CYP1A1 and CYP2E1 genotypes and risk of esophageal squamous cell carcinoma in a high-incidence region,Kashmir

The study analyzed the relationship between genetic polymorphisms of phase I xenobiotic metabolizing enzymes, cytochromes P450 (CYP) 1A1 and CYP2E1 and esophageal squamous cell carcinoma (ESCC) in Kashmir, India. The different genotypes of CYP1A1 and CYP2E1 were analyzed by polymerase chain reaction and restriction fragment length polymorphism in 526 ESCC cases and equal number of matched controls. Conditional logistic regression models were used to assess the association of various genotypes with ESCC, gene–gene, and gene–environment interactions. High risk of ESCC was found in participants who carried CYP1A1 Val/Val genotype (OR?=?2.87; 95 % CI?=?1.00–8.44) and the risk increased in such individuals when c1/c1 of CYP2E1 genotype was also present (OR?=?5.68; 95 % CI?=?1.09–29.52). Risk due to CYP1A1 Val/Val genotype was further enhanced (OR?=?8.55; 95 % CI?=?1.86–42.20) when the analysis was limited to ever smokers. Participants who carried CYP2E1 c1/c2 genotype showed an inverse relation (OR?=?0.27; 95 % CI?=?0.17–0.43) with ESCC. The inverse association of CYP2E1 c1/c2 genotype was retained when CYP1A1 Ile/Ile was also present (OR?=?0.18; 95 % CI?=?0.09–0.32), as well as when analysis was limited to ever smokers (OR?=?0.45; 95 % CI?=?0.23–0.90). Significant interaction was found between CYP1A1 (Val/Val) and CYP2E1 (c1/c1) genotypes (OR?=?1.30; 95 % CI?=?1.12–1.51; P?=?0.001) and between CYP1A1 (Val/Val) and smoking (OR?=?1.31; 95 % CI?=?1.01–1.69; P?=?0.043). The study suggests CYP1A1 Val/Val and CYP2E1 c1/c1 genotypes are significantly associated with ESCC risk.     

A variant in CYP26B1 associated with esophageal squamous cell carcinoma risk by affecting retinoic acid metabolism

All-trans retinoic acid (ATRA) is the natural and synthetic analogue of vitamin A, playing an essential tumor suppressive role in multiple cancers including the esophageal squamous cell carcinoma (ESCC). Cytochrome P450 family 26 subfamily B member 1 (CYP26B1) exerts a critical regulator of ATRA levels through specific inactivation of ATRA to hydroxylated forms. Our previous exome-wide analyses revealed a rare missense variant in CYP26B1 significantly associated with ESCC risk in the Chinese population. However, it is still unclear whether there are common variants in CYP26B1 affect the susceptibility of ESCC and the tumor promotion role of CYP26B1 in vivo. In this research, we conducted a two-stage case-control study comprised of 5057 ESCC cases and 5397 controls, followed by a series of biochemical experiments to explore the function of CYP26B1 and its common variants in the tumorigenesis of ESCC. Intriguingly, we identified a missense variant rs2241057[A>G] in the fourth exon of CYP26B1 significantly associated with the ESCC risk (combined odds ratio = 1.28; 95% confidence interval = 1.15–1.42; p = 2.96 × 10⁻⁶). Through further functional analysis, we demonstrated that ESCC cells with the overexpression of rs2241057[G] had a significant lower level of retinoic acid, compared with the overexpression of rs2241057[A] or the control vector. In addition, the CYP26B1 overexpression and knock-out ESCC cells affected cell proliferation rate both in vitro and in vivo. These results highlighted the carcinogenicity of CYP26B1 related to the ATRA metabolism in ESCC risk.     

