Significant association between CYP1A1 T3801C polymorphism and cervical neoplasia risk: a systematic review and meta-analysis

Association of xenobiotic-metabolizing genes polymorphisms with cervical cancer risk in the Tunisian population

BACKGROUND

Host genetic characteristics and environmental factors interactions may play a crucial role in cervical carcinogenesis. We investigated the impact of functional genetic variants of four xenobiotic-metabolizing genes (AhR, CYP1A1, GSTM1, and GSTT1) on cervical cancer development in Tunisian women.

METHODS

The AhR gene polymorphism was analyzed using the tetra-primer ARMS-PCR, whereas the CYP1A1 polymorphism genotypes were identified by PCR-RFLP. A multiplex ligation-dependent polymerase chain reaction approach was applied for the analysis of GSTM1 and GSTT1 polymorphisms.

RESULTS

The homozygous A/A genotype of the AhR gene (rs2066853) and the heterozygous T/C genotype of the CYP1A1 SNP (CYP1A1-MspI) appeared to be associated with an increased risk of cervical tumorigenesis (OR^a = 2.81; OR^a = 5.52, respectively). Furthermore, a significantly increased risk of cervical cancer was associated with the GSTT1 null genotype (OR^a = 2.65). However, the null GSTM1 genotype showed any significant association with the risk of cervical cancer compared to the wild genotype (OR^a = 1.18; p = 0.784). Considering the combined effect, we noted a significantly higher association with cancer risk for individuals with at least two high-risk genotypes of CYP1A1/GSTT1 (OR^a = 4.2), individuals with at least two high-risk genotypes of CYP1A1/GSTT1/AhR (OR^a = 11.3) and individuals with at least two high-risk genotypes of CYP1A1/GSTM1/GSTT1/AhR exploitation low-risk genotype as a reference.

CONCLUSION

This study indicated that the single-gene contribution and the combined effect of xenobiotic-metabolizing gene polymorphisms (AhR, CYP1A1-MspI, GSTM1, and GSTT1) may have a considerable association with increased cervical cancer risk.

The point mutation analysis of Cyp2C9*2 (Arg144Cys C>T), Cyp2C9*3 (Ile359Leu A>C) and VKORC1 (1639G>A) in women with cervical cancer related to HPV: A case-control study

Human papillomavirus (HPV) is the most common sexually transmitted viral infection worldwide. HPV tumorigenesis genotypes are the causative agents of cervical cancer and genital malignancies. The scientific literature has demonstrated that life style, environmental, epigenetic accompanied with HR-HPV genotypes are potential risk factors for cervical cancer progression. The frequencies of the Cyp2C9*2 , Cyp2C9*3 , and vitamin K epoxide reductase complex subunit 1 (VKORC1) genotypes as potential molecular biomarkers have been investigated on Iranian women with cervical malignancy related to HPV genotypes. As a case-control study, the mutations were appraised using a polymerase chain reaction-restriction fragment length polymorphism procedure on women suffering from HPV infection (60 cases), CC (46 cases), and 40 subjects of as healthy control. The outcomes demonstrated that Cyp2C9*3  showed a meaningful relationship between women diagnosed with cervical cancer and the healthy population (AA vs. AC; OR, 7.15; 95% CI, 1.94-26.3; p = .003). It was also observed that the Cyp2C9*3 mutation in women with cervical cancer and VKORC1 in healthy population with HPV (+), did not follow the Hardy-Weinberg equilibrium. Our findings aid understanding the genetic polymorphism distribution of Cyp2C9*2 , Cyp2C9*3 , and VKORC1 in women with genital malignancies. This can also be useful in predicting the susceptibility risk factors for developing cervical cancer. However, allelic discrimination as a molecular biomarker requires further research.

Genetic susceptibility in cervical cancer: From bench to bedside

Cervical cancer (CC) is the third most common malignancy in women globally, and persistent infection with the oncogenic human papillomaviruses (HPV) is recognized as the major risk factor. The pathogenesis of CC relies on the interplay between the tumorigenic properties of the HPV and host factors. Host-related genetic factors, including the presence of susceptibility loci for cervix tumor is substantial importance. Preclinical and genome-wide association studies (GWAS) have reported the associations of genetic variations in several susceptibility loci for the development of cervical cancer. However, many of these reports are inconsistent. In this review, we discuss the findings to date of candidate gene association studies, and GWAS in cervical cancer. The associations between these genetic variations with response to chemotherapy are also discussed.

CYP1A1 MspI Polymorphism and Cervical Carcinoma Risk in the Multi-Ethnic Population of Malaysia: a Case-Control Study

BACKGROUND

Tobacco smoking is considered a risk factor for cervical cancer development due to the presence of tobacco based carcinogenic metabolites in cervical cells of female smokers. In this study, we investigated the role of the T3801C (MspI) polymorphism of CYP1A1, a gene encoding an enzyme necessary for the initiation of tobacco based carcinogen metabolism, on cervical cancer risk. The T to C substitution may alter CYP1A1 activities, potentially elevating cervical cancer risk. Since results of gene-disease association studies vary according to the study population, the multi-ethnic population of Malaysia provides an excellent representative cohort for identifying and comparing the cervical cancer risk among the 3 major ethnics in Southeast Asia in relation to CYP1A1 MspI polymorphism.

