Germline genetic polymorphisms of CYP1A1, GSTM1 and GSTT1 genes in Indian cervical cancer: Associations with tumor progression, age and human papillomavirus infection

Assessment of the association of CYP1A1 gene polymorphisms with the susceptibility of cervical cancer: A case-control study and meta-analysis

Background

Cervical cancer (CC) is the second most common type of female malignancy in Bangladesh. Polymorphisms in the CYP1A1 gene have been reported to be associated with CC in different populations. This case-control study with meta-analysis was undertaken to assess the relation of CYP1A1 rs4646903 and rs1048943 polymorphisms with the susceptibility of CC.

Methods

A total of 185 CC patients and 220 controls were recruited, and the PCR-RFLP (Polymerase chain reaction-restriction fragment length polymorphism) technique was applied for genotyping. Again, 42 eligible studies (24 with rs4646903 and 18 with rs1048943) were included for meta-analysis, and RevMan 5.3 and the MetaGenyo web-based tool were used.

Results

The rs4646903 polymorphism was significantly linked with CC in all association models, namely, additive 1, additive 2, dominant, recessive, overdominant, and allele models (OR = 2.41, 4.75, 2.67, 3.61, 2.13, and 2.44 with corresponding 95% CI = 1.55-3.76, 1.81-12.45, 1.75-4.07, 1.39-9.35, 1.38-3.30, and 1.71-3.48, respectively). On the contrary, rs1048943 showed no association (p > 0.05) with CC. Haplotype analysis revealed AT and AC haplotypes significantly decreased (OR = 0.45) and increased (OR = 4.86) CC risk, respectively, and SNPs are in strong linkage disequilibrium (D' = 0.912, r² = 0.448). Again, rs4646903 carriers with a contraception history and >5 years of taking contraceptives showed an enhanced risk of CC (OR = 2.39, OR = 3.05). Besides, rs1048943 carriers aged >40 years (OR = 0.44), conceived first child aged ≤18 years (OR = 3.45), and history of contraceptives (OR = 2.18) were significantly linked with CC. Our meta-analysis found that for CYP1A1 rs4646903 codominant 1 (COD 1), codominant 2 (COD 2), codominant 3 (COD 3), dominant model (DM), recessive model (RM), and allele model (AM) in Caucasians and overdominant model (OD) in the overall population are associated with an elevated risk of CC, whereas rs1048943 is also associated with CC in overall, Caucasians and Asians in some genetic models.

Conclusion

Our case-control study and meta-analysis summarize that CYP1A1 rs4646903 and rs1048943 polymorphisms may be correlated with cervical cancer.

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.

Individual effects of GSTM1 and GSTT1 polymorphisms on cervical or ovarian cancer risk: An updated meta-analysis

Background: Studies have shown that glutathione S-transferase M1 (GSTM1) and. glutathione S-transferase T1 (GSTT1) null genotype may increase the risk of cervical cancer (CC) or ovarian cancer (OC), however, the results of published original studies and meta-analyses are inconsistent. Objectives: To investigate the association between GSTM1 present/null and GSTT1 present/null polymorphisms, with the risk of cervical cancer or ovarian cancer. Methods: The odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the association between GSTM1 present/null and GSTT1 present/null polymorphisms and the risk of cervical cancer or ovarian cancer. To assess the confidence of statistically significant associations, we applied false positive reporting probability (FPRP) and bayesian false discovery probability (BFDP) tests. Results: Overall analysis showed that GSTM1 null was associated with an increased risk of cervical cancer, and subgroup analysis showed a significant increase in cervical cancer risk in Indian and Chinese populations; GSTT1 was not found null genotype are significantly associated with cervical cancer. Overall analysis showed that GSTM1 and GSTT1 null were not associated with the risk of ovarian cancer, subgroup analysis showed that GSTM1 null was associated with an increased risk of OC in East Asia, and GSTT1 null was associated with an increased risk of OC in South America. However, when we used false positive reporting probability and bayesian false discovery probability to verify the confidence of a significant association, all positive results showed "low confidence" (FPRP > .2, BFDP > .8). Conclusion: Overall, this study strongly suggests that all positive results should be interpreted with caution and are likely a result of missing plausibility rather than a true association.

