Association between CYP2E1 polymorphisms and susceptibility to prostate cancer.

Several genetic alterations have been associated with sporadic prostate cancer (PCa). In this study, the association between RsaI and DraI polymorphisms of CYP2E1 and PCa risk was analysed in a case-control study of 227 individuals using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Regarding DraI polymorphisms, the DD genotype is over-represented in PCa cases when compared with the control group (odds ratio (OR) 2.12; 95% confidence interval (CI) 1.11-4.05; P=0.022). Regarding the RsaI polymorphism, no significant differences were found. The results of this study indicate that DraI polymorphisms of the CYP2E1 gene may be associated with a twofold increased risk for the development of PCa.     

Cytochrome P450 2E1 RsaI/PstI and DraI polymorphisms are risk factors for lung cancer in Mongolian and Han population in inner Mongolia

Objective: To explore the relationship between cytochrome P450 2E1 (CYP2E1) RsaI/PstI and DraI polymorphism and lung cancer susceptibility in Mongolian and Han population in Inner Mongolia of China. Methods: CYP2E1 RsaI/PstI and DraI polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism in 64 lung cancer patients, 150 healthy Mongolian and 150 healthy Han individuals. The distribution of genotype and allele frequencies of CYP2E1 RsaI/PstI and DraI polymorphisms we...     

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。     

细胞色素P450 2E1和谷胱甘肽转硫酶P1基因与食管癌易患性

目的研究与致癌物亚硝胺代谢激活有关的细胞色素Ｐ４５０２Ｅ１基因（ＣＹＰ２Ｅ１）,和与致癌物代谢解毒有关的谷胱甘肽转硫酶Ｐ１基因（ＧＳＴＰ１）多型性与食管癌易患性的关系。方法采用病例－对照分子流行病学方法。以ＰＣＲ－ＲＦＬＰ方法分析食管癌、食管上皮重度增生病例,和与其年龄性别配对的正常对照者（各４５例）ＣＹＰ２Ｅ１和ＧＳＴＰ１的基因型。结果ＧＳＴＰ１基因型在病例和对照者中的分布无显著差别,但ＲｓａＩ识别的ＣＹＰ２Ｅ１基因型,在食管癌、食管上皮重度增生病例及其正常对照者中的分布差别显著。ＣＹＰ２Ｅ１突变型基因频率在正常对照组中为５５．６％,显著高于食管上皮重度增生病例（１７．８％）和食管癌病例（２０．０％;χ２＝２０．８,Ｐ＜０．００１）;携带野生型ＣＹＰ２Ｅ１的个体,发生食管上皮重度增生和食管癌的危险性,比携带变异型ＣＹＰ２Ｅ１的个体各高５倍。结论ＣＹＰ２Ｅ１基因是涉及食管癌变早期过程的遗传易患性因素。     

Role of alcohol dehydrogenase 3 and cytochrome P-4502E1 genotypes in susceptibility to cancers of the upper aerodigestive tract

Alcohol is a recognized risk factor for upper aerodigestive tract (UAT) cancers, but the mechanism by which alcohol causes cancer remains obscure. Ethanol is oxidized to acetaldehyde (the suspected carcinogenic agent in alcohol) by alcohol dehydrogenases (ADHs) and cytochrome P-4502E1 (CYP2E1), both of which exhibit great inter-individual variability in activity. The hypothesis that these polymorphisms influence susceptibility to alcohol-related cancers remains poorly documented. We investigated whether ADH(3) and CYP2E1 DraI and RsaI genotypes modified the risk of UAT cancers among 121 oral cavity/pharyngeal cancer patients, 129 laryngeal cancer patients, and 172 controls, all French Caucasians. Cancer risks and gene-alcohol interactions were analyzed by unconditional logistic regression, accounting for potential confounders. ADH(3) genotype was not associated with UAT cancer. In contrast, a 2-fold risk of oral cavity/pharyngeal (OR = 2.0, 95% CI 1.0-3.9) and laryngeal (OR = 1.8, 95% CI 1.0-3.5) cancers was observed for carriers of the CYP2E1 DraI C variant allele compared with other individuals. The risk associated with the CYP2E1 RsaI c2 variant allele also increased for oral cavity/pharyngeal cancer (OR = 2.6, 95% CI 1.0-6. 6). The effects of ADH(3) or CYP2E1 genotype and alcohol or tobacco were independent. The highest risk of oral cavity/pharyngeal cancer was observed among the heaviest drinkers (>80 g/day) with the CYP2E1 DraI C allele (OR = 5.8, 95% CI 1.9-18.2) or the CYP2E1 RsaI c2 allele (OR = 7.2, 95% CI 1.4-38.2) compared with lighter drinkers with other genotypes. Our study suggests that CYP2E1 genotype modifies the risk of UAT cancers, but due to the low frequency of CYP2E1 variant alleles, large-scale studies are needed to confirm our findings.     

