Cytochrome P450 2E1 RsaI/PstI polymorphism and risk of esophageal cancer: A meta-analysis of 17 case-control studies

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.

Identification of crucial miRNAs and genes in esophageal squamous cell carcinoma by miRNA-mRNA integrated analysis

Esophageal squamous cell carcinoma (ESCC) is a malignancy that severely threatens human health and carries a high incidence rate and a low 5-year survival rate. MicroRNAs (miRNAs) are commonly accepted as a key regulatory function in human cancer, but the potential regulatory mechanisms of miRNA-mRNA related to ESCC remain poorly understood.The GSE55857, GSE43732, and GSE6188 miRNA microarray datasets and the gene expression microarray datasets GSE70409, GSE29001, and GSE20347 were downloaded from Gene Expression Omnibus databases. The differentially expressed miRNAs (DEMs) and differentially expressed genes (DEGs) were obtained using GEO2R. Gene ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis for DEGs were performed by Database for Annotation, Visualization and Integrated Discovery (DAVID). A protein-protein interaction (PPI) network and functional modules were established using the STRING database and were visualized by Cytoscape. Kaplan-Meier analysis was constructed based on The Cancer Genome Atlas (TCGA) database.In total, 26 DEMs and 280 DEGs that consisted of 96 upregulated and 184 downregulated genes were screened out. A functional enrichment analysis showed that the DEGs were mainly enriched in the ECM-receptor interaction and cytochrome P450 metabolic pathways. In addition, MMP9, PCNA, TOP2A, MMP1, AURKA, MCM2, IVL, CYP2E1, SPRR3, FOS, FLG, TGM1, and CYP2C9 were considered to be hub genes owing to high degrees in the PPI network. MiR-183-5p was with the highest connectivity target genes in hub genes. FOS was predicted to be a common target gene of the significant DEMs. Hsa-miR-9-3p, hsa-miR-34c-3p and FOS were related to patient prognosis and higher expression of the transcripts were associated with a poor OS in patients with ESCC.Our study revealed the miRNA-mediated hub genes regulatory network as a model for predicting the molecular mechanism of ESCC. This may provide novel insights for unraveling the pathogenesis of ESCC.

Association between polymorphisms in the CYP1A1, CYP2E1 and GSTM1 genes, and smoking, alcohol and upper digestive tract carcinomas in a high-incidence area of northern China

Metabolic gene variants, smoking, and alcohol consumption are important upper digestive tract cancer (UDTC) risk factors. However, the gene-gene and gene-environment interactions remain unclear. A case-control study in a high incidence area for upper digestive tract cancer was conducted in China. DNA was extracted from buffy coat samples for PCR or PCR-restriction fragment length polymorphism. Smoking and alcohol drinking status was determined by questionnaires. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the associations. After adjusting for confounding factors, smoking increased esophageal cancer (EC), gastric cardia cancer (GCC) and gastric antral carcinoma (GAC) risk by 3.594, 4.658, and 3.999-fold, respectively. Alcohol consumption increased EC, GCC and GAC risk by 1.953, 2.442 and 1.765-fold, respectively. The cytochrome P4501A1 (CYP1A1) rs4646903 T>C polymorphism increased GCC risk, the cytochrome P4502E1 (CYP2E1) rs2031920 C>T polymorphism increased EC risk, while the GSTM1 null genotype decreased EC risk. An association existed between the following: CYP1A1 rs4646903 and smoking in EC, GCC and GAC; CYP1A1 rs4646903 and alcohol consumption in EC and GCC; CYP2E1 rs2031920 and smoking in EC, GCC and GAC and CYP2E1 rs2031920 and alcohol consumption in EC and GCC. No association was observed between CYP1A1 and CYP2E1. The glutathione S-transferase mu 1 (GSTM1) null genotype decreased EC risk (OR=0.510). Smoking/drinking are upper digestive tract cancer risk factors. The CYP1A1 rs4646903 and CYP2E1 rs2031920 polymorphisms were risk factors of GCC or EC, and the GSTM1 null genotype may serve a protective role against EC. The results of the present study indicated that gene-environment interactions increase the risk of UDTC.

