Influence of smoking in the glutathione-S-transferase M1 deficiency--associated risk for squamous cell carcinoma of the bladder in schistosomiasis patients in Egypt

Association of Glutathione S-transferase gene polymorphism with bladder Cancer susceptibility

BACKGROUND

We conducted a meta-analysis to evaluate the relationship between the glutathione S-transferase μ1 (GSTM1)- and glutathione S-transferase θ1 (GSTT1)- null genotypes and susceptibility to bladder cancer.

METHODS

We identified association reports from the databases of PubMed, Embase, the Cochrane Library and the China Biological Medicine Database (CBM disc) on July 1, 2017 and synthesized eligible investigations. Results were expressed using odds ratios (ORs) for dichotomous data, and we also calculated 95% confidence intervals (CIs).

RESULTS

In this meta-analysis, we found that the GSTM1-null genotype was associated with bladder cancer risk in the overall population, and individually in whites, Africans and Asians (overall population: OR = 1.40, 95% CI: 1.31-1.48, P<0.00001; whites: OR = 1.39, 95% CI: 1.26-1.54, P<0.00001; Africans: OR = 1.54, 95% CI: 1.16-2.05, P = 0.003; Asians: OR = 1.45, 95% CI: 1.33-1.59, P<0.00001). The GSTT1-null genotype was associated with bladder cancer risk in the overall population, but not in whites, in Africans or Asians (overall population: OR = 1.11, 95% CI: 1.01-1.22, P = 0.03; whites: OR = 1.16, 95% CI: 0.99-1.36, P = 0.07; Africans: OR = 1.07, 95% CI: 0.65-1.76, P = 0.79; Asians: OR = 1.05, 95% CI: 0.91-1.22, P = 0.51). Interestingly, a dual-null GSTM1-GSTT1 genotype was associated with bladder cancer risk in the overall population and in Asians (overall population: OR = 1.48, 95% CI: 1.15-1.92, P = 0.002; Asians: OR = 1.62, 95% CI: 1.15-2.28, P = 0.006). In conclusion, the GSTM1-null, GSTT1-null and dual-null GSTM1-GSTT1 genotypes might be associated with the onset of bladder cancer, but additional genetic-epidemiological studies should be conducted to explore this association further.

Glutathione S-Transferase M1, T1 and P1 Polymorphisms and Bladder Cancer Risk in Egyptians

Previous studies suggest that bladder cancer risk may vary with GST genotype but these results are inconsistent. The aim of this study was to explore whether GSTM1, GSTT1 and GSTP polymorphisms were associated with increased bladder cancer risk in an Egyptian population. GSTM1, GSTT1 and GSTP1 genotype frequencies were determined in bladder cancer cases (n=72) and healthy controls with no history of malignancies (n=82) using PCR-based techniques. The GSTT1*2 genotype was particularly associated with increased risk (OR 2.71, 95%CI 1.27–5.73) and the GSTM1*2 genotype to a lesser extent (OR 1.63, 95%CI 0.85–3.10). 18.1% of cases but only 7.3% of controls were GSTP1*B*B homozygotes (OR 2.38, 95%CI 0.83–6.87). The presence of two or more a priori at-risk genotypes was associated with increased bladder cancer risk (OR 2.42; 95%CI 1.47–3.97). These results suggest that polymorphisms in the GST genes are associated with increased risk of bladder cancer among Egyptians.

GSTA1, GSTM1, GSTP1, and GSTT1 polymorphisms and susceptibility to smoking-related bladder cancer: a case-control study

OBJECTIVES

Glutathione S-transferases (GSTs) are a family of enzymes involved in detoxification. Genes encoding for GSTA1, GSTM1, GSTP1, and GSTT1 proteins are polymorphic, which can result in complete or partial loss of enzyme activity. Previous studies have associated polymorphisms of GSTA1, GSTM1, and GSTP1 genes with a higher risk of bladder cancer, but this is still controversial. Potential role of GSTA1 polymorphism in susceptibility to bladder cancer in Whites is lacking. We examined association between GSTA1, GSTM1, GSTP1, and GSTT1 gene variants and bladder cancer risk and evaluated whether they were modified by smoking.

MATERIALS AND METHODS

A hospital-based case-control study recruited 201 incidence cases and 122 age-matched controls. Deletion polymorphism of GSTM1 and GSTT1 was identified by polymerase chain reaction method. Single nucleotide polymorphism of GSTA1 and GSTP1 was identified by restriction fragment length polymorphism method. Uniconditional multivariate logistic regression was applied to model association between genetic polymorphisms and bladder cancer risk, as well as effect modification by smoking.