GSTT1 and GSTM1 polymorphisms with human papillomavirus infection in women from southern Brazil: a case-control study

BACKGROUND

Important risk factors for the most common sexually transmitted infection (STI) in the world, human papillomavirus (HPV), include early sexual activity, use of contraceptives, tobacco smoking, and immunological and genetic factors. This study aimed to investigate the relationship between GSTM1 and GSTT1 polymorphisms and HPV infection and associated risk factors in a group of women assisted in the public health system of southwestern Paraná, Brazil.

METHODS AND RESULTS

A case-control study was designed with 21 women with HPV matched by age in the case group and 84 women without the virus in the control group. Viral detection was conducted via polymerase chain reaction (PCR) and GSTM1 and GSTT1 genotyping by Multiplex PCR. The results showed that the GSTT1 null allele was a protective factor against infection (ORadj 0.219; 95% CI 0.078-0.618; p = 0.004). No relationship was observed for the GSTM1 gene. Smoking was defined as a risk factor (ORadj 3.678; 95% CI 1.111-12.171; p = 0.033), increasing the chances of HPV by up to 3.6 times.

CONCLUSION

This study showed, for the first time, the relationship between GSTM1 and GSTT1 genetic polymorphisms and HPV. We found that this relationship protected women from southern Brazil from viral infection, but not from susceptibility.

The risk and impact of organophosphate esters on the development of female-specific cancers: Comparative analysis of patients with benign and malignant tumors

Environmental pollution has become a concern for public health. As endocrine disruptors, organophosphate esters (OPEs) causes many diseases via human exposure. However, there is limited research on the risk of OPE exposure to female-specific cancers. Blood measurements are biomarkers for chemical exposures by their definition. Thus, in the present study, 11 OPEs were analyzed in the plasma of patients with 4 female-specific tumors. 2-Ethylhexyl diphenyl phosphate (EHDPP) was detected at the highest levels in all groups. The Spearman correlation test results showed significantly positive correlations between some OPEs in each group, which indicated that those OPEs had similar sources and/or behaved similarly in the patients of each group. However, compared with different patient groups, obvious differences in the correlation results were noted, implying the differences in the metabolism of OPEs between different groups. The results of the correlation analysis showed that EHDPP concentration was associated with the risk of breast cancer (p < 0.05), while tri-n-butyl phosphate (TNBP), tris (methylphenyl) phosphate (TMPP), triphenyl phosphate (TPHP), and EHDPP concentrations were associated with the risk of cervical cancer (p < 0.05 or p < 0.01). These findings indicated that OPEs were associated with the risk of breast and cervical cancer.

Meta-Analysis of Polymorphic Variants Conferring Genetic Risk to Cervical Cancer in Indian Women Supports CYP1A1 as an Important Associated Locus

Objective: Association of multiple polymorphic variants with cervical cancer has been elucidated by several candidate gene based as well as genome-wide association studies. However, contradictory outcomes of those studies have failed to estimate the true effect of the polymorphic variants on cervical cancer. Methods: Literature mining of the PubMed database was done to gather all the publications related to genetic association with cervical cancer in India. Out of 98 PubMed hits only 29 genetic association studies were selected for meta-analysis based on specific inclusion criteria. A fixed-effect meta-analysis was performed to evaluate the overall association of the genetic polymorphisms with cervical cancer. Cochran’s Q test was performed to assess between study heterogeneity. Publication bias was also estimated by funnel plots and Egger’s regression test. Further, sub-group analysis was conducted by fixed-effect meta-regression to assess the impact of polymorphisms on cervical cancer in the presence of Human Papilloma Virus (HPV). Result: Following a fixed-effect model, meta-analysis was conducted that revealed 2 polymorphic variants viz. ‘deletion polymorphism (Del2) (OR=1.79, 95% CI= 1.08-2.95, P=0.023) in GSTM1’ and ‘rs1048943 (OR = 2.34, 95% CI=1.37-3.99, P=0.0018) in CYP1A1’ to be associated with cervical cancer. However, multiple testing correction showed only rs1048943 of CYP1A1 to be significantly associated (P-value=0.029) with cervical cancer with significant publication bias (P-value=0.0113) as estimated by Egger’s regression test. The polymorphic variants ‘rs1801131’, ‘rs1801133’, ‘rs2430561’, ‘rs1799782’, ‘rs25486’ and ‘rs25487’ showed significant (p<0.05) evidence of heterogeneity between studies by Cochran’s Q test and also by heterogeneity index (I2) calculation. Conclusion: Therefore, our study revealed significant association of rs1048943 in CYP1A1, but a nominal association of deletion polymorphism (Del2) in GSTM1 with cervical cancer, which provides a comprehensive insight on the true effect of the polymorphisms, reported in various case-control studies, on the risk of the development of cervical cancer in Indian women.

