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Colin P Dinney

Publications and source records attributed to Colin P Dinney.

At least 19 recordsLinked to original sources

Genetic polymorphism in bladder cancer.

Individual variation in the genetic constitution of humans may affect the host responses to constant assaults from exogenous and endogenous carcinogens, which will eventually impact cancer risk, disease prognosis and clinical outcome. Bladder cancer is one of the most common cancers in the world. In this review, the published research articles studying the association between genetic polymorphisms and bladder cancer risk and disease progression are summarized. Genetic polymorphisms are categorized based on their primary cellular functions: genes in carcinogen metabolism, DNA repair, cell cycle control, inflammation, apoptosis, methylation, genes functioning as G proteins, and cell adhesion molecules. Furthermore, we discuss a number of limitations of current genetic susceptibility research and suggest future directions in molecular epidemiology study. This review presents an overview of current molecular epidemiology of bladder cancer and provides a useful resource for understanding the pathogenesis of bladder cancer.

Apoptosis↗

High-order interactions among genetic variants in DNA base excision repair pathway genes and smoking in bladder cancer susceptibility.

Cancer is a common multifactor human disease resulting from complex interactions between many genetic and environmental factors. In this study, we used a multifaceted analytic approach to explore the relationship between eight single nucleotide polymorphisms in base excision repair (BER) pathway genes, smoking, and bladder cancer susceptibility in a hospital-based case-control study. Overall, we did not find an association between any single BER gene single nucleotide polymorphism and bladder cancer risk. However, in stratified analysis, the OGG1 S326C variant genotypes in ever smokers (odds ratio, 0.74; 95% confidence interval, 0.56-0.99) and ADP-ribosyltransferase (ADPRT) V762A variant genotypes in never smokers (odds ratio, 0.58; 95% confidence interval, 0.37-0.91) conferred a significantly reduced risk. Using logistic regression, we observed that there was a two-way interaction between ADPRT V762A and smoking status. We next used classification and regression tree analysis to explore high-order gene-gene and gene-environment interactions. We found that smoking is the most important influential factor for bladder cancer risk. Consistent with the above findings, we found that the ADPRT V762A was only significantly involved in bladder cancer risk in never smokers and the OGG1 S326C was only significantly involved in ever smokers. We also observed gene-gene interactions among OGG1 S326C, XRCC1 R194W, and MUTYH H335Q in ever smokers. Using multifactor dimensionality reduction approach, the four-factor model, including smoking status, OGG1 S326C (rs1052133), APEX1 D148E (rs3136820), and ADPRT762 (rs1136410), had the best ability to predict bladder cancer risk with the highest cross-validation consistency (100%) and the lowest prediction error (37.02%; P < 0.001). These results support the hypothesis that genetic variants in BER genes contribute to bladder cancer risk through gene-gene and gene-environmental interactions.

Algorithms↗

Matrix metalloproteinase polymorphisms and bladder cancer risk.

Matrix metalloproteinases (MMP) contribute to tumor microenvironment and are associated with bladder cancer. A study examining the association between MMP polymorphisms and bladder cancer risk has never been published. We analyzed the association of 11 single nucleotide polymorphisms (SNPs) and one microsatellite polymorphism in MMP genes MMP-1, MMP-2, MMP-3, MMP-8, MMP-9, and MMP-12 with bladder cancer risk in 560 Caucasian patients and 560 controls matched on age, gender, and ethnicity. Individual, combination, haplotype, and diplotype analyses were done. No associations between individual MMP polymorphisms and overall bladder cancer risk were seen. The MMP-9 microsatellite > or =24 CA repeat allele and the MMP-12-82 GG polymorphisms were associated with invasive bladder cancer risk [odds ratio (OR), 2.60; 95% confidence interval (95% CI), 1.07-6.26; and OR, 4.59; 95% CI, 1.21-17.32, respectively]. Smoke-stratified analyses revealed several associations between MMP polymorphisms, alone and in combination, with bladder cancer risk, particularly in light smokers. Linkage disequilibrium was seen in all of the MMP-1, MMP-3, MMP-8, and MMP-12 SNPs and in four of five MMP-9 polymorphisms tested. Several MMP-9 haplotype and diplotypes were associated with overall and invasive bladder cancer risk. Our study suggests that genetic variations in the MMP family are associated with bladder cancer risk. Heavy carcinogen exposure may overwhelm some of the genetic effects of MMP polymorphisms. Our study confirms the importance of taking a multigenic pathway-based approach to risk assessment.

Case-Control Studies↗

Molecular markers of urothelial cancer and their use in the monitoring of superficial urothelial cancer.