RESULTS

No significant difference was observed in the distributions of GSTM1, GSTT1, GSTA1, and GSTP1 gene variants between patients and controls. None of the examined polymorphisms was significantly associated with bladder cancer risk independently. The results of gene-smoking interaction analyses indicated a significant combined effect of smoking and all common GST polymorphisms tested (P for trend = 0.001). However, the most significant effect on bladder cancer risk was observed in smokers carrying lower activity GSTA1-AB/BB and GSTM-null genotype (OR = 3.5, P < 0.05) compared with GSTA1-AA and GSTM1-active non-smokers. Overall, the risk observed did not significantly differ with respect to quantity of cigarettes smoked. However, heavy smokers with GSTM1-null genotype had 2 times higher risk of bladder cancer than GSTM1-null light smokers (OR = 4.8 vs. OR = 2.0) when GSTM1-active non-smokers served as reference group. Smokers carrying both GSTM1-null and GSTA1-AB + BB genotypes exhibited the highest risk of bladder cancer (OR = 2.00, P = 0.123).

CONCLUSIONS

Null or low-activity genotypes of the GSTA1, GSTM1, GSTT1, and GSTP1 did not contribute independently towards the risk of bladder cancer in our patients. However, in association with smoking, both low activity GSTA1 and GSTM1-null genotype increase individual susceptibility to bladder cancer.

GSTM1, GSTT1 null variants, and GPX1 single nucleotide polymorphism are not associated with bladder cancer risk in Egypt

BACKGROUND

Bladder cancer is the most common male malignancy in Egypt, consists predominantly of urothelial cell carcinoma (UCC) and squamous cell carcinoma (SCC), and disparities in incidence exist between men and women regardless of geographic region. Tobacco smoke exposure and Schistosoma haematobium (SH) infection and the presence of GSTM1, GSTT1, and GPX1 genotypes, as modulators of the carcinogenic effect of reactive oxidative species, were hypothesized to modify bladder cancer risk and possibly explain these gender differences.

METHODS

We evaluated the association between bladder cancer risk and functional polymorphisms in the GSTM1, GSTT1, and GPX1 genes in 625 cases and 626 matched population-based controls in Egypt and assessed for potential interactions between these candidate genes and environmental exposures, such as smoking and SH infection. We analyzed the risk for developing UCC and SCC separately.

RESULTS

None of these functional polymorphisms were significantly associated with bladder cancer risk. There were no significant interactions between genotypes and smoking or SH infection in this population, nor was any difference detected in genotypic risk between men and women.

CONCLUSIONS

Our findings suggest that common genetic variations in GSTM1, GSTT1, and GPX1 are not associated with bladder cancer risk overall and that well-known environmental risk factors, such as smoking and SH infection, do not interact with these genes to modulate the risk.

IMPACT

Our data indicate that common genetic variations in GSTM1, GSTT1, and GPX1 were not associated with bladder cancer risk.

Insertion/deletion polymorphism of the angiotensin-converting enzyme gene is associated with schizophrenia in a Spanish population

A number of factors make the angiotensin-converting enzyme (ACE) a candidate gene for psychiatric disorders, including its action on neurotransmitters such as dopamine. An insertion/deletion (I/D) polymorphism in an ACE gene intron is associated with ACE levels. Here we examine whether the ACE I/D polymorphism is a risk factor for schizophrenia. Participants comprised 243 subjects diagnosed with schizophrenia and related disorders, and 291 hospital-based controls. The D allele of the ACE gene was identified as a protective factor, significantly reducing the risk of developing schizophrenia and related disorders (by 40%) and of developing schizophrenia (by 50%). This protection is explained by the additive genotype risk model, in which the protection increases with the number of D alleles. Our results indicate that the ACE D allele is involved in the development of schizophrenia.

Glutathione S-transferase M1 gene polymorphism in bladder cancer patients. a marker for invasive bladder cancer?

The glutathione S-transferase M1 (GSTM1) gene is polymorphic in humans, and the deficiency in enzyme activity of GSTM1 is caused by the inherited homozygous absence of the GSTM1 gene, or the "null" genotype (GSTM1, 0/0). The increased risk of bladder cancer has been shown to correspond with this gene defect. No reports, however, have been found in the literature regarding GSTM1 gene deficiency with superficial and invasive bladder cancer. In this study, we examined the association of the GSTM1-null genotype with superficial and invasive bladder cancer. Using a polymerase chain reaction (PCR)-based method, we examined the frequency of the GSTM1 gene defect in Turkish patients with superficial bladder cancer (N = 61), invasive bladder cancer (N = 42), and control subjects (N = 202) who had no history of cancer. The GSTM1 null genotype was observed in 34.7% of the control subjects and in 54.3% of total bladder cancer patients (OR: 2.246; 95% CI: 1.384-3.645, P: 0.00094). In other words, the presence of the GSTM1-null genotype significantly increased the risk of bladder cancer development. Among invasive bladder cancers, the frequency of the GSTM1-null genotype was 64.3% (OR: 0.294, 95% CI: 0.147-0.590, P: 0.0003). This was also significantly higher than control subjects, indicating that patients carrying this genotype were at increased risk for developing invasive bladder cancer. This relationship was not statistically significant in the superficial bladder cancer group (OR: 0.585, 95% CI: 0.327-1.045, P: 0.06). Our results indicate that GSTM1 gene polymorphism should be considered as an important risk modifier in the development of bladder cancer and might be used as a predictive marker for invasive bladder cancer.