Polymorphisms in DNA repair genes, smoking, and bladder cancer risk: findings from the international consortium of bladder cancer

Risk Factors Associated with Urothelial Bladder Cancer

BACKGROUND

Urothelial bladder carcinoma (UBC) is the most frequent histologic form of bladder cancer, constituting 90% of the cases. It is important to know the risk factors of UBC to avoid them and to decrease its recurrence after treatment. The aim of this review was to provide an overview of the risk factors associated with UBC incidence.

METHODS

A comprehensive literature search from 2012 to 2024 was carried out in databases such as PubMed, Google Scholar, and Medline with potential keywords such as "bladder cancer", "urothelial bladder cancer", "incidence of urothelial bladder cancer worldwide", "mortality rate of bladder cancer", "incidence according to gender", "treatment for bladder cancer", and "risk factors of bladder cancer". Smoking tobacco was comprehended to be the major risk factor for UBC. Smoke from tobacco products contains polycyclic aromatic hydrocarbons (PAHs) and aromatic amines such as 4-aminobiphenyl, which are known to cause UBC. Smoking-related bladder cancer mortality ranks just second to smoking-related lung cancer mortality. For non-smokers, pollution became a major risk factor associated with UBC. Polycyclic aromatic hydrocarbons (PAHs) are linked to many cancers, especially to UBC. Indoor and outdoor pollution generates VOCs (volatile organic compounds) and PAHs. Small-particle matter < 2.5 is linked to UBC and lung cancers. Drinking chlorinated water is linked to UBC. Also, swimming in chlorinated pools that produce trihalomethanes increases the risk of many cancers, and especially of bladder cancer. Occupational exposure to carcinogens, specifically aromatic amines, is a significant UBC risk factor. It has been estimated that approximately 20% of all UBCs may be linked to this type of exposure, primarily in industrial settings that treat dye, paint, petroleum chemicals, and metal. The other risk factors included genetics, diet, and medical conditions. Alcohol, consumption of processed meat and whole milk, and higher intakes of selenium and vitamins A and E also contribute to the development of UBC. Further, chemotherapeutic agents, oral hypoglycemic drugs, and radiation therapy are positively associated with UBC.

CONCLUSIONS

The significance of the initial prevention of UBC must be emphasized, and especially programs for quitting cigarettes should be encouraged and supported. However, smoking is not the only risk factor for UBC. For non-smokers, other risk factors should be investigated. Air and water pollution are linked to UBC. Indoor and outdoor pollution should be more controlled. Patients and people should be informed of the risk of drinking chlorinated water and swimming in chlorinated pools.

Association between tobacco exposure and bladder cancer recurrence: A systematic review and meta-analysis

BACKGROUND

However, the connection between smoking and the prognosis of patients with bladder cancer remains unclear.

AIM

To determine whether smoking is linked to the recurrence and progression of bladder cancer.

METHODS

As of July 20, 2022, relevant English-language research was identified by searching PubMed, the Web of Science, and the Cochrane Library. We pooled the available data from the included studies using a random effects model. Subgroup analysis and sensitivity analysis were also conducted.

RESULTS

A total of 12 studies were included in this meta-analysis. The combined analysis revealed that tobacco exposure was associated with a significantly greater recurrence rate than nonsmoking status [odd ratios (OR) = 1.76, 95%CI: 1.84-2.93], and the progression of bladder cancer was significantly greater in smokers than in nonsmokers (OR = 1.21, 95%CI: 1.02-1.44). Stratified analysis further revealed that current smokers were more likely to experience relapse than never-smokers were (OR = 1.85, 95%CI: 1.11-3.07). Former smokers also had a greater risk of relapse than did never-smokers (OR = 1.73, 95%CI: 1.09-2.73). Subgroup analysis indicated that non-Caucasians may be more susceptible to bladder cancer recurrence than Caucasians are (OR = 2.13, 95%CI: 1.74-2.61).

CONCLUSION

This meta-analysis revealed that tobacco exposure may be a significant risk factor for both the recurrence and progression of bladder cancer.

Risk prediction of bladder cancer among person with diabetes: A derivation and validation study

AIMS

This study aimed to devise and validate a clinical scoring system for risk prediction of bladder cancer to guide urgent cystoscopy evaluation among people with diabetes.

METHODS

People with diabetes who received cystoscopy from a large database in the Chinese population (2009-2018). We recruited a derivation cohort based on random sampling from 70% of all individuals. We used the adjusted odds ratios (aORs) for independent risk factors to devise a risk score, ranging from 0 to 5: 0-2 'average risk' (AR) and 3-5 'high risk' (HR).

RESULTS

A total of 5905 people with diabetes, among whom 123 people with BCa were included. The prevalence rate in the derivation (n  = 4174) and validation cohorts (n  = 1731) was 2.2% and 1.8% respectively. Using the scoring system constructed, 79.6% and 20.4% in the derivation cohort were classified as AR and HR respectively. The prevalence rate in the AR and HR groups was 1.57% and 4.58% respectively. The risk score consisted of age (18-70: 0; >70: 2), male sex (1), ever/ex-smoker (1) and duration of diabetes (≥10 years: 1). Individuals in the HR group had 3.26-fold (95% CI = 1.65-6.44, p  = 0.025) increased prevalence of bladder than the AR group. The concordance (c-) statistics was 0.72, implying a good discriminatory capability of the risk score to stratify high-risk individuals who should consider earlier cystoscopy.

CONCLUSIONS

The risk prediction algorithm may inform urgency of cystoscopy appointments, thus allowing a more efficient use of resources and contributing to early detection of BCa among people planned to be referred.

Role of human papillomavirus and associated viruses in bladder cancer: An updated review

Bladder cancer (BC) is a complex disease affecting the urinary system and is regulated by several carcinogenic factors. Viral infection is one such factor that has attracted extensive attention in BC. Human papillomavirus (HPV) is the most common sexually transmitted infection, and although multiple researchers have explored the role of HPV in BC, a consensus has not yet been reached. In addition, HPV-associated viruses (e.g., human immunodeficiency virus, herpes simplex virus, BK virus, and JC virus) appear to be responsible for the occurrence and progression of BC. This study systematically reviews the relationship between HPV-associated viruses and BC to elucidate the role of these viruses in the onset and progression of BC. In addition, the study aims to provide a greater insight into the biology of HPV-associated viruses, and assess potential strategies for treating virus-induced BC. The study additionally focuses on the rapid development of oncolytic viruses that provide a potentially novel option for the treatment of BC.

Risk of urinary tract cancers following arsenic exposure and tobacco smoking: a review

Bladder cancer, prostate cancer, and kidney cancer, due to their high morbidity and mortality rates, result in significant economic and health care costs. Arsenic exposure affects the drinking water of millions of people worldwide. Long-term exposure to arsenic, even in low concentrations, increases the risk of developing various cancers. Smoking is also one of the leading causes of bladder, prostate and kidney cancers. Accordingly, this research reviews the relationship between arsenic exposure and smoking with three kinds of urinary tract cancers (bladder cancer, prostate cancer, and kidney cancer) due to their widespread concern for their negative impact on public health globally. In this review, we have gathered the most current information from scientific databases [PubMed, Scopus, Google Scholar, ISI web of science] regarding the relationship between arsenic exposure and tobacco smoking with the risk of bladder, prostate, and kidney cancer. In several studies, a significant relationship was determined between the incidence and mortality rate of the above-mentioned cancers in humans with arsenic exposure and tobacco smoking. The decrease or cessation of smoking and consumption of arsenic-free water significantly declined the incidence of bladder, prostate, and kidney cancers.

