Polymorphisms of N-acetyltransferases, glutathione S-transferases, microsomal epoxide hydrolase and sulfotransferases: influence on cancer susceptibility

Sexual dimorphism in bladder cancer: a review of etiology, biology, diagnosis, and outcomes

Bladder carcinoma represents a prevalent malignancy, wherein the influence of sex extends across its incidence, biological attributes, and clinical outcomes. This scholarly exposition meticulously examines pertinent investigations, elucidating the nuanced impact of sex on bladder cancer, and posits cogent avenues for future research and intervention modalities. In the initial discourse, an exhaustive scrutiny is undertaken of the etiological underpinnings of bladder cancer, encompassing variables such as tobacco consumption, occupational exposures, and genetic aberrations. Subsequently, a comprehensive dissection unfolds, delving into the intricate biological disparities inherent in sex vis-à-vis the initiation and progression of bladder cancer. This analytical framework embraces multifaceted considerations, spanning sex hormones, sex chromosomal dynamics, metabolic enzymatic cascades, and the intricate interplay with the microbiome. Lastly, a synthesized exposition encapsulates the ramifications of gender differentials on the diagnostic and prognostic landscapes of bladder cancer, underscoring the imperative for intensified investigative endeavors directed towards elucidating gender-specific variances and the formulation of tailored therapeutic strategies.

Association of NAT2, GSTT1, and GSTM1 gene polymorphisms withprostate cancer risk in Bangladeshi population

One of the leading causes of cancer-related mortality in males is prostate cancer. The latest molecular studies revealed the interconnection of genetic polymorphism of N acetyltransferase (NAT) and Glutathione-S-transferase (GST) gene in the genesis of prostate cancer. The study's aim was to find out the association of NAT2, GSTT1, and GSTM1 gene polymorphisms with the risk of prostate cancer in the Bangladeshi population. This case-control study included 207 histopathologically diagnosed cases of prostate cancer and 200 age-matched healthy controls. After taking informed written consent, 5.0 ml of venous blood was collected to extract genomic DNA for genetic analysis ofNAT2, GSTT1& GSTM1 by PCR-RFLP by multiplex PCR methods. In this study, the mean±SD age of cases and control was 67.3±8.3, and 62.2±6.8 years, respectively. A higher frequency of mutant NAT2*5A, NAT2*6A, and NAT2*7A in prostate cancer cases was observed in this study, in comparison to controls. Prostate cancer risk was found considerably increased in patients with NAT2 slow genotypes, GSTT1 and GSTM1 null genotypes, compared to control. Furthermore, Prostate cancer risk was found very significantly associated with the presence of combined genotypes that included NAT2 (slow), GSTT1 (null), and GSTM1 (null), and the risk rose 9.64-fold when compared to the wild genotype for NAT1, GSTT1, and GSTM1. Again, it was observed that individuals with positive smoking history/family history of cancer along with NAT2 slow genotype had significantly increased risk for prostate cancer. Moreover, the likelihood of developing a moderate to a high-grade tumor (Gleason score 7), as well as locally progressed or metastatic prostate cancer was considerably greater in persons with NAT2 slow genotypes, GSTT1, and GSTM1 null genotypes. This study established the association of genetic polymorphisms of NAT2, GSTT1, and GSTM1 genes with prostate cancer risk in the Bangladeshi population.

VDR Signaling via the Enzyme NAT2 Inhibits Colorectal Cancer Progression

Recent epidemiological and preclinical evidence indicates that vitamin D₃ inhibits colorectal cancer (CRC) progression, but the mechanism has not been completely elucidated. This study was designed to determine the protective effects of vitamin D₃ and identify crucial targets and regulatory mechanisms in CRC. First, we confirmed that 1,25(OH)₂D₃, the active form of vitamin D₃, suppressed the aggressive phenotype of CRC in vitro and in vivo. Based on a network pharmacological analysis, N-acetyltransferase 2 (NAT2) was identified as a potential target of vitamin D₃ against CRC. Clinical data of CRC patients from our hospital and bioinformatics analysis by online databases indicated that NAT2 was downregulated in CRC specimens and that the lower expression of NAT2 was correlated with a higher metastasis risk and lower survival rate of CRC patients. Furthermore, we found that NAT2 suppressed the proliferation and migration capacity of CRC cells, and the JAK1/STAT3 signaling pathway might be the underlying mechanism. Moreover, Western blot and immunofluorescence staining assays demonstrated that 1,25(OH)₂D₃ promoted NAT2 expression, and the chromatin immunoprecipitation assay indicated that the vitamin D receptor (VDR) transcriptionally regulated NAT2. These findings expand the potential uses of vitamin D₃ against CRC and introduce VDR signaling via the enzyme NAT2 as a potential diagnostic and therapeutic target for CRC.

Association of GSTP1 p.Ile105Val (rs1695, c.313A > G) Variant with the Risk of Breast Carcinoma among Egyptian Women

Several reports examined the association of the GSTP1 p.Ile105Val (rs1695, c.313A > G) variant with the elevated risk of multiple cancerous diseases involving breast carcinoma, but with inconclusive findings. The primary purpose of this study is to test the association of this essential variant with the risk of breast carcinoma among Egyptian females. This case-control study was conducted based on 200 participants involving 100 women diagnosed with breast carcinoma and 100 unrelated cancer-free controls from the same district. The genomic DNA for all participants was genotyped utilizing T-ARMS-PCR procedure. The frequencies of the GSTP1 p.Ile105Val (rs1695, c.313A > G) variant indicated a statistically significant with the elevated risk of breast carcinoma under various genetic models, including allelic (OR = 2.48, P-value < 0.001) and dominant (OR = 2.36, P-value = 0.003) models. In conclusion, the GSTP1 p.Ile105Val (rs1695, c.313A > G) variant was considered as an independent risk factor for breast carcinoma among Egyptian women.

Prenatal Exposure to Parabens Affects Birth Outcomes through Maternal Glutathione S-Transferase (GST) Polymorphisms: From the Mothers and Kids Environmental Health (MAKE) Study

Introduction: Human exposure to parabens is very common in daily life, and prenatal exposure to these chemicals is associated with poor birth outcomes. Therefore, the aim of this study was to investigate the effect of glutathione S-transferase (GST) polymorphisms on the association between prenatal exposure to parabens and birth outcomes. Methods: We conducted a multivariate analysis involving 177 subjects to determine the association between paraben concentrations and birth outcomes in mothers with GST mu 1 (GSTM1) and GST theta 1 (GSTT1) polymorphisms from 2017 to 2019. Furthermore, we determined the interactive effect between paraben levels and GSTM1/GSTT1 polymorphisms using regression analysis, in addition to a generalized linear model after stratifying GSTM1/GSTT1 genotype into three categories. Results: Methyl and propyl paraben concentrations were significantly and positively associated with birth weight (methyl, β = 116.525, 95% confidence interval (CI) = 22.460–210.590; propyl, β = 82.352, 95% CI = 9.147–155.557) in individuals with the GSTM1-null genotype. Moreover, the propyl paraben concentration was significantly associated with an increase in gestational age (β = 0.312, 95% CI = 0.085–0.539) in individuals with the GSTM1-null genotype. Conclusions: This study reported the association between prenatal paraben exposure and birth outcomes in individuals with GST polymorphisms. We found positive relationships of maternal exposure to methyl parabens with birth weight in both mothers with GSTM1 and GSTT1-null genotypes.

