Ile/Ile基因型的 1.969倍和3 .15 0倍 ;当按吸烟分层后 (将Ile/Val、Val/Val基因型合并分析 ) ,吸烟组中Ile/Val、Val/Val合并基因型患肺癌的危险是Ile/Ile基因型的 3 .0 5 9倍 ,而在不吸烟组其OR为 1.687;Msp1位点多态性在肺癌组和对照组差异无统计学意义。结论　CYP1A1第 7外显子的Ile/Val、Val/Val基因型与肺癌的易感性有关 ,可望作为肺癌易感人群筛选的重要指标 ;尚不能认为Msp1多态性与肺癌的易感性有关     

Genetic polymorphisms in cytochrome P450 (CYP) 1A1, CYP1A2, CYP2E1, glutathione S-transferase (GST) M1 and GSTT1 and susceptibility to prostate cancer in the Japanese population

Associations between genetic polymorphisms of CYP1A1, CYP1A2, CYP2E1, GSTM1 and GSTT1 and prostate cancer (PCa) were analyzed in a case-control study of 315 individuals. The frequency of valine (Val)/valine (Val) genotypes for CYP1A1 was 11.3% in cases compared with 5.5% in controls, this polymorphism thus being associated with a significantly increased risk of PCa (odds ratio=2.4, 95% confidence interval (CI)=1.01-5.57). No links were detected between PCa and polymorphisms in other enzymes. However, the combination of CYP1A1 (Ile/Val and/or Val/Val) polymorphisms with the GSTM1 null type resulted in an OR of 2.2 (CI=1.10-4.57, 1.12-4.20, respectively). This study suggests that the CYP1A1 polymorphism and its combination with GSTM1 may be associated with PCa susceptibility in the Japanese population.     

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?P?P?相似文献   

CYP 1A1 polymorphism and risk of lung cancer in relation to tobacco smoking: a case-control study in China

The impact of genetic polymorphisms in CYP1A1 on susceptibility to lung cancer has received particular interest in recent years since this enzyme plays a central role in activation of major classes of tobacco carcinogens. Several polymorphisms in the CYP1A1 locus have been identified and their genotypes appear to exhibit population frequencies that depend on ethnicity. We have assessed the role of CYP1A1 genotype in lung cancer risk in the Chinese population via a case-control study. Three polymorphisms, m1 (MSP:I), m2 (exon 7 Ile-->Val) and m4 (exon 7 Thr-->Asn), were determined by PCR-RFLP in 404 controls and 217 lung cancer cases. While no polymorphic alleles were detectable in the m4 site among our study subjects, the allele frequencies for CYP1A1 m1 and CYP1A1 m2 were found to be 35.6 and 25.6% among controls, compared with 42.6 and 34.2% among cases. Multivariate analysis showed an elevated risk for lung cancer in subjects having at least one m1 allele [odds ratio (OR) = 2.0, 95% confidence interval (CI) = 1.4-2.8] or having at least one m2 allele (OR = 1.9, 95% CI = 1.3-2.7). However, this increased risk was limited to squamous cell carcinoma (SCC), but not adenocarcinoma or other histological types of lung cancer. Stratified analysis indicated a multiplicative interaction between tobacco smoking and variant CYP1A1 m1 genotypes on the risk of SCC. The ORs of SCC for the variant CYP1A1 m1 genotype, tobacco smoking and both factors combined were 2.8, 9.1 and 29.9, respectively. When the data was stratified by the pack-year values, this joint effect was consistent and stronger among the heaviest smokers. The interaction between tobacco smoking and the variant CYP1A1 m2 genotypes followed the same pattern. Our findings support the conclusion that CYP1A1 m1 and CYP1A1 m2 polymorphisms are associated with smoking-related lung cancer risk in Chinese.     