A Significant Increasing Risk Association between Cigarette Smoking and XPA and XPC Genes Polymorphisms

Cigarette smoking (CS) is a major cause of various serious diseases due to tobacco chemicals. There is evidence suggesting that CS has been linked with the DNA damage repair system, as it can affect genomic stability, inducing genetic changes in the genes involved in the repair system, specifically the nucleotide excision repair (NER) pathway, affecting the function and/or regulation of these genes. Single nucleotide polymorphism (SNP), along with CS, can affect the work of the NER pathway and, therefore, could lead to different diseases. This study explored the association of four SNPs in both XPA and XPC genes with CS in the Saudi population. The Taq Man genotyping assay was used for 220 healthy non-smokers (control) and 201 healthy smokers to evaluate four SNPs in the XPA gene named rs10817938, rs1800975, rs3176751, and rs3176752 and four SNPs in the XPC gene called rs1870134, rs2228000, rs2228001, and rs2607775. In the XPA gene, SNP rs3176751 showed a high-risk association with CS-induced diseases with all clinical parameters, including CS duration, CS intensity, gender, and age of smokers. On the other hand, SNP rs1800975 showed a statistically significant low-risk association with all clinical parameters. In addition, rs10817938 showed a high-risk association only with long-term smokers and a low-risk association only with younger smokers. A low-risk association was found in SNP rs3176752 with older smokers. In the XPC gene, SNP rs2228001 showed a low-risk association only with female smokers. SNP rs2607775 revealed a statistically significant low-risk association with CS-induced diseases, concerning all parameters, except for male smokers. However, SNP rs2228000 and rs1870134 showed no association with CS. Overall, the study results demonstrated possible significant associations (effector/and protector) between CS and SNPs polymorphisms in DNA repair genes, such as XPA and XPC, except for rs2228000 and rs1870134 polymorphisms.

Impact of smoking on urologic cancers: a snapshot of current evidence

PURPOSE

The purpose of this paper is to present evidence regarding the associations between smoking and the following urologic cancers: prostate, bladder, renal, and upper tract urothelial cancer (UTUC).

METHODS

This is a narrative review. PubMed was queried for evidence-based analyses and trials regarding the associations between smoking and prostate, bladder, renal, and UTUC tumors from inception to September 1, 2022. Emphasis was placed on articles referenced in national guidelines and protocols.

RESULTS

Prostate-multiple studies associate smoking with higher Gleason score, higher tumor stage, and extracapsular invasion. Though smoking has not yet been linked to tumorigenesis, there is evidence that it plays a role in biochemical recurrence and cancer-specific mortality. Bladder-smoking is strongly associated with bladder cancer, likely due to DNA damage from the release of carcinogenic compounds. Additionally, smoking has been linked to increased cancer-specific mortality and higher risk of tumor recurrence. Renal-smoking tobacco has been associated with tumorigenesis, higher tumor grade and stage, poorer mortality rates, and a greater risk of tumor recurrence. UTUC-tumorigenesis has been associated with smoking tobacco. Additionally, more advanced disease, higher stage, lymph node metastases, poorer survival outcomes, and tumor recurrence have been linked to smoking.

CONCLUSION

Smoking has been shown to significantly affect most urologic cancers and has been associated with more aggressive disease, poorer outcomes, and tumor recurrence. The role of smoking cessation is still unclear, but appears to provide some protective effect. Urologists have an opportunity to engage in primary prevention by encouraging cessation practices.

Impact of Age at Diagnosis of Bladder Cancer on Survival: A Surveillance, Epidemiology, and End Results-Based Study 2004-2015

BACKGROUND

An older age contributes to the development of bladder cancer. However, the relationship between advanced age at the diagnosis and prognosis of bladder cancer has been few reported. This study aimed to determine the effect of age on survival in bladder cancer with different subgroups.

METHODS

117,275 patients with bladder cancer, identified from the Surveillance, Epidemiology, and End Results database during 2004-2015 in America, were divided into 4 age groups (≤54, 55 to 64, 65 to 74, and ≥75 years). Multivariable Cox proportional-hazards model and competing risk model were conducted according to different age groups. Heat maps were plotted to show the impact of age on survival in subgroups classified by other clinicopathological variables. Moreover, restricted cubic spline was used to model the association between age and the risk of death.

RESULTS

Patients aged ≥75 years had shorter overall survival in comparison with those aged ≤54 years (hazard ratio [HR] = 5.36, 95% confidence interval [CI] = 5.13-5.59). Compared with patients aged ≤54 years, patients older than 75 years experienced a decreased rate of bladder cancer-specific survival (subdistribution HR = 2.15, 95% CI = 2.04-2.25). Heat maps also showed that older ages were associated with worse overall cumulative mortality and bladder cancer-specific cumulative mortality. Similarly, restricted cubic spline verified the impact of age on survival of bladder cancer.

CONCLUSIONS

Age at diagnosis of bladder cancer was found to be a significant predictor for the worse overall survival and bladder cancer-specific survival even in an era with more effective therapies. Exploring the reasons why older age contributes to poor outcomes for bladder cancer will be the focus of future research.

Epidemiology, Screening, and Prevention of Bladder Cancer

CONTEXT

Bladder cancer (BC) represents a significant health problem due to the potential morbidity and mortality associated with disease burden, which has remained largely unaltered over time.

OBJECTIVE

To provide an expert collaborative review and describe the incidence, prevalence, and mortality of BC and to evaluate current evidence for BC screening and prevention.

EVIDENCE ACQUISITION

Data on the estimated incidence and mortality of BC for 2020 in 185 countries were derived from the International Agency for Research on Cancer GLOBOCAN database. A review of English-language articles published over the past 5 yr was conducted using PubMed/MEDLINE to identify risk factors in addition to contemporary evidence on BC screening and prevention.

EVIDENCE SYNTHESIS

BC is the tenth most common cancer worldwide, with 573 278 cases in 2020. BC incidence is approximately fourfold higher in men than women. Tobacco smoking remains the principal risk factor, accounting for approximately 50% of cases. There is insufficient evidence to recommend routine BC screening. However, targeted screening of high-risk individuals (defined according to smoking history or occupational exposure) may reduce BC mortality and should be the focus of prospective randomized trials. In terms of disease prevention, smoking cessation represents the most important intervention, followed by a reduction in exposure to occupational and environmental carcinogens.

CONCLUSIONS

BC confers a significant disease burden. An understanding of BC epidemiology and risk factors provides an optimal foundation for disease prevention and the care of affected patients.

PATIENT SUMMARY

Bladder cancer is the tenth most common cancer worldwide and is approximately four times more common among men than among women. The main risk factors are tobacco smoking, followed by exposure to carcinogens in the workplace or the environment. Routine screening is not currently recommended, but may be beneficial in individuals at high risk, such as heavy smokers. Primary prevention is extremely important, and smoking cessation represents the most important action for reducing bladder cancer cases and deaths.

Case report: Identification of a novel heterozygous germline ERCC2 mutation in a patient with dermatofibrosarcoma protuberans

Dermatofibrosarcoma protuberans (DFSP) is a kind of soft tissue sarcoma, mostly occurs in the trunk, followed by proximal extremities and head and neck. Surgical resection is the most important treatment for DFSP, but the local recurrence rate of DFSP is high. Except reported specific chromosomal tran7slocations occurred in DFSP, the association between DNA repair gene mutations and DFSP still unknown. In this report we found a 19-year-old boy with DFSP carries a novel heterozygous germline ERCC2 mutation, which belongs to the nucleotide excision repair (NER) pathway and genetic defects in ERCC2 may contribute to the cancer susceptibility xeroderma pigmentosum (XP), Cocaine syndrome (CS), and trichothiodystrophy (TTD). Different mutations of the ERCC2 gene can lead to diverse diseases, but there are no targeted therapies. In summary, our results enlarged the mutation spectrum of the DFSP patients. It also provides new insights into genetic counseling and targeted therapeutic strategies for patients with DFSP.

Diagnostic and prognostic potential clustered miRNAs in bladder cancer

At specific genomic loci, miRNAs are in clusters and their association with copy number variations (CNVs) may exhibit abnormal expression in several cancers. Hence, the current study aims to understand the expression of miRNA clusters residing within CNVs and the regulation of their target genes in bladder cancer. To achieve this, we used extensive bioinformatics resources and performed an integrated analysis of recurrent CNVs, clustered miRNA expression, gene expression, and drug–gene interaction datasets. The study identified nine upregulated miRNA clusters that are residing on CNV gain regions and three miRNA clusters (hsa-mir-200c/mir-141, hsa-mir-216a/mir-217, and hsa-mir-15b/mir-16-2) are correlated with patient survival. These clustered miRNAs targeted 89 genes that were downregulated in bladder cancer. Moreover, network and gene enrichment analysis displayed 10 hub genes (CCND2, ETS1, FGF2, FN1, JAK2, JUN, KDR, NOTCH1, PTEN, and ZEB1) which have significant potential for diagnosis and prognosis of bladder cancer patients. Interestingly, hsa-mir-200c/mir-141 and hsa-mir-15b/mir-16-2 cluster candidates showed significant differences in their expression in stage-specific manner during cancer progression. Downregulation of NOTCH1 by hsa-mir-200c/mir-141 may also sensitize tumors to methotrexate thus suggesting potential chemotherapeutic options for bladder cancer subjects. To overcome some computational challenges and reduce the complexity in multistep big data analysis, we developed an automated pipeline called CmiRClustFinder v1.0 (https://github.com/msls-bioinfo/CmiRClustFinder_v1.0), which can perform integrated data analysis of 35 TCGA cancer types.