Urobiome in Gender-Related Diversities of Bladder Cancer

Bladder cancer (BC) remains the most common malignancy of urinary tract. Sex-related differences in BC epidemiology, diagnosis, therapy, and outcomes have been reported. Throughout the recent years, extensive research has been devoted to genetic and molecular alterations in BC. Apart from the molecular background, another related concept which has been speculated to contribute to gender diversities in BC is the role of urinary pathogens in bladder carcinogenesis. Microbiome studies, fueled by the availability of high-throughput DNA-based techniques, have shown that perturbation in the microbiome is associated with various human diseases. The aim of this review is to comprehensively analyze the current literature according to sex-related differences in the microbiome composition in BC.

Polymorphic variants conferring genetic risk to cervical lesions support GSTs as important associated loci

To analyze the association between glutathione S-transferases polymorphisms and the risk of cervical lesions.Case-control studies focusing on the association between glutathione S-transferase polymorphisms and the risk of cervical lesions were collected from the PubMed, Web of Science, Cochrane Library, Embase, Medline, CNKI, VIP and Wanfang databases from inception to August 2018. Pooled odds ratios and 95% confidence intervals were employed to evaluate the strength of the association. Subgroup analysis and sensitivity analysis were used to test the potential discrepancy and robustness, respectively.A total of 30 studies comprising 3961 patients and 4726 healthy controls satisfied the inclusion criteria. Of these, 6 studies contained information about GSTP1, 27 studies contained information about GSTM1, and 22 studies contained information about GSTT1. Our results supported that there was no statistical association between GSTP1 polymorphism and the risk of cervical lesions (odds ratio [OR] = 1.08, P = .40). The GSTM1 null variant showed increased susceptibility to cervical lesions (OR = 1.45, P < .001). Subgroup analysis revealed that the GSTM1 null variant caused cervical lesions among HPV infection cases (OR = 1.69, P = .02) and among the Chinese and Indian populations (OR = 2.24 and OR = 1.87, respectively, P < .001). The GSTT1 null variant increased the risk of cervical lesions in smokers (OR = 1.52, P = .03). The GSTT1 null genotype was also related to high-grade intraepithelial neoplasia (HSIL) and cervical cancer risk (OR = 1.30 and OR = 1.78, respectively, P < .05).The GSTM1 null variant caused cervical lesions, especially among HPV infection cases and among the Chinese and Indian populations. The GSTT1 null variant increased the risk of cervical lesions in smokers and was also related to HISL and cervical cancer risk.

The Relation between Polymorphisms in Exon 5 and Exon 6 of GSTP1 Gene and the Risk of Lung Cancer in Iranian People

Objective:

The GSTP1 gene, which is located on chromosome 11q13, consists of 7 exons and 6 introns. There are two polymorphisms in GSTP1 that have been exposed to a transposition for codon 105 (Ile/Val) and 114 (Ala/Val) in exons 5 and 6, which have been studied previously in relation to lung cancer. Since the level of GSTP1 expression in lung tissues and other human epithelial tissues is high, GSTP1Val-105 polymorphism is recognized as a sensitive factor for tobacco-related cancers, especially lung cancer.

Methods:

One hundred and twenty tissue block samples of patients with lung cancers and 120 peripheral blood samples of the control group were obtained from two referral cancer centers in Tehran, Iran, from 2011 to 2016. Genomic DNA was extracted from tissue blocks and buffy coat of study cases to detect SNP of GSTP1 gene using Tetra-primer ARMS-PCR.

Results:

There was a notable correlation between the incidence of lung cancer and variant Val105 (P-value=0.001; OR=2/6; 95% CI=1.49-4.53) and Ile105 (P-value=0.003; OR=0.41; 95% CI=0.23-0.73). The odds ratio for lung cancer in the homozygous Ile105/Ile105 genotype was 3.56 times higher than that of individual with heterozygous Ile105/Val105 (P-value<0.001; OR=3/56; 95% CI=1.826-6.934) genotype, that was statistically significant. Furthermore, the results showed that there was no significant correlation between Ala114/Val114 genotypes and lung cancer. The BC (P-value=0.007; OR=0.16; 95% CI=0.04-0.61) and AA (P=0.001) genotypes were statistically significant (P-value <0.05); and for those who had AA genotype, the odds ratio was almost six times higher than those with BC genotype.

Conclusions:

The study of GSTP1 polymorphisms indicated that unlike the polymorphism in exon 5, the GSTP1 exon 6 polymorphism correlated with the lung cancer risk in the select group of Iranian people. Likewise, the potential use of this genetic polymorphism as a lung cancer predictor is confirmed.

The role of phase I and II genetic polymorphisms, smoking, alcohol and cancer family history, in the risk of developing testicular cancer

BACKGROUND

Testicular cancer (TCa) is a malignant tumor with highest incidence and mortality rates in Chile. The genes coding for cytochrome P450, glutathione-S-transferases (GSTs), and UDP glucuronyl transferases (UGT) participate in the biotransformation and detoxification of xenobiotics. Mutations in these genes have been associated with a high incidence of various types of cancer and an increased risk of presenting adverse reactions to drugs.

OBJECTIVE

The aim of this study was to relate the presence of genetic polymorphisms in cytochrome P450 1A1 (CYP1A1), CYP3A4, GSTM1, GSTP1, GSTT1, and UGT1A1 genes and nongenetic factors with the risk of developing TCa.

METHODS

A total of 276 volunteers from the Chilean general population and 251 Chilean TCa patients were recruited for the study. Genotypic analyses were performed using qPCR and PCR-RFLP.

RESULTS

Variant alleles found to increase the risk of developing TCa were CYP1A1*2C (rs1048943), GSTP1 (rs1695), and GSTT1null, especially when in conjunction with a cancer family history and/or a smoking habit. The results of the multivariate analysis showed that the presence of variant alleles of GSTP1 (rs1695) together with a smoking habit and a family history of cancer accounted for a 15.9% risk of developing TCa in the Chilean population. CYP1A1*2C, GSTM1null, GSTT1null, and GSTP1 (rs1695) are statistically related to the risk of appearance of TCa, alone or associated with nongenetic factors.

CONCLUSION

Therefore, phase I and II variant alleles might be useful in evaluating susceptibility to TCa in the studied population.

Combined effects of GSTM1 and GSTT1 polymorphisms on breast cancer risk: A MOOSE-compliant meta-analysis and false-positive report probabilities test

Many molecular epidemiology studies have reported an association between the combined effects of glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) polymorphisms on breast cancer risk. However, the results have been controversial.A meta-analysis was performed to clarify this issue.Meta-analysis of observational studies in epidemiology guidelines was used. Pooled the crude odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model or fixed-effects model. Several subgroup analyses were conducted by ethnicity, source of control, matching, and menopausal status. In addition, we also performed sensitivity analysis and publication bias. Moreover, a false-positive report probability (FPRP) test was applied to assess positive results.A significantly increased breast cancer risk was observed in overall population (GSTM1 null/GSTT1 present [- +] vs GSTM1 present/GSTT1 present [+ +]: OR = 1.19, 95% CI: 1.03-1.36, GSTM1 null/GSTT1 null [- -] vs + +: OR = 1.63, 95% CI: 1.29-2.06, (- +) + GSTM1 present/GSTT1 null (+ -) vs + +: OR = 1.17, 95% CI: 1.05-1.31, (- +) + (+ -) + (- -) vs + +: OR = 1.27, 95% CI: 1.12-1.44, and - - vs (- +) + (+ -) + (+ +): OR = 1.39, 95% CI: 1.17-1.66) and several subgroup analyses, such as Caucasians, Indians, postmenopausal women, and so on. However, positive results were only considered noteworthy in overall population (- - vs + +: FPRP = 0.150 and (- +) + (+ -) + (- -) vs + +: FPRP = 0.162). Moreover, no significant association was observed when we used the trim and fill method to adjust the pooled data from all populations. Further, none of positive results of sensitivity analysis were considered noteworthy (FPRP >0.2).These positive findings should be interpreted with caution and indicate that an increased breast cancer risk may most likely result from false-positive results, rather than from true associations or biological factors on the combined effects of GSTM1 and GSTT1. Future studies should be based on sample sizes well-powered and attention needs to be paid to study design to further identify this issue.

