CYP1A1 Ile462Val polymorphism and cervical cancer: evidence from a meta-analysis

Genetic polymorphisms of CYP1A, CYP1B, CYP2C and risk of cervical cancer among rural population of Maharashtra: Findings from a hospital-based case-control study

BACKGROUND

Last few decades, multiple studies all over the world revealed the association of genetic polymorphism in cytochrome P450 (CYP) genes with risk of developing different type of cancers, but contradictory outcomes were evidenced in case of cervical cancer (CC) risk. Therefore, the discrepancies in earlier reports influenced us to evaluate the association of CYP1A1*2A rs4646903, CYP1B1*3 rs1056836, CYP2C8*2 rs11572103, CYP2C9*2 rs1799853, CYP2C9*3 rs1057910, and CYP2C19*2 rs4244285 polymorphisms and CC susceptibility in the women of rural population of Maharashtra.

MATERIALS AND METHODS

In this case-control study, genetic association of the polymorphisms in CYP genes was studied by using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method. The study was conducted among 350 clinically confirmed CC patients and 350 healthy volunteers in a population of south-western Maharashtra. The odds ratio (OR) with 95% confidence interval (CI) and P value were evaluated to get the level of association where P ≤ 0.005 was considered as statistically significant.

RESULTS

After the analysis of single-nucleotide polymorphism (SNPs) of CYP1A1, CYP1B1, CYP2C8, CYP2C9, and CYP2C19, we noticed that CYP1B1*3 rs1056836 (Leu4326Val) polymorphism possessed a significantly elevated risk (OR = 3.28; 95% CI: 2.18-4.94; P < 0.0001), whereas CYP2C19*2 rs4244285 showed significantly lower risk (OR: 0.53, 95% CI: 0.33-0.85 P < 0.009) of CC in the studied rural population.

CONCLUSION

The findings from this study supported that rs1056836 SNP of CYP1B1*3 increase CC development, whereas rs4244285 of CYP2C19*2 lowers the CC risk in the studied population.

CYP1A1 Ile462Val Polymorphism Is Associated with Cervical Cancer Risk in Caucasians Not Asians: A Meta-Analysis

Objective: Previous studies have reported that Ile462Val polymorphism in the gene Cytochrome P450 1A1 (CYP1A1) is associated with the risk of cervical cancer, but inconsistent results have emerged. Hence, we performed this updated and cumulative meta-analysis to ascertain a more accurate association between CYP1A1 Ile462Val polymorphism and risk of cervical cancer.

Methods: Studies involving the CYP1A1 Ile462Val polymorphism associated with cervical cancer risk were searched from the databases of PubMed, Scopus, ScienceDirect, and Chinese National Knowledge Infrastructure (CNKI). The strength of correlation was evaluated through calculating summary odds ratios (ORs) with the corresponding 95% confidence intervals (95% CIs). Subgroup analyses according to ethnicity, source of control and HWE were completed to further explore specific association between the polymorphism and the cancer risk.

Results: Altogether, 11 eligible case-control studies were ultimately encompassed into the current meta-analysis, with 1,932 patients and 2,039 healthy controls. The total analysis revealed a borderline relationship between CYP1A1 Ile462Val polymorphism and cervical cancer risk in general population. Interestingly, after subgroup analyses based on ethnicity and source of control, the polymorphism increased the susceptibility of cervical cancer in Caucasian (G vs. A: OR = 1.97, 95% CI = 1.24–3.13; GG vs. AA: OR = 3 .24, 95% CI = 1.24–8.46; GA vs. AA: OR = 1.62, 95% CI = 1.25–2.10; GA+GG vs. AA: OR = 1.68, 95% CI = 1.16–2.43; GG vs. AA+GA: OR = 2.73, 95% CI = 1.05–7.10) and population-based (G vs. A: OR = 1.49, 95% CI = 1.10–2.02; GA vs. AA: OR = 1.41, 95% CI = 1.20–1.67; GA+GG vs. AA: OR = 1.40, 95% CI = 1.19–1.64) groups.