The Role of Adjuvant Single Postoperative Instillation of Gemcitabine for Non-Muscle-Invasive Bladder Cancer: A Systematic Review and Meta-Analysis

Bladder cancer is a heterogeneous disease with variable natural history. Non-muscle-invasive bladder cancer has a favorable prognosis following transurethral resection, but the optimal adjuvant chemotherapy plan is still in debate. The aim of this study was to evaluate the effect of the adjuvant intravesical administration of a single dose of gemcitabine in the outcome of this disease. For that purpose, we performed a systematic review and meta-analysis on available randomized control trials on MEDLINE, EMBASE, Cochrane, Scopus, and Google Scholar databases. Ultimately, two studies were included with a total number of 654 patients. The statistical analysis performed showed that a single post-operative intravesical dose of gemcitabine does not affect the recurrence rate of non-muscle-invasive bladder cancer compared to placebo. Therefore, this therapeutic strategy does not offer any significant improvement on the outcomes of the disease. Nonetheless, due to the plethora of available therapeutic agents and treatment strategies, further research is needed to establish the optimal treatment in this category of patients.

Comparative Analysis of Differentially Mutated Genes in Non-Muscle and Muscle-Invasive Bladder Cancer in the Chinese Population by Whole Exome Sequencing

Objective: To characterize the spectra of mutations in non-muscle invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC) in the Chinese population to identify any mutational features and find potential therapeutic targets. Materials and methods: We collected fresh bladder tumor samples from NMIBC (n = 9) and MIBC patients (n = 11) along with adjacent normal bladder tissue specimen and peripheral blood sample. Using whole exome sequencing (WES), we analyzed the mutation spectra of those NMIBC and MIBC bladder cancer (BCa) specimen. Results: Our results demonstrated that 95% of BCa patients (19/20) had varying degrees of driver gene mutations, FGFR3 (45%), KMT2D (40%), PIK3CA (35%), ARID1A (20%), EP300 (20%), KDM6A (20%), KMT2C (20%), and STAG2 (20%) were the most frequently mutated genes in BCa patients. NMIBC and MIBC exhibited different genomic alterations. FGFR3 (67%), PIK3CA (56%), and RHOB (44%) were the most frequently mutated genes in NMIBC patients. Of note, RHOB mutation only occurred in NMIBC, whereas mutations of KMT2D (55%), TP53 (36%) and KMT2B (27%) were frequently detected in MIBC, and TP53 and KMT2B mutation only occurred in MIBC. The frequency of mutations in DNA-damage repair (DDR) gene was higher in MIBC than that in NMIBC (91 vs 78%, 6.2 vs 2.4 gene mutations per patient). Copy number alterations (CNAs) occurred at more diverse chromosomal locations in NMIBC, but the CNA burden was higher in MIBC [9.01 (2.07-31.51) vs 4.98 (0.99-9.73) mutations/Mb]., the trend of which was consistent with the tumor mutation burden (TMB) [8.26 (4.63-21.84) vs 5.58 (3.87-9.58) mutations/Mb]. Among the current set of single-base substitution (SBS) signatures including SBS 1, 2, 5, 13, and 40, we identified one differently expressed signature between NMIBC and MIBC patients: SBS13. Conclusions: There were different gene mutational characteristics and signatures between NMIBC and MIBC in the Chinese population. Frequency of DDR, CNA burden and TMB were higher in MIBC. Our analysis revealed that several genes in NMIBC did not overlap with those reported in MIBC, suggesting that a fraction of NMIBC and MIBC likely developed secondary to different precursor lesions.

Smoking and XPC Gene Polymorphism Interact to Modulate the Risk of Oral Cancer

Purpose

Oral cancer is the most common cancer among the Indian men and the second most common cancer among the Indian women. Such high incidence of oral cancer in India is due to consumption of tobacco in different form including smoking of cigarette. Smoke of tobacco contains different carcinogens which causes DNA damage. Such DNA damage if remain unrepaired due to faulty DNA repair system can cause mutation and eventual development of cancer.

Methodology

In the present study, we aimed to check the role of smoking as well as interaction of smoking and XPC polymorphism in risk modulation of oral cancer. Total of 372 subjects including 300 healthy controls and 72 patients of oral cancers been genotyped for the XPC PAT D/I, A/C and C/T polymorphisms with PCR based or PCR-RFLP based method. Genotype frequency was analyzed by chi-square test and strength of associations by odds ratio with 95% confidence intervals.

Results

The present study showed that compared to nonsmokers, smokers are at five times higher risk to develop oral cancer (p value= 0.001, OR= 5.03, 95% CI 2.91-8.69) and three times higher risk to develop node-positive (p value= 0.01, OR= 3.66, 95% CI 1.34-9.95) oral cancer. It has also been observed that individuals who were smokers and carrier of variant allele genotypes (AC and CC) for XPC A/C polymorphism were at threefold higher risk (p value= 0.01, OR=2.97, 95% CI 1.29-6.86) to develop oral cancer compared to individual who were smokers but do not carry the C allele (AA genotype). This observation indicates that C allele of XPC A/C polymorphism interacts with smoking and significantly increases the risk of oral cancer.

Conclusion

This study demonstrates a possible role of smoking and gene-smoking interaction in risk enhancement of oral cancer.

DNA Repair Gene Polymorphisms and Susceptibility to Urothelial Carcinoma in a Southeastern European Population

Single nucleotide polymorphisms (SNPs) in DNA repair genes may predispose to urothelial carcinoma of the bladder (UCB). This study focused on three specific SNPs in a population with high exposure to environmental carcinogens including tobacco and alcohol. A case-control study design was used to assess for presence of XPC PAT +/-, XRCC3 Thr241Met, and ERCC2 Lys751Gln DNA repair gene SNPs in peripheral blood from patients with UCB and healthy individuals. One hundred patients and equal number of healthy subjects were enrolled. The XPC PAT +/+ genotype was associated with a 2-fold increased risk of UCB (OR = 2.16; 95%CI: 1.14-4; p = 0.01). The -/+ and +/+ XPC PAT genotypes were more frequently present in patients with multiple versus single tumors (p = 0.01). No association was detected between ERCC2 Lys751Gln genotypes/alleles, and risk for developing UCB. Presence of the XRCC3 TT genotype (OR = 0.14; 95%CI:0.07-0.25; p < 0.01) and of the T allele overall (OR = 0.26; 95%CI:0.16-0.41; p < 0.01) conferred a protective effect against developing UCB. The XPC PAT -/+ and XRCC3 Thr241Met SNPs are associated with predisposition to UCB. The XPC PAT -/+ SNP is also an indicator of bladder tumor multiplicity, which might require a more individualized surveillance and treatment.

The Interplay between Oxidative Stress, Inflammation and Angiogenesis in Bladder Cancer Development

In 2018, 550,000 people were diagnosed with bladder cancer (BC), of which nearly 200,000 people died. Moreover, men are 4 times more likely than women to be diagnosed with BC. The risk factors include exposure to environmental and occupational chemicals, especially tobacco smoke, benzidine and genetic factors. Despite numerous studies, the molecular basis of BC development remains unclear. A growing body of evidence suggests that inflammation, oxidant-antioxidant imbalance and angiogenesis disorders may play a significant role in the development and progression of bladder cancer. The patients with bladder cancer were characterised by an increased level of reactive oxygen species (ROS), the products of lipid peroxidation, proinflammatory cytokines and proangiogenic factors as compared to controls. Furthermore, it was shown that polymorphisms localised in genes associated with these pathways may modulate the risk of BC. Interestingly, ROS overproduction may induce the production of proinflammatory cytokines, which finally activated angiogenesis. Moreover, the available literature shows that both inflammation and oxidative stress may lead to activation of angiogenesis and tumour progression in BC patients.