Trends in the incidence and mortality of transitional cell carcinoma of the bladder for the last four decades in the USA: a SEER-based analysis

BACKGROUND

Transitional cell carcinoma (TCC) accounts for around 95% of bladder cancers and is the 4th most common cancer among men and the tenth most common in women, in the US. There is a constant need to clarify current TCC incidence and mortality rates among different population groups for better clinical practice guidelines. We aimed to describe the TCC incidence and incidence-based mortality by demographic and tumor-related characteristics over the last 40 years in the US.

METHODS

We obtained data from the SEER 18 registries to study TCC cases that were diagnosed between the years 1973 and 2014. We calculated incidence rates and incidence-based mortality rates in different demographic and tumor-related characteristics and expressed rates by 100,000 person-years. We then calculated the annual changes in incidence and incidence-based mortality rates and displayed them as annual percent changes (APCs).

RESULTS

There were 182,114 patients with TCC between 1973 and 2014 in the United States. Overall incidence rates of TCC increased 0.16% (95% CI, 0.02-0.30, p = .02) per year over the study period. However, the incidence declined significantly since 2007; (95%CI,-1.89- -0.77, p < .001), except among the elderly and African Americans, which increased significantly over the study period. Overall TCC mortality rates did not change over the study period. However, since 2000 it started to decrease significantly.

CONCLUSION

TCC incidence and incidence-based mortality rates had been showing significant increases over the previous decades. However, significant declines in both incidence and incidence-based mortality rates have been observed over the recent years, except in some patients with certain racial groups. Improved understanding of the etiological and ecological factors of TCC could lead to further declines in incidence and incidence-based mortality rates.

Identification and Quantification of Novel Major Metabolites of the Steroidal Aromatase Inhibitor, Exemestane

Exemestane (EXE) is an aromatase inhibitor used for the prevention and treatment of estrogen receptor–positive breast cancer. Although the known major metabolic pathway for EXE is reduction to form the active 17β-dihydro-EXE (17β-DHE) and subsequent glucuronidation to 17β-hydroxy-EXE-17-O-β-D-glucuronide (17β-DHE-Gluc), previous studies have suggested that other major metabolites exist for exemestane. In the present study, a liquid chromatography–mass spectrometry (LC-MS) approach was used to acquire accurate mass data in MS^E mode, in which precursor ion and fragment ion data were obtained simultaneously to screen novel phase II EXE metabolites in urine specimens from women taking EXE. Two major metabolites predicted to be cysteine conjugates of EXE and 17β-DHE by elemental composition were identified. The structures of the two metabolites were confirmed to be 6-methylcysteinylandrosta-1,4-diene-3,17-dione (6-EXE-cys) and 6-methylcysteinylandrosta-1,4-diene-17β-hydroxy-3-one (6-17β-DHE-cys) after comparison with their chemically synthesized counterparts. Both underwent biosynthesis in vitro in three stepwise enzymatic reactions, with the first involving glutathione conjugation. The cysteine conjugates of EXE and 17β-DHE were subsequently quantified by liquid chromatography–mass spectrometry in the urine and matched plasma samples of 132 subjects taking EXE. The combined 6-EXE-cys plus 6-17β-DHE-cys made up 77% of total EXE metabolites in urine (vs. 1.7%, 0.14%, and 21% for EXE, 17β-DHE, and 17β-DHE-Gluc, respectively) and 35% in plasma (vs. 17%, 12%, and 36% for EXE, 17β-DHE, and 17β-DHE-Gluc, respectively). Therefore, cysteine conjugates of EXE and 17β-DHE appear to be major metabolites of EXE in both urine and plasma.

Glutathione S-Transferase P1 313 (A > G) Ile105Val Polymorphism Contributes to Cancer Susceptibility in Indian Population: A Meta-analysis of 39 Case-Control Studies

GSTP1 involved in the metabolism of carcinogens and toxins, reduces damage of DNA and act as a suppressor of carcinogenesis. Many studies have reported that 313 A > G polymorphism is associated with different cancer in Indian population, but the results remain conflicting rather than conclusive. Therefore, we have performed meta-analysis to clarify the more precise association of GSPT1 313 A > G polymorphism with cancer risk in Indian population. We retrieved all relevant published literature from PubMed (Medline) and Google scholar web database and included those study only based on the established inclusion criteria. Pooled ORs and 95% CIs were used to appraise the strength of association. Publication bias and sensitivity analysis was also evaluated. A total of 6581 confirmed cancer cases and 8218 controls were included from eligible thirty nine case-controls studies. Pooled analysis suggested that the variant genotypes significantly increased the risk of cancer in allele (G vs. A: OR 1.266, 95% CI 1.129-1.418, p = 0.001), heterozygous (AG vs. AA: OR 1.191, 95% CI 1.047-1.355, p = 0.008), homozygous (GG vs. AA: OR 1.811, 95% CI 1.428-2.297, p = 0.001), dominant (GG + AG vs. AA: OR 1.276, 95% CI 1.110-1.466, p = 0.001) and recessive (GG vs. AG + AA: OR 1.638, 95% CI 1.340-2.002, p = 0.001) genetic models. The stability of these observations was confirmed by a sensitivity analysis. Begger's funnel plot and Egger's test did not reveal any publication bias. This meta-analysis suggests that the GSTP1 313 A > G polymorphism may contribute to genetic susceptibility to cancer in Indian population. However, larger studies and randomized clinical trial will be required to elucidate the biological and molecular mechanism of GSTP1 gene in cancer.

GSTM1 and GSTT1 polymorphisms are associated with increased bladder cancer risk: Evidence from updated meta-analysis

BACKGROUND

Previous studies have indicated association between GSTM1 and GSTT1 gene polymorphisms and bladder cancer susceptibility, but the results have been inconclusive. Here, we performed a meta-analysis to investigate the association between GSTM1/GSTT1 deletion polymorphisms and bladder cancer susceptibility.

METHODS

We searched for all studies investigating the association between GSTM1 or GSTT1 polymorphism and bladder cancer susceptibility in Pubmed, Web of Knowledge, and the Cochrane Central Search Library. A systematic review and meta-analysis were performed. Subgroup analyses were performed on different ethnicity, population-based and smoking status.