Association of CYP1A1 and microsomal epoxide hydrolase polymorphisms with lung squamous cell carcinoma

Lung cancer is the leading cause of death among cancers in Taiwan. Although the etiology of lung cancer has yet to be defined, genetic variability in activities of metabolic enzymes has been correlated with lung cancer. In the present study, the possibility of association of CYP1A1 and microsomal epoxide hydrolase (HYL1) genetic polymorphisms with lung cancer was examined among 132 lung cancer patients and 259 controls in Taiwan. No significant association was observed for either CYP1A1 or HYL1 polymorphism alone and the overall incidence of lung cancer after adjusting for age, gender and smoking status. When cases were stratified according to histological type, there was significant association between CYP1A1*2A homozygote and squamous cell carcinoma (SCC) (odds ratio (OR) 2.86; 95% confidence interval (CI) 1.33-6.12). Similarly, the proportion of HYL1 genotypes corresponding to high or normal enzyme activities was higher in SCC than in controls (OR 1.96; 95% CI 1.04-3.70). A combination of susceptible CYP1A1 and HYL1 genotypes was found to be highly associated with lung cancer, especially with SCC (OR 6.76; 95% CI 2.29-19.10). Our results suggest that the combination of CYP1A1 and HYL1 polymorphisms is an important risk factor for lung SCC.     

Interaction between CYP1A2-T2467DELT polymorphism and smoking in adenocarcinoma and squamous cell carcinoma of the lung

This study aimed to identify new genetic characteristics contributing to individual susceptibility to smoke-induced lung cancer. Despite functional evidence of a possible role of cytochrome P450 1A2 (CYP1A2) in lung cancer susceptibility, no studies have evaluated the influence of CYP1A2 genotypes on lung cancer risk. We investigated the interaction between CYP1A2-T2467delT (allele*1D) polymorphism and smoking in Tunisian lung cancer cases (n=101 male smokers) separately for the histological types squamous cell carcinoma (SCC) (n=60) and adenocarcinoma (n=41), and in controls (n=98 male smokers) using a case-only study design. A significant interaction between CYP1A2-T/delT or delT/delT genotypes and tobacco consumption (pack-years) adjusted for age was evident (OR (95% CI) 7.78 (1.52-42.8)) in the SCC cases who smoked relatively less (< or =33 pack-years, I quartile value), but not in adenocarcinoma and controls. Our results suggest that CYP1A2-T2467delT polymorphism has an important role in lung carcinogenesis, especially SCC, among smokers.     

CYP1A1 Ile462Val and MPO G-463A interact to increase risk of adenocarcinoma but not squamous cell carcinoma of the lung

Common polymorphisms in genes encoding phase I and phase II enzymes are considered to modify lung cancer risk due to changes in enzyme activity. Candidates include genetic variants of glutathione S-transferases (GSTM1, GSTT1 and GSTP1) and myeloperoxidase (MPO). We performed a large case-control study of these candidate genes in 1103 patients with non-small cell lung cancer (NSCLC) and 627 controls without NSCLC. Associations between deletion genotypes of GSTM1 and GSTT1 and between single nucleotide polymorphisms (SNPs) of GSTP1 Ile105Val and MPO G-463A were first tested by adjusted logistic regression. Then we analysed gene-gene interactions, also incorporating our published data on the Ile462Val SNP in the phase I enzyme, cytochrome P450 CYP1A1. The homozygous GSTP1 105Val genotype was significantly under-represented in NSCLC compared with controls (OR = 0.73; 95%CI 0.53-1.00; P = 0.050), especially in females (OR = 0.57; 95%CI 0.34-0.98; P = 0.04). The GSTT1-null genotype was significantly over-represented in adenocarcinomas (OR = 1.41; 95%CI 1.06-1.90; P = 0.02) but not in squamous cell carcinomas (OR = 1.03; 95%CI 0.76-1.41; P = 0.84). There was weak risk reduction associated with GSTM1 null in heavy smokers (OR = 0.71; 95%CI 0.54-0.94; P = 0.02), but neither GSTM1 nor MPO genotypes affected the overall risk of NSCLC. The MPO and CYP1A1 risk genotypes interacted to increase the overall risk of NSCLC (OR = 2.88; 95%CI 1.70-5.00; P < 0.001). The data are consistent with the concept that multiple genes of modest effect interact to confer genomic-based susceptibility to lung cancer.     