CYP2E1PstI/RsaI polymorphism and interaction with tobacco, alcohol and GSTs in gastric cancer susceptibility: A meta-analysis of the literature

Studies investigating the association between cytochrome P450 2E1 (CYP2E1) 5'-flanking region (PstI/RsaI) polymorphism and gastric cancer risk report conflicting results. The rationale for this meta-analysis was to determine whether CYP2E1*2 (c2) variant allele of CYP2E1 increases gastric cancer risk, especially by interacting with smoking, alcohol and other metabolic gene polymorphisms. Two investigators independently searched the Medline and Embase databases. A qualitative scoring of papers was applied to their evaluation. Authors of the identified papers were contacted to obtain data on the mentioned co-exposures. A measurement of the biological interaction among two putative risk factors was estimated by the attributable proportion (AP) due to interaction. We identified 13 case-control studies, which included 2066 gastric cancer cases and 2754 controls. Using the random effects model, we found no association between PstI/RsaI genotype and gastric cancer risk [odds ratio (OR) = 0.97 (95% confidence interval (CI): 0.79-1.18) for c2 allele carriers and OR = 1.36 (95% CI: 0.82-2.25) for c2 homozygotes compared with homozygotes wild-type]. When only high-quality scored studies were considered, a statistically significant increased risk appeared among Asians [OR = 1.50 (95% CI: 1.16-1.94) for c2 carriers and OR = 2.62 (95% CI: 1.23-5.57) for c2 homozygotes]. No interaction was detected between CYP2E1-smoking/alcohol (AP = 0), while an AP of 60% appeared for individuals both c2 homozygotes and glutathione S-transferase M1 (GSTM1) null compared with both homozygotes wild-type. This meta-analysis suggests that the CYP2E1 PstI/RsaI polymorphism may be a risk factor for gastric cancer in Asians, and that a synergic relation among GSTM1 and CYP2E1 may account for a proportion of gastric cancer cases.     

Functional RsaI/PstI Polymorphism in Cytochrome P450 2E1 Contributes to Bladder Cancer Susceptibility: Evidence from a Meta-analysis

Background: Cytochrome P450 2E1 (CYP2E1) might be involved in the development of bladder cancer. However, previous studies of any association between CYP2E1 RsaI/PstI polymorphism and bladder cancer risk have yielded conflicting results. In this study, we performed a more precise estimation of the relationship by a meta-analysis based on the currently available evidence from the literature. Method: To assess the effect of CYP2E1 RsaI/PstI polymorphism on bladder cancer susceptibility, a meta-analysis of 6 available studies with 1,510cases and 1,560 controls were performed through Feb 2014. Summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were used to estimate the strength of association for CYP2E1 RsaI/PstI polymorphism under different genetic models. Results: When available studies were pooled into the meta-analysis, we found that the C1C2 and C2C2 genotypes of CYP2E1 RsaI/PstI polymorphism significantly decreased bladder cancer risk under different genetic models (heterozygote: OR=0.766, 95%CI=0.613-0.957, POR=0.019; homozygote: OR=0.51, 95%CI=0.303- 0.858, POR=0.011; dominant: OR=0.733, 95%CI=0.593-0.905, POR=0.004; recessive: OR=0.565, 95%CI=0.337-0.947, POR=0.030). Subgroup analysis indicated that C2C2 genotype was significantly associated with decreased bladder cancer risk under the homozygote genetic model in Caucasians. There was no evidence of heterogeneity or publication bias. Conclusions: The current meta-analysis suggested that the CYP2E1 RsaI/PstI polymorphism might be associated with bladder cancer susceptibility, especially in Caucasians. Further studies are needed to validate the above conclusion.     