58. Susceptibility to lung cancer is associated with genetic polymorphisms of CYP1A1、GSTM1

Objective: To investigate the association of lung cancer susceptibility with genetic Polymorphism of CYP1A1 and GSTM1. Methods: The study was conducted on 65 lung cancer cases and 60 no-cancer controls. The genetic polymorphism both CYP1A1 and GSTM1 were performed in cancer tissues of all patients and peripheral blood leukocytes of no-cancer controls. First by RFLP-PCR, then after incubating with restriction enzyme Ncol and Hinfl. Results: ①There were no significant differences in the frequency distribution of CYP1A1 polymorphisms between lung cancer patients and controls, but the frequency of CYP1A1(Val/Val) was significant higher than that controls (P<0.05). ②If OR for CYP1A1 (Ile/Ile) genotype was 1.0, the OR of CYP1A1 (Ile/VaL)、CYP1A1 (Val/Val) was 1.68 (95%CI, 0.79～3.59) and 3.2 (95%CI, 1.06～10.26), respectively. ③The significant difference were observed that GSTM1(-) became markedly expressed (63.1%, 41/65) in elung cancer patients than in the corresponding controls (45%, 27/60) (P<0.05), OR was 2.09 (95%CI, 1.02～4.26); ④When analysis combined CYP1A1 and GSTM1 genotype, we found that individual who take along CYP1A1 (Ile/Ile)/GSTM1 (-) or CYP1A1 (Ile/Val+Val/Val)/GSTM1 (+) genotype had higher odds ratio than CYP1A1 (Ile/Ile)/GSTM1 (+) genotype, the OR was 3.82 (95%CI, 1.27～11.45) and 3.5 (95%CI 1.18～10.41), respectively, but the CYP1A1 (Val/Val) / GSTM1 (-) genotype was the hightest odds ratio, the OR was 10.5 (95%CI, 1.70～64.73). ⑤We observed that the individual who carry CYP1A1(Val/Val) genotype can increased risk of squamous cell carcinoma of lung (P<0.05), OR was 2.75 (95%CI, 1.24～6.17), there was no significant associated of pathologic with GSTM1 genotype. ⑥Stratified analysis suggested an interaction between cigarettes smoking and CYP1A1 (Ile/Val+Val/Val)、GSTM1 (-) genotype. Conclusion: ①The individuals who carried genotype of CYP1A1 (Val/Val) and GSTM1 (-) were susceptible to lung cancer. ②the individuals who carried CYP1A1 (Ile/Ile) /GSTM1 (-) or CYP1A1 (Ile/Val+Val/Val) /GSTM1 (+) genotype with higher risk of developing lung cancer than that CYP1A1 (Ile/Ile)/GSTM1 (+) genotype. ③There were interaction between smoking and CYP1A1 (Ile/Val+Val/Val)、GSTM1 (-)     

CYP1A1 GSTM1基因多态性和吸烟与肺癌易感性关系的病例对照研究

目的:探讨天津市居民致癌物代谢酶CYP1A1和GSTM1基因多态性对肺癌易感性的影响。方法:利用限制性片断长度多态性-聚合酶链反应(RFLP-PCR)方法检测原发性肺癌患者和健康对照者细胞色素P450酶基因CYP1A1Msp位点和谷胱甘肽硫转移酶基因GSTM1的多态性情况。结果:肺癌组与对照组之间CYP1A1和GSTM1基因型分布差异均存在统计学显著意义(P<0.05)。携带CYP1A1变异基因型或GSTM1阴性基因型的个体患肺癌的危险性增高,比值比(OR)分别达到2.44(1.04～5.81)和1.84(1.03～3.29)。多因素分析结果显示具有CYP1A1变异基因型、GSTM1阴性基因型的吸烟个体患肺癌的风险较大。结论:CYP1A1Msp位点变异基因型和GSTM1阴性基因型可能是肺癌的易感因素,吸烟与肺癌易感基因之间具有协同作用。     

Susceptibility of Lung Cancer with Polymorphisms of CYP1A1, GSTM1, GSTM3, GSTT1 and GSTP1 Genotypes in the Population of Inner Mongolia Region