Cytochrome P450 1A1 gene polymorphisms and cervical cancer risk: A systematic review and meta-analysis

OBJECTIVE

This meta-analysis aims to examine whether the MspI and Ile462Val polymorphisms of cytochrome P450 1A1 (CYP1A1) are associated with cervical cancer risk.

METHODS

Eligible case-control studies were identified dated until July 2017. Pooled odds ratios (ORs) were used to assess the strength of the association between the two variants and cervical cancer risk.

RESULTS

Thirteen studies were eligible (2148 cases and 2252 controls) concerning MspI polymorphism and 8 studies were eligible (1466 cases and 1690 controls) for Ile462Val polymorphism. MspI polymorphism seemed to result in cervical cancer risk in any genetic model (C allele vs T allele: OR = 1.44, 95% confidence interval [CI] = 1.16-1.79; heterozygous model: OR = 1.40, 95% CI = 1.08-1.82; homozygous model: OR = 2.22, 95% CI = 1.48-3.33, dominant model: OR = 1.50, 95% CI = 1.14-1.98 and recessive model: OR = 1.80, 95% CI = 1.35-2.41); similar significantly increased risk was found among Caucasians and Asians. Ile462Val polymorphism was associated with elevated cervical cancer risk (Val allele vs Ile allele: OR = 1.85, 95% CI = 1.27-2.67; heterozygous model: OR = 1.42, 95% CI = 1.28-1.61; homozygous model: OR = 2.94, 95% CI = 1.15-7.54; dominant model: OR = 2.00, 95% CI = 1.33-3.00); this finding was replicated upon Caucasian population.

CONCLUSION

This meta-analysis demonstrated that polymorphisms in MspI and Ile462Val of CYP1A1 were risk factors for developing cervical cancer.

Green Tobacco Sickness among Brazilian farm workers and genetic polymorphisms

OBJECTIVE

Green Tobacco Sickness (GTS) is an occupational illness caused by dermal absorption of nicotine from tobacco leaves. It affects thousands of farm workers worldwide. Brazil is the second tobacco producer in the world; despite this, there are few studies on GTS among Brazilian harvesters. This study aimed to determine the prevalence of GTS among a population of tobacco workers from a producing area in northeastern Brazil and investigate whether the occurrence of the disease was influenced by factors such age, gender and smoking status. In addition, it was investigated if there was association between the onset of GTS and genetic polymorphisms in genes that encode some detoxification enzymes. A semi-structured questionnaire was used to collect demographic, behavioral and occupational data from the referred workers. Polymorphisms were tested through the Polymerase Chain Reaction technique.

RESULTS

The total prevalence of GTS found was 56.9%, with a significant difference between genders (71.7% for women and 35.3% for men, p < 0.0001). No association was identified between the investigated polymorphisms and GTS. This study confirms the occurrence of GTS among tobacco harvesters in Brazil with high prevalence. The investigation suggests the need to take preventive measures to protect tobacco workers against this disease.

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.

Polymorphism of CYP1A1 gene variants rs4646903 and rs1048943 relation to the incidence of cervical cancer in Chhattisgarh

Cytochrome P450 CYP1A1 is a phase 1 xenobiotic metabolizing enzyme involved in the metabolism of toxins, endogenous hormones and pharmaceutical drugs. It is therefore possible that polymorphism of CYP1A1 gene producing functional changes in the enzyme may be susceptible factors in cervical carcinogenesis. This study was aimed to look association of CYP1A1m1 (T>C) and m2 (A>G) gene polymorphisms in Chhattisgarh population. In this case-control study, we analyzed leukocyte DNA from a total of 200 subjects form Chhattisgarh (100 cases and 100 controls). All subjects were genotyped for CYP1A1m1 (T>C) and m2 (A>G) using PCR-RFLP with statistical analysis by using SPSS version 16.0 and VassarStats (online). Among the two gene variants rs4646903 (T>C) and rs1048943 (A>G), individuals with AG and GG genotypes of CYP1A1m2 polymorphism have significantly higher and increased risk of cervical cancer (OR=2.0, 95%CI=1.04-3.84, p=0.035; OR=62.9, 95%CI=3.72-1063.83, p=0.004 respectively) and the association of CYP1A1m1 polymorphism did not show any significant relationship with cervical cancer patients (p=0.23). The 'G' allele showed strong association with the disease (p<0.0001). Thus, CYP1A1m2 polymorphism showed an increased risk in the population leading to cervical cancer. Our study suggested that the presence of 'C' allele of rs4646903 (T>C) showed no risk and 'G' allele of rs1048943 (A>G) might be a leading allele to cause increased cervical cancer susceptibility due to significant association of CYP1A1m2 gene polymorphism.