Conclusion: The CYP1A1 Ile462Val polymorphism may enhance the susceptibility to cervical cancer in Caucasian females.

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.

The association of the CYP1A1 Ile462Val polymorphism with head and neck cancer risk: evidence based on a cumulative meta-analysis

Objective

The aim of this study was to address the association between the Ile462Val polymorphism in the gene encoding cytochrome P450 1A1 (CYP1A1) and the risk of head and neck cancer (HNC).

Materials and methods

The Medline/PubMed, EMBASE, and Web of Science databases were searched. The strength of the association was evaluated by calculating the odds ratio (OR) with a 95% confidence interval (CI).

Results

Overall, we observed an increased risk of HNC in patients with the Ile/Val+Val/Val genotype compared to those with the Ile/Ile genotype among the 6,367 cases and 6,395 controls evaluated in the 34 eligible studies, with a pooled OR of 1.284 (95% CI: 1.119–1.473). In addition, we observed an increased risk of HNC in patients with the Ile/Val+Val/Val genotype compared to those with the Ile/Ile genotype in the subgroup analyses (OR =1.362, 95% CI: 1.102–1.685 for laryngeal cancer; OR =1.519, 95% CI: 1.253–1.843 for pharyngeal cancer; OR =1.371, 95% CI: 1.111–1.693 for Asians; and OR =1.329, 95% CI: 1.138–1.551 for patients in studies using hospital-based controls).

Conclusion

This cumulative meta-analysis suggests that the CYP1A1 Ile462Val polymorphism might contribute to the risk of HNC, particularly for pharyngeal cancer and laryngeal cancer.

Stratification analysis and case-control study of relationships between interleukin-6 gene polymorphisms and cervical cancer risk in a Chinese population

Interleukin-6 (IL-6), a central proinflammatory cytokine, maintains immune homeostasis and also plays important roles in cervical cancer. Therefore, we aimed to evaluate any associations of IL-6 gene polymorphisms at positions -174 and -572 with predisposition to cervical cancer in a Chinese population. The present hospital- based case-control study comprised 518 patients with cervical cancer and 518 healthy controls. Polymorphisms of the IL-6 gene were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Patients with cervical cancer had a significantly higher frequency of the IL-6 -174 CC genotype [odds ratio (OR) =1.52, 95% confidence interval (CI) = 1.06-2.19; p=0.02], IL-6 -572 CC genotype (OR =1.91, 95% CI = 1.16-3.13; p=0.01) and IL-6 -174 C allele (OR =1.21, 95% CI = 1.02-1.44; p=0.03) compared to healthy controls. When stratifying by the FIGO stage, patients with III-IV cervical cancer had a significantly higher frequency of IL-6 -174 CC genotype (OR =1.64, 95% CI =1.04-2.61; p=0.04). The CC genotypes of the IL-6 gene polymorphisms at positions -174 and -572 may confer a high risk of cervical cancer. Additional studies with detailed human papillomavirus (HPV) infection data are warranted to validate our findings.

CYP1A1 Ile462Val polymorphism as a risk factor in cervical cancer development in the Polish population

Background and objective

There are inconsistent data of the cytochrome P450 1A1 (CYP1A1) Ile462Val (rs1048943) single nuclear polymorphism (SNP) as a genetic susceptibility factor for cervical cancer in various populations. Moreover, little is known about the interaction of this SNP with other risk factors, including contraceptive use, postmenopausal status, parity, and tobacco smoking.

Methods

Polymerase chain reaction-restriction fragment length polymorphism was used to study the prevalence of the CYP1A1 Ile462Val SNP in women with cervical cancer (n = 456) and controls (n = 495).