Background: To study the relationship of susceptibility to lung cancer with the gene polymorphisms of CYP1A1, GSTM1, GSTM3, GSTT1, GSTP1 and smoking status in Han and Mongolian populations of Inner Mongolia, an autonomous region of China. Materials and Methods: PCR-RFLP, allele-specific and multiplexPCR were employed to identify the genotypes of CYP1A1, GSTM1, GSTM3, GSTT1 and GSTP1 in a case-control study of 322 lung cancer patients diagnosed by bronchoscopy and 456 controls free of malignancy. Results: There is a significant difference in genotypic frequency of GSTT1 of healthy Mongolian and Han subjects. A statistically prominent association was found between CYP1A1 Msp1 (vt/vt) (OR=4.055, 95%CI:2.107-7.578, p=0.000), GSTM1 (-) (OR=2.290, 95%CI:1.467-3.573, p=0.000) and lung cancer in Mongolians. Similarly, in the Han population, CYP1A1 Msp1 (vt/vt) (OR=3.194, 95%CI:1.893-5.390, p=0.000) and GSTM1 (-) (OR=1.884, 95%CI:1.284-2.762, p=0.001) carriers also had an elevated risk of lung cancer. The smokers were more susceptibleto lung cancer 2.144 fold and 1.631 fold than non-smokers in Mongolian and Han populations, respectively. The mokers who carried with CYP1A1 Msp1 (wt/vt+vt/vt), exon7 (Val/Val+Ile /Val), GSTM1 (-), GSTM3 (AB+BB),and GSTT1 (-) respectively were found all to have a high risk of lung cancer. Conclusions: CYP1A1 Msp1 (vt/vt) and GSTM1 (-) are risk factors of lung cancer in Han and Mongolian population in the Inner Mongolia egion. The smokers with CYP1A1 Msp1 (wt/vt+vt/vt), CYP1A1 exon7 (Val/Val+Ile /Val), GSTM1 (-), GSTM3(AB+BB), and GSTT1 (-) genotypes, respectively, are at elevated risk of lung cancer.     

GSTM1和CYP1A1基因多态性与宫颈癌发生及发展的相关性

目的:探讨谷胱苷肽硫转移酶M1（GSTM1）和CYP1A1 Exon7基因多态性与宫颈癌发生发展的关系。方法:选取2013年5月至2015年5月我院收治的宫颈癌患者184例为宫颈癌组,203例进行体检的健康人群为参照组。用限制性片段长度多态性-聚合酶链反应（RFLP-PCR）检测所有受试者GSTM1和CYP1A1 Exon7基因型;记录无进展生存期（PFS）,并随访观察生存和死亡情况。结果:GSTM1分为野生型（wt）和突变缺失型（null）,CYP1A1 Exon7野生型为Ⅱe/Ⅱe,突变型包括突变纯合型（Val/Val）、突变杂合型（Ⅱe/Val）。宫颈癌组携带GSTM1突变型基因型比例与参照组间比较,差异无统计学意义（P＞0.05）;宫颈癌组携带CYP1A1 Exon7突变型基因型比例显著高于参照组（P＜0.05）,且携带突变型基因型个体患宫颈癌的风险是携带野生型基因型个体的2.333倍。GSTM1、CYP1A1 Exon7基因型与宫颈癌患者年龄、病理分期、肿瘤分化程度、肿瘤直径及淋巴结转移均无关（P＞0.05）,与患者病理类型有关（P＜0.05）。GSTM1、CYP1A1 Exon7突变型宫颈癌患者PFS中位数与野生型患者比较,差异均无统计学意义（P＞0.05）。GSTM1、CYP1A1 Exon7突变型宫颈癌患者基因型与宫颈癌患者预后无关（P＞0.05）。结论:GSTM1及CYP1A1 Exon7基因多态性是宫颈癌发生发展的危险因素,尤其是CYP1A1 Exon7突变型,为预防宫颈癌提供依据。     

Association of CYP1A1, CYP1A2, GSTM1 and NAT2 gene polymorphisms with colorectal cancer and smoking.