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.

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.

Functional variants in CYP1A1 and GSTM1 are associated with clearance of cervical HPV infection

OBJECTIVE

We evaluated time to clearance of high risk (HR) HPV infection in relation to functional variants in three genes (CYP1A1, GSTT1, and GSTM1).

METHODS

The study group consisted of 450 HR-HPV infected women from the Atypical squamous cells of undetermined significance-low-grade squamous intraepithelial Lesion Triage Study (ALTS) cohort followed up at the clinical center at Birmingham, Alabama. The Cox proportional hazard model with the Wei-Lin-Weisfeld (WLW) approach was used, controlling for relevant covariates.

RESULTS

Women who were polymorphic for CYP1A1 experienced an HR-HPV clearance rate that was 20% (HR=0.80, p=0.04) lower than women without the polymorphism for CYP1A1, adjusting for all other cofactors. The GSTM1 null genotype was associated with higher HR-HPV clearance rate (HR=1.39, p=0.006). The polymorphism in GSTT1 was not significantly associated with time to clearance of HR-HPV.

CONCLUSIONS

Xenobiotic metabolism genes may influence the natural history of HR-HPV infection and its progression to cervical cancer.

Human papillomavirus and host genetic polymorphisms in carcinogenesis: a systematic review and meta-analysis

BACKGROUND

As the role of human papillomavirus (HPV) in carcinogenesis continues to rise, the role of genetic factors that modify this risk have become increasingly important. In this study, we reviewed the literature for associations between polymorphisms and HPV in carcinogenesis.

OBJECTIVE

To identify any associations of genetic polymorphisms with oncogenic HPV in carcinogenesis and to evaluate the methodology used.

STUDY DESIGN

Systematic literature review of HPV, genetic polymorphisms, and cancer risk. Odds ratios (OR), interaction terms, and p-values were tabulated. Meta-analyses and measures of heterogeneity were estimated using RevMan 5.1.

RESULTS

The cervix was the most frequently studied cancer site followed by the head and neck. Overall risk of cancer (cancer vs. control) was the most common comparison, whereas reports of initiation (pre-cancer vs. control) and progression (cancer vs. pre-cancer) were rare. Case-series and joint-effect of HPV and genotype on risk was evaluated frequently, but the independent effect of either risk factor alone was rarely provided. P53-Arg72Pro was the most commonly studied polymorphism studied. No consistent interaction was detected by meta-analysis in the HPV(+) [OR 0.98 (0.55-1.76)] or the HPV(-) [OR 1.10 (0.76-1.60)] subsets in head and neck cancer risk. Polymorphisms in genes known to encode proteins that physically interact with HPV were infrequently studied.

CONCLUSION

No consistent polymorphism-HPV interactions were observed. Study design, choice of candidate polymorphisms/genes, and a focus on overall risk rather than any specific portions of the carcinogenic pathway may have contributed to lack of significant findings.

Glutathione S-transferase polymorphism interactions with smoking status and HPV infection in cervical cancer risk: an evidence-based meta-analysis

BACKGROUND

Human papillomavirus (HPV) infection is considered the major cause of cervical cancer (CC), but a number of infected women do not develop invasive lesions, suggesting the role of genetic susceptibility and environmental co-factors for cancer outbreak. Glutathione S- transferases (GSTs) are multifunctional enzymes that play a key role in the detoxification of varieties of both endogenous products of oxidative stress and exogenous carcinogens.

METHODS

MEDLINE, EMBASE, and Cochrane databases were searched. All studies evaluating the association between GSTM1 polymorphisms and cervical cancer were included. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using fixed-or random-effects model.

RESULTS

A total of 23 case-control studies were included in the meta-analysis. The overall result showed that the association between GSTM1 null genotype and risk for cervical cancer was statistically significant (OR = 1.56; 95%CI, 1.39-1.75). Subgroup analyses were performed based on ethnicity, smoking and HPV infection. Our results showed that smokers with null GSTM1 genotype had higher risk of cervical cancer (OR = 2.27, 95%CI, 1.46-3.54). For the ethnicity stratification, significant increased risk of null GSTM1 genotype was found in Chinese and Indian population, but no increased risk in other population was found.