Polymorphism in CYP1A1 and CYP2E1 genes and susceptibility to leukoplakia in Indian tobacco users

Inter-individual genetic differences may contribute to differences in susceptibility to human diseases triggered by environmental exposures. In this study, we investigated polymorphisms at two sites in the CYP1A1 and three sites in the CYP2E1 genes in 99 leukoplakia patients and 227 controls from one Indian population. The frequencies of genotypes at these polymorphic sites (MspI and Ileu/Val) in the CYP1A1 and (PstI, RsaI and DraI) in the CYP2E1 genes, were similar in patient and control groups. But the combined rare and heterozygous genotypes (CC+CD) at the DraI site in the CYP2E1 gene were over-represented among patients compared with controls (age-adjusted odds ratio (OR)=2.02, 95% confidence interval (CI)=1.21-3.35). Light tobacco smokers (i.e. <21 pack-year) and light tobacco chewers (i.e. <104 chewing-year) with a "rare" C allele at the DraI site had high risk of leukoplakia (OR=2.88, 95% CI=1.16-7.22; OR=2.94, 95% CI=1.15-7.65, respectively). The "mixed tobacco" users with "rare" C allele are more susceptible to the disease than "exclusive" tobacco smokers and chewers. The results indicate that the "rare" C allele at the DraI polymorphic site in CYP2E1 gene may enhance susceptibility to leukoplakia among tobacco users in this population. But the low sample size limited the power to precisely estimate the tobacco-genotype interactions.     

Updated Meta-analysis of the Association Between CYP2E1 RsaI/PstI Polymorphisms and Lung Cancer Risk in Chinese Population

Background: A number of studies have reported relationships of CYP2E1 RsaI/PstI polymorphisms with susceptibility to lung cancer in Chinese population. However, the epidemiologic results have been conflictive rather than conclusive. The purpose of this study was to address the associations of CYP2E1 RsaI/PstI polymorphisms with lung cancer risk in Chinese population comprehensively. Materials and Methods: Systematic searches were conducted in the PubMed, Science Direct, Elsevier, CNKI and Chinese Biomedical Literature Databases. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of association. Results: Overall, we observed a decreased lung cancer risk among subjects carrying CYP2E1 RsaI/PstI c1/c2 and c1/c2+c2/c2 genotypes (OR=0.76, 95%CI: 0.64-0.90 and OR=0.78, 95%CI: 0.66-0.93, respectively), as compared with subjects carrying the c1/c1 genotype. In subgroup analysis, we observed a decreased lung cancer risk among c1/c2 carriers in hospital-based studies (OR=0.81, 95%CI: 0.68-0.98) and among carriers with c1/c2 and c1/c2+c2/c2 genotypes in population-based studies(OR=0.57, 95%CI: 0.42-0.79 and OR=0.58, 95%CI: 0.43-0.79, respectively), as compared with subjects carrying the c1/c1 genotype. Limiting the analysis to studies with controls in Hardy-Weinberg equilibrium (HWE), we similarly observed a decreased lung cancer risk among c1/c2 and c1/c2+c2/c2 carriers (OR=0.73, 95%CI: 0.60-0.88 and OR=0.73, 95%CI: 0.60-0.88, respectively), as compared with c1/c1. Conclusions: Our results suggested that CYP2E1 RsaI/PstI c1/c2 and c1/c2+c2/c2 variants might be a protective factor for developing lung cancer in Chinese population. Further well-designed studies with larger sample size are required to verify our findings.     

Effects of cytochrome P450 (CYP) 2A6 gene deletion and CYP2E1 genotypes on gastric adenocarcinoma

Cytochrome P450 (CYP) 2A6 and CYP2E1 are enzymes with a high ability to activate a nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), to its potent and ultimate carcinogens. The polymorphic CYP2A6 and CYP2E1 have been implicated in increased susceptibility to certain malignancies. In our study, 120 Japanese patients with gastric adenocarcinoma and 158 healthy controls were compared for frequencies of CYP2A6 and CYP2E1 genotypes. The frequency with which the subjects carried homozygotes of the CYP2A6 gene deletion allele, which causes lack of the enzyme activity, was significantly higher in the gastric cancer patients than in the healthy control subjects (OR = 3.14, 95% confidence interval (95% CI) = 1.05-9.41). Subdividing gastric adenocarcinoma according to tumor differentiation, patients with the well-differentiated type were 4.9-fold more likely to have the CYP2A6 homozygote deletion genotype (OR = 4.91, 95% CI 1.17-20.52). Stratifying by smoking status, we did not find the risk of CYP2A6 gene deletion allele in gastric adenocarcinoma. The CYP2E1 polymorphism detected by RsaI was not significantly different between gastric adenocarcinoma patients (40.8%) and the control population (44.3%). No statistically significant changes were observed when the CYP2E1 genotype was examined relative to tumor differentiation and smoking status. These results suggest that the CTY2A6 deletion is associated with gastric adenocarcinoma among Japanese populations.     