RESULTS

Our search identified 63 studies. GSTM1 null, GSTT1 null and GSTM1/GSTT1 double-null genotypes were associated with increased risk of bladder cancer (OR: 1.36 95% CI: 1.25-1.47, P<0.01; OR: 1.13 95% CI: 1.02-1.25, P<0.01; OR: 1.84 95% CI: 1.50-2.26, P<0.01). Subgroup analyses indicated that the GSTM1-null genotype was associated with increased risk of bladder cancer in Caucasians and Asians, while the GSTT1-null genotype was associated with increased risk of bladder cancer in Caucasians. The GSTM1/GSTT1 double-null genotype was associated with increased risk of bladder cancer in Caucasians, Asians, and Africans. Stratified analyses of population-based associations indicated increased bladder cancer risk associated with GSTM1-null and GSTM1/GSTT1 double-null genotypes in hospital-based and population-based studies. GSTM1 deletion was associated with increased bladder cancer risk in both smokers and nonsmokers. Non-smokers with the GSTM1/GSTT1 double-null genotype had an increased bladder cancer risk.

CONCLUSION

This meta-analysis demonstrates that the GSTM1-null, GSTT1-null, and GSTM1/GSTT1 double-null genotypes are associated with increased bladder cancer risk.

Identification and replication of the interplay of four genetic high-risk variants for urinary bladder cancer

Little is known whether genetic variants identified in genome-wide association studies interact to increase bladder cancer risk. Recently, we identified two- and three-variant combinations associated with a particular increase of bladder cancer risk in a urinary bladder cancer case-control series (Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund (IfADo), 1501 cases, 1565 controls). In an independent case-control series (Nijmegen Bladder Cancer Study, NBCS, 1468 cases, 1720 controls) we confirmed these two- and three-variant combinations. Pooled analysis of the two studies as discovery group (IfADo-NBCS) resulted in sufficient statistical power to test up to four-variant combinations by a logistic regression approach. The New England and Spanish Bladder Cancer Studies (2080 cases and 2167 controls) were used as a replication series. Twelve previously identified risk variants were considered. The strongest four-variant combination was obtained in never smokers. The combination of rs1014971[AA] near apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3A (APOBEC3A) and chromobox homolog 6 (CBX6), solute carrier family 1s4 (urea transporter), member 1 (Kidd blood group) (SLC14A1) exon single nucleotide polymorphism (SNP) rs1058396[AG, GG], UDP glucuronosyltransferase 1 family, polypeptide A complex locus (UGT1A) intron SNP rs11892031[AA] and rs8102137[CC, CT] near cyclin E1 (CCNE1) resulted in an unadjusted odds ratio (OR) of 2.59 (95% CI = 1.93-3.47; P = 1.87 × 10-10), while the individual variant ORs ranged only between 1.11 and 1.30. The combination replicated in the New England and Spanish Bladder Cancer Studies (ORunadjusted = 1.60, 95% CI = 1.10-2.33; P = 0.013). The four-variant combination is relatively frequent, with 25% in never smoking cases and 11% in never smoking controls (total study group: 19% cases, 14% controls). In conclusion, we show that four high-risk variants can statistically interact to confer increased bladder cancer risk particularly in never smokers.

Glutathione S-transferase P1 Ile105Val Polymorphism and Male Infertility Risk: An Updated Meta-analysis

BACKGROUND

Several studies concerning the association between glutathione S-transferase P1 (GSTP1) Ile105Val polymorphism and male infertility risk have reported controversial findings. The present study was aimed to explore this association using a meta-analysis.

METHODS

The PubMed, EMBASE, China National Knowledge Infrastructure (CNKI), and Wanfang databases were searched. Odds ratios (OR s) with 95% confidence intervals (CI s) were calculated to estimate the strength of the association.

RESULTS

A total of 3282 cases and 3268 controls in nine case-control studies were included. There was no significant association between GSTP1 Ile105Val polymorphism and male infertility in the overall population, but significant associations were found under the dominant (OR = 1.23, 95% CI = 1.04-1.46, I2 = 32.2%) and heterozygote (OR = 1.29, 95% CI = 1.08-1.53, I2 = 26.8%) models after excluding studies for which the data did not satisfy Hardy-Weinberg equilibrium (HWE). Similarly, subgroup analyses revealed no significant association in Asians or Chinese population although a significant association was apparent among Chinese population in studies with HWE under the heterozygote model (OR = 1.25, 95% CI = 1.03-1.52, I2 = 44.1%). Significant heterogeneity could be observed in some genetic models, but this heterogeneity was not significant when stratified by HWE. No evidence for publication bias was found.

CONCLUSIONS

The GSTP1 Ile105Val polymorphism might not be associated with male infertility risk, and thus additional well-designed studies with larger sample size are warranted.

A meta-analysis of association between glutathione S-transferase M1 gene polymorphism and Parkinson's disease susceptibility

The aim of this meta-analysis was to evaluate whether there was an association between glutathione S-transferase M1(GSTM1)gene polymorphism and Parkinson’s disease (PD) susceptibility by pooling published data.

We performed comprehensive electronic database search for articles published between February12,2015 and April30 2016. The published case-control or cohort studies related to GSTM1 gene polymorphism and Parkinson’s disease susceptibility were screened, reviewed, and included in this meta-analysis. The correlation between GSTM1 gene polymorphism and PD susceptibility was expressed by odds ratio (OR) and its corresponding 95% confidence interval (95%CI). Publication bias was evaluated by Begg’s funnel plot and Egger’s line regression test. All analysis was done by stata11.0 software.

After searching the PubMed, EMBASE, and CNKI databases, seventeen case-control studies with 3,538 PD and 5,180 controls were included in the final meta-analysis. The data was pooled by a fixed-effect model for lack of statistical heterogeneity across the studies; the results showed GSTM1 null expression can significant increase the susceptibility of PD (OR=1.11, 95% CI:1.01-1.21, P<0.05). Subgroup analysis indicated GSTM1 gene polymorphism was associated with PD susceptibility in the Caucasian ethnic group (OR=1.15, 95% CI:1.05-1.27, P<0.05) but not in the Asian ethnic group (OR=0.89, 95% CI:0.70-1.12, P>0.05). Begg’s funnel plot and Egger’s line regression test showed no significant publication bias.

Based on the present evidence, GSTM1 null expression can significant increase the susceptibility of PD in persons of Caucasian ethnicity.

GSTT1 (rs4025935) null genotype is associated with increased risk of sickle cell disease in the populations of Tabuk-Northwestern region of Saudi Arabia

BACKGROUND

Glutathione system plays an important role in the protection of cells and tissue against damage from oxidative stress. Impairment of the glutathione system due to genetic polymorphism of GST genes may increase the risk and severity of sickle cell disease (SCD). Present study was, therefore, undertaken to examine the relative impact of the genetic polymorphism of GSTT1 and GSTM1 (rs4025935 and rs71748309) on susceptibility and hematological aspects of the patients with SCD.

METHODS

Present study included 100 patients with SCD and 200 healthy controls from northwestern region of Saudi Arabia. GSTM1 and GSTT1 (rs4025935 and rs71748309) genotypes were investigated by using single-tube multiplex PCR technique.

RESULTS

It was observed that patients with SCD possessed significantly higher frequency of GSTT1 null genotype (26%) than healthy controls (15%), (P = 0.00001). Compared to the presence of GSTT1 genotype, the OR for the GSTT1 null genotype were estimated to be 4.3 (2.17-8.64, P = 0.00001). However, such association was not observed with respect to the presence of GSTM1 null genotype. In addition, it was observed that SCD in patients with GSTT1 genotype, the mean percentage levels for HbF and HbS were 0.48 and 35.4%, respectively; however, among SCD patients with GSTT1 null genotype, the mean percentage levels were significantly higher 1.62% (P = 0.004) and 39.38% (P = 0.02), respectively.