CONCLUSIONS

this meta-analysis provided strong evidence that the GSTM1 genotype is associated with CC development, especially in Chinese and Indian populations. Smoking and HPV infection modified the association between the null GSTM1 genotype and CC.

Meta-analysis of the association between GSTM1 and GSTT1 gene polymorphisms and cervical cancer

AIM

We conducted a meta-analysis to analyze the influence of GSTM1 and GSTT1 gene polymorphisms on cervical cancer risk, and explore gene-environment interactions.

METHODS

Identification of relevant studies was carried out through a search of Medline and the EMbase up to Oct. 2011. All case-control studies that investigated the association between GSTM1 and GSTT1 gene polymorphisms and risk of cervical cancer were included. The pooled odds ratio (OR) was used for analyses of results and the corresponding 95% confidence intervals (CI) were estimated.

RESULTS

A total of 21 case-control studies were included in the meta-analysis of GSTM1 (2,378 cases and 2,639 controls) and GSTT1 (1,229 cases and 1,223 controls) genotypes. The overall results showed that the GSTM1 null was related to an increased risk of cervical cancer (OR=1.50, 95% CI=1.21-1.85). Subgroup analysis were performed based on smoking and ethnicity. Our results showed that smokers with null GSTM1 genotype had a moderate increased risk of cervical cancer (OR=1.85, 95% CI=1.07-3.20). For the ethnicity stratification, moderate significantly increased risk of null GSTM1 genotype was found in Chinese (OR=2.12, 95% CI=1.43-3.15) and Indian populations (OR=2.07, 95% CI=1.49-2.88), but no increased risk was noted in others.

CONCLUSION

This meta-analysis provided strong evidence that the GSTM1 genotype is associated with the development of cervical cancer, especially in smokers, and Chinese and Indian populations. However, no association was found for GSTT1 null genotype carriers.

A comprehensive review on host genetic susceptibility to human papillomavirus infection and progression to cervical cancer

Cervical cancer is the second most common cancer in women worldwide. This is caused by oncogenic types of human papillomavirus (HPV) infection. Although large numbers of young sexually active women get HPV-infected, only a small fraction develop cervical cancer. This points to different co-factors for regression of HPV infection or progression to cervical cancer. Host genetic factors play an important role in the outcome of such complex or multifactor diseases such as cervical cancer and are also known to regulate the rate of disease progression. The aim of this review is to compile the advances in the field of host genetics of cervical cancer. MEDLINE database was searched using the terms, ‘HPV’, ‘cervical’, ‘CIN’, ‘polymorphism(s)’, ‘cervical’+ *the name of the gene* and ‘HPV’+ *the name of the gene*. This review focuses on the major host genes reported to affect the progression to cervical cancer in HPV infected individuals.

Cytochrome P450 1A1 (CYP1A1) gene polymorphisms and cervical cancer risk: a meta-analysis

This meta-analysis aims to examine whether the genotype status of MspI and Ile462Val polymorphisms in Cytochrome-P450 1A1 (CYP1A1) is associated with cervical cancer risk. Eligible case-control studies were identified through search in MEDLINE (end of search: October 2010). Pooled odds ratios (ORs) were appropriately derived from fixed-effects or random effects models. Concerning MspI polymorphism, six studies were eligible (722 cases and 770 controls); four studies were eligible (350 cases and 519 controls) for Ile462Val. MspI polymorphism was associated with elevated cervical cancer risk (for heterozygous TC vs. TT carriers OR = 1.50, 95% CI: 0.93-2.42, random effects; for homozygous CC vs. TT carriers OR = 2.66, 95% CI: 1.14-6.19, random effects). Similarly, Ile462Val polymorphism was associated with elevated cervical cancer risk (for heterozygous Ile/Val vs. Ile/Ile carriers OR = 2.36, 95% CI: 1.10-5.08, random effects; for homozygous Val/Val vs. Ile/Ile carriers OR = 2.73, 95% CI: 1.21-6.15, fixed effects). The results were replicated upon Caucasian subjects, who represented the majority of existing data. The two examined CYP1A1 genotype polymorphisms seem to confer additional risk for cervical cancer. Accumulation of further data seems mandatory for future race-specific analyses and for the demonstration of CYP1A1-smoking interactions.