Targeting Germline- and Tumor-Associated Nucleotide Excision Repair Defects in Cancer

PURPOSE

Nucleotide excision repair (NER) gene alterations constitute potential cancer therapeutic targets. We explored the prevalence of NER gene alterations across cancers and putative therapeutic strategies targeting these vulnerabilities.

EXPERIMENTAL DESIGN

We interrogated our institutional dataset with mutational data from more than 40,000 patients with cancer to assess the frequency of putative deleterious alterations in four key NER genes. Gene-edited isogenic pairs of wild-type and mutant ERCC2 or ERCC3 cell lines were created and used to assess response to several candidate drugs.

RESULTS

We found that putative damaging germline and somatic alterations in NER genes were present with frequencies up to 10% across multiple cancer types. Both in vitro and in vivo studies showed significantly enhanced sensitivity to the sesquiterpene irofulven in cells harboring specific clinically observed heterozygous mutations in ERCC2 or ERCC3. Sensitivity of NER mutants to irofulven was greater than to a current standard-of-care agent, cisplatin. Hypomorphic ERCC2/3-mutant cells had impaired ability to repair irofulven-induced DNA damage. Transcriptomic profiling of tumor tissues suggested codependencies between DNA repair pathways, indicating a potential benefit of combination therapies, which were confirmed by in vitro studies.

CONCLUSIONS

These findings provide novel insights into a synthetic lethal relationship between clinically observed NER gene deficiencies and sensitivity to irofulven and its potential synergistic combination with other drugs.See related commentary by Jiang and Greenberg, p. 1833.

Catalog of exogenous risk factors for bladder carcinogenesis

PURPOSE OF REVIEW

The aim of this article is to provide an overview of recent findings regarding the risk factors for bladder cancer.

RECENT FINDINGS

Most of the available data derive from retrospective analysis. Smoking represents the most common and important risk factor. Occupational, dietary, and environmental exogenic carcinogen exposure, as well as several lifestyle factors, can increase the risk of developing bladder cancer.

SUMMARY

Bladder cancer is a common malignancy worldwide. Cigarette smoking, exposure to aromatic amines and arsenic are known risk factors for bladder cancer. Evidence on other modifiable risk factors such as carcinogen exposure derived from the diet or environment as well as occupational hazards is still weak. Medical conditions leading to chronic inflammation, altering insulin resistance, negatively modulating the immune system and/or genetic alterations may have a role in bladder cancer carcinogenesis. Further studies are, however, necessary to identify possible exogenic risk factors, as well as their interactions, that partake in the carcinogenesis of bladder cancer.

Micronuclei Formation upon Radioiodine Therapy for Well-Differentiated Thyroid Cancer: The Influence of DNA Repair Genes Variants

Radioiodine therapy with ¹³¹I remains the mainstay of standard treatment for well-differentiated thyroid cancer (DTC). Prognosis is good but concern exists that ¹³¹I-emitted ionizing radiation may induce double-strand breaks in extra-thyroidal tissues, increasing the risk of secondary malignancies. We, therefore, sought to evaluate the induction and 2-year persistence of micronuclei (MN) in lymphocytes from 26 ¹³¹I-treated DTC patients and the potential impact of nine homologous recombination (HR), non-homologous end-joining (NHEJ), and mismatch repair (MMR) polymorphisms on MN levels. MN frequency was determined by the cytokinesis-blocked micronucleus assay while genotyping was performed through pre-designed TaqMan^® Assays or conventional PCR-restriction fragment length polymorphism (RFLP). MN levels increased significantly one month after therapy and remained persistently higher than baseline for 2 years. A marked reduction in lymphocyte proliferation capacity was also apparent 2 years after therapy. MLH1 rs1799977 was associated with MN frequency (absolute or net variation) one month after therapy, in two independent groups. Significant associations were also observed for MSH3 rs26279, MSH4 rs5745325, NBN rs1805794, and tumor histotype. Overall, our results suggest that ¹³¹I therapy may pose a long-term challenge to cells other than thyrocytes and that the individual genetic profile may influence ¹³¹I sensitivity, hence its risk-benefit ratio. Further studies are warranted to confirm the potential utility of these single nucleotide polymorphisms (SNPs) as radiogenomic biomarkers in the personalization of radioiodine therapy.

Effect of diabetes mellitus on survival in patients with gallbladder Cancer: a systematic review and meta-analysis

Background

Increasing evidences indicated that diabetes might increase the incidence of gallbladder cancer. However, no sufficient data has ever clarified the impact of diabetes on the survival of patients with gallbladder cancer.

Methods

We comprehensively searched PubMed, Embase, and the Cochrane Library databases through July 2019 in order to find sufficient eligible researches. The pooled hazard risks (HRs) and relative risks (RRs) with 95% confidence intervals (CIs) were calculated with either fix-effects or random-effects model. Due to the low gallbladder cancer mortality in general population, the RRs and standard mortality ratios (SMRs) were considered the similar estimates of the HRs.

Results

Ten eligible studies were included in this meta-analysis. Analysis of eight cohorts found that diabetes was closely associated with the mortality of gallbladder cancer (HR = 1.10; 95% CI: 1.06–1.14; P < 0.00001). However, the mortality in male diabetes patients was not higher than female patients (RR = 1.08, 95%CI = 0.57–2.04, P = 0.80).

Conclusions

These findings indicated that diabetes patients had a higher mortality of gallbladder cancer compared with non-diabetes.

Mutation signatures to Pan-Cancer Atlas: Investigation of the genomic landscape of muscle-invasive bladder cancer

The Cancer Genome Atlas (TCGA) for bladder cancer was published in 2014 with updated annotation of over 400 patients with muscle-invasive bladder cancer (MIBC) in 2017. This tremendous work established the foundation of the genomic landscape of MIBC. The next steps to utilize information from The Cancer Genome Atlas is to (1) identify the causes of mutation, (2) determine the significant differences and sources of heterogeneity, and (3) apply these tools toward patient care. In this review, we discuss the full spectrum of the genomic landscape of MIBC toward the goal of therapeutic application.

Cancer Susceptibility Mutations in Patients With Urothelial Malignancies

PURPOSE

Urothelial cancers (UCs) have a substantial hereditary component, but, other than their association with Lynch syndrome, the contribution of genetic risk factors to UC pathogenesis has not been systematically defined. We sought to determine the prevalence of pathogenic/likely pathogenic (P/LP) germline variants in patients with UC and identify associated clinical factors.

PATIENTS AND METHODS

Overall, 586 patients with UC underwent prospective, matched tumor-normal DNA sequencing. Seventy-seven genes associated with cancer predisposition were analyzed; allele frequencies were compared with publicly available database.

RESULTS

P/LP germline variants were identified in 80 (14%) of 586 individuals with UC. The most common P/LP variants in high- or moderate-penetrance genes were BRCA2 (n = 9; 1.5%), MSH2 (n = 8; 1.4%), BRCA1 (n = 8; 1.4%), CHEK2 (n = 6; 1.0%), ERCC3 (n = 4; 0.7%), and NBN and RAD50 (n = 3; 0.5% each). Sixty-six patients (83%) had germline P/LP variants in DNA-damage repair (DDR) genes, of which 28 (42%) had biallelic inactivation. Patients with P/LP variants were more commonly diagnosed at an early age (22% v 6% in those without variants; P = .01). BRCA2 and MSH2 were significantly associated with an increased risk for UC (odds ratio, 3.7 [P = .004] and 4.6 [P = .001], respectively). Current clinical guidelines for referral for genetic testing failed to identify 6 (26%) patients with high-penetrance variants.

CONCLUSION

Clinically significant P/LP germline variants in DDR genes frequently are present in patients with advanced UC. The presence of DDR germline variants could guide cancer screening for patients and their families and serve as predictive biomarkers of response to targeted or immunotherapies. Family history-based criteria to identify patients with hereditary UC susceptibility are insensitive. Broader germline testing in UC, particularly in those of young ages, should be considered.

