Shared genetic links between bladder cancer and obesity-related traits: A conjunctional false discovery rate study

Bladder cancer (BCa) is a common cancer worldwide and is often linked with obesity-related comorbidities, but little is known about the underlying genetic mechanisms. To investigate these mechanisms, we used various quantitative tools, including conditional quantile-quantile (Q-Q) plots, conditional false discovery rate (cFDR), and conjunctional conditional false discovery rate (ccFDR), to explore the pleiotropic enrichment of risk loci between BCa and obesity-related traits. We also performed an expression quantitative trait locus (eQTL) analysis to assess the relationship between shared risk loci and gene expression. Finally, we conducted functional annotation using Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) analysis. Our findings indicated that there was successive enrichment for a range of obesity-related traits, including body fat percentage, body mass index, fasting insulin, type 2 diabetes mellitus, fasting glucose, high-density lipoprotein cholesterol, total triglycerides, and waist-to-hip ratio. Using the tools mentioned above, we identified 18 significant SNPs and 18 closely related genes (cFDR<0.01) under the condition of 8 obesity-related traits. The SNPs included rs143004880, rs73301337, rs10798572, rs11594929, rs17019138, rs2877, rs149795948, rs142509736, rs12727575, rs1571277, rs12131828, rs635634, rs76895963, rs118081211, rs7044247, rs138895564, rs4135275, and rs148023060. Additionally, we identified 15 novel loci using ccFDR, including rs143004880, rs73301337, rs10798572, rs11594929, rs17019138, rs2877, rs142509736, rs1571277, rs635634, rs76895963, rs12131828, rs118081211, rs7044247, rs138895564, and rs4135275. Of the 2 significant loci that modify gene expression, rs12131828 and rs635634 were identified. The functional annotation indicated that the conditional risk genes mainly participated in the regulation of gene silencing. Our study provided evidence of pleiotropic enrichment between BCa and 8 obesity-related traits, and we identified potential genetic mechanisms underlying this relationship. These findings may help in developing targeted clinical treatments for BCa.

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.

Inherited forms of bladder cancer: a review of Lynch syndrome and other inherited conditions

Environmental factors that play a role in the urothelial carcinogenesis have been well characterized. Current research is continuously exploring potential heritable forms of bladder cancer. Lynch syndrome is a well-known inheritable disease that increases the risk for a variety of cancers, including urothelial carcinomas. Screening of patients with known Lynch syndrome is important to evaluate for development of new primary tumors. Further study may provide more information on what level of follow-up each patient needs. Recent data suggest that mismatch repair mutations confer a greater risk for urothelial cancer. Additional large patient series as well as advancement of molecular testing may provide triage for Lynch syndrome patients in regards to the frequency and type of screening best suited for individual patient.

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.

The relationship between GSTA1, GSTM1, GSTP1, and GSTT1 genetic polymorphisms and bladder cancer susceptibility: A meta-analysis

BACKGROUND

Previous studies have investigated the relationship between GSTA1, GSTM1, GSTP1, and GSTT1 polymorphisms and bladder cancer (BCa) susceptibility, respectively, but the results remain inconsistent. So, we conducted this meta-analysis including 79 case-control studies to explore such relationships.

METHODS

We searched PubMed, EMBASE, Cochrane library, Web of Science, and CNKI for relevant available studies. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were implemented to evaluate the intensity of associations. Publication bias was estimated using Begg funnel plots and Egger regression test. To assess the stability of the results, we used sensitivity analysis with the method of calculating the results again by omitting 1 single study each time. Between-study heterogeneity was tested using the I statistic.

RESULTS

No significant association between GSTA1 polymorphism and BCa susceptibility (OR = 1.05, 95% CI 0.83-1.33) was noted. Besides, meaningful association between individuals who carried the GSTM1 null genotype and increased BCa risk was detected (OR = 1.39, 95%CI 1.28-1.51). When stratified by ethnicity, significant difference was found in both Caucasian (OR = 1.39, 95% CI 1.23-1.58) and Asian populations (OR = 1.45, 95% CI 1.31-1.61). Moreover, in the subgroup analysis by source of controls (SOC), the results were significant in both hospital-based control groups (OR = 1.49, 95% CI 1.35-1.64) and population-based control groups (OR = 1.21, 95% CI = 1.07-1.37). Additionally, the analysis revealed no significant association between GSTP1 polymorphism and BCa risk (OR = 1.07, 95% CI 0.96-1.20). What is more, significant associations between GSTT1 polymorphism and BCa susceptibility were discovered (OR = 1.11, 95% CI 1.00-1.22). In the subgroup analysis by ethnicity, significant associations between GSTT1 null genotype and BCa risk were observed only in Caucasians (OR = 1.25, 95% CI 1.09-1.44). Furthermore, when stratified by SOC, no obvious relationship was found between the GSTT1 null genotype polymorphism with hospital-based population (OR = 1.11, 95% CI 0.97-1.28) or population-based population (OR = 1.10, 95% CI 0.96-1.27).