CONCLUSION

GSTT1 null genotype is significantly associated with increased risk of SCD among the population of northwestern region of Saudi Arabia. In addition, it may be one of the important factors responsible for hematological manifestations of SCD.

Glutathione S-Transferase Pi-Ile 105 Val Polymorphism and Susceptibility to T2DM in Population from Turabah Region of Saudi Arabia

Type 2 diabetes mellitus is characterized by chronic hyperglycemia and associated with oxidative stress resulting from accumulation of free radicals in body's tissues, which especially affects beta cells in pancreas and is an important factor in the development of diabetes and its complications. Glutathione S-transferases (GSTs) are a family of antioxidant enzymes that play important roles in decreasing ROS species and act as a kind of antioxidant defense. In a case-control study, we investigated the role of GSTP1 Ile105Val polymorphism in predisposition to T2DM in patients from Tarabah province, Saudi Arabia. The polymorphism was screened by PCR-RFLP in 90 T2DM patients and 87 healthy controls. The genotypes and alleles frequencies in cases and controls were assessed using Cochran-Armitage trend test and odds ratios (ORs), and 95 % confidence intervals (CIs) in different genetic models of inheritance were calculated. Our data indicate that G allele (Val) is associated with an increased risk for T2DM in this population in any combination (OR 4.101, 95 % CI 1.986-8.469, P = 0.00008). This indicates that individuals who are carriers for the mutant allele, either in homozygous (GG) or heterozygous (AG) state, are at fourfold higher risk for development of T2DM than other subjects in this population.

GSTP1 and GSTO1 single nucleotide polymorphisms and the response of bladder cancer patients to intravesical chemotherapy

SNPs may restrict cell detoxification activity and be a potential risk factor for cancer chemosensitivity. We evaluated the predictive value of these polymorphisms on the sensitivity of bladder cancer patients to epirubicin and mitomycin chemotherapy instillation as well as their toxicities. SNPs were analyzed by TaqMan genotyping assays in 130 patients treated with epirubicin and 114 patients treated with mitomycin. Recurrence-free survival (RFS) was estimated by the Kaplan-Meier method, and hazard ratios (HRs) and 95% confidence intervals (CIs) of the HRs were derived from multivariate Cox proportional hazard models. GSTP1 rs1695 and GSTO1 rs4925 were also associated with RFS in the epirubicin group. Patients carrying the GSTP1 AG+GG and GSTO1 AC+AA genotypes had an unfavorable RFS. Patients with the GSTP1 AA and GSTO1 CC genotypes had a reduced risk of recurrence after the instillation of epirubicin. In addition, patients with the GSTP1 rs1695 AA genotype had an increased risk of irritative voiding symptoms; while patients with the GSTO1 rs4925 CC genotype had a decreased risk of hematuria. Our results suggest that GSTP1 and GSTO1 polymorphisms are associated with epirubicin treatment outcomes as well as with epirubicin-related toxicity.

Causes of genome instability: the effect of low dose chemical exposures in modern society

Genome instability is a prerequisite for the development of cancer. It occurs when genome maintenance systems fail to safeguard the genome's integrity, whether as a consequence of inherited defects or induced via exposure to environmental agents (chemicals, biological agents and radiation). Thus, genome instability can be defined as an enhanced tendency for the genome to acquire mutations; ranging from changes to the nucleotide sequence to chromosomal gain, rearrangements or loss. This review raises the hypothesis that in addition to known human carcinogens, exposure to low dose of other chemicals present in our modern society could contribute to carcinogenesis by indirectly affecting genome stability. The selected chemicals with their mechanisms of action proposed to indirectly contribute to genome instability are: heavy metals (DNA repair, epigenetic modification, DNA damage signaling, telomere length), acrylamide (DNA repair, chromosome segregation), bisphenol A (epigenetic modification, DNA damage signaling, mitochondrial function, chromosome segregation), benomyl (chromosome segregation), quinones (epigenetic modification) and nano-sized particles (epigenetic pathways, mitochondrial function, chromosome segregation, telomere length). The purpose of this review is to describe the crucial aspects of genome instability, to outline the ways in which environmental chemicals can affect this cancer hallmark and to identify candidate chemicals for further study. The overall aim is to make scientists aware of the increasing need to unravel the underlying mechanisms via which chemicals at low doses can induce genome instability and thus promote carcinogenesis.

Gender and Bladder Cancer: A Collaborative Review of Etiology, Biology, and Outcomes

CONTEXT

The incidence of bladder cancer is three to four times greater in men than in women. However, women are diagnosed with more advanced disease at presentation and have less favorable outcomes after treatment.

OBJECTIVE

To review the literature on potential biologic mechanisms underlying differential gender risk for bladder cancer, and evidence regarding gender disparities in bladder cancer presentation, management, and outcomes.

EVIDENCE ACQUISITION

A literature search of English-language publications that included an analysis of the association of gender with bladder cancer was performed using Pubmed. Ninety-seven articles were selected for analysis with the consensus of all authors.

EVIDENCE SYNTHESIS

It has been shown that the gender difference in bladder cancer incidence is independent of differences in exposure risk, including smoking status. Potential molecular mechanisms include disparate metabolism of carcinogens by hepatic enzymes between men and women, resulting in differential exposure of the urothelium to carcinogens. In addition, the activity of the sex steroid hormone pathway may play a role in bladder cancer development, with demonstration that both androgens and estrogens have biologic effects in bladder cancer in vitro and in vivo. Importantly, gender differences exist in the timeliness and completeness of hematuria evaluation, with women experiencing a significantly greater delay in urologic referral and undergoing guideline-concordant imaging less frequently. Correspondingly, women have more advanced tumors at the time of bladder cancer diagnosis. Interestingly, higher cancer-specific mortality has been noted among women even after adjusting for tumor stage and treatment modality.

CONCLUSIONS

Numerous potential biologic and epidemiologic factors probably underlie the gender differences observed for bladder cancer incidence, stage at diagnosis, and outcomes. Continued evaluation to define clinical applications for manipulation of the sex steroid pathway and to improve the standardization of hematuria evaluation in women may improve future patient outcomes and reduce these disparities.

PATIENT SUMMARY

We describe the scientific basis and clinical evidence to explain the greater incidence of bladder cancer in men and the adverse presentation and outcomes for this disease in women. We identify goals for improving patient survival and reducing gender disparities in bladder cancer.

N-Acetyltransferase 2 (NAT2) polymorphism as a risk modifier of susceptibility to pediatric acute lymphoblastic leukemia

N-Acetyltransferases (NAT) have been known to modify the risk to a variety of solid tumors. However, the role of NAT2 polymorphism in risk susceptibility to childhood acute lymphoblastic leukemia (ALL) is still not well known. We performed a case-control study to determine if the common NAT2 polymorphisms play a role in altering susceptibility to pediatric ALL. DNA of 92 pediatric ALL patients and 312 healthy controls was analyzed for the NAT2 polymorphisms using the PCR-RFLP method. The wild-type NAT2*4 was encountered in 8.6 % of patients versus 11.8 % of controls (P = 0.23). The rapid acetylators NAT2*12 803A>G, AG, GG, and AG/GG were overrepresented in controls (P = 0.0001; odds ratio (OR) 0.22, 0.19, and 0.21 respectively). NAT2*5D 341T>C and NAT2*11A 481C>T were of comparable frequencies. For their combination, NAT2*5A, a slow acetylator, both TCTT and CCCT were overrepresented in patients (P < 0.001; OR 15.8 and 17.9 respectively). NAT2*5B (803A>G, 341T>C, 481C>T) was overrepresented in controls (P < 0.001; OR 0.12). Apparently, 803A>G ameliorated the combined effect of 341T>C and 481C>T. A similar effect was obtained with NAT2*5C (341T>A, 803A>G) (P < 0.0001; OR 0.11). For slow acetylator NAT2*7A 857G>A, GA and GA/AA were overrepresented in patients (P = 0.009 and 0.01; OR 2.74 and 2.72 respectively). NAT2*13 282C>T, NAT2*6B 590G>A, and NAT2*14A 191G>A were of comparable frequencies. NAT2 282C>A in combination with NAT2 857G>A (NAT2*7B) showed a synergistic effect in patients versus controls (P < 0.0001; OR 3.51). In conclusion, NAT2 gene polymorphism(s) with slow acetylator phenotype is generally associated with the risk of development of ALL in children.

Glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) null polymorphisms and the risk of hypertension: a meta-analysis

BACKGROUND

Some studies have recently focused on the association between glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) null polymorphisms and hypertension; however, results have been inconsistent.

OBJECTIVE

In order to drive a more precise estimation, the present systematic review and meta-analysis is performed to investigate the relationship between the GSTM1 and GSTT1 null polymorphisms and hypertension.

METHODS

Eligible articles were identified by a search of several bibliographic databases for the period up to August 17, 2013. Odds ratios were pooled using either fixed-effects or random-effects models.

RESULTS

Regarding the GSTM1 null/present genotype, 14 case-control studies were eligible (2773 hypertension cases and 3189 controls). The meta-analysis revealed that it might present a small increased risk for hypertension, although the effect was not statistically significant (odd ratio (OR) = 1.16, 95% confidence interval (CI): 0.96, 1.40; P = 0.002, I2 = 59.8%). Further subgroup analysis by ethnicity and control source suggested that the association was still not significant. Thirteen case-control studies were eligible for GSTT1 (2497 hypertension cases and 3078 controls). No statistically significant association was observed between the GSTT1 null genotype and hypertension risk (OR = 1.14, 95% CI: 0.85, 1.53; P = 0.000, I2 = 80.3%). Furthermore, stratification by ethnicity and control source indicated no association between the GSTT1 null genotype and hypertension risk. We further confirmed the association by sensitivity analysis. No publication bias was detected.

CONCLUSION

This meta-analysis suggests that the GSTM1 and GSTT1 null polymorphisms are not associated with the risk of hypertension. Future large well-designed epidemiological studies with individual information, lifestyle factors, and environmental factors are warranted to validate the present findings.

Ovarian xenobiotic biotransformation enzymes are altered during phosphoramide mustard-induced ovotoxicity

The anti-neoplastic prodrug, cyclophosphamide, requires biotransformation to phosphoramide mustard (PM), which partitions to volatile chloroethylaziridine (CEZ). PM and CEZ are ovotoxicants, however their ovarian biotransformation remains ill-defined. This study investigated PM and CEZ metabolism mechanisms through the utilization of cultured postnatal day 4 (PND4) Fisher 344 (F344) rat ovaries exposed to vehicle control (1% dimethyl sulfoxide (DMSO)) or PM (60μM) for 2 or 4 days. Quantification of mRNA levels via an RT(2) profiler PCR array and target-specific RT-PCR along with Western blotting found increased mRNA and protein levels of xenobiotic metabolism genes including microsomal epoxide hydrolase (Ephx1) and glutathione S-transferase isoform pi (Gstp). PND4 ovaries were treated with 1% DMSO, PM (60μM), cyclohexene oxide to inhibit EPHX1 (CHO; 2mM), or PM + CHO for 4 days. Lack of functional EPHX1 increased PM-induced ovotoxicity, suggesting a detoxification role for EPHX1. PND4 ovaries were also treated with 1% DMSO, PM (60μM), BSO (Glutathione (GSH) depletion; 100μM), GEE (GSH supplementation; 2.5mM), PM ± BSO, or PM ± GEE for 4 days. GSH supplementation prevented PM-induced follicle loss, whereas no impact of GSH depletion was observed. Lastly, the effect of ovarian GSH on CEZ liberation and ovotoxicity was evaluated. Both untreated and GEE-treated PND4 ovaries were plated adjacent to ovaries receiving PM + GEE or PM + BSO treatments. Less CEZ-induced ovotoxicity was observed with both GEE and BSO treatments indicating reduced CEZ liberation from PM. Collectively, this study supports ovarian biotransformation of PM, thereby influencing the ovotoxicity that ensues.

Association between esophageal cancer risk and EPHX1 polymorphisms: A meta-analysis

AIM: To summarize the relationship between p.Tyr113His and p.His139Arg polymorphisms in microsomal epoxide hydrolase (EPHX1) and risk for esophageal cancer (EC).

METHODS: The MEDLINE/PubMed and EMBASE databases were searched for studies of the association between EPHX1 polymorphisms and EC risk that were published from the database inception date to April 2013. A total of seven case-control studies, including seven on p.Tyr113His (cases, n = 1118; controls, n = 1823) and six on p.His139Arg (cases, n = 861; controls, n = 1571), were included in the meta-analysis. After data extraction by two investigators working independently, the meta-analyses were carried out with STATA 11.0 software. Pooled odds ratios and 95%CI were calculated using a fixed-effects model or a random-effects model, as appropriate.

RESULTS: The pooled EPHX1 p.Tyr113His polymorphism data showed no significant association with EC in any of the genetic models (OR = 1.00, 95%CI: 0.70-1.48 for Tyr/His vs Tyr/Tyr; OR = 1.10, 95%CI: 0.77-1.57 for His/His vs Tyr/Tyr; OR = 1.06, 95%CI: 0.75-1.49 for a dominant model; OR = 1.09, 95%CI: 0.89-1.34 for a recessive model). Similar results were obtained from the p.His139Arg polymorphism analysis (Arg/His vs His/His: OR = 1.02, 95%CI: 0.84-1.23; Arg/Arg vs His/His: OR = 0.96, 95%CI: 0.60-1.54; OR = 1.03, 95%CI: 0.78-1.37 for the dominant model; OR = 0.97, 95%CI: 0.61-1.56 for the recessive model). Subgroup analyses for ethnicity, subtype of EC, and source of controls (population-based or hospital-based) showed trends that were consistent with the pooled analysis (reported above), with no significant associations found.

CONCLUSION: This meta-analysis suggests that the p.Tyr113His and p.His139Arg polymorphisms in EPHX1 may not be associated with EC development.

Association between the SULT1A1 Arg213His polymorphism and the risk of bladder cancer: a meta-analysis

Several previous studies have investigated the association between the SULT1A1 Arg213His polymorphism and the risk of bladder cancer in various populations. However, these results remain inconsistent. Therefore, we performed this meta-analysis to evaluate the relationship between the SULT1A1 Arg213His polymorphism and the risk of bladder cancer. An extensive literature search was performed to identify all eligible studies regarding this association. The odds ratios (ORs) with 95 % confidence intervals (CIs) were used to estimate the strength of risk under fixed and random effects models. We identified and included eight case-control studies including 2,036 cases and 2,273 controls. No significant association was found between the SULT1A1 Arg213His polymorphism and the risk of bladder cancer under the dominant model; however, those with the SULT1A1 Arg/Arg genotype had a significantly increased risk (OR = 1.218, 95 % CI = 1.067-1.392, P = 0.0044) under the recessive model. In the subgroup analysis of ethnicity, a significant association was observed in Caucasians under the recessive model (OR = 1.269, 95 % CI = 1.069-1.506, P = 0.007). Furthermore, an increased risk of bladder cancer was observed between the Arg213His polymorphism and never smokers in the recessive model (OR = 1.428, 95 % CI = 1.079-1.890, P = 0.013). The results of this meta-analysis indicate that the SULT1A1 Arg213His polymorphism is associated with the risk bladder cancer under a recessive model; however, a possibly higher risk for Caucasians with the Arg/Arg genotype and never smokers needs further investigation.

