Sequence variant on 3q28 and urinary bladder cancer risk: findings from the Los Angeles-Shanghai bladder case-control study

Cigarette smoking and risk of bladder cancer: a dose-response meta-analysis

INTRODUCTION

The disease burden of bladder cancer is increasing worldwide; therefore, to deal with this situation, many studies on bladder cancer have been carried out extensively. Among these studies, the risk factors studies may provide a possible way to reduce the incidence of bladder cancer. Meta-analyses and original researches have confirmed that smoking is a risk factor of bladder cancer. However, the specific dose-response relationship between smoking and bladder cancer risk was still unclear. This meta-analysis addresses this research gap by summarizing the accumulated evidences, quantitatively.

METHODS

Relevant studies were obtained by searching PubMed, Embase and Web of Science database since inception until August 10, 2021, without restrictions. To obtain more comprehensive data, reference lists of identified articles were also browsed. Studies that reported risk estimates (relative risks (RR) or odds ratio (OR)) with 95% confidence intervals (CIs) focusing on the association between cigarette smoking and risk of bladder cancer were included in a dose-response meta-analysis.

RESULTS

A non-linear dose-response relationship was confirmed between cigarette smoking and risk of bladder cancer on the basis of 8 cohorts and 44 case-control studies. The summary relative risk of developing bladder cancer for 1 more cigarettes/day (7 cohorts and 24 case-control studies) was 1.039 (95% CI 1.038-1.040, I² = 0%), for 1 more pack-year (3 cohorts and 21 case-control studies) was 1.017(95% CI 1.016-1.019, I² = 0%) and for 1 more year of exposure (16 case-control studies) was 1.021 (95% CI 1.020-1.023, I² = 0%).

CONCLUSION

A positive non-linear dose-response relationship is confirmed between all smoking intensity, pack-years of smoking, smoking duration(years) and the risk of bladder cancer, but the plateau only occurred when smoking intensity reached 20 cigarettes/day. Further studies should report more detailed results, including those for subtypes of gender, age, region and be stratified by other risk factors to rule out residual confounding.

Systematic Review: Genetic Associations for Prognostic Factors of Urinary Bladder Cancer

INTRODUCTION

Many germline associations have been reported for urinary bladder cancer (UBC) outcomes and prognostic characteristics. It is unclear whether there are overlapping genetic patterns for various prognostic endpoints. We aimed to review contemporary literature on genetic associations with UBC prognostic outcomes and to identify potential overlap in reported genes.

METHODS

EMBASE, MEDLINE, and PubMed databases were queried for relevant articles in English language without date restrictions. The initial search identified 1346 articles. After exclusions, 112 studies have been summarized. Cumulatively, 316 single-nucleotide polymorphisms (SNPs) were reported across prognostic outcomes (recurrence, progression, death) and characteristics (tumor stage, grade, size, age, risk group). There were considerable differences between studied outcomes in the context of genetic associations. The most commonly reported SNPs were located in OGG1, TP53, and MDM2. For outcomes with the highest number of reported associations (ie, recurrence and death), functional enrichment annotation yields different terms, potentially indicating separate biological mechanisms.

CONCLUSIONS

Our study suggests that all UBC prognostic outcomes may have different biological origins with limited overlap. Further validation of these observations is essential to target a phenotype that could best predict patient outcome and advance current management practices.

Association of rs8444 polymorphism in the LASS2 3'-UTR and bladder cancer risk in Chinese population

The aim of the present study was to explore the correlations between single nucleotide polymorphisms in LASS2 gene 3'-untranslated regions and bladder cancer risk in Chinese population. We first performed PCR and sequence for LASS2-3'-UTR in 105 bladder cancer patients and 100 control subjects. Next, multivariate logistic regression analysis was used to determine the relationship between single nucleotide polymorphisms frequency and susceptibility of bladder cancer, and clinical features in 105 cases. In addition, survival curves and Cox Regression analysis were used to investigate the effect of single nucleotide polymorphisms on clinical outcome in 58 cases. Finally, quantitative reverse-transcription PCR and immunohistochemical were performed to explore the influence of single nucleotide polymorphisms on LASS2 expression. We found that a single nucleotide polymorphism (rs8444 C>T) located in the 3'-UTR of LASS2 was significantly associated with the risk of bladder cancer. We also showed the frequency of rs8444 T genotype was higher in bladder cancer group and correlated with the risk of clinical prognosis. Yet, there were no significant correlations between T/C allele frequencies and the distributions of rs8444 genotype and tumor-node-metastasis stage, histological grade and distant metastasis in bladder cancer. Furthermore, we demonstrated that rs8444 C>T could affect LASS2 expression by single nucleotide polymorphism-related mRNA stability. Our results showed that LASS2-3'-UTR rs8444 C>T polymorphism was significantly associated with the individual risk and the poor overall survival of bladder cancer, suggesting that rs8444 TT genotype maybe act as an independent risk factor of susceptibility and clinical prognosis for bladder cancer in Chinese population.