MATERIALS AND METHODS

A total of 195 Thin Prep Pap smear samples from HPV negative and cancer free females were randomly selected as controls while 106 formalin fixed paraffin embedded samples from females with invasive cervical cancer were randomly selected for the cases group. The polymorphisms were identified using restriction fragment length polymorphism (RFLP) PCR.

RESULTS

We found no significant associations between CYP1A1 MspI polymorphism and cervical cancer in the general Malaysian female population. However, upon ethnic stratification, the variant C/C genotype was significantly associated with a 4.66-fold increase in cervical cancer risk in Malay females (95% CI= 1.21-17.9; p=0.03). No significant association was observed in the Chinese and Indian females. Additionally, there were no significant associations in the dominant model and allele frequency model analysis in both the general and ethnically stratified female population of Malaysia.

CONCLUSIONS

Our findings suggest that the C/C genotype of CYP1A1 MspI polymorphism is associated with the development of cervical carcinoma in the Malay females of Malaysia.

The Association of CYP1A1 Gene With Cervical Cancer and Additional SNP-SNP Interaction in Chinese Women

AIMS

The aim of this study was to investigate the association between CYP1A1 gene polymorphism and cervical cancer risk, and the impact of SNP-SNP interaction on cervical cancer risk in Chinese women.

METHODS

A total of 728 females with a mean age of 60.1 ± 14.5 years old were selected, including 360 cervical cancer patients and 368 normal controls. Logistic regression was performed to investigate association between single-nucleotide polymorphisms (SNP) and cervical cancer risk. Generalized multifactor dimensionality reduction (GMDR) was used to analyze the SNP-SNP interaction.

RESULTS

Logistic analysis showed a significant association between rs4646903 and increased cervical cancer risk. The carriers of homozygous mutant of rs4646903 polymorphism revealed increased cervical cancer risk than those with wild-type homozygotes, OR (95%CI) were 1.45 (1.20-1.95). There was a significant two-locus model (P = 0.0107) involving rs4646903 and rs1048943, indicating a potential SNP-SNP interaction between rs4646903 and rs1048943. Overall, the two-locus models had a cross-validation consistency of 10 of 10, and had the testing accuracy of 60.72%. Subjects with TC or CC of rs4646903 and AG or GG of rs1048943 genotype have the highest cervical cancer risk, compared to subjects with TT of rs4646903 and AA of rs1048943 genotype, OR (95%CI) was 2.03 (1.42-2.89).

CONCLUSIONS

rs4646903 minor alleles and interaction between rs4646903 and rs1048943 were associated with increased cervical cancer risk.

Genetic susceptibility to esophageal cancer due to CYP1A1 gene variant rs4646903 in tobacco addicted patients of Pashtun ethnicity: a case control study in Khyber Pakhtunkhwa province of Pakistan

The purpose of this study was to evaluate associations of the CYP1A1 gene variant rs4646903 polymorphism with the risk of developing esophageal cancer (EC). A case-control study was carried out in Pashtun population of Khyber Pakhtunkhwa province of Pakistan in which 140 hospital based EC cases and 196 population based healthy controls exposed to similar environmental conditions were included. A specific method based on the real time polymerase chain reaction (RT-PCR) was used to detect genotypes in case and control groups and results were then analyzed with SPSS version 20. In our population, individuals with CC and TC genotypes of the CYP1A1 rs4646903 polymorphism had significantly higher risk of EC (adjusted odds (OR): 15.709, 95%CI: 6.065-40.686, OR: 3.256 95%CI: 1.902-5.574 respectively). The 'C' allele was strongly associated with the disease (p< 0.0001). Adjusted OR was higher (1.5 times in C/C) in case of variant alleles that show the contribution of environmental and nutritional factors towards the development of EC. Our findings suggest that presence of the 'C' allele of rs4646903 (T>C) may be one of the risk alleles for EC susceptibility in Pashtun population.

Association of 42 SNPs with genetic risk for cervical cancer: an extensive meta-analysis

Background

A large number of single nucleotide polymorphisms (SNPs) associated with cervical cancer have been identified through candidate gene association studies and genome-wide association studies (GWAs). However, some studies have yielded different results for the same SNP. To obtain a more comprehensive understanding, we performed a meta-analysis on previously published case–control studies involving the SNPs associated with cervical cancer.

Methods

Electronic searches of PubMed and Embase were conducted for all publications about the association between gene polymorphisms and cervical cancer. One-hundred and sixty-seven association studies were included in our research. For each SNP, three models (the allele, dominant and recessive effect models) were adopted in the meta-analysis. For each model, the effect summary odds ratio (OR) and 95% CI were calculated. Heterogeneity between studies was evaluated by Cochran’s Q test. If the p value of Q test was less than 0.01, a random effect model was used; otherwise, a fixed effect model was used.