CONCLUSION

This study suggested that GSTM1 null genotype and GSTT1 null genotype might be related to higher BCa risk, respectively. However, no associations were observed between GSTA1 or GSTP1 polymorphisms and BCa susceptibility.

Polymorphisms of NRF2 and NRF2 target genes in urinary bladder cancer patients

PURPOSE

NRF2 transcription factor is involved in modulation of various antioxidant and metabolic genes and, therefore, may modulate anti-carcinogenic potential. Association between polymorphisms of NRF2 and five NRF2-regulated genes and urinary bladder cancer (BC) risk was analyzed.

METHODS

The study group included 244 BC patients, while the control group comprised 365 individuals with no evidence of malignancy. Genotyping of GSTM1 (deletion), GSTT1 (deletion), GSTA1 -69C/T (rs3957357), GSTP1 Ile105Val (rs1695), SOD2 Ala16Val (rs4880) and NRF2 -617C/A (rs6721961) in blood genomic DNA was performed by means of real-time PCR assays. The associations between gene polymorphism and BC risk were computed by logistic regression.

RESULTS

The frequency of GSTA1, GSTP1, SOD2 and NRF2 genotypes did not differ in both groups. A significantly higher BC risk was associated with GSTM1 null genotype after adjusting to age, sex and smoking habit (OR 1.85, 95 % CI 1.30-2.62; P = 0.001). GSTT1 null (OR 0.50, 95 % CI 0.31-0.81; P = 0.005) and GSTP1 Val105Val (OR 0.52, 95 % CI 0.27-0.98; P = 0.04) genotypes were associated with reduced BC risk separately or in combination (OR 0.24, 95 % CI 0.11-0.51; P < 0.0001) (P heterogeneity = 0.01). Combined GSTT1 null and SOD2 with at least one 16Val allele among never smokers encompass reduced BC risk (OR 0.14, 95 % CI 0.03-0.63; P = 0.01) (P heterogeneity = 0.04).

CONCLUSIONS

This study supports hypothesis that GSTM1 null genotype may be a moderate BC risk factor. The gene-gene and gene-environment interactions associated with combined GSTP1/GSTT1 and combined GSTT1/SOD2 genetic polymorphisms along with cigarette smoking habit may play a significant role in BC risk modulation.

Association between vascular endothelial growth factor gene polymorphisms and bladder cancer risk

Vascular endothelial growth factor (VEGF) gene polymorphisms are associated with susceptibility to a number of cancers. The present case-controlled study aimed to investigate the correlation between VEGF gene polymorphisms and the risk of bladder cancer. The effects of VEGF polymorphisms were investigated in patients with bladder cancer and healthy controls in our hospital between May, 2008 and May, 2013. Peripheral blood samples were obtained from 480 patients with bladder cancer and 420 healthy controls. The polymerase chain reaction-restriction fragment length polymorphism technique was used to detect three VEGF gene polymorphisms (rs3025039 C/T, rs833052 C/A and rs1570360 G/A) in these subjects. The genotype and allele frequencies were also investigated in order to determine their association with stage, grade and histological type of bladder cancer, as well as smoking status. Our results suggested that the frequency of the rs833052 AA genotype was significantly higher in patients with bladder cancer [odds ratio (OR)=1.75; 95% confidence interval (CI): 1.05-2.92; P=0.03] compared to that in healthy controls. There was no significant correlation between the rs833052 AA genotype and bladder cancer stage, grade or histological type, whereas smoking was identified as a risk factor for bladder cancer in the included patients (OR=1.48; 95% CI: 1.13-1.93; P=0.004). The rs3025039 and rs1570360 gene polymorphisms were not found to be correlated with the risk of bladder cancer or its progression. In conclusion, our results suggested that the VEGF rs833052 C/A polymorphism may be associated with a modest increase in the risk of bladder cancer in Chinese individuals.