Cumulative evidence for association between genetic polymorphisms and esophageal cancer susceptibility: A review with evidence from meta-analysis and genome-wide association studies

An increasing number of publications had reported the association between single‐nucleotide polymorphisms (SNPs) and esophageal cancer (EC) risk in the past decades. Results from these publications were controversial. We used PubMed, Medline, and Web of Science to identify meta‐analysis articles published before 30 July 2018, that summarize a comprehensive investigation for cumulative evidence of genetic polymorphisms of EC and its subtype risk. Two methods, Venice criteria and false‐positive report probability (FPRP) tests, were used to assess cumulative evidence of significant associations. At last, 107 meta‐analyses were considered to be in conformity with the inclusion criteria, yielding 51 variants associated with EC or esophageal squamous cell carcinoma (ESCC). Thirty‐eight variants were considered to be nominally significant associated with risk of EC or ESCC, whereas the rest showed non‐association. In additional, five variants on five genes were rated as strong cumulative epidemiological evidence for a nominally significant association with EC and ESCC risk, including CYP1A1 rs1048943, EGF rs444903, HOTAIR rs920778, MMP2 rs243865, and PLCE1 rs2274223, 10 variants were rated as moderate, and 18 variants were rated as weak. Additionally, 17 SNPs were verified noteworthy in six genomewide association studies (GWAS) using FPRP methods. Collectively, this review offered a comprehensively referenced information with cumulative evidence of associations between genetic polymorphisms and EC and ESCC risk.

Association between CYP2E1 genetic polymorphisms and urinary cancer risk: a meta-analysis

Objective

Studies investigating the contribution of Cytochrome P4502E1 (CYP2E1) polymorphisms to the etiology of urinary cancer draw inconsistent conclusions. Thus, we performed a meta-analysis to evaluate the association between CYP2E1 Rsa I/Pst I and Dra I polymorphisms and urinary cancer susceptibility.

Materials and Methods

Meta-analysis based on the eligible case-control studies that assess the association of CYP2E1 Rsa I/Pst I and Dra I polymorphisms with urinary cancer was conducted. Subgroup analyses based on ethnicity and cancer type were also carried out. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated to evaluate the strength of the associations between the two polymorphisms. Funnel plot and Begg’s test were used for publication bias diagnosis.

Results

We found decreased urinary cancer risk among subjects carrying CYP2E1 RsaI/PstI c1c2 + c2c2 genotype and c2 allele (OR = 0.73, 95% CI = 0.68–0.79 and OR = 0.79, 95% CI = 0.74–0.85, respectively), with 3,301 cases and 3,786 controls from 14 studies. We also observed a significant difference in c1c2 + c2c2 vs. c1c1 and c2 vs. c1 among Asians (OR = 0.68, 95% CI = 0.60–0.78 and OR = 0.75, 95% CI = 0.66–0.85, respectively). However, the meta-analysis based on 5 eligible studies showed no significant association between CYP2E1 Dra I polymorphism and urinary cancer susceptibility in either dominant model or the allele model.

Conclusions

Our meta-analysis concluded that CYP2E1 Rsa I/Pst I polymorphism correlates with urinary cancers risk in Asian population; while CYP2E1 Dra I polymorphism might be not significantly associated with the urinary cancer risks. Large and well-designed studies are needed to confirm these results.