Results

Logistic regression analysis adjusting for age, parity, oral contraceptive use, tobacco smoking, and menopausal status demonstrated that that the CYP1A1 Ile/Val polymorphism was not associated with an increased risk of cervical cancer in all patients. The adjusted odds ratio (OR) for patients with the Ile/Val genotype vs. Ile/Ile genotype was 1.539 (95 % confidence interval [CI] 0.932–2.541, p = 0.091). However, an increase in cervical cancer risk was seen among patients with a positive history of tobacco smoking and parity. The adjusted OR for positive history of tobacco smoking with the Ile/Val vs. Ile/Ile genotypes was 2.978 (95 % CI 1.382–6.418, p = 0.0052). The adjusted OR for parity with the Ile/Val vs. Ile/Ile genotype was 1.739 (95 % CI 1.006–3.009, p = 0.0472).

Conclusion

Our genetic study suggests that the CYP1A1 Ile462Val SNP may be a risk factor for cervical cancer among patients with a positive history of tobacco smoking and parity.

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.

CYP1A1 Ile462Val polymorphism and colorectal cancer risk in Polish patients

Colorectal cancer (CRC) is an epidemiological problem of a great importance in Poland; each year approximately 14,600 new cases of the disease are diagnosed. Mortality associated with CRC reaches approximately 10,400 cases per year (according to the National Cancer Registry). The 5-year survival rate is approximately 25 %, which is one of the lowest rates in Europe. The etiology of sporadic colorectal cancer (CRC) is multifactorial and has been attributed to an interplay between both environmental and genetic risk factors. In addition, there is a general consensus that genetic factors may modulate the influence of environmental insults. Following these assumptions, we performed a study on widely described polymorphisms in xenobiotic-metabolizing enzymes and DNA repair genes which may influence individual susceptibility to cancer. We selected five candidate polymorphisms in following genes: ERCC1 Asp118Asn (rs11615), XPC i11C/A (rs2279017), XRCC3 Met241Thr (rs861539) CYP1A1 Ile462Val (rs1048943) and NAT2 A803G (rs1208) and assessed the importance of chosen SNPs on groups consisting of 478 CRC patients and 404 controls. Only CYP1A1 Ile462Val was statistically significant in CRC patients over 50 years old: OR 2.05 (1.29–3.28); p = 1.25E−02 and this association was more pronounced in the female group of CRC patients after the age of 50: OR 2.72 (1.43–5.14); p = 1.14E−02.

The polymorphisms in the MGMT gene and the risk of cancer: a meta-analysis

Polymorphisms in the MGMT gene have been implicated in susceptibility to cancer, but the published studies have reported inconclusive results. The objective of the current study was to investigate the genetic risk of polymorphisms in the MGMT gene for cancer. A meta-analysis was carried out to analyze the association between polymorphisms in the MGMT gene and cancer risk. Five polymorphisms (Leu84Phe, Leu53Leu, Ile143Val, Lys178Arg, and -485C/A) with 98 case-control studies from 49 articles were analyzed. The results indicated that individuals who carried the Phe/Phe homozygote genotype of Leu84Phe had a 31 % increased risk of cancer compared with the Leu allele (Leu + Leu/Phe) carriers (odds ratio [OR] = 1.32, 95 % confidence interval [CI] = 1.15-1.52, P < 0.0001 for Phe/Phe vs. Phe/Leu + Leu/Leu). However, there was no significant association between the risk of cancer and the other four polymorphisms (Leu53Leu, Ile143Val, Lys178Arg, and -485C/A). In further stratified analyses for the Leu84Phe and Ile143Val polymorphisms, the increased risk of cancer remained in subgroups of Caucasians, patients with esophageal cancer for the Leu84Phe polymorphism, and patients with lung cancer for the Ile143Val polymorphism. Results from the current meta-analysis suggested that Leu84Phe and Ile143Val in the MGMT gene are risk factors for cancer. In the future, more studies should be performed to validate our results.