Meta-analysis of association between GSTM1 gene polymorphism and cervical cancer

OBJECTIVE

To investigate association between glutathione S-transferases (GSTs) and cervical cancer.

METHODS

Published literature from PubMed, EMBASE, and other databases were retrieved. All studies evaluating the association between GSTM1/GSTT1 polymorphisms and cervical were included. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using fixed- or random-effects model.

RESULTS

A total of 15 case-control studies were included in the meta-analysis of GSTM1 genotypes (1,825 cases and 2,104 controls). The overall result showed that the association between GSTM1 null genotype and risk for cervical cancer was statistically significant (OR=1.53, 95%CI=1.18-2.00). Great heterogeneity was found between studies. Subgroup analysises were performed based on smoking and ethnicity. Our results showed that smokers with null GSTM1 genotype had higher risk of cervical cancer (OR=1.56, 95%CI=1.01-2.41). For the ethnicity stratification, significant increased risk of null GSTM1 genotype was found in Chinese and Indian population, but no increased risk in other population.

CONCLUSIONS

This meta-analysis provides strong evidence that the GSTM1 null genotype is associated with the development of cervical cancer, and especially in Chinese and Indian population, and smoking shows a modification on the association between GSTM1 null genotype and cervical cancer.

Polymorphisms in GSTM1, CYP1A1, CYP2E1, and CYP2D6 are associated with susceptibility and chemotherapy response in non-small-cell lung cancer patients

BACKGROUND

Studies of polymorphisms in CYP1A1, CYP2E1, CYP2D6, and GSTM1 and their relationship to lung cancer susceptibility and chemotherapy response have been reported, but the results are not consistent. In this study we selected four polymorphisms in these genes, several of which have previously been researched, and investigated their association with lung cancer susceptibility and chemotherapy response.

METHODS

We genotyped the four polymorphisms in a cohort composed of 217 non-small-cell lung cancer (NSCLC) patients and 198 controls. Of these, 145 advanced NSCLC patients underwent chemotherapy and were monitored for 5 years.

RESULTS

Significant differences in the GSTM1 polymorphism were observed between the case and control groups (P = 0.02). We observed a synergistic effect of smoking and GSTM1. Smokers with deficient-type GSTM1 had a 4.96-fold increased risk of developing lung cancer. Significant differences in GSTM1 and CYP1A1 polymorphisms were observed between the response and nonresponse groups (P = 0.004 and P = 0.026). Moreover, patients with deficient-type GSTM1 were superior responders to platinum drugs than those carrying wild-type GSTM1 (P = 0.014). In addition, patients carrying TT CYP1A1 responded better to nonplatinum drugs than those carrying TC and CC CYP1A1 (P = 0.01). Polymorphisms in the four enzymes had no effect on the overall survival of NSCLC patients.

CONCLUSIONS

Our findings support the hypothesis that a polymorphism in GSTM1 is associated with lung cancer susceptibility. Furthermore, polymorphisms in GSTM1 and CYP1A1 were associated with chemotherapy response. In particular, smokers carrying deficient-type GSTM1 were at a higher risk of developing lung cancer. Patients carrying deficient-type GSTM1 responded better to platinum drugs, while those with TT CYP1A1 were better responders to nonplatinum drugs.

Null genotypes of GSTM1 and GSTT1 contribute to risk of cervical neoplasia: an evidence-based meta-analysis

Background and Objectives

Glutathione S-transferases (GSTs) are multifunctional enzymes that play a key role in the detoxification of varieties of both endogenous products of oxidative stress and exogenous carcinogens.

Methods

In this meta-analysis, twenty-five studies were identified by searching PubMed, EMBASE, ISI Web of Science and CBM databases: 23 evaluated GSTM1 and 19 evaluated GSTT1. Crude odds ratios with corresponding 95% confidence intervals were used to estimate the association between GSTM1 and GSTT1 polymorphisms and risk of cervical neoplasia. Subgroup analyses were conducted by pathological history, ethnicity, source of DNA for genotyping, quality score, and matching variable.