In silico dissection of miRNA targetome polymorphisms and their role in regulating miRNA-mediated gene expression in esophageal cancer

Esophageal cancer is the eighth most common cancer worldwide. Also middle-aged obese adults with higher body mass index during childhood have a greater risk to develop esophageal cancer. The contribution of microRNAs to esophageal cancer has been extensively studied and it became clear that these noncoding RNAs may play crucial roles in pathogenesis, diagnosis and prognosis of the disease. Increasing evidences have suggested that polymorphisms perturbing microRNA targetome (i.e., the compendium of all microRNA target sites) are associated with cancers including esophageal cancer. However, the extent to which such variants contribute to esophageal cancer is still unclear. In this study, we applied an in silico approach to systematically identify polymorphisms perturbing microRNA targetome in esophageal cancer and performed various analyses to predict the functional consequences of the occurrence of these variants. The computational results were integrated to provide a prioritized list of the most potentially disrupting esophageal cancer-implicated microRNA targetome polymorphisms along with the in silico insight into the mechanisms with which such variations may modulate microRNA-mediated regulation. The results of this study will be valuable for future functional experiments aimed at dissecting the roles of microRNA targetome polymorphisms in the onset and progression of esophageal cancer.

Cytochrome P450 2E1 RsaI/PstI polymorphism is associated with urologic cancer risk: evidence from a meta-analysis

Cytochrome P450 2E1 (CYP2E1) is involved in the metabolic activation of various carcinogens. CYP2E1 RsaI/PstI polymorphism has been identified in urologic cancer patients, while studies of the polymorphism have shown inconclusive trends in the risk of urologic cancers. Therefore, we performed this systematic review to provide a complete picture and conducted a meta-analysis to derive a precise estimation. We searched PubMed, Embase and Web of Science to identify eligible studies up to December 15, 2014. 12 studies with 2712 cases and 2977 controls were included in the meta-analysis.The odds ratio with a 95% confidence interval was used to assess the strength of associations. We observed that the c2 allele of CYP2E1 RsaI/PstI polymorphism was associated with a decreased risk of urologic cancer under all genetic models (c2 vs. c1: OR = 0.742, 95% CI = 0.659-0.835); c2c2 vs. c1c1: OR = 0.516, 95% CI = 0.357-0.745; c1c2 vs. c1c1: OR = 0.748, 95% CI = 0.748 (0.648-0.863; c2c2 + c1c2 vs. c1c1: OR = 0.722, 95% CI = 0.629-0.829; c2c2 vs. c1c1 + c1c2: OR = 0.578, 95% CI = 0.401-0.832). In the subgroup analysis by cancer type, statistically significant associations were found in urothelial cancer in all genetic models. When stratified by ethnicity, a same trend was also indicated in Asians in all genetic models.To conclude, our results support the conclusion that the CYP2E1 RsaI/PstI polymorphism may be associated with urologic cancer susceptibility. The c2 allele is a low-penetrance risk factor for urologic cancer development.

Development of esophageal cancer in Chaoshan region, China: association with environmental, genetic and cultural factors

Esophageal squamous cell carcinoma (ESCC) is the eighth most common cancer by incidence worldwide. Although the cancer is located at a readily recognizable and accessible site in the body, it is the sixth most common cause of cancer death. The 1- and 5-year survival rates in China are 50% and 15%, respectively. Furthermore, the cancer has distinct geographic and etiological risk factors in different locations around the world. Since ESCC is highly prevalent in the Chaoshan (Southeastern) region of China, this report will focus on a review of risk factors for the cancer in this area. From the review, it is clear that some important and traditional factors are involved, e.g. environmental mutagens, genetic predisposition. However, unique factors, e.g. the drinking of very hot tea, may play an important role. This review highlights the role of complex risk factors (environmental, genetic and cultural) which contribute to the multistage development of cancer: localized injury, inflammation, mitogenesis, mutagenesis, carcinogenesis and eventually mortality. The latter is contributed by unnecessary delay in seeking medical care which may be culturally related. The review emphasizes the need to identify causal mechanisms for the complex carcinogenic process which can provide opportunity for prevention and treatment of this potentially curable cancer.