Metadherin confers chemoresistance of cervical cancer cells by inducing autophagy and activating ERK/NF-κB pathway

Overexpression of metadherin (MTDH) has been reported in many solid tumors and implicated in chemoresistance. This study aimed to examine MTDH expression in cervical cancer tissues and explore its role in chemoresistance of cervical cancer. MTDH expression in cervical cancer biopsies and several cervical cancer cell lines was detected by immunoblotting and immunohistochemisty. MTDH expression level was experimentally modulated in HeLa cells to determine the effects on chemoresistance to cisplatin. The results showed that MTDH expression was higher in tissues from both cervical squamous carcinoma and cervical adenocarcinoma, compared to normal cervical tissues. MTDH expression was not correlated to patient age or cervical cancer grade, although nuclear MTDH expression was correlated with poor differentiation of cervical cancer. In SiHa, HeLa, CasKi, and C33A cells, MTDH expression level was positively correlated with chemoresistance to cisplatin. MTDH increased autophagy in HeLa cells, which was associated with decreased cleavage of Caspase-3 and the activation of EER/NF-κB pathway. In conclusion, MTDH expression is high in cervical cancer, and it contributes to chemoresistance of cervical cancer. MTDH could be utilized as a therapeutic target to overcome chemoresistance of cervical cancer.

The association between the poly(A) polymorphism in the VDR gene and cancer risk: a meta-analysis

The poly(A) polymorphism (L/S) in the VDR gene has been implicated in susceptibility of cancer, but a number of studies have reported inconclusive results. The aim of this study is to investigate the relationship between the poly(A) polymorphism in the VDR gene and cancer risk by meta-analysis. We searched PubMed database, EMBASE database, CNKI database, and Wanfang database, covering all studies until January 22, 2013. Statistical analysis was performed by using the software Revman4.2 and STATA 10.0. A total 8,186 cancer cases and 8,685 controls in 19 case-control studies from 15 studies were identified for data analysis. The results suggested that the S allele carriers (SS+SL) did not have an increased or decreased risk of cancer when compared with the homozygote LL carriers (odds ratio (OR) =0.96, 95 % CI=0.87-1.06, P=0.43 for SS+SL vs. LL). In addition, in the subgroup analysis by ethnicity and cancer type, no significant association was found among Caucasians, African-Americans, prostate cancer, or breast cancer. This current meta-analysis suggested that the poly(A) polymorphism in the VDR gene may not contribute to the risk of cancer. Future studies are needed to validate our findings.

Quantitative synthesis of the association between the cytochrome P450 1A1 Ile462Val polymorphism and prostate cancer risk

The association between the cytochrome P450 1A1 (CYP1A1) Ile462Val polymorphism and prostate cancer risk remains inconclusive owing to the conflicting findings from previous studies. To get a more precise estimate of the possible association, we performed the present meta-analysis. We searched the PUBMED, EMBASE, and Wanfang databases for the studies which met the inclusion criteria. The pooled odds ratio (OR) with corresponding 95 % confidence interval (95 % CI) was used to estimate the association between CYP1A1 Ile462Val polymorphism and prostate cancer risk. A total of 13 studies with 2,350 cases and 2,992 controls were included in the meta-analysis. The results indicated that there was an obvious association between CYP1A1 Ile462Val polymorphism and increased risk of prostate cancer (for Val versus Ile: OR=1.27, 95 % CI 1.13-1.43, P<0.001; for ValVal versus IleIle: OR=1.51, 95 % CI 1.14-2.01, P=0.004; for ValVal + ValIle versus IleIle: OR=1.31, 95 % CI 1.14-1.51, P<0.001; for ValVal versus IleIle + ValIle: OR=1.38, 95 % CI 1.05-1.81, P=0.020). Subgroup analyses by ethnicity suggested that CYP1A1 Ile462Val polymorphism was associated with prostate cancer risk in Asians but not in Caucasians. This meta-analysis suggests that there is an association between CYP1A1 Ile462Val polymorphism and increased risk of prostate cancer. More studies with large sample are needed to further assess the association in Caucasians.