Association of the glutathione s-transferase m1, t1 polymorphisms with cancer: evidence from a meta-analysis

BACKGROUND

Glutathione S-transferases (GSTs) are a family of multifunctional enzymes that are involved in the metabolism of many xenobiotics, including a wide range of environmental carcinogens. While the null genotypes in GSTM1 and GSTT1 have been implicated in tumorigenesis, it remains inconsistent and inconclusive. Herein, we aimed to assess the possible associations of the GSTM1 and GSTT1 null genotype in cancer risks.

METHODS

A meta-analysis based on 506 case-control studies was performed. Odds ratios (OR) with corresponding 95% confidence intervals (CIs) were used to assess the association.

RESULTS

The null genotypes of GSTM1 and GSTT1 polymorphisms were associated with a significantly increased risk in cancer (for GSTM1: OR = 1.17; 95%CI = 1.14-1.21; for GSTT1: OR = 1.16; 95%CI = 1.11-1.21, respectively). When the analysis was performed based on their smoking history, the risk associated of GSTM1 null and GSTT1 null genotypes with cancer is further increased (for GSTM1: OR = 2.66; 95%CI = 2.19-3.24; for GSTT1: OR = 2.46; 95%CI = 1.83-3.32, respectively).

CONCLUSIONS

These findings indicate that GSTM1 and GSTT1 polymorphisms may play critical roles in the development of cancer, especially in smokers.

Glutathione S-transferase M1 and T1 polymorphisms: susceptibility and outcomes in muscle invasive bladder cancer patients

BACKGROUND

We investigated whether genetic polymorphisms in the glutathione S transferase mu (GSTM1) and theta (GSTT1) genes modulated risk, disease progression and survival in primary muscle invasive bladder cancer (MIBC).

METHODS

GSTM1 and GSTT1 polymorphisms were analysed by multiplex polymerase chain reaction (PCR) using blood genomic DNA in 110 MIBC patients and 220 gender- and age-matched healthy controls. The influence of the genetic polymorphisms on patient survival was evaluated by Kaplan-Meier survival curves and Cox Proportional Hazard models. We also evaluated whether cigarette smoking and treatment modality modified the association between genotype and prognosis.

RESULTS

GSTM1-null individuals exhibited increased risk for MIBC and an association with cigarette smoking. GSTT1-null subjects showed significant disease progression and cancer-specific death. In the combined analysis, GSTT1-null genotype was an independent risk factor for disease progression and cancer specific death regardless of GSTM1 genotype. Significant differences in progression-free survival (PFS) and cancer-specific survival (CSS) were seen based on GSTT1 genotype. The survival impact of the GSTT1 genotype was only valid for smokers. The GSTT1-null genotype was an independent prognostic factor for shorter PFS in patients who received chemotherapy and those who did not undergo radical cystectomy. By multivariate Cox regression analysis, GSTT1-null genotype was a predictive factor for disease progression and cancer specific survival regardless of treatment modality.

CONCLUSIONS

The GSTM1-null genotype plays an important role in genetic susceptibility to MIBC and the GSTT1-null genotype is associated with disease progression and shorter survival in MIBC.

XRCC1 Arg399Gln polymorphism and bladder cancer risk: updated meta-analyses based on 5767 cases and 6919 controls

Previous reports implicate XRCC1 Arg399Gln polymorphism as a possible risk factor for several cancers. Published meta-analyses have been conducted on the association of XRCC1 Arg399Gln polymorphism with susceptibility to bladder cancer, and have generated conflicting results. The present study aimed to derive a more precise estimation of the relationship. Updated meta-analyses assessing the association of XRCC1 Arg399Gln polymorphism with bladder cancer were conducted and subgroup analyses on ethnicity, smoking status and source of controls were further performed. Eligible studies were identified for the period up to May 2012. A total of 19 case-control studies comprising 5767 cases and 6919 controls were lastly selected for analysis. The overall data failed to indicate significant associations between XRCC1 Arg399Gln polymorphism and bladder cancer risk (Gln/Gln versus Arg/Arg: odds ratio (OR) = 0.97; 95% CI = 0.85-1.10; dominant model: OR = 1.02; 95% CI = 0.94-1.09; recessive model: OR = 0.95; 95% CI = 0.84-1.07). In subgroup analyses stratified by ethnicity, smoking status and source of controls, respectively, similar results were obtained. In conclusion, the results of the present study suggest that XRCC1 Arg399Gln polymorphism might not modify the susceptibility to bladder cancer. Further large and well-designed studies are needed to confirm this conclusion.