Results

The null genotypes of GSTM1 and GSTT1 polymorphisms were associated with a significantly increased risk of cervical neoplasia (for GSTM1: OR = 1.40; 95%CI, 1.19–1.65; for GSTT1: OR = 1.30; 95%CI, 1.05–1.62, respectively). Subgroup analyses showed that the null genotype of GSTM1 increased the risk of cervical neoplasia in Asians, studies with DNA isolation from white blood cells and tissue samples, both high and low quality studies, and matched studies. In GSTM1-GSTT1 interaction analysis, individuals with dual null genotype were associated with a significantly increased risk of cervical neoplasia (OR = 1.72; 95%CI, 1.18–2.51).

Conclusion

These findings indicate that GSTM1 and GSTT1 polymorphisms, particularly GSTM1-GSTT1 interaction, may play critical roles in the development of cervical neoplasia. A conservative manner should be adopted to interpret these results because of obvious heterogeneity between-study, unadjusted data, and relatively small sample size in this meta-analysis. Well designed studies with larger sample size are of great value to confirm these results.

Germline polymorphisms of glutathione-S-transferase GSTM1, GSTT1 and p53 codon 72 in cervical carcinogenesis

The clinical significance of glutathione-S-transferase GSTM1, GSTT1 and p53 codon 72 polymorphisms in cervical carcinogenesis was investigated. Germline polymorphisms of GSTM1, GSTT1 and p53 codon 72 together with human papillomavirus (HPV) types were examined in a total of 457 blood and cervical smear samples from normal healthy women and the patients with premalignant and malignant cervical lesions. The 167 patients with low-grade squamous intraepithelial lesion (LSIL), 49 with high-grade SIL (HSIL) and 83 with squamous cell carcinoma (SCC) had significantly higher frequency of high-risk HPV than 158 controls. The 49 patients with HSIL and 83 with SCC had statistically higher frequency of null GSTT1 genotype than 158 controls. There was an increased odds ratio for null GSTT1 genotype in HSIL and SCC cases compared with controls among 191 patients with high-risk HPV. The 67 cases with HPV types 16 and/or 18 had higher frequency of the GSTT1 null genotype than 186 with other types of HPV. There was no statistical difference in the polymorphic frequency of GSTM1 and p53 codon 72 genotypes between SILs and controls with or without high-risk HPV. These results suggest that GSTT1 null genotype may increase the risk of cervical cancer particularly in the cases with high-risk HPV types in a Japanese population.

GST (GSTM1, GSTT1, and GSTP1) polymorphisms in the genetic susceptibility of Turkish patients to cervical cancer

OBJECTIVE

This work investigates the role of glutathione S-transferase M1 (GSTM1), glutathione S-transferase T1 (GSTT1), and glutathione S-transferase P1 (GSTP1) enzymes and polymorphisms, which are found in phase II detoxification reactions in the development of cervical cancer.

METHODS

This study was conducted with 46 patients diagnosed with cervical cancer and 52 people with no cancer history. Multiplex PCR methods were used to evaluate the GSTM1 and GSTT1 gene polymorphism. However, the GSTP1 (Ile105Val) gene polymorphism was studied using a PCR-RFLP method. The patient and control groups were compared using a chi-square test with p<0.05.

RESULTS

In the patient group, statistical significance was determined for gravidity (p=0.03), parity (p=0.01), and the number of living children (p=0.01) compared to the control group. The gene frequency of GSTM1, GSTT1, and GSTP1 polymorphisms was evaluated. We observed that GSTM1 and GSTT1 null genotype frequencies were 54.3% and 32.6% respectively, while GSTP1 (Ile/Val), (Ile/Ile), (Val/Val) genotype frequencies were 52%, 44%, and 4%, respectively, in the cervical cancer patients. No statistical variation was determined between the control and patient groups in terms of GSTM1, GSTT1, and GSTP1 polymorphisms (p>0.05).

CONCLUSION

Our results demonstrate that GSTT1, GSTM1, and GSTP1 polymorphisms are not associated with cervical cancer in Turkish patients.

Interaction between glutathione-S-transferase polymorphisms, smoking habit, and HPV infection in cervical cancer risk

PURPOSE

Human papillomavirus (HPV) infection is considered the major cause of cervical cancer (CC), but a number of infected women do not develop invasive lesions, suggesting the role of genetic susceptibility and environmental co-factors for cancer outbreak. The aim of this study was to investigate whether some GST polymorphisms could influence the risk to develop CC, either by themselves or in combination with smoking habit, in a cohort of high-risk HPV (HR-HPV) infected Italian women.