CYP2E1 rs2031920, COMT rs4680 Polymorphisms,Cigarette Smoking,Alcohol Use and Lung Cancer Risk in a Japanese Population

Background Cytochrome P450 2E1 (CYP2E1) and catechol-O-methyltransferase (COMT) genes may contribute to susceptiblity to lung cancer becuase of their critical involvement in mechanisms of carcinogenesis. Materials and Methods We evaluated the role of CYP2E1 rs2031920 and COMT rs4680 in a case-control study involving 462 lung cancer cases and 379 controls in Japanese. Logistic regression was used to assess adjusted odds ratios (OR) and 95% con dence intervals (CI). Multiplicative and additive interactions with cigarette smoking or alcohol use were also examined. Results Neither CYP2E1 rs2031920 nor COMT rs4680 was associated with lung cancer risk overall. However, smokers with the CC genotype of CYP2E1 rs2031920 (OR 3.57, 95% CI 2.26-5.63) presented a higher risk of lung cancer than those with at least one T allele (OR 2.91, 95% CI 1.70-4.98) as compared to never-smokers with at least one T allele (reference). Subjects with excessive drinking and the CC genotype of CYP2E1 rs2031920 had a signi cantly higher risk (OR2.22, 95% CI 1.39-3.56) than appropriate drinkers with at least one T allele. A similar tendency was observed between COMT rs4680 and either smoking or drinking habits. There were no multiplicative or additive interactions between the polymorphisms and either smoking or alcohol use. Conclusions Our ndings indicate that CYP2E1 rs2031920 and COMT rs4680 are not major contributors to lung cancer risk in our Japanese population. Future studies on the genetics of lung cancer in Japanese and their environment interactions are required.     

Lung cancer risk and CYP1A1 genotype in African Americans

The role of CYP1A1 genotype in lung cancer risk was assessed in African Americans through a case control study. The complete CYP1A1 genotype, including the frequency of all three polymorphisms (Msp1 [CYP1A1*2], exon 7 [CYP1A1*3] and African American specific [CYP1A1*4]) was determined by PCR on 307 controls and 105 cases of lung cancer among African Americans. We have confirmed our earlier observation of a significant increased risk (odds ratio = 2.8, 95% CI = 1.3-6.5) for lung adenocarcinoma among people with the *4 polymorphism, although we did not observe any association of this polymorphism with overall lung cancer risk. As previously reported, we found that lung adenocarcinoma patients with the *4 RFLP smoked significantly less than patients without this polymorphism, suggesting an important role in cancer risk of low exposure levels to cigarette smoke in subjects carrying susceptibility polymorphisms. There was no association with the other two polymorphisms and lung cancer in this population. When we examined lung cancer risk as a function of composite genotype, taking into account all three polymorphisms simultaneously in each subject, our preliminary data suggested an association of one rare genotype (homozygous Msp1, heterozygous exon 7 or *2/*2*3) with overall lung cancer risk (OR = 8.4, 95% CI = 1.6-43.2).      

Glutathione S-transferase M1 polymorphism and lung cancer risk in African-Americans

Glutathione S:-transferase M1 (GSTM1) can detoxify many carcinogens, including polycyclic aromatic hydrocarbons such as those from cigarette smoke. Though a number of studies have been published about the association between GSTM1 polymorphism and lung cancer, this association has received limited attention in the African-American population. We conducted a case-control study to investigate the role of GSTM1 polymorphism in the development of lung cancer in African-Americans. Specimens of DNA from 117 lung cancer cases and 120 controls were assayed for detection of GSTM1 genotype by polymerase chain reaction (PCR). The odds ratios (ORs) and 95% confidence intervals (CIs) for lung cancer associated with homozygous deletion of the GSTM1 gene and other risk factors were estimated by logistic regression. Thirty-seven of the 117 cases (31. 6%) and 24 of the 120 controls (20.0%) had the GSTM1 null genotype; the OR was 2.10 (95% CI 1.07-4.11) after adjustment for age, gender and smoking. The association was higher for squamous cell carcinoma (OR 2.98, 95% CI 1.09-8.19) than for adenocarcinoma (OR 1.95, 95% CI 0.81-4.66). We observed a stronger association between GSTM1 null genotype and lung cancer among heavy smokers with > or =30 pack-years (OR 4.35, 95% CI 1.16-16.23). This association was also found in squamous cell carcinoma (OR 6.26, 95% CI 1.31-29.91). In the analysis combining GSTM1 polymorphism and smoking, smokers with the null genotype had high risk (OR 8.19, 95% CI 2.35-28.62) compared with non-smokers with the wild-type genotype, and the risk increased with smoking cigarette pack-years (P: = 0.0001 for trend). Our results suggest that GSTM1 polymorphism plays a role in the development of lung cancer and modifies the risk for smoking-related lung cancer in African-Americans.     