Meta-analysis of the CYP1A2 -163C>A polymorphism and lung cancer risk

Many published studies have concerned associations between the CYP1A2 -163 C>A polymorphism and risk of lung cancer, but the results have been inconsistent. Therefore, we performed a meta-analysis to obtain a more precise estimate. We searched the PubMed database up to March 1, 2013 for relevant cohort and case-control studies. Supplementary search was conducted manually by searching the references of the included studies and relevant meta-analyses. A meta-analysis was performed using RevMan 5.2 software for calculation of pooled odds ratios (ORs) and relevant 95% confidence intervals (CIs) after data extraction. Finally, seven case-control studies and one nested case-control study involving 1,675 lung cancer patients and 2,393 controls were included. The meta-analysis showed that there was no association of CYP1A2 -163 C>A polymorphism with risk of lung cancer overall [(OR=0.89, 95%CI= 0.74-1.07) for C vs. A; (OR=0.73, 95%CI= 0.50-1.07) for AA vs. CC ; (OR=0.82, 95%CI= 0.62-1.09) for AC vs. CC; (OR=0.79, 95%CI= 0.58-1.07) for (AC+AA) vs. CC; and (OR=0.87, 95%CI= 0.67-1.13) for AA vs. (CC+AC)]. Subgroup analysis indicated that there was an associationbetween CYP1A2 -163C>A polymorphism and lung cancer risk for population-based controls, a trend risk for SCCL (squamous cell carcinoma of lung) and Caucasians. These results suggested that -163 C>A polymorphism is likely to be associated with risk of lung cancer compared with population-based controls.

Interleukin-1α -899 (+4845) C→T polymorphism is not associated with aggressive periodontitis susceptibility: A meta-analysis based on 19 case-control studies

A number of published studies investigated the association between interleukin-1α (IL-1α) −899 (+4845) C→T polymorphism and susceptibility to aggressive periodontitis (AgP). However, the results from different studies are controversial. This study was conducted to further investigate the association between IL-1α −899 (+4845) C→T polymorphism and AgP using a meta-analysis. A search was conducted through PubMed up to May 1, 2013 and a total of 19 relevant case-control studies were identified. The results of this meta-analysis demonstrated that IL-1α −899 (+4845) C→T polymorphism is not associated with susceptibility to AgP under allele T vs. C [odds ratio (OR)=1.00, 95% confidence interval (CI): 0.88–1.14, P=0.98; I²=28.86%] or allele A vs. C comparison (OR=0.99, 95% CI: 0.85–1.14, P=0.85; I²=33.66%). The subgroup analyses based on ethnicity, source of controls and Hardy-Weinberg equilibrium (HWE) also revealed no such association. There existed a weak publication bias (Egger’s test P=0.02). In conclusion, based on the currently available evidence, there is no association between IL-1α −899 (+4845) C→T polymorphism and susceptibility to AgP.

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.

Polymorphisms in the human cytochrome P450 and arylamine N-acetyltransferase: susceptibility to head and neck cancers

The occurrence of head and neck cancer (HNC) is associated with smoking and alcohol drinking. Tobacco smoking exposes smokers to a series of carcinogenic chemicals. Cytochrome P450 enzymes (CYP450s), such as CYP1A1, CYP1B1, and CYP2D6, usually metabolize carcinogens to their inactive derivatives, but they occasionally convert the chemicals to more potent carcinogens. In addition, via CYP450 (CYP2E1) oxidase, alcohol is metabolized to acetaldehyde, a highly toxic compound, which plays an important role in carcinogenesis. Furthermore, two N-acetyltransferase isozymes (NATs), NAT1 and NAT2, are polymorphic and catalyze both N-acetylation and O-acetylation of aromatic and heterocyclic amine carcinogens. Genetic polymorphisms are associated with a number of enzymes involved in the metabolism of carcinogens important in the induction of HNC. It has been suggested that such polymorphisms may be linked to cancer susceptibility. In this paper, we select four cytochrome P450 enzymes (CYP1A1, CYP1BA1, CYP2D6, and CYP2E1), and two N-acetyltransferase isozymes (NAT1 and NAT2) in order to summarize and analyze findings from the literature related to HNC risk by focusing on (i) the interaction between these genes and the environment, (ii) the impact of genetic defect on protein activity and/or expression, and (iii) the eventual involvement of race in such associations.