The emerging landscape of germline variants in urothelial carcinoma: Implications for genetic testing

Urothelial carcinoma (UC) of the bladder and upper tract (ureter, renal pelvis) is one of the most frequently occurring malignancies. While the majority of UC are chemically induced by smoking, accumulating evidence from genetic studies have demonstrated a small, but consistent impact of heritable gene variants and family history of UC on the development of the disease. Beyond the established association between upper tract UC and germline mismatch DNA repair defects as a defining feature of Lynch syndrome, newer investigations focusing on moderate- and high-risk cancer-related gene variants in DNA damage repair and other signaling pathways are expanding our knowledge on the heritable genetic basis of UC, opening new avenues in the breadth of genetic testing and in clinical counseling of these patients. Overcoming existing challenges in the interpretation of uncertain findings and family cascade testing may help expand our testing approach and guidelines. Following the paradigm of other tumor types, such as breast and ovarian cancers, germline genetic testing, particularly when combined with somatic testing, has the potential to directly benefit affected UC patients and their families in the future through therapeutic targeting (i.e. with poly(ADP-ribose)) polymerase inhibitors, immune checkpoint inhibitors) and genetically informed screening/surveillance, respectively.

Genetic diversity and functional effect of common polymorphisms in genes involved in the first heterodimeric complex of the Nucleotide Excision Repair pathway

Nucleotide excision repair is a multistep process that recognizes and eliminates a spectrum of DNA damages. Five proteins, namely XPC, RAD23, Centrin 2, DDB1 and DDB2 act as a heterodimeric complex at the early steps of the NER pathway and play a crucial role in the removal of DNA lesions. Several exonic mutations on genes coding for these proteins have been identified as associated with Xeroderma-pigmentosum (XP), a rare monogenic disorder. However, the role of regulatory polymorphisms in disease development and inter-ethnic diversity is still not well documented. Due to the high incidence rate of XP in Tunisia, we performed a genotyping analysis of 140 SNPs found on these 5 genes in a set of 135-subjects representing the general Tunisian-population. An inter-ethnic comparison based on the genotype frequency of these SNPs have been also conducted. For the most relevant variants, we performed a comprehensive assessment of their functional effects. Linkage disequilibrium and principal component analysis showed that the Tunisian-population is an admixed and intermediate population between Sub-Saharan Africans and Europeans. Using variable factor maps, we identified a list of 20 polymorphisms that contribute considerably to the inter-ethnic diversity of the NER complex. In-silico functional analysis showed that SNPs on XPC, DDB1 and DDB2 are associated with eQTLs mainly DDB2-rs10838681 that seems to decrease significantly the expression level of ACP2 (p = 6.1 × 10^-26). Statistical analysis showed that the allelic frequency of DDB2-rs10838681 in Tunisia is significantly different from all other populations. Using rVarBase, we identified 5 variants on XPC, DDB1 and DDB2 that seem to alter the binding sites of several transcription factors considered as key players in DNA-repair pathways. Results presented in this study provide the first report on regulatory polymorphisms of the NER-complex genes in Tunisia. These results may also help to establish a baseline database for future association and functional studies.

Epidemiology of Bladder Cancer: A Systematic Review and Contemporary Update of Risk Factors in 2018

CONTEXT

Bladder cancer (BC) is a significant health problem, and understanding the risk factors for this disease could improve prevention and early detection.

OBJECTIVE

To provide a systematic review and summary of novel developments in epidemiology and risk factors for BC.

EVIDENCE ACQUISITION

A systematic review of original articles was performed by two pairs of reviewers (M.G.C., I.J., F.E., and K.P.) using PubMed/Medline in December 2017, updated in April 2018. To address our primary objective of reporting contemporary studies, we restricted our search to include studies from the last 5yr. We subdivided our review according to specific risk factors (PICO [Population Intervention Comparator Outcome]).

EVIDENCE SYNTHESIS

Our search found 2191 articles, of which 279 full-text manuscripts were included. We separated our manuscripts by the specific risk factor they addressed (PICO). According to GLOBOCAN estimates, there were 430000 new BC cases and 165000 deaths worldwide in 2012. Tobacco smoking and occupational exposure to carcinogens remain the factors with the highest attributable risk. The literature was limited by heterogeneity of data.

CONCLUSIONS

Evidence is emerging regarding gene-environment interactions, particularly for tobacco and occupational exposures. In some populations, incidence rates are declining, which may reflect a decrease in smoking. Standardisation of reporting may help improve epidemiologic evaluation of risk.

PATIENT SUMMARY

Bladder cancer is common worldwide, and the main risk factors are tobacco smoking and exposure to certain chemicals in the working and general environments. There is ongoing research to identify and reduce risk factors, as well as to understand the impact of genetics on bladder cancer risk.

Cruciferous Vegetables, Isothiocyanates, and Bladder Cancer Prevention

Bladder cancer is a significant health burden due to its high prevalence, risk of mortality, morbidity, and high cost of medical care. Epidemiologic evidence suggests that diets rich in cruciferous vegetables, particularly broccoli, are associated with lower bladder cancer risk. Phytochemicals in cruciferous vegetables, such as glucosinolates, which are enzymatically hydrolyzed to bioactive isothiocyanates, are possible mediators of an anticancer effect. In vitro studies have shown inhibition of bladder cancer cell lines, cell cycle arrest, and induction of apoptosis by these isothiocyanates, in particular sulforaphane and erucin. Although not yet completely understood, many mechanisms of anticancer activity at the steps of cancer initiation, promotion, and progression have been attributed to these isothiocyanates. They target multiple pathways including the adaptive stress response, phase I/II enzyme modulation, pro-growth, pro-survival, pro-inflammatory signaling, angiogenesis, and even epigenetic modulation. Multiple in vivo studies have shown the bioavailability of isothiocyanates and their antitumoral effects. Although human studies are limited, they support oral bioavailability with reasonable plasma and urine concentrations achieved. Overall, both cell and animal studies support a potential role for isothiocyanates in bladder cancer prevention and treatment. Future studies are necessary to examine clinically relevant outcomes and define guidelines on ameliorating the bladder cancer burden.

Prevention of bladder cancer incidence and recurrence: tobacco use

PURPOSE OF REVIEW

To summarize the current knowledge about smoking carcinogenesis in bladder cancer (BCa), individual susceptibility and impact of smoking on incidence and outcomes of nonmuscle invasive BCa (NMIBC) and muscle-invasive BCa (MIBC). To assess the impact of smoking cessation on oncological outcomes.

RECENT FINDINGS

Smoking pattern, intensity, and duration are responsible for an increased risk of developing BCa and for worse tumor features at presentation. Tobacco consumption is associated with a higher risk of recurrence in NMIBC and with an impaired intravesical therapy efficacy. To date, the impact of smoking on oncological outcomes after radical surgery remains unclear.

SUMMARY

Smoking cessation decreases the risk of BCa and may also allow benefits on treatment outcomes. Nonetheless, the magnitude of the effect remains unclear and prospective series with the specific aim of weighing smoking cessation on outcomes are needed. Because even a 5-min counseling in the urology setting may be sufficient to significantly enhance smoking cessation rates, adequate knowledge of links between tobacco and BCa, from its molecular pathophysiology and its harms to benefits of cessation is paramount for urologists and for everyday clinical practice.

CAD/POLD2 gene expression is associated with poor overall survival and chemoresistance in bladder urothelial carcinoma

Somatic mutations in DNA repair genes have been clinically associated with chemosensitivity, although few studies have interrogated the nucleotide synthesis pathways that supply DNA repair processes. Previous work suggests that bladder urothelial carcinoma is uniquely enriched for mutations in nucleotide excision repair genes, and that these mutations are associated with response to platinum-based therapy and favorable survival. Conversely, the de novo pyrimidine synthesis pathway has recently emerged as a putative clinical target. This anabolic process is thought to supply DNA repair processes such as nucleotide excision repair; that is, DNA repair enzymes may require a sufficient nucleotide supply available to reverse the intended genotoxic damage of systemic chemotherapy in rapidly proliferating cancer cells. Therefore, we explored the prognostic complementarity between de novo pyrimidine synthesis and nucleotide excision repair expression in a total of 570 bladder urothelial carcinoma patients. Ultimately, we show that the de novo pyrimidine synthesis gene CAD is associated with poor survival (P = 0.008) and is co-altered with the nucleotide excision repair gene POLD2. High expression of POLD2 was also associated with poor overall survival (P = 0.019) and was significantly correlated with CAD expression in pre-treatment patient tumor samples (P = 2.44e-4). Expression of each gene was associated with cisplatin-based therapy resistance, and accordingly, CADhighPOLD2high patients were associated with worse survival than CADhighPOLD2low and CADlowPOLD2high patients. Together, these biomarkers could help elucidate mechanisms of chemoresistance to further personalize therapeutic strategies in bladder urothelial carcinoma.