Substantial reduction in risk of lung adenocarcinoma associated with genetic polymorphism in CYP2A13, the most active cytochrome P450 for the metabolic activation of tobacco-specific carcinogen NNK

Cytochrome P450 2A13 (CYP2A13), an enzyme expressed predominantly in the human respiratory tract, exhibits high efficiency in the metabolic activation of tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). A C-->T transition in the CYP2A13 gene causes Arg257Cys amino acid substitution and, thus, results in a significantly reduced activity toward NNK and other substrates. In this case-control study, we genotyped 724 patients with lung cancer and 791 controls for this polymorphism to examine the hypothesis that the variant CYP2A13 may have impact on risk of lung cancer in relation to tobacco smoking. A gene deletion polymorphism (CYP2A6*4) in CYP2A6, another enzyme involved in the metabolic activation of tobacco nitrosamines, was also analyzed as a comparison. We found that, compared with the CC genotype, the variant CYP2A13 genotype (CT + TT) was associated with substantially reduced risk for lung adenocarcinoma [odds ratio (OR), 0.41; 95% confidence interval (CI), 0.23-0.71], but not squamous cell carcinoma (OR, 0.86; 95% CI, 0.57-1.29) or other types of lung cancer (OR, 0.58; 95% CI, 0.32-1.09). Stratification analysis shows that the reduced risk of lung adenocarcinoma related to the variant CYP2A13 genotype was limited to smokers, especially light smokers (OR, 0.23; 95% CI, 0.08-0.68) but not nonsmokers or heavy smokers. No association was observed between CYP2A6 genotype and risk of lung cancer. Our results demonstrate for the first time that the variant CYP2A13 allele is associated with reduced risk of lung adenocarcinoma, suggesting the role of NNK-CYP2A13 interaction as a causative factor for the cancer.     

Genetic Polymorphism of Drug Metabolizing Enzymes (CYP2E1, GSTP1) and Susceptibility to Bladder Cancer in North India

Glutathione-S-transferases (GSTs) are active in the detoxification of wide variety of endogenous or exogenous ‍carcinogens and genetic polymorphisms of CYP2E1 and GSTP1 genes have been studied extensively to evaluate the ‍relative risk of various cancers. In the present study, we examined associations with CYP2E1 and GSTP1 gene ‍polymorphisms in sporadic bladder cancers from North Indian patients. The subjects were 106 bladder cancer (Ca- ‍B) cases and 162 age-matched controls. The GSTP1 313 A/G polymorphism was determined by the PCR/RFLP ‍method using peripheral blood DNA. Binary Logistic Regression Model was used for assessing differences in genotype ‍prevalence and their associations between patient and the control group. We observed a non-significant association ‍in Pst1 polymorphism of the CYP2E1 gene; though the A/G genotype (OR = 2.69, 95% CI=1.57- 4.59, P= 0.000) and ‍G/G genotype (OR = 7.68, 95% CI=2.77- 21.26, P= 0.000) of the GSTP1 gene polymorphism alone or in combination ‍with tobacco users were highly significant (OR=24.06; 95% CI: 4.80- 120.42; P =0.000) when compared to the ‍controls. The results of our study demonstrated that the GSTP1 313 G/G polymorphism is a strong predisposing ‍risk factor for bladder cancer in the North Indian population.     