GSTT1 and GSTM1 polymorphisms predict treatment outcome for acute myeloid leukemia: a systematic review and meta-analysis

Glutathione S-transferases (GSTs) contribute to the metabolism of different xenobiotics and anticancer drugs and confer protection against oxidative stress thus may influence the treatment outcome of acute myeloid leukemia (AML). Studies regarding the association between GSTT1 and GSTM1 polymorphisms and treatment outcome in AML patients showed an inconsistent result. A systematic review and meta-analysis were performed to further explore this association. PubMed, Hartford User Group Exchange (HUGE), and China National Knowledge Infrastructure (CNKI) databases were searched for all related publications. Statistical analyses were analyzed by using RevMan 5.0 and Stata 9.0 softwares. A total of 1,837 patients in 11 studies were included. GSTT1 null genotype was found to be significantly associated with a reduced response after first course of induction chemotherapy (odds ratio (OR) = 0.894, 95 % confidence interval (CI) = 0.818-0.977, P = 0.013), progression-free survival (PFS; hazard ratio (HR) = 0.698, 95 % CI = 0.520-0.937, P = 0.017), and overall survival (OS; HR = 0.756, 95 % CI = 0.618-0.925, P = 0.007) in Asian population. GSTM1/GSTT1 double-null genotype was also identified to be significantly associated with response after the first course of induction chemotherapy (OR = 0.40, 95 % CI = 0.24-0.67, P = 0.0003). Our study suggested that GSTT1 null genotype and GSTT1/GSTM1 double-null genotype were associated with a worse treatment outcome for AML patients, especially in Asian population.

Lack of association between EPHX1 polymorphism and esophageal cancer risk: evidence from meta-analysis

The microsomal epoxide hydrolase 1 (EPHX1) Tyr113His and His139Arg polymorphisms have been reported to be associated with esophageal cancer (EC) risk, yet the results of these previous results have been inconsistent or controversial. The objective of this study was to explore whether the EPHX1 Tyr113His and His139Arg polymorphisms confer risk to EC. The relevant studies were identified through a search of PubMed, Excerpta Medica Database (Embase), Elsevier Science Direct, and Chinese Biomedical Literature Database until May 2013. The association between the EPHX1 Tyr113His and His139Arg polymorphisms and EC risk was pooled by odds ratios (ORs) together with their 95% confidence intervals (95%CIs). A total of eight case-control studies with 1163 EC patients and 1868 controls (seven studies for both Tyr113His and His139Arg polymorphisms, one study only for Tyr113His polymorphism) were eventually identified. We found no association between EPHX1 Tyr113His and His139Arg polymorphisms and EC risk in overall population (For Tyr113His: His vs. Tyr: OR = 1.05, 95%CI = 0.95-1.15, P = 0.379; His/His vs. Tyr/Tyr: OR = 1.04, 95%CI = 0.88-1.22, P = 0.208; His/Tyr vs. Tyr/Tyr: OR = 0.96, 95%CI = 0.80-1.15, P = 0.577; His/His vs. His/Tyr + Tyr/Tyr: OR = 1.10, 95%CI = 0.96-1.26, P = 0.164; His/His + His/Tyr vs. Tyr/Tyr: OR = 1.01, 95%CI = 0.90-1.12, P = 0.543. For His139Arg: Arg vs. His: OR = 1.04, 95%CI = 0.94-1.14, P = 0.465; Arg/Arg vs. His/His: OR = 1.06, 95%CI = 0.91-1.24, P = 0.470; Arg/His vs. His/His: OR = 1.03, 95%CI = 0.91-1.16, P = 0.673; Arg/Arg vs. Arg/His + His/His: OR = 1.04, 95%CI = 0.85-1.27, P = 0.708; Arg/Arg + Arg/His vs. His/His: OR = 1.02, 95%CI = 0.93-1.13, P = 0.617). In subgroup analysis based on ethnicity, significant association has been found in neither EPHX1 Tyr113His nor His139Arg polymorphism. The current meta-analysis suggests no evidence of association between the EPHX1 polymorphism and EC risk.

Genetic polymorphism of glutathione S-transferase P1 (GSTP1) in Delhi population and comparison with other global populations

Glutathione S-transferases (GSTs) belong to a super family of phase II detoxification enzymes, which play an important role in protecting cells from damage caused by endogenous and exogenous compounds by conjugating reactive intermediates with glutathione to produce less reactive water-soluble compounds. In the present study, we determined the frequencies of two polymorphisms in exon 5 and exon 6 of GSTP1 gene in 500 normal individuals from Delhi. GSTP1 polymorphism was analysed by PCR-RFLP using amplification refractory mutation system (ARMS) assay. Two polymorphic sites in GSTP1 (Ile105 → Val105; Ala114 → Val114) have been analysed simultaneously, which results in four alleles: GSTP1*A (wild-type Ile105; Ala114), GSTP1*B (Val105; Ala114), GSTP1*C (Val105; Val114) and GSTP1*D (Ile105; Val114). The GSTP1 allele frequency in Delhi population was 0.663, 0.248, 0.069, and 0.020 for GSTP1*A, GSTP1*B, GSTP1*C, and GSTP1*D respectively. The frequency of Ile105 and Val105 allele was 0.683 and 0.317 respectively and it was calculated for the purpose of comparison with published data where all the four alleles were not analysed. GSTP1 alleles from Delhi population were compared with reported frequencies from all over India, and from other ethnic groups worldwide. This study would provide a basic database for future genetic studies.

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.

N-acetyltransferase 2 genetic variants confer the susceptibility to head and neck carcinoma: evidence from 23 case-control studies

Previous evidence indicated that N-acetyltransferase 2 (NAT2) polymorphisms might be a risk factor for several cancers. A number of studies have been conducted on the association between NAT2 polymorphisms and head and neck cancer (HNC) risk. Nevertheless, the results were conflicting. Published meta-analysis on this issue has generated inconclusive results. Thus, we aimed to derive a more precise estimation of the relationship by conducting an updated meta-analysis. Published data prior to August 2013 have been searched and screened. Subgroup analysis on ethnicity, source of controls, sample size, and genotyping method were also performed. As a result, a total of 23 case-control studies including 4,028 cases and 4,872 controls were selected for analysis. Interestingly, the results showed that NAT2 polymorphisms might increase HNC risk for the overall data (OR 1.23, 95% CI 1.01-1.49). Moreover, in subgroup analyses according to ethnicity, data showed that slow acetylators might increase HNC susceptibility among Asians (OR 1.78, 95% CI 1.27-2.49), but not among Caucasians or mixed ethnicities. In conclusion, NAT2 polymorphism might be a low-penetrant risk factor for HNC among Asians.