The interaction between smoking and GSTM1 variant on lung cancer in the Chinese population

Smoking and the deletion of GSTM1 variant are two risk factors of lung cancer. This meta-analysis was performed to examine the GSTM1-smoking interaction on lung cancer in the Chinese population. PubMed, Web of Science, and other Chinese databases were searched to include all the related studies. The number of subjects with two GSTM1 genotypes across different smoking status was extracted. The pooled odds ratios (ORs) with 95 % confidence intervals (CIs) were calculated using fixed- or random-effect model. A total of 4,345 cases and 5,031 controls from 30 studies were included in the meta-analysis. Compared with nonsmokers having power GSTM1, the pooled ORs with 95 % CIs for lung cancer in smokers with power GSTM1, in nonsmokers with null GSTM1, and in smokers with null GSTM1 were 2.24 (1.82-2.76), 1.48 (1.23-1.79), and 4.18 (3.38-5.16), respectively. This meta-analysis showed that there was an interaction between the GSTM1 and smoking on the risk of lung cancer in the Chinese. Further studies are needed to examine the interactions between other environmental factors and GSTM1 on the risk of lung cancer.

Glutathione S-transferase P1 gene polymorphism and bladder cancer susceptibility: an updated analysis

Studies investigating the association between glutathione S-transferase P1 (GSTP1) gene polymorphism and bladder cancer (BC) risk have reported conflicting results. In order to clarify the effect of GSTP1 polymorphism on the BC susceptibility, we conducted an updated system review of published epidemiology studies to provide more precise evidence. We performed a systematic search of PubMed, EMBASE, and China National Knowledge Infrastructure (CNKI). 20 studies with 4,428 BC cases and 5,457 controls were identified. The combined analyses based on all studies showed that there was a significant difference in the genotype distribution in GSTP1(A313G) polymorphism between BC cases and controls not only in Asians (GG vs. AA + AG, OR = 1.59, 95 % CI = 1.01-2.51) but also in Caucasians (GG vs. AA + AG, OR = 1.51, 95 % CI = 1.11-2.06). Upon stratification for smoking status, we observed no statistically significant difference in genotype distribution of GSTP1 in ever-smokers. Combination of the high-risk genotypes (GSTM1 null + GSTT1 null + GSTP1 313 A/G or G/G) demonstrated further increase in the BC risk (OR = 6.64, 95 %CI = 3.63-12.16). This meta-analysis suggests that GSTP1 313 G/G polymorphism is a strong predisposing risk factor for BC.

Dietary intake of meat, fruits, vegetables, and selective micronutrients and risk of bladder cancer in the New England region of the United States

Background:

Despite many studies on diet and bladder cancer, there are areas that remain unexplored including meat mutagens, specific vegetable groups, and vitamins from diet.

Methods:

We conducted a population-based case–control study of bladder cancer in Maine, New Hampshire, and Vermont. A total of 1171 cases were ascertained through hospital pathology records and cancer registries from 2001 to 2004. Overall, 1418 controls were identified from the Department of Motor Vehicles (<65 years) and Center for Medicaid and Medicare Services (65–79 years) and were frequency-matched to cases by state, sex, and age (within 5 years). Diet was assessed with a self-administered Diet History Questionnaire. Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI).

Results:

Processed meat intake was positively associated with bladder cancer (highest vs lowest quartile OR: 1.28; 95% CI: 1.00–1.65; P_trend=0.035), with a stronger association for processed red meat (OR: 1.41; 95% CI: 1.08–1.84; P_trend=0.024). There were no associations between intake of fruits or vegetables and bladder cancer. We did, however, observe an inverse association with vitamin B12 intake (OR: 0.77; 95% CI: 0.61–0.99; P=0.019).

Conclusion:

Vitamin B12 from diet may be protective against bladder cancer, whereas consuming processed meat may increase risk.