CYP2E1 T7632A and 9-bp insertion polymorphisms and colorectal cancer risk: a meta-analysis based on 4,592 cases and 5,918 controls

Previous studies suggest that genetic factors play important roles in the development of colorectal cancer. CYP2E1 T7632A and 9-bp insertion polymorphisms may influence the risk of colorectal cancer, but published results are conflicting. We therefore conducted a meta-analysis comprising 9 case–control studies with 4,592 cases and 5,918 controls. Odds ratios (ORs) with 95 % confidence interval (95 % CI) were used to assess the strength of the associations of CYP2E1 T7632A and 9-bp insertion polymorphisms with colorectal cancer. For CYP2E1 T7632A polymorphism, meta-analysis showed that there was no significant association between the CYP2E1 T7632A polymorphism and colorectal cancer risk under all contrast models (A vs. T: OR?=?1.06, 95 % CI 0.88–1.29, P?=?0.528; AA vs. TT: OR?=?0.85, 95 % CI 0.61–1.19, P?=?0.351; AA/TA vs. TT: OR?=?1.08, 95 % CI 0.87–1.34, P?=?0.484; and AA vs. TT/TA: OR?=?0.87, 95 % CI 0.62–1.21, P?=?0.395). For CYP2E1 96-bp insertion polymorphism, meta-analysis showed that there was a significant association between the CYP2E1 96-bp insertion polymorphism and colorectal cancer risk under the allele contrast model and the dominant contrast model (for the allele contrast model: OR?=?1.20, 95 % CI 1.06–1.36, P?=?0.005; for the dominant contrast model: OR?=?1.25, 95 % CI 1.07–1.45, P?=?0.005). Subgroup analysis by race suggested that there was an obvious association between the CYP2E1 96-bp insertion polymorphism and colorectal cancer risk in Asians under the codominant contrast model. In conclusion, our meta-analysis demonstrates that there is a significant association between the CYP2E1 96-bp insertion polymorphism and colorectal cancer risk, and CYP2E1 9-bp insertion polymorphism is a risk factor for developing colorectal cancer.     

CYP2D6 and CYP2E1 Gene Polymorphisms and their Association with Cervical Cancer Susceptibility: A Hospital Based Case-Control Study from South-Western Maharashtra

Background: In last few years several studies all over the world discovered the genetic polymorphisms in different cytochrome P450 genes associated with risk of various cancers, but contradictory outcomes were evidenced in case of cervical cancer risk.  In this case-control study we aimed to see whether the polymorphism of CYP2D6 or CYP2E1 genes may or may not be associated with cervical cancer risk in women of rural Maharashtra. Methods: In this case-control study, the association of CYP2D6 and CYP2E1 gene polymorphism with cervical cancer risk was studied by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The study was conducted with 350 clinically confirmed cervical cancer patients and 350 healthy women in a population of South-Western Maharashtra. The Odds ratio (OR) with 95% confidence interval and p-value were evaluated, where p ≤0.005 was considered as statistically significant. Results: After the analysis of SNP (rs389209) of CYP2D6 and SNPs (rs2031920, rs6413432, rs6413420) of CYP2E1, we noticed that variant allele A of CYP2E1*6 showed significant increase in cervical cancer cases (OR=4.81; 95% CI: 1.57- 14.77; p=0.005). The genotypic distribution of heterozygote G/A genotype of CYP2D6*4 showed negative association with cervical cancer development when age of cancer occurrence (OR=0.41; 95% CI: 0.27- 0.61; p<0.0001) and tobacco history (OR=0.35; 95% CI: 0.20- 0.59; p=0.0001) was considered. Conclusion: The findings from this study supported that rs6413432 SNP of CYP2E1*6 increased cervical cancer risk in the studied rural women population.     

Genetic Polymorphisms of CYP2E1 and GSTM1 in a Thai Population

Cytochrome P450 2E1 and GSTM1 play major roles in metabolic activation and detoxification of many carcinogensand polymorphisms in the encoding genes have been reported to be individually associated with increased susceptibilityto certain cancer. In the present study, we investigated the RsaI, PstI and DraI polymorphisms of the CYP2E1 geneand the null GSTM1 genotype in a Thai population. DNA samples from 485 individuals were analysed by polymerasechain reaction with restriction fragment length (PCR/RFLP). The frequency of RsaI and PstI predominanthomozygous alleles (c1/c1) was 73.2%, heterozygous allele (c1/c2) was 25.6% and rare homozygous allele (c2/c2)was 1.2%. For the DraI polymorphism, the frequency of the predominant allele (DD) was 59.6%, heterozygous (CD)was 40% and rare allele (CC) was 0.4%. The frequency of GSTM1 null genotype was 62.7%. The distribution andfrequencies of these alleles showed different pattern from those found in Caucasian and some other Asian populations.With the large population in this study, we believed that our results are reliable estimates of the frequencies of thepolymorphic CYP2E1 and GSTM1 alleles in Thai population and should provide a base for further epidemiologicalstudies on their links with cancer development.