The NQO1 polymorphism C609T (Pro187Ser) and cancer susceptibility: a comprehensive meta-analysis

Background:

Evidence is increasingly emerging about multiple roles for the NAD(P)H quinone oxidoreductase 1 enzyme in cancer. The C609T (rs1800566, Pro187Ser) null polymorphism of the NQO1 gene contributes significantly to the variation in enzymatic activity across different populations. NQO1 C609T polymorphism was thoroughly investigated with respect to cancer susceptibility. The results were inconsistent partly due to low sample sizes. The aim of the present work was to perform a meta-analysis to assess association for all common cancer sites separately and in combination.

Methods:

Our meta-analysis involved 92 studies including 21 178 cases and 25 157 controls. Statistical analysis involved individual cancer sites and the combined cancer risk. Association was tested under different genetic models.

Results:

We found a statistically significant association between the variant T allele and overall cancer risk in the worldwide population (for the TT vs CC model, OR=1.18 (1.07–1.31), P=0.002, I²=36%). Stratified analysis revealed that this association was largely attributed to the Caucasian ethnicity (for the TT vs CC model, OR=1.28 (1.12–1.46), P=0.0002, I²=1%). Stratification by tumour site showed significant association for bladder cancer in the worldwide population (for the TT vs CC model, OR=1.70 (1.17–2.46), P=0.005, I²=0%), and in the Asian population (for the TT vs CC model, 1.48 (1.14–1.93), P=0.003, I²=16%). Positive association was also found for gastric cancer in the worldwide population under the dominant model (OR=1.34 (1.09–1.65), P=0.006, I²=15%).

Conclusion:

Our results indicate that the C609T polymorphism of the NQO1 gene is an important genetic risk factor in cancer.

Glutathione S-transferase P1 and DNA polymorphisms influence response to chemotherapy and prognosis of bone tumors

Osteosarcoma is the most common primary bone malignancy in children and adolescents, and its clinical outcome is poor. We evaluated the influence of GSTP1, ERCC1 and ERCC2 polymorphisms on response to chemotherapy among osteosarcoma patients, and the significnace of these genes for prognosis. A total of 187 patients with osteosarcoma were administered methotrexate, cisplatin/adriamycin, actinomycin D, cyclophosphamide, or vincristine. GSTP1, ERCC1 and ERCC2 polymorphisms were genotyped by PCR-RFLP assay. The results showed the average survival time of 187 patients were 38.4 months. Some 97 patients showed response to neoadjuvant chemotherapy. The GSTP1 Val and ERCC2 A/A genotypes had significantly higher rates of response to chemotherapy, with adjusted OR (95% CI) of 2.19 (1.15-6.21) and 2.88 (1.14-13.3). Individuals with the ERCC2 A/A genotype were likely to have a lower risk of death from oseosarcoma, and the adjusted HR was 0.32 (0.13-0.95). Our study indicated that GSTP1 and ERCC2 Lys751Gln polymorphisms might be candidate pharmacogenomic factors to be explored in the future to identify osteosarcoma patients who might benefit from chemotherapy.

GSTP1 Ala114Val polymorphism and colorectal cancer risk: a meta-analysis

Studies investigating the association between cytochrome glutathione S-transferase P1 (GSTP1) Ala114Val polymorphism and colorectal cancer (CRC) risk report conflicting results. The aim of this study was to quantitatively summarize the evidence for such a relationship. Two investigators independently searched the Medline, Embase, China National Knowledge Infrastructure, and Chinese Biomedicine databases. Summary odds ratios (ORs) and 95 % confidence intervals (95 % CIs) for GSTP1 polymorphism and CRC were calculated in a fixed effects model (the Mantel-Haenszel method) and a random effects model (the DerSimonian and Laird method) when appropriate. The pooled ORs were performed for co-dominant model (ValVal vs. AlaAla, AlaVal vs. AlaAla), dominant model (ValVal + AlaVal vs. AlaAla), and recessive model (ValVal vs. AlaVal + AlaAla). This meta-analysis included seven case-control studies, which included 3,173 CRC cases and 3,323 controls. Overall, the variant genotypes (ValVal and AlaVal) of the Ala114Val were not associated with CRC risk when compared with the wild-type AlaAla homozygote. Similarly, no associations were found in the dominant and recessive models. When stratifying for ethnicity, Hardy-Weinberg equilibrium in controls, study sample size, and source of controls, a significantly increased risk was observed among Asians (AlaVal vs. AlaAla, OR=1.67, 95 % CI=1.08-2.59; dominant model, OR=1.74, 95 % CI=1.14-2.67). No heterogeneity or publication bias was found in the present study. This meta-analysis suggests that the GSTP1 Ala114Val polymorphism may not be associated with CRC risk, while the observed increase in risk of CRC may be due to small-study bias.

Predictive potential of glutathione S-transferase polymorphisms for prognosis of osteosarcoma patients on chemotherapy

OBJECTIVE

To evaluate the predictive value of glutathione S-transferase (GST) gene polymorphisms for the prognosis of osteosarcoma patients receiving chemotherapy.

METHODS

A total of 159 patients were included in our study between January 2005 and December 2007., with follow-up until January 2012. Genotyping was based upon the duplex polymerase-chain-reaction with the PCR-CTPP method.

RESULTS

At the time of diagnosis, 15.4% of the patients presented with metastasis, while 22.3% developed metastasis during follow-up. At the time of final analysis on January 2012, the median follow-up was 45.5 months. Patients with null GSTM1 and GSTT1 had a higher event free survival rate than non-null genotype, but no significant association was found between the two genotypes and prognosis of osteosarcoma. Individuals with GSTP1 Val/Val genotype tended to live shorter than with the IIe/IIe genotype, and we found a significantly higher risk of death from osteosarcoma (adjusted HR=2.35, 95% CI=1.13-4.85).

CONCLUSION

The GSTP1 gene polymorphism may have an important role in the prognosis of osteosarcoma patients with chemotherapy. Further analyses with larger samples and more genes encoding metabolizing and DNA repair enzymes are warranted.

The GSTP1 Ile105Val polymorphism is not associated with susceptibility to colorectal cancer

The glutathione S transferase (GST) family is a major part of cellular defense mechanisms against endogenous and exogenous substances, many of which have carcinogenic potential. Alteration in the expression level or structure of the glutathione-S-transferase (GST) enzymes may lead to inadequate detoxification of potential carcinogens and consequently contribute to cancer development. A member of the glutathione-S-transferase (GST) family, GSTP1, is an attractive candidate for involvement in susceptibility to carcinogen-associated colorectal cancer. An A>G transition in exon 5 resulting in an Ile105Val amino acid substitution has been identified which alters catalytic efficiency. The present study investigated the possible impact of Ile105Val GSTP1 polymorphism on susceptibility to colorectal cancer. in Jordan We examined 90 tissue samples previously diagnosed with colorectal carcinoma, and 56 non-cancerous colon tissues. DNA was extracted from paraffin embedded tissues and the status of the GSTP1 polymorphism was determined using a polymerase chain reaction restriction fragment length polymorphism (RFLP) method. No statistically significant differences were found between colorectal cancer cases and controls for the GSTP1 Ile/Ile, Ile/Val and Val/Val genotypes. The glutathione S-transferase polymorphism was not associated with risk in colorectal cancer cases in Jordan stratified by age, sex, site, grade or tumor stage. In conclusion, the GSTP1 Ile105Val polymorphism is unlikely to affect the risk of colorectal cancer.