MicroRNAs in Smoking-Related Carcinogenesis: Biomarkers, Functions, and Therapy

Long-term heavy cigarette smoking is a well-known high-risk factor for carcinogenesis in various organs such as the head and neck, lungs, and urinary bladder. Furthermore, cigarette smoking can systemically accelerate aging, and as the result, promoting carcinogenesis via changing the host microenvironment. Various inflammatory factors, hormones, and chemical mediators induced by smoking mediate carcinoma-related molecules and induce carcinogenesis. MicroRNAs (miRNAs) are a family of short noncoding RNA molecules that bind to mRNAs and inhibit their expression. Cigarette smoke induces the expression of various miRNAs, many of which are known to function in the post-transcriptional silencing of anticancer molecules, thereby leading to smoking-induced carcinogenesis. Analysis of expression profiles of smoking-induced miRNAs can help identify biomarkers for the diagnosis and prognosis of smoking-related cancers and prediction of therapeutic responses, as well as revealing promising therapeutic targets. Here, we introduce the most recent and useful findings of miRNA analyses focused on lung cancer and urinary bladder cancer, which are strongly associated with cigarette smoking, and discuss the utility of miRNAs as clinical biomarkers.

Bladder Cancer Genetic Susceptibility. A Systematic Review

Background:

The variant/gene candidate approach to explore bladder cancer (BC) genetic susceptibility has been applied in many studies with significant findings reported. However, results are not always conclusive due to the lack of replication by subsequent studies.

Objectives:

To identify all epidemiological investigations on the genetic associations with BC risk, to quantify the likely magnitude of the associations by applying metaanalysis methodology and to assess whether there is a potential for publication/reporting bias.

Methods:

To address our aims, we have catalogued all genetic association studies published in the field of BC risk since 2000. Furthermore, we metaanalysed all polymorphisms with data available from at least three independent case-control studies with subjects of Caucasian origin analyzed under the same mode of inheritance.

Results:

The characterization of the genetic susceptibility of BC is composed of 28 variants, GWAS contributing most of them. Most of the significant variants associated with BC risk are located in genes belonging to chemical carcinogenesis, DNA repair, and cell cycle pathways. Causal relationship was also provided by functional analysis for GSTM1-null, NAT2-slow, APOBEC-rs1014971, CCNE1-rs8102137, SLC14A1-rs10775480, PSCA-rs2294008, UGT1A-rs1189203, and TP63-rs35592567.

Conclusions:

Genetic susceptibility of BC is still poorly defined, with GWAS contributing most of the strongest evidence. The systematic review did not provide evidence of further genetic associations. The potential public health translation of the existing knowledge on genetic susceptibility on BC is still limited.

Association of smoking status with prognosis in bladder cancer: A meta-analysis

There is considerable controversy regarding the association between smoking and prognosis in surgically treated bladder cancer. The present meta-analysis was performed to quantify the role of smoking status in bladder cancer recurrence, progression and patient survival by pooling the available previous data. Pubmed, Embase and the Cochrane Library databases were searched for eligible studies published prior to April 2016. Random and fixed effects models were used to calculate the summary relative risk estimates (SRRE). A total of 10,192 patients from 15 studies were included in the meta-analysis. There was evidence of positive associations between current smoking and the risk of recurrence (SRRE=1.23; 95% CI, 1.05–1.45) and mortality (SRRE=1.28; 95% CI, 1.07-1.52) in bladder cancer. Furthermore, former smoking had positive associations with bladder cancer recurrence (SRRE=1.22; 95% CI, 1.09-1.37) and mortality (SRRE=1.20; 95% CI, 1.03-1.41). However, there was no significant association between bladder cancer progression risk and current (SRRE=1.11; 95% CI, 0.71-1.75) or previous smoking (SRRE=1.16; 95% CI, 0.92-1.46). The findings indicate that current and former smoking increase the risk of recurrence and mortality in patients with bladder cancer. However, due to the nonrandomized and retrospective nature of the current study, patients may be prone to potential selection bias. Prospective and larger epidemiological studies with a longer follow-up are required to confirm these findings.

Effect of HMGB1 Polymorphisms on Urothelial Cell Carcinoma Susceptibility and Clinicopathological Characteristics

The high mobility group box 1 gene (HMGB1) plays a prominent role in cancer progression, angiogenesis, invasion, and metastasis. This study explored the effect of HMGB1 polymorphisms on clinicopathological characteristics of urothelial cell carcinoma (UCC). In total, 1293 participants (431 patients with UCC and 862 healthy controls) were recruited. Four single-nucleotide polymorphisms (SNPs) of HMGB1 (rs1412125, rs1360485, rs1045411, and rs2249825) were assessed using TaqMan real-time polymerase chain reaction assay. The results indicated that individuals carrying at least one T allele at rs1045411 had a lower risk of UCC than those with the wild-type allele [adjusted odds ratio = 0.722, 95% confidence interval (CI) = 0.565-0.924]. Furthermore, female patients with UCC carrying at least one T allele at rs1045411 were at a lower invasive tumor stage than those with the wild-type allele [odds ratio (OR) = 0.396, 95% CI = 0.169-0.929], similar to nonsmoking patients (OR = 0.607, 95% CI = 0.374-0.985). In conclusion, this is the first report on correlation between HMGB1 polymorphisms and UCC risk. Individuals carrying at least one T allele at rs1045411 are associated with a lower risk of UCC and a less invasive disease in women and nonsmokers.

A Versatile Assay for Detection of Aberrant DNA Methylation in Bladder Cancer

Urothelial carcinoma of the bladder is one of the most common malignancies in the industrialized world, mainly caused by smoking and occupational exposure to chemicals. The favorable prognosis of early stage bladder cancer underscores the importance of early detection for the treatment of this disease. The high recurrence rate of this malignancy also highlights the need for close post-diagnosis monitoring of bladder cancer patients. As for other malignancies, aberrant DNA methylation has been shown to play a crucial role in the initiation and progression of bladder cancer, and thus holds great promise as a diagnostic and prognostic biological marker. Here, we describe a protocol for a versatile DNA methylation enrichment method, the Methylated CpG Island Recovery Assay (MIRA), which enables analysis of the DNA methylation status in individual genes or across the entire genome. MIRA is based on the ability of the methyl-binding domain (MBD) proteins, the MBD2B/MBD3L1 complex, to specifically bind methylated CpG dinucleotides. This easy-to-perform method can be used to analyze the methylome of bladder cancer or urothelial cells shed in the urine to elucidate the evolution of bladder carcinogenesis and/or identify epigenetic signatures of chemicals known to cause this malignancy.

Association of nineteen polymorphisms from seven DNA repair genes and the risk for bladder cancer in Gansu province of China

Background

Balance of DNA damage and proper repair plays an important role in progression of bladder cancer. Here we aimed to assess the associations of nineteen polymorphisms from seven DNA repair–associated genes (PRAP1, OGG1, APEX1, MUTYH, XRCC1, XRCC2 and XRCC3) with bladder cancer and their interactions in the disease in a Han Chinese population.

Methodology/Principal Findings

A chip-based TaqMan genotyping for the candidate genes was performed on 227 bladder cancer patients and 260 healthy controls. APEX1 rs3136817, MUTYH rs3219493, three SNPs (rs3213356, rs25487 and rs1799782) in XRCC1, and three SNPs (rs1799794, rs861531 and rs861530) in XRCC3 showed significant associations with the risk of bladder cancer. In haplotype analysis, elevated risks of bladder cancer were observed in those with either haplotype GT (OR = 1.56, P = 0.003) of APEX1, or GGGTC (OR = 2.05, P = 0.002) of XRCC1, whereas decreased risks were in individuals with either GCGCC (OR = 0.40, P = 0.001), or GCGTT (OR = 0.60, = 0.005) of XRCC1, or CCC (OR = 0.65, P = 0.004) of MUTYH, or TTTAT (OR = 0.36, P = 0.009) of XRCC3. Interaction analysis showed that the two-loci model (rs1799794 and rs861530) was the best with the maximal testing accuracy of 0.701, and the maximal 100% cross-validation consistency (P = 0.001).