Results

The results of our meta-analysis showed that: (1) There were 8, 2 and 8 SNPs that were significantly associated with cervical cancer (P < 0.01) in the allele, dominant and recessive effect models, respectively. (2) rs1048943 (CYP1A1 A4889G) showed the strongest association with cervical cancer in the allele effect model (1.83[1.57, 2.13]); in addition, rs1048943 (CYP1A1 A4889G) had a very strong association in the dominant and recessive effect model. (3) 15, 11 and 10 SNPs had high heterogeneity (P < 0.01) in the three models, respectively. (4) There was no published bias for most of the SNPs according to Egger’s test (P < 0.01) and Funnel plot analysis. For some SNPs, their association with cervical cancer was only tested in a few studies and, therefore, might have been subjected to published bias. More studies on these loci are required.

Conclusion

Our meta-analysis provides a comprehensive evaluation of cervical cancer association studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-015-0168-z) contains supplementary material, which is available to authorized users.

Lessons and implications from association studies and post-GWAS analyses of cervical cancer

Cervical cancer has a heritable genetic component. A large number of genetic associations with cervical cancer have been reported in hypothesis-driven candidate gene studies, but many of these results are either inconsistent or have failed to be independently replicated. Genome-wide association studies (GWAS) have identified additional susceptibility loci previously not implicated in cervical cancer development, highlighting the power of genome-wide unbiased association analyses. Post-GWAS analyses including pathway-based analysis and functional characterization of associated variants have provided new insights into the pathogenesis of cervical cancer. In this review we summarize findings from candidate gene association studies, GWAS, and post-GWAS analyses of cervical cancer. We also discuss gaps in our understanding, possible clinical implications of the findings, and lessons for studies of other complex diseases.

The association between cytotoxic T lymphocyte-associated antigen-4 and cervical cancer

Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) gene polymorphisms have been associated with many autoimmune diseases and malignancy susceptibility, but the relationship between CTLA-4 and cervical cancer is still controversial. Hence, a meta-analysis of the published studies for the CTLA-4 gene polymorphisms and the risk of cervical cancer was performed to evaluate the association between them. Odds ratios (ORs) and 95% confidence intervals (CIs) for the codominant, dominant, and recessive genetic models were assessed. The fixed or random effect pooled measure was selected on the basis of the heterogeneity test among studies. The heterogeneity among studies was evaluated using the I (2). Eight studies with 2,835 cases and 2,560 controls were included. In seven studies for the CTLA-4 +49A/G polymorphism, a significant association was showed between the A allele and the increased risk of cervical cancer in the codominant (OR 1.16, 95% CI 1.05-1.29), dominant (OR 1.18, 95% CI 1.03-1.36), and recessive (OR 1.24, 95% CI 1.05-1.56) models. In five studies for the CTLA-4 -318C/T polymorphism, the meta-analysis showed a significant association of the C allele with the reduced risk of cervical cancer in the codominant (OR 0.79, 95% CI 0.66-0.94) and recessive (OR 0.76, 95% CI 0.63-0.93) models. This meta-analysis suggested that +49A/G and -318C/T polymorphisms of the CTLA-4 gene were significantly associated with the risk of cervical cancer. However, further studies are required to draw a solid conclusion on the relation between the CTLA-4 polymorphism and the risk of cervical cancer.

Tumor necrosis factor alpha rs1800629 polymorphism and risk of cervical lesions: a meta-analysis

Background

Tumor necrosis factor- alpha (TNF-α) is an inflammatory cytokine which may play important role on the immune response may control the progression of cervical lesions. There is a possible association between TNF-α rs1800629 G/A polymorphism and cervical lesions, but previous studies report conflicting results. We performed a meta-analysis to comprehensively assess the association between TNF-α rs1800629 polymorphism and cervical lesions risk.

Methods

Literature searches of Pubmed, Embase, Web of Science, and Wanfang databases were performed for all publications on the association between TNF-α rs1800629 polymorphism and cervical lesions through December 15, 2012. The pooled odds ratios (ORs) with their 95% confidence interval (95%CIs) were calculated to assess the strength of the association.

Results

Twenty individual case-control studies from 19 publications with a total of 4,146 cases and 4,731 controls were finally included into the meta-analysis. Overall, TNF-α rs1800629 polymorphism was significantly associated with increased risk of cervical lesions under two main genetic comparison models (For A versus G: OR 1.22, 95%CI 1.04–1.44, P = 0.017; for AA versus GG: OR 1.32, 95%CI 1.02–1.71, P = 0.034). Subgroup analysis by ethnicity further showed that there was a significant association between TNF-α rs1800629 polymorphism and increased risk of cervical lesions in Caucasians but not in Asians. Subgroup analysis by the types of cervical lesions showed that there was a significant association between TNF-α rs1800629 polymorphism and increased risk of cervical cancer (For A versus G: OR 1.24, 95%CI 1.05–1.47, P = 0.011; for AA versus GG: OR 1.31, 95%CI 1.01–1.70, P = 0.043; for AA/GA versus GG: OR 1.25, 95%CI 1.01–1.54, P = 0.039).

Conclusion

The meta-analysis suggests that TNF-α rs1800629 polymorphism is associated with increased risk of cervical lesions, especially in Caucasians.