We investigated CYP1A1*2A, CYP1A1*2C, CYP1A2*1C, CYP1A2*1F, GSTM1 and NAT2 gene polymorphisms, involving enzymes which metabolize many carcinogens, with reference to colorectal cancer risk. The distribution of these genotypes was not associated with risk overall. However, the CYP1A1*2A T/C genotype showed a significant association with colorectal cancer risk in never-smokers (odds ratio [OR], 3.06; 95% confidence interval [95% CI], 1.11-8.40; p = 0.030). The risk of the NAT2 rapid genotype in never-smokers was also statistically significantly increased (OR, 5.38; 95%CI, 1.80-16.1; p = 0.003). Furthermore, the joint effects of NAT2 rapid plus other genotypes were associated with colorectal cancer overall (OR, 3.12; 95%CI, 1.15-8.51; p = 0.026, for NAT2 rapid plus combined CYP1A1*2C Ile/Val and Val/Val, OR, 3.25; 95%CI, 1.09-9.74; p = 0.035, for NAT2 rapid plus CYP1A2*1C G/G, and OR, 4.20; 95%CI, 1.09-16.1; p = 0.037, for NAT2 rapid plus GSTM1 null, respectively). In never-smokers, the joint effects of NAT2 rapid plus other genotypes were remarkable (OR, 15.9; 95%CI, 1.87-135.8; p = 0.011, for NAT2 rapid plus combined CYP1A1*2A T/C and C/C, OR, 5.71; 95%CI, 1.49-21.9; p = 0.011, for NAT2 rapid plus combined CYP1A1*2C Ile/Val and Val/Val, and OR, 9.14; 95%CI, 2.05-40.7; p = 0.004, for NAT2 rapid plus CYP1A2*1F A/A, respectively). The joint effect of CYP1A2*1F A/A plus CYP1A2*1C G/G genotypes was also increased in never-smokers (OR, 6.16; 95%CI, 1.26-30.1; p = 0.025). Our findings suggest that the CYP1A1*2A T/C and NAT2 rapid genotypes is associated with colorectal cancer susceptibility without smoking exposure. These results also indicate that the NAT2 in combination with CYP1A1*2C, CYP1A2*1C, or GSTM1 genotypes may strongly confer susceptibility to colorectal cancer. In particular, the combination of NAT2 plus CYP1A1*2A, CYP1A1*2C, or CYP1A2*1F genotypes, and that of CYP1A2*1F plus CYP1A2*1C genotype may define a group of persons who are genetically susceptible to colorectal cancer in never smokers.     

Oral cancer susceptibility associated with the CYP1A1 and GSTM1 genotypes in Chilean individuals

Polycyclic aromatic hydrocarbons (PAHs) contained in tobacco smoke acquire carcinogenicity following their activation by xenobiotic-metabolizing enzymes to highly reactive metabolites. The cytochrome P4501A1 (CYP1A1) enzyme is central to the metabolic activation of these PAHs, and GSTM1 is the main enzyme responsible for its detoxification. CYP1A1 and GSTM1 polymorphisms were evaluated in 124 Chilean healthy controls and 48 oral cancer patients through PCR-based restriction fragment length polymorphism. In the healthy controls, frequencies of the CYP1A1 variant alleles for m1 (CYP1A1(*)2A) and the GSTM1null genotype were found to be 0.25 and 0.19, respectively. In the oral cancer patients, these frequencies were 0.33 and 0.50, respectively. Thus, the GSTM1 and m1 rare alleles were significantly more frequent in the oral cancer patients compared to the controls. The estimated relative risk for oral cancer associated with the single genotype CYP1A1 or GSTM1 was 2.08 for wt/m1, 1.04 for m1/m1 and 4.16 for the GSTM1null genotype. For smokers, the estimated relative risk (adjusted by age and gender) was higher in the individuals carrying the m1 allele of CYP1A1 [wt/m1: odds ratio (OR)=5.68, P=0.0080; m1/m1: OR=7.77, P=0.0420] or GSTM1null genotype (OR=20.81, P<0.0001). Combined genotypes CYP1A1 and GSTM1 increased the risk significantly (wt/m1/GSTM1null: OR=19.14, P=0.0030; m1/m1/GSTM1null: OR=21.39, P=0.0130). Taken together, these findings suggest that Chilean individuals carrying single or combined GSTM1 and CYP1A1 polymorphisms may be more susceptible to oral cancer induced by environmental tobacco smoking.     