Conclusions

Polymorphisms and haplotypes of DNA repair genes are associated with the risk of bladder cancer, and of which the SNPs (rs1799794 and rs861530) in XRCC3 gene might be two major loci in relation to the susceptibility to bladder cancer in a northwest Chinese population.

A 3' untranslated region polymorphism rs2304277 in the DNA repair pathway gene OGG1 is a novel risk modulator for urothelial bladder carcinoma

Altered DNA repair capacity may affect an individual's susceptibility to cancers due to compromised genomic integrity. This study was designed to elucidate the association of selected polymorphisms in DNA repair genes with urothelial bladder carcinoma (UBC). OGG1 rs1052133 and rs2304277, XRCC1 rs1799782 and rs25487, XRCC3 rs861539, XPC rs2228001, and XPD rs13181 were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 200 UBC cases and 200 controls. We found association of OGG1 rs2304277 [odds ratio (OR)_GG = 3.55, 95% confidence interval (CI) = 1.79-7.06] and XPC rs2228001 (OR_AC = 2.38, 95% CI = 1.43-3.94) with UBC. In stratified analysis with respect to smoking status, OGG1 rs2304277 and XPC rs2228001 exhibited increased risk in smokers [(rs2304277 OR_GG = 4.96, 95% CI = 1.51-16.30) (rs2228001 OR_AC = 2.19, 95% CI = 1.02-4.72)] as well as nonsmokers [(rs2304277 OR_GG = 2.95, 95% CI = 1.26-6.90) (rs2228001 OR_AC = 2.57, 95% CI = 1.31-5.04)]. These polymorphisms were also associated with both low-grade [(rs2304277 OR_GG = 3.73, 95% CI = 1.72-8.09) (rs2228001 OR_AC = 2.18, 95% CI = 1.21-3.92)] and high-grade tumors [(rs2304277 OR_GG = 3.45, 95% CI = 1.52-7.80) (rs2228001 OR_AC = 2.81, 95% CI = 1.48-5.33)] as well as with non-muscle-invasive bladder cancer [(rs2304277 OR_GG = 4.03, 95% CI = 1.87-8.67) (rs2228001 OR_AC = 2.14, 95% CI = 1.20-3.81)] and muscle-invasive bladder cancer [(rs2304277 OR_GG = 3.06, 95%CI = 1.31-7.13) (rs2228001 OR_AC = 2.95, 95%CI = 1.51-5.75)]. This is the first study on DNA repair gene polymorphisms and UBC in the Pakistani population. It identifies OGG1 rs2304277 and replicates XPC rs2228001 as significant modulators of UBC susceptibility.

ERCC1 as a prognostic factor for survival in patients with advanced urothelial cancer treated with platinum based chemotherapy: A systematic review and meta-analysis

BACKGROUND

The predictive role of excision repair cross-complementing group 1 (ERCC1) as a predictive factor in patients with advanced urothelial cancer (AUC) treated with platinum-based treatment is not well defined. Here, we evaluate the role of ERCC1 in patients with AUC treated with platinum-based treatment.

METHODS

We performed comprehensive, systematic computerized search to identify relevant studies through Medline, Embase, Cochrane Controlled Trials Register (CCTR) databases and abstracts from American Society of Clinical Oncology (ASCO) and ASCO Genitourinary Cancers Symposium, European Society For Medical Oncology (ESMO) and European Association of Urology (EAU) meeting up to July 2015. A systematic review and meta-analysis were performed.

RESULTS

We included a total of 1475 patients from 13 studies. We found that ERCC1 positivity was significantly associated with worse progression-free survival (pooled HR: 1.54, 95% CI: 1.13-2.11, p=0.006). There was no significant association with overall survival (pooled HR1.63, 95% CI: 0.93-2.88, p=0.09) and disease-free survival (pooled HR: 1.092, 95% CI: 0.63-1.90, p=0.75).

CONCLUSION

ERCC1 positivity might be a prognostic indicator for poorer survival outcomes among patients with AUC. ERCC1 positivity was trending to poorer OS but was statistically worse for PFS. Further large prospective studies are warranted as ERCC1 could be used as a predictive marker to direct treatment of patients with AUC.

Diabetes mellitus and the risk of bladder cancer: A PRISMA-compliant meta-analysis of cohort studies

BACKGROUND

Epidemiologic studies have reported inconsistent results regarding the relationship between diabetes mellitus (DM) and the incidence of bladder cancer. This comprehensive systematic review and meta-analysis explored and evaluated this relationship in participants with different characteristics.

METHODS

Studies indexed in the PubMed, Embase, and the Cochrane Library databases that compared bladder cancer incidence mortality between DM and non-DM participants were included in the present study. The relative risks (RRs) of a random-effects model were used to assess these associations.

RESULTS

The final analysis included 21 cohort studies, involving a total of 13,505,643 participants. Overall, DM was associated with an increased risk of bladder cancer or cancer mortality when compared with non-DM participants (RR: 1.23; 95% confidence interval [CI]: 1.12-1.35; P < .001). Furthermore, DM had a harmful impact on subsequent bladder cancer risk in men compared with those without DM (RR: 1.23; 95% CI: 1.06-1.42; P = .005), whereas no significant relationship was observed between DM and bladder cancer in women (RR: 1.24; 95% CI: 0.95-1.61; P = .119). There was no significant gender difference for this relationship (ratio of RR: 0.99; 95% CI: 0.73-1.34; P = .958). In addition, cancer incidence (RR: 1.21; 95% CI: 1.09-1.35; P < .001) and cancer mortality (RR: 1.25; 1.17-1.35; P < .001) both increased in DM patients. Finally, smoking status and follow-up duration might also affect this relationship in men and women.

CONCLUSIONS

The findings of this study indicated that DM was associated with elevated bladder cancer or cancer mortality risk, especially in men. This relationship in women requires further exploration.

DNA Damage Response and Repair Gene Alterations Are Associated with Improved Survival in Patients with Platinum-Treated Advanced Urothelial Carcinoma

Purpose: Platinum-based chemotherapy remains the standard treatment for advanced urothelial carcinoma by inducing DNA damage. We hypothesize that somatic alterations in DNA damage response and repair (DDR) genes are associated with improved sensitivity to platinum-based chemotherapy.Experimental Design: Patients with diagnosis of locally advanced and metastatic urothelial carcinoma treated with platinum-based chemotherapy who had exon sequencing with the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) assay were identified. Patients were dichotomized based on the presence/absence of alterations in a panel of 34 DDR genes. DDR alteration status was correlated with clinical outcomes and disease features.Results: One hundred patients were identified, of which 47 harbored alterations in DDR genes. Patients with DDR alterations had improved progression-free survival (9.3 vs. 6.0 months, log-rank P = 0.007) and overall survival (23.7 vs. 13.0 months, log-rank P = 0.006). DDR alterations were also associated with higher number mutations and copy-number alterations. A trend toward positive correlation between DDR status and nodal metastases and inverse correlation with visceral metastases were observed. Different DDR pathways also suggested variable impact on clinical outcomes.Conclusions: Somatic DDR alteration is associated with improved clinical outcomes in platinum-treated patients with advanced urothelial carcinoma. Once validated, it can improve patient selection for clinical practice and future study enrollment. Clin Cancer Res; 23(14); 3610-8. ©2017 AACR.

Rare variants in BRCA2 and CHEK2 are associated with the risk of urinary tract cancers

Previous studies have shown that two rare variants, rs11571833 in BRCA2 and rs17879961 in CHEK2 were associated with lung cancer. However, the associations between these two variants and urinary tract cancers risk remain largely unexplored. We applied imputation of three genome-wide association studies published in the database of Genotypes and Phenotypes (dbGaP). Unconditional logistic regression analysis and meta-analysis were performed to assess the association between these two variants and the risk of urinary tract cancers. Our results showed that rs11571833[T] had an effect on urinary tract cancers predisposition (ORmeta = 1.45, Pmeta = 0.013), especially associated with increased the risk of bladder cancer (ORmeta = 1.60, Pmeta = 0.010). Moreover, rs17879961[C] had a protective effect on the urinary tract cancers (ORmeta = 0.67, Pmeta = 1.0 × 10(-3)) and was mostly associated with a lower incidence of renal cell carcinoma (ORmeta = 0.51, Pmeta = 2.0 × 10(-3)). Together, our study indicates that BRCA2 and CHEK2 play an important role in the genetic susceptibility to urinary tract cancers.