The Functional Haplotypes of CHRM3 Modulate mRNA Expression and Associate with Bladder Cancer among a Chinese Han Population in Kaohsiung City

Bladder cancer is one of the major cancer types and both environmental factors and genetic background play important roles in its pathology. Kaohsiung is a high industrialized city in Taiwan, and here we focused on this region to evaluate the genetic effects on bladder cancer. Muscarinic acetylcholine receptor M3 (CHRM3) was reported as a key receptor in different cancer types. CHRM3 is located at 1q42-43 which was reported to associate with bladder cancer. Our study attempted to delineate whether genetic variants of CHRM3 contribute to bladder cancer in Chinese Han population in south Taiwan. Five selected SNPs (rs2165870, rs10802789, rs685550, rs7520974, and rs3738435) were genotyped for 30 bladder cancer patients and 60 control individuals and genetic association studies were performed. Five haplotypes (GTTAT, ATTGT, GCTAC, ACTAC, and ACCAC) were found significantly associated with low CHRM3 mRNA level and contributed to increased susceptibility of bladder cancer in Kaohsiung city after rigid 10000 consecutive permutation tests. To our knowledge, this is the first genetic association study that reveals the genetic contribution of CHRM3 gene in bladder cancer etiology.

Quantified relations between exposure to tobacco smoking and bladder cancer risk: a meta-analysis of 89 observational studies

BACKGROUND

Smoking is a major risk factor for bladder cancer (BC). This meta-analysis updates previous reviews on smoking characteristics and BC risk, and provides a more quantitative estimation of the dose-response relationship between smoking characteristics and BC risk.

METHODS

In total, 89 studies comprising data from 57 145 BC cases were included and summary odds ratios (SORs) were calculated. Dose-response meta-analyses modelled relationships between smoking intensity, duration, pack-years and cessation and BC risk. Sources of heterogeneity were explored and sensitivity analyses were conducted to test the robustness of findings.

RESULTS

Current smokers (SOR = 3.14, 95% CI = 2.53-3.75) and former smokers(SOR = 1.83, 95% CI = 1.52-2.14) had an increased risk of BC compared with never smokers. Age at first exposure was negatively associated with BC risk. BC risk increased gradually by smoking duration and a risk plateau at smoking 15 cigarettes a day and 50 pack-years was observed. Smoking cessation is most beneficial from 20 years before diagnosis. The population-attributable risk of BC for smokers has decreased from 50% to 43% in men and from 35% to 26% in women from Europe since estimated in 2000. Results were homogeneous between sources of heterogeneity, except for lower risk estimates found in studies of Asian populations.

CONCLUSIONS

Active smokers are at an increased risk of BC. Dose-response meta-analyses showed a BC risk plateau for smoking intensity and indicate that even after long-term smoking cessation, an elevated risk of bladder cancer remains.

A functional variant in TP63 at 3q28 associated with bladder cancer risk by creating an miR-140-5p binding site

The first genome-wide association study (GWAS) for bladder cancer has identified a susceptibility locus at 3q28 in the European ancestry. However, the causal variant at 3q28 remains unknown. We conducted a three-stage fine mapping study to identify potential causal variants in the region. A total of 41 single nucleotide polymorphisms (SNPs) across 120 kb at 3q28 were tested for association with bladder cancer risk among 3,094 bladder cancer cases and 3,738 controls. Resequencing and functional assays were further evaluated. The SNP rs35592567 in the 3'-UTR of TP63 was consistently associated with bladder cancer risk in all three stages. In the combined analysis, the T allele of rs35592567 was significantly associated with a decreased risk for bladder cancer (OR = 0.82, 95% CI = 0.75-0.90, P = 9.797 × 10(-6) in the additive model). Biochemical assays revealed that the T allele reduced the post-transcriptional levels of TP63 mediated by interfering binding efficiency of miR-140-5p. In addition, overexpression of miR-140-5p inhibited bladder cancer cell proliferation and attenuated cell migration, invasion and G1 cell-cycle arrest. Together, these results suggest that rs35592567 in TP63 may be a novel causal variant contributing to the susceptibility to bladder cancer, which provides additional insight into the pathogenesis of bladder carcinogenesis.