METHODS

The study population comprises 192 Italian women including 81 HR-HPV infected women bearing cervical lesions and 111 healthy controls. The cases include: 26 low-grade squamous intraepithelial lesions (LSILs), 30 high-grade-SIL, and 25 CCs, while controls were all negative for HPV. DNA was extracted from peripheral blood samples or cytobrush and individuals were genotyped for GSTM1, GSTT1, and GSTP1 polymorphisms using PCR and PCR/RFLP techniques.

RESULTS

On studying the association of GSTs gene polymorphisms with cervical cancer lesions, the combination of GSTM1 null, GSTT1 null and GSTP1 AA genotypes, independently on smoking habit, seems to be related to a 5.7-fold increased risk of developing CLs with a considerable statistical significance (P = 0.0091).

CONCLUSIONS

We suggest that the investigation of multiple gene polymorphisms, versus single genes, could contribute to a better understanding of the effect of susceptibility genes on cancer risk.

Association of GSTM1, GSTT1, and GSTM3 gene polymorphisms and susceptibility to cervical cancer in a North Indian population

OBJECTIVE

The objective of the study was to evaluate the influence of genetic polymorphisms of GSTM1, GSTT1, and GSTM3 on the susceptibility of cervical cancer.

STUDY DESIGN

Blood samples from 150 women with biopsy-confirmed cervical cancer and 168 healthy controls were analyzed by multiplex polymerase chain reaction (PCR) to detect the presence or absence of GSTM1 and GSTT1. Insertion/deletion polymorphism in intron 6 of GSTM3 was determined by PCR.

RESULTS

The frequencies of homozygous GSTM1 null and GSTT1 null genotypes were found to be significantly higher in cancer patients as compared with healthy controls (P = .009, odds ratio [OR] 1.52, 95% confidence interval [CI], 1.1 to 2.0 and P = .0004, OR 2.4, 95% CI: 1.4 to 4.0, respectively). The AB genotype of GSTM3 also conferred higher risk of cancer (P = .053, OR 1.64, 95% CI, 1.0 to 2.6). However, no significant association of at-risk genotypes was observed with any stages of cervical cancer. Interactions among GSTM1 null, GSTT1 null, and AB genotype of GSTM3 resulted in additive predictive risks of cervical cancer. In case-only analysis, carriers of the AA genotype of GSTM3 among tobacco users were at elevated risk of cervical cancer (P = .024, OR 2.1, 95% CI, 1.0 to 4.1) as compared with AB and BB genotypes.

CONCLUSION

GSTM1 null, GSTT1 null, and GSTM3*AB genotypes may confer higher susceptibility to cervical cancer and cancer risk because at-risk genotypes are additive. Tobacco usage by carriers of GSTM3*AA has enhanced the risk of cervical cancer as compared with nonusers.

Glutathione-S-transferase M1 and T1 and cytochrome P1A1 genetic polymorphisms and susceptibility to cervical intraepithelial neoplasia in Greek women

The aim of the study was to determine the importance of genetic polymorphisms of glutathione-S-transferase T1 and M1 and cytochrome P1A1 genes in the development of cervical intraepithelial neoplasia in Greek women. This was a prospective, case-control study conducted by the Cervical Pathology and Colposcopy Unit of a University Ob/Gyn Department from 1999 to 2003. Cervical smears from 114 controls without any cytological and/or colposcopical evidence of cervical pathology and from 166 women with history of cervical intraepithelial neoplasia (56 CIN I, 54 CIN II and 56 CIN III) were examined with polymerase chain reaction for the above-mentioned genetic polymorphisms, taking also in mind their smoking attitudes. Statistical analysis was performed to detect any association between the null genotype of GSTM1 and GSTT1 genes and the CYP1A1 m1 polymorphism and the severity of cervical intraepithelial neoplasia. The distributions of the GSTT1 and GSTM1 wild-type genotypes were 57.48 and 39.75%, respectively. No woman with homozygous GSTT1 and GSTM1 null/null genotype was identified. CYP1A1 m1 polymorphism frequency was 24.49%. No woman with homozygous CYP1A1 m1/m1 genotype was detected as well. No significant difference in the frequencies of the GSTM1 and GSTT1 null alleles, and the CYP1A1 m1 polymorphism, was found between cases and controls. After application of Mantel-Haenszel chi procedure, there was no linear severity of the lesion and the frequency of these polymorphisms. According to our results, glutathione-S-transferase T1 and M1 and cytochrome P1A1 genetic polymporphisms do not appear to be a risk factor for cervical disease irrespective of smoking habits.