Polymorphisms in the XPC gene affect urinary bladder cancer risk: a case-control study, meta-analyses and trial sequential analyses

Compromised activity of the DNA repair enzymes may raise the risk of a number of cancers. We analyzed polymorphisms in the Xeroderma Pigmentosum, Complementation Group C (XPC) gene for their correlation with urinary bladder cancer. Ala499Val and Lys939Gln polymorphisms were genotyped in 234 urinary bladder cancer cases and 258 control samples. A significant association between Ala499Val polymorphism and bladder cancer was observed (OR = 1.78, CI = 1.19–2.66, p = 0.005); however, Lys939Gln was unrelated (OR = 0.97, CI = 0.65–1.45, P = 0.89). Further analysis revealed that Ala499Val was a significant risk factor only in the presence of smoking (OR = 2.23, CI = 1.28–3.87, p < 0.004) or tobacco chewing (OR = 2.40, CI = 1.43–4.04, p = 0.0008). To further appraise the association, we undertook meta-analyses on seven studies (2893 cases and 3056 controls) on Ala499Val polymorphism and eleven studies (5064 cases and 5208 controls) on Lys939Gln polymorphism. Meta-analyses corroborated the above results, showing strong association of Ala499Val (OR = 1.54, CI = 1.21–1.97, p = 0.001) but not that of Lys939Gln (OR = 1.13, CI = 0.95–1.34, p = 0.171) with urinary bladder cancer risk. In conclusion, XPC Ala499Val substitution increases urinary bladder cancer risk, but Lys939Gln appears to be neutral.

Somatic ERCC2 mutations are associated with a distinct genomic signature in urothelial tumors

Alterations in DNA repair pathways are common in tumors and can result in characteristic mutational signatures; however, a specific mutational signature associated with somatic alterations in the nucleotide- excision repair (NER) pathway has not yet been identified. Here we examine the mutational processes operating in urothelial cancer, a tumor type in which the core NER gene ERCC2 is significantly mutated. Analysis of three independent urothelial tumor cohorts demonstrates a strong association between somatic ERCC2 mutations and the activity of a mutational signature characterized by a broad spectrum of base changes. In addition, we note an association between the activity of this signature and smoking that is independent of ERCC2 mutation status, providing genomic evidence of tobacco-related mutagenesis in urothelial cancer. Together, these analyses identify an NER-related mutational signature and highlight the related roles of DNA damage and subsequent DNA repair in shaping tumor mutational landscape.

Caffeine Suppresses Apoptosis of Bladder Cancer RT4 Cells in Response to Ionizing Radiation by Inhibiting Ataxia Telangiectasia Mutated-Chk2-p53 Axis

Background:

Caffeine suppresses ataxia telangiectasia and Rad3 related and ataxia telangiectasia mutated (ATM) activities; ATM is the major kinase for DNA damage detection. This study aimed to investigate the effects of caffeine on DNA damage responses in cells from the bladder cancer cell line RT4 those were exposed to ionizing radiation (IR).

Methods:

Immunofluorescent staining was performed to investigate changes in the proteins involved in DNA damage responses with or without caffeine. A mouse xenograft model was used to study the effects of caffeine on the DNA damage responses. Western blotting was used to investigate the effects of caffeine pretreatment on the ATM-Chk2-p53-Puma axis, while real-time polymerase chain reaction (RT-PCR) assessed changes in messenger RNA levels of p53 and downstream targets responding to IR. Finally, terminal deoxynucleotidyl transferase-dUTP nick end labeling assay. Western blotting and colony formation assay were used to measure the effects of caffeine on radiation-related apoptosis. All of the data were analyzed with a two-tailed Student's t-test.

Results:

Immunofluorescent staining showed that caffeine pretreatment profoundly suppressed the formation of γH2AXand p53-binding protein 1 foci in RT4 cells in response to irradiation. Cellular and animal experiments suggested that this suppression was mediated by suppression of the ATM-Chk2-p53-Puma DNA damage-signaling axis. RT-PCR indicated caffeine also attenuated transactivation of p53 and p53-inducible genes. The colony formation assay revealed that caffeine displayed radioprotective effects on RT4 cells in response to low-dose radiation compared to the radiosensitization effects on T24 cells.

Conclusion:

Caffeine may inhibit IR-related apoptosis of bladder cancer RT4 cells by suppressing activation of the ATM-Chk2-p53-Puma axis.

Review of the Gene-Environment Interaction Literature in Cancer: What Do We Know?

BACKGROUND

Risk of cancer is determined by a complex interplay of genetic and environmental factors. Although the study of gene-environment interactions (G×E) has been an active area of research, little is reported about the known findings in the literature.

METHODS

To examine the state of the science in G×E research in cancer, we performed a systematic review of published literature using gene-environment or pharmacogenomic flags from two curated databases of genetic association studies, the Human Genome Epidemiology (HuGE) literature finder and Cancer Genome-Wide Association and Meta Analyses Database (CancerGAMAdb), from January 1, 2001, to January 31, 2011. A supplemental search using HuGE was conducted for articles published from February 1, 2011, to April 11, 2013. A 25% sample of the supplemental publications was reviewed.

RESULTS

A total of 3,019 articles were identified in the original search. From these articles, 243 articles were determined to be relevant based on inclusion criteria (more than 3,500 interactions). From the supplemental search (1,400 articles identified), 29 additional relevant articles (1,370 interactions) were included. The majority of publications in both searches examined G×E in colon, rectal, or colorectal; breast; or lung cancer. Specific interactions examined most frequently included environmental factors categorized as energy balance (e.g., body mass index, diet), exogenous (e.g., oral contraceptives) and endogenous hormones (e.g., menopausal status), chemical environment (e.g., grilled meats), and lifestyle (e.g., smoking, alcohol intake). In both searches, the majority of interactions examined were using loci from candidate genes studies and none of the studies were genome-wide interaction studies (GEWIS). The most commonly reported measure was the interaction P-value, of which a sizable number of P-values were considered statistically significant (i.e., <0.05). In addition, the magnitude of interactions reported was modest.

CONCLUSION

Observations of published literature suggest that opportunity exists for increased sample size in G×E research, including GWAS-identified loci in G×E studies, exploring more GWAS approaches in G×E such as GEWIS, and improving the reporting of G×E findings.

Epidemiology of bladder cancer

Bladder cancer incidence is higher in old men, shows geographic variation, and is mostly an environmental disease. Cigarette smoking, occupational exposures, water arsenic, Schistosoma haematobium infestation, and some medications are the best established risk factors. Low-penetrance genetic factors also contribute to its origin, some through interaction with environmental factors. Bladder cancer has high prevalence and a low mortality, being largely a chronic disease. Data on environmental and genetic factors involved in the disease outcome are inconclusive.

MicroRNA expression profiling in bladder cancer: the challenge of next-generation sequencing in tissues and biofluids

Bladder cancer (BC) is a heterogeneous disease characterized by a high recurrence rate that necessitates continuous cystoscopic surveillance. MicroRNAs (miRNAs) are detectable in tissues and biofluids such as plasma/serum and urine. They represent promising biomarkers with potential not only for detecting BC but also informing on prognosis and monitoring treatment response. In this review, the many aspects of the application of next-generation sequencing (NGS) to evaluate miRNA expression in BC is discussed, including technical issues as well as a comparison with results obtained by qRT-PCR. The available studies investigating miRNA profiling in BC by NGS are described, with particular attention to the potential applicability on biofluids. Altered miRNA levels have been observed in BC tissues by NGS, but these results so far only partially overlapped among studies and with previous data obtained by qRT-PCR. The discrepancies can be ascribed to the small groups of BC patients sequenced. The few available studies on biofluids are mainly focused on implementing RNA isolation and sequencing workflow. Using NGS to analyze miRNAs in biofluids can potentially provide results comparable to tissues with no invasive procedures for the patients. In particular, the analyses performed on exosomes/microvesicles appear to be more informative. Thanks to the improvement of both wet-lab procedures and pipelines/tools for data analyses, NGS studies on biofluids will be performed on a larger scale. MiRNAs detected in urine and serum/plasma will demonstrate their potentiality to describe the variegated scenario of BC and to become relevant clinical markers.