Genetic Polymorphisms of CYP2E1 and GSTP1 in a South Indian Population - Comparison with North Indians,Caucasians and Chinese

CYP2E1 and GSTP1 enzymes belong to phase I and phase II group of drug metabolizing enzymes respectively ‍which are involved in the metabolic activation and detoxification of various potential genotoxic compounds. The ‍functional polymorphism in these genes exhibit inter-individual variations in susceptibility towards various diseases ‍and difference in therapeutic response. The variant sequences of these genes differ considerably between ethnic ‍groups. Therefore, the objective of the study was to assess the prevalence of CYP2E1 & GSTP1 gene variants in ‍healthy volunteers of Tamilnadu, a population of South India. The genotype distribution of CYP2E1*1B A2A2, A2A1 ‍and A1A1 were 61%, 36% and 3% respectively. The distribution of CYP2E1*5B c1c1, c1c2 genotypes were 99.2%and ‍0.8%. CYP2E1*6 DD, DC and CC genotype frequencies were 72%, 25% and 3% respectively. The allele frequencies ‍of CYP2E1*1B, CYP2E1*5B and CYP2E1*6 were A2- 0.79 A1- 0.21, c1-0.996 c2 - 0.004 and D- 0.84 C- 0.16 respectively. ‍The genotypic distribution of GSTP1 (Ile/Val) were Ile/Ile - 44%, Ile/Val -47% and Val/Val- 9 % whereas, the allelic ‍frequencies were 0.67 for Ile and 0.33 for Val allele. The molecular studies in these enzymes provide basis for further ‍epidemiological investigations in the population where the functional mutations in the genes alter therapeutic response ‍and acts as susceptibility markers for various clinical conditions.     

Genetic polymorphisms of cytochrome P450 1A1 and risk of gallbladder cancer

The relation between cytochrome P4501A1 (CYP1A1) gene polymorphisms and the risk of gallbladder cancer was examined. To clarify individual differences in susceptibility to gallbladder carcinogenesis, we investigated the frequency of the Mspl and Ile-Val polymorphisms of the CYP1A1 gene, in 52 patients with gallbladder cancer (32 females, 20 males) and 104 healthy controls (64 females, 40 males). We then examined the relationship between the CYP1A1 polymorphisms and the development of gallbladder cancer in members of both sexes. A statistical difference in the frequencies of the MspI and Ile-Val polymorphisms or their alleles (ml, m2 and Ile, Val) was not observed in the male patients and controls. Among females, however, the frequencies of genotypes C and Ile/Val were significantly higher (p < 0.05) in the patients than in their controls. Moreover, the frequency of the hetero genotype Ile/Val was statistically higher (p < 0.05) in the female patients than in the male patients. This study demonstrated a significant over-representation of genotypes C and Ile/Val in female patients with gallbladder cancer. Females with genotypes C and/or Ile/Val may have a high genetic susceptibility to the development of gallbladder cancer.     

中国人肺癌易患性与CYP2E1基因多型性相关

目的　研究致癌物代谢酶细胞色素P45 0 2E1基因 (CYP2E1)多型性与肺癌风险的关系。方法　以PCR RFLP方法 ,分析 92例肺癌患者和 137例正常对照者RsaI识别的CYP2E1基因型。结果　c1/c1基因型频率在肺癌病例组为 72 8% ,显著 (P <0 0 1)高于对照组的 5 4 7%。多因素分析表明 ,携带c1/c1的个体发生肺癌的危险性比携带c1/c2和c2 /c2的个体高 2 5倍 (OR 2 5 ,95 %CI 1 8～ 3 8)。分层分析发现 ,c1/c1基因型主要增加肺鳞状细胞癌的危险性 (OR 2 6 ,95 %CI 2 3～ 5 8)。重要的是 ,研究发现CYP2E1c1/c1基因型与吸烟有协同作用。c1/c1基因型或吸烟单因素作用的OR分别为 3 9和 4 1,而二者联合作用的OR为 7 9;当吸烟量 <2 0包 年时 ,c1/c2和c2 /c2基因型的OR为 2 4,而c1/c1基因型的OR为 7 6 ;当吸烟量≥ 2 0包 年时 ,前者的OR为 5 5 ,而后者的OR增加到8 7。结论　CYP2E1c1/c1基因型是中国人肺癌的遗传易患性因素 ,此种基因型与吸烟有协同作用。