Cumulative effect of genome-wide association study-identified genetic variants for bladder cancer

Recent genome-wide association studies have identified 14 genetic variants associated with bladder cancer in Caucasians. The effects of these risk variants and their cumulative effects in Asian populations are unknown. We genotyped these newly identified variants in a case-control study of 1,050 patients diagnosed with bladder cancer and 1,404 controls in the Chinese population. Odds rations (ORs) and 95% confidence intervals (CIs) were computed by logistic regression, and cumulative effect of risk alleles were evaluated. Overall, seven of the 14 variants were significantly associated with bladder cancer risk (p = 9.763 × 10(-3) for rs9642880 at 8q24.21, p = 3.004 × 10(-3) for rs2294008 at 8q24.3, p = 0.012 for rs798766 at 4p16.3, p = 0.034 for rs1495741 at 8p22, p = 2.306 × 10(-4) for GSTM1, p = 8.507 × 10(-8) for rs17674580 at 18q12.3, p = 7.179 × 10(-4) for rs10936599 at 3q26.2) and the odds ratios (ORs) ranged from 1.13 to 1.65. Moreover, there were a significant increased risk for bladder cancer positively correlated numbers of risk alleles and smoking status (Ptrend  = 7.060 × 10(-16) ). However, no allelic interaction effects on bladder cancer risk were observed between cumulative effects of variants and clinical characteristics. These findings suggest that seven bladder cancer risk-associated variants (rs9642880, rs2294008, rs798766, rs1495741, GSTM1 null, rs17674580 and rs10936599) may be used, collectively, to effectively measure inherited risk for bladder cancer.

Genetic susceptibility to bladder cancer risk and outcome

Bladder cancer is an excellent model for studying genetic susceptibility and gene-environment interaction in cancer etiology. The candidate gene approach found NAT2 slow acetylator and GSTM1-null genotypes to be bladder cancer susceptibility loci and also demonstrated interactions between these two genotypes and smoking in modulating bladder cancer risk. Recent genome-wide association studies identified at least eight novel genetic susceptibility loci for bladder cancer. Genetic determinants of clinical outcomes have been inconclusive. The future directions are to identify more genetic susceptibility loci for bladder cancer risk and outcome through a genome-wide association study approach, identify the causal genes and variants, study the biological mechanisms underlying the association between the causal variants and bladder cancer risk, detect gene-environment interactions and incorporate genetic knowledge into clinically applicable risk prediction models to benefit patients and public health.

Genetic variations on chromosomes 5p15 and 15q25 and bladder cancer risk: findings from the Los Angeles-Shanghai bladder case-control study

Genome-wide association studies have associated common variations at chromosomes 5p15 and 15q25 with lung cancer risk. The 5p15 locus has also been associated with increased bladder cancer risk in a recent report. The 15q25 locus has been associated with nicotine dependence and self-reported number of cigarettes smoked per day in some studies and it was proposed that its association with lung cancer may be mediated through differences in smoking behavior. Here, we investigated the roles of variations at 5p15 (rs401681, rs402710, rs2736098 and rs2736100) and 15q25 (rs1051730 and rs8034191) in bladder cancer etiology in two case-control studies conducted separately in Los Angeles County, CA, USA (498 cases and 588 controls) and in Shanghai, China (506 cases and 530 controls). We replicated the association between the 5p15 locus and bladder cancer among non-Hispanic whites (NHW) in Los Angeles [for rs2736100, per C allele odds ratio (OR) = 1.23; 95% confidence interval (CI), 1.02-1.48; P = 0.029] and among Chinese in Shanghai (OR = 1.22; 95% CI, 1.02-1.47; P = 0.033). Both rs1051730 and rs8034191 at 15q25 were rare among Chinese. Among NHW, a significant association was found between rs8034191 and bladder cancer which persisted after adjustment for cigarette smoking status, number of cigarettes smoked per day and number of years of smoking (per C allele OR = 1.26; 95% CI, 1.04-1.54; P = 0.017). Our results support 5p15 and 15q25 as susceptibility regions for bladder cancer risk.

Genome-wide association studies of bladder cancer risk: a field synopsis of progress and potential applications

The advent of the genome era after the completion of the Human Genome Project has resulted in intensive efforts to identify all genetic variants that modify human health and disease, including cancer. The development of genome-wide association study (GWAS) approach has facilitated this goal by unbiased examination of the entire human genome for disease association. Here, we review some of the GWAS data, particularly for bladder cancer, and assess their significance in risk prediction and prognosis. A mechanistic understanding of the risk association through functional studies and phenotypic assays is also discussed. The ultimate goal is the development of a comprehensive risk prediction model which integrates genetic, environment, and person risk factors to benefit disease diagnosis, prevention, and treatment.