Association between CYP2E1 genetic polymorphisms and lung cancer risk: A meta-analysis

Genetic variations in metabolic genes are thought to modify the metabolic process of carcinogens and are suggested to be related to cancer risk. However, epidemiological results are not always consistent. In this meta-analysis, we assessed reported studies of associations between polymorphisms of CYP2E1 RsaI/PstI and DraI, and the risk of lung cancer. We found decreased lung cancer risk among subjects carrying CYP2E1 RsaI/PstI c1/c2 and c1/c2 + c2/c2 genotype [odds ratio (OR) = 0.80, 95% confidence interval (CI): 0.72–0.89 and OR = 0.82, 95% CI: 0.72–0.93, respectively], using 4436 cases and 6385 controls from 26 studies. We also observed a decreased lung cancer risk among subjects carrying c1/c2 and c1/c2 + c2/c2 genotypes in the Asian population and on the basis of population control in stratified analysis. We found a protective effect of the CYP2E1 DraI CC and CD + CC polymorphisms for lung cancer (OR = 0.58, 95% CI: 0.41–0.81 and OR = 0.84, 95% CI: 0.73–0.96, respectively). The meta-analysis suggests that CYP2E1 RsaI/PstI and DraI polymorphisms may affect the susceptibility of lung cancer, and a study with a larger sample size is needed to further evaluate gene–environment interaction on CYP2E1 polymorphisms and lung cancer risk.     

Polymorphism in cytochrome P450 1A2 and their interaction with risk factors in determining risk of squamous cell lung carcinoma in men

The present case-control study was carried out to investigate the association of functionally important polymorphisms of cytochrome P450 1A2 (CYP1A2) involved in the metabolic activation of tobacco derived procarcinogens with squamous cell carcinoma (SCC) of lung in North Indian men. The study consisted of 200 male cases with SCC of lung and an equal number of age and sex matched healthy controls. Our data showed that variant genotype of CYP1A2*1D and CYP1A2*1F were significantly associated with increased susceptibility to SCC of lung. Likewise, GSTM1 null genotype was found to be over represented in patients when compared to controls. Haplotype analysis revealed that haplotype, G-Tdel-T-C was significantly associated with risk to SCC of lung. Moreover, a significant increase in the risk to SCC of lung in the cases carrying combination of variant genotype of CYP1A2 with either CYP1A1 or GSTM1 have shown that gene-gene interactions may play an important role in squamous cell lung cancer risk. Our data also revealed that smokers or tobacco chewers carrying variant alleles of either CYP1A2*1D or CYP1A2*1F were at increased risk to SCC of lung, further demonstrating that CYP1A2 genotypes interact with environmental risk factors in enhancing the risk to squamous cell lung carcinoma.     

Quantitative assessment of the influence of CYP1B1 polymorphisms and head and neck squamous cell carcinoma risk

The associations between CYP1B1 polymorphisms and head and neck squamous cell carcinoma (HNSCC) risk have been conflicting. We therefore performed a meta-analysis to derive a more precise relationship. Six published case–control studies were collected; odds ratios (ORs) with 95 % confidence interval (CI) were used to assess the association between CYP1B1 Leu432Val, Asn453Ser polymorphisms, and HNSCC risk. The Sensitivity analysis and publication bias also were performed to guarantee the statistical power. Overall, the pooled OR with 95 % CIs indicated that CYP1B1 Leu432Val polymorphism was significantly related with HNSCC risk (for Val vs. Leu: OR = 1.13, 95 % CI = 1.03–1.25, P?=?0.014, P _{heterogeneity}?=?0.141; for Val/Val vs. Leu/Leu: OR = 1.30, 95 % CI = 1.06–1.60, P?=?0.013, P _{heterogeneity}?=?0.253; for Val/Val vs. Leu/Leu + Leu/Val: OR = 1.23, 95 % CI = 1.05–1.46, P?=?0.013, P _{heterogeneity}?=?0.456). The similar results were also been found in succeeding analysis of HWE and stratified analysis of Caucasian population. Furthermore, no significant association between CYP1B1 Asn453Ser polymorphism and HNSCC risk was found in this meta-analysis. In conclusion, our meta-analysis demonstrates that CYP1B1 Leu432Val polymorphism may be a risk factor for developing HNSCC.     

CYP2E1基因多态性与肝癌易感性的关系

目的 :研究细胞色素P45 0 2E1(CYP2E1)基因多态性与肝癌易感性的关系。方法 :在肝癌高发区泰兴市进行病例对照研究 ,调查研究对象的饮酒习惯 ,以PCR RFLP方法分析CYP2E1基因型。结果 :肝癌病例组与对照组中CYP2E1变异基因型 (C1/C2 C2 /C2 )的分布频率分别为 41 0 6%和 3 7 0 2 % ,两者差异无统计学意义 ;从饮酒习惯等方面分析 ,携带CYP2E1变异基因型的饮酒者与携带野生基因型的不饮酒者间患肝癌危险性差异无统计学意义。结论 :CYP2E1基因多态性与泰兴市肝癌的发生无关     

细胞色素CYP2E1和GST M1与肺癌易感性的病例对照研究

目的探讨谷胱甘肽转硫酶(GST)和细胞色素CYP2E1多态性与肺癌易感性的关系.方法选取广州市广东籍新发肺癌病人91例及同期非肺部疾患及相同性别的病人91例作匹配,调查他们的吸烟、饮酒等因素的暴露情况.用聚合酶链式反应(PCR)和限制性片段长度多态性(RFLP)技术检测CYP2E1和GST的基因多态性.结果CYP2E1 C1C1基因型与C1C2基因型比较,其OR为1.82(95%CI=0.95～3.40),GSTM1基因缺失型的OR值为1.26(0.69～2.30),而两者联合分析时,则可增加患肺癌的危险,其OR值为2.13(0.82～5.56),但无统计学意义(P＞0.05).吸烟与肺癌关系密切,其OR值为2.82(1.56～5.12),当吸烟与这两种基因型协同作用时,可明显提高患肺癌的危险性,携带CYP2E1 C1C1基因型的吸烟者的OR值为5.42(2.05～14.32),GSTM1基因缺失型的吸烟者的OR值为4.38(1.81～10.61).多因素logistic回归分析结果表明:文化程度(OR为0.63,0.45～0.86)、吸烟量(OR为1.56,1.14～2.14)、元抽油烟机(OR为3.77,1.48～9.56)、食用动物油(OR为1.67,1.25～2.24)、胡萝卜(OR为0.47,0.22～0.98)、饮酒(OR为6.58,1.53～28.3)、直系亲属肺癌史(OR为3.75,1.64～8.58)等因素与肺癌有关,而上述两种基因均未进入模型.结论CYP2E1和GSTM1在单因素分析中未显示出与肺癌风险的联系.这两种基因分别与吸烟协同作用时明显提高肺癌的危险性.然而在多因素分析中均未进入logistic模型,说明它们均不是肺癌个体易感性的主效基因,而是次效基因.     

转录因子E2F1在外阴鳞癌中的表达及意义

目的:探讨转录因子E2F1在外阴鳞癌(VSCC)中的表达情况及其临床意义。方法:采用PCR（qRT-PCR）、Western blot和免疫组化检测30例VSCC及对应癌旁组织中E2F1的水平,分析E2F1表达与临床病理参数的关系。结果:VSCC组织中E2F1的mRNA相对表达量为(1.27±0.04),高于癌旁外阴组织的E2F1水平(0.84±0.06)（P＜0.05）;VSCC组织中E2F1的蛋白相对表达量为(1.16±0.04),高于癌旁外阴组织的E2F1水平(0.93±0.03)（P＜0.05）;免疫组化示VSCC组织中E2F1的阳性表达率(56.67%,17/30)明显高于癌旁外阴组织(33.33%,10/30)(P＜0.05),且其阳性表达率与FIGO分期有关(P＜0.05)。结论:E2F1在VSCC组织中表达上调,且与FIGO分期有关,提示E2F1可能与VSCC的发生、发展有关。     

空洞型肺鳞癌与非空洞型肺鳞癌的临床特征分析

Objective： To identify the differences between cavitating squamous cell lung carcinoma （cSLC） and non-cavitating squamous cell lung carcinoma （ncSLC）. Methods： Fifty-one patients with cSLC and 281 with ncSLC confirmed by surgery in our hospital between 1999 to 2000 were collected and their clinical, histological and survival features were retrospectively ana（yzed. Results： Patients with cSLC had more frequent manifestation of infection and weight loss. They usually experienced longer duration of pre-diagnosis and showed bigger tumor mass, larger primary tumor invasion with worse differentiated than ncSLC patients. There was no significant difference in age, sex, smoking history, family tumor history, personal tuberculosis history, disease location, TNM stage, lymph node invasion, and metastasis between the two groups. Median survival time was 29 months for cSLC and 35 months for ncSLC. One- and 3- year survival rates were 86.3% and 43.1% for cSLC vs. 91.1% and 47,0% for ncSLC respectively （P〉0.05）. Conclusion： Patients with cSLC presented with a bigger mass, a larger extent of primary tumor invasion, worse differentiated, more obstructed pneumonia that might result in longer duration of pre-diagnosis and more weight loss. As lack of differences in disease stages, lymph node invasion, metastasis and especially survival time with ncSLC, cSLC couldn＇t be classified as a special type of squamous cell carcinoma by present evidences.     

Gene-environment interaction: the role of SULT1A1 and CYP3A5 polymorphisms as risk modifiers for squamous cell carcinoma of the oesophagus

An imbalance in the activities of enzymes involved in the metabolism, conjugation and transport of xenobiotics may account for the variability in susceptibility to the development of complex diseases such as cancer between different population groups. In this study we investigated a functional polymorphism in the SULT1A1 gene in 245 patients and 288 controls. Previous studies have shown that the 638G-->A polymorphism that results in the substitution of arginine by histidine at codon 213 (SULT1A1*2) results in decreased SULT1A1 activity. The same group of samples used in this study had been previously genotyped for CYP3A5 genetic polymorphisms. Among Black subjects the burning of wood or charcoal for cooking and keeping warm was significantly associated with increased risk for oesophageal cancer (OC) (AOR, 15.2; P=0.001) as was the consumption of home-brewed beer (AOR, 6.97; P=0.0001). Among the Mixed Ancestry group, tobacco smoking combined with alcohol consumption were significantly associated with higher risk for OC (AOR, 5.18; P=0.0005). In both Blacks and Mixed Ancestry subjects, starting to smoke below the age of 20 years was associated with significantly increased risk for OC (AOR, 3.5 among the Blacks and AOR, 12 among the Mixed Ancestry). The homozygous SULT1A1*2/*2 genotype was associated with increased risk for OC among smokers. The SULT1A1*2/*2 genotype in combination with the CYP3A5 heterozygous genotypes was associated with significantly increased risk for OC (AOR, 3.60; P=0.001) with the risk being even higher among smokers compared with non-smokers. The above findings confirm the association between alcohol consumption and tobacco smoking with increased risk for OC. The genotype results show that SULT1A1*2/*2 genotype is associated with increased risk for OC among subjects exposed to tobacco-smoke-related carcinogens.     

A functional variant at the miR-184 binding site in TNFAIP2 and risk of squamous cell carcinoma of the head and neck

Although the role of TNFAIP2 is still unclear, it is an important gene involved in apoptosis, and there are single-nucleotide polymorphisms (SNPs) at its microRNA (miRNA)-binding sites that could modulate miRNA target gene function. In this study, we evaluated associations of four selected SNPs (rs8126 T > C, rs710100 G > A, rs1052912 G > A and rs1052823 G > T) in the miRNA-binding sites of the 3' untranslated region (UTR) with squamous cell carcinoma of the head and neck (SCCHN) risk in 1077 patients with SCCHN and 1073 cancer-free controls in a non-Hispanic White population. We found that, compared with the rs8126 TT genotype, the variant C allele were associated with increased SCCHN risk in an allele dose-response manner (adjusted odds ratio = 1.48 and 95% confidence interval = 1.06-2.05 for CC, respectively; P(trend) = 0.009). No significant associations were seen for the other three SNPs (rs710100 G > A, rs1052912 G > A and rs1052823 G > T). Additionally, we identified that the rs8126 T > C SNP is within the miR-184 seed binding region in the 3' UTR of TNFAIP2. Further functional analyses showed that the rs8126 variant C allele led to significantly lower luciferase activity, compared with the T allele. In the genotype-phenotype correlation analysis of peripheral blood mononuclear cells from 64 SCCHN patients, the rs8126 CC genotype was associated with reduced expression of TNFAIP2 messenger RNA. Taken together, these findings indicate that the miR-184 binding site SNP (rs8126 T > C) in the 3' UTR of TNFAIP2 is functional by modulating TNFAIP2 expression and contributes to SCCHN susceptibility. Larger replication studies are needed to confirm our findings.