Multiple molecular markers have been described for use in bladder cancer patients. Some of these have been studied more extensively than others, and it is difficult for the clinician to maintain a perspective over the myriad findings that have been made. We have reviewed a selection of markers used for surveillance with an emphasis on clinical utility. The best studied markers and those with the most promising preliminary results were selected. Only studies that included surveillance for recurrence in patients with a history of bladder cancer were considered. Each marker is briefly described and its performance in monitoring bladder cancer patients is summarized. Several promising markers are available, although only four have obtained US Food and Drug Administration approval. The clinical applications that have been studied include replacement or reduction in the number of cystoscopies performed in the surveillance of bladder cancer patients, substitution for or complementary use with urinary cytology in the same setting, predicting disease recurrence and progression, and predicting and monitoring treatment response. None of the markers have been proved sensitive and specific enough to replace cystoscopy. Others, such as nuclear matrix protein 22 (NMP22) and UroVysion, appear to have some utility when used to complement or replace cytology. The other applications have not been adequately studied for any given marker. While multiple molecular markers exist for bladder cancer, their full clinical utility will not be realized until more multicenter prospective trials are conducted to verify their efficacy and safety in the monitoring of patients with superficial bladder cancer.

Biomarkers, Tumor↗

Genotypes, haplotypes and diplotypes of XPC and risk of bladder cancer.

Xeroderma pigmentosum complementation group C (XPC) is responsible for DNA damage recognition in the initial steps of the nucleotide excision repair pathway. Genetic variations in the XPC gene may be associated with impaired protein function and increased risk for bladder cancer. To elucidate the roles of common polymorphisms of XPC in the etiology of bladder cancer, we conducted a hospital-based case-control study including 578 Caucasian incident bladder cancer patients and 578 age- and gender-matched Caucasian controls. We analyzed the associations of the genotypes, haplotypes and diplotypes of three XPC polymorphisms, Ala499Val (C-->T), PAT (-/+) and Lys939Gln (A-->C), with the risk of bladder cancer. No significant association was found for any individual polymorphism. However, the C-C and T-A (indicated as in the order of Ala499Val-PAT-Lys939Gln) haplotypes were associated with reduced bladder cancer risks, with odds ratios (ORs) of 0.51 [95% confidence interval (CI) = 0.34-0.78] and 0.79 (0.60-1.04), respectively. The protective effects were more evident in men, people younger than 59 years, and ever-smokers. We also found that four diplotypes were significantly associated with reduced bladder cancer risk, with ORs (and 95% CIs) of 0.53 (0.34-0.82) for C-A/T-A, 0.48 (0.27-0.84) for C-A/C-C, 0.18 (0.053-0.60) for C-C/C-C and 0.57 (0.36-0.90) for C+C/C+C. These results suggest that sequence variants in the XPC gene might modulate the risk of bladder cancer.

Aged↗

Relevance of extracapsular extension of pelvic lymph node metastasis in patients with bladder cancer treated in the contemporary era.

BACKGROUND: Previous reports have suggested that extracapsular extension (ECE) is a prognostic factor in patients with urothelial carcinoma who have positive lymph nodes at the time of radical cystectomy. In the current study, the relevance of ECE in patients treated in the contemporary era was evaluated. METHODS: A database search from 1993 to 2003 revealed 150 patients with pN+M0 disease detected after radical cystectomy; of these, 108 patients did not receive neoadjuvant chemotherapy and form the basis of the current report. Overall survival (OS), disease-specific survival (DSS), and recurrence-free survival (RFS) data were analyzed by the Kaplan-Meier method, with log-rank tests used to evaluate associations between survival and variables studied. RESULTS: Five-year OS, DSS, and RFS rates were 30.9%, 45.5%, and 29.7%, respectively. Adjuvant chemotherapy was administered to 70% of patients. On multivariate analysis, adjuvant chemotherapy was significantly associated with prolonged OS, DSS, and RFS (P </= .01). For patients overall and when stratified by pN status, the presence of ECE of lymph node metastasis was not found to be significantly associated with OS (P = .52), DSS (P = .43), or RFS (P = .83). CONCLUSIONS.: The current study suggests that ECE is not an independent prognostic factor in a contemporary series of patients with positive lymph nodes at radical cystectomy. This might be reflective of a paradigm shift that encompasses the adoption of multimodal therapy.

Aged↗

Clinical model of lifetime cost of treating bladder cancer and associated complications.

OBJECTIVES: To estimate the lifetime cost of bladder cancer and the contribution of complications to the total costs. METHODS: We reviewed the medical records of a retrospective cohort of 208 patients with bladder cancer who registered at our comprehensive cancer center from 1991 to 1999. We multiplied the number of resources used during management of bladder cancer by their unit charges. We converted charges into costs using the Medicare cost-to-charge ratio and inflated these to 2005 U.S. dollars. We estimated future costs by creating two extreme hypothetical scenarios. In the best-case scenario, we assumed patients with superficial disease developed recurrences at the cohort's mean rate and that patients with muscle-invasive disease were disease free after definitive therapy. Survival was based on the U.S. life expectancy in both cases. In the worst-case scenario, we assumed patients with superficial disease developed muscle-invasive disease and that all patients subsequently died of bladder cancer. RESULTS: The average cost of bladder cancer was 65,158 dollars among the cohort patients. Sixty percent of this cost (39,393 dollars) was associated with surveillance and treatment of recurrences, and 30% (19,811 dollars) was attributable to complications. The lifetime cost of bladder cancer was lower for the worst-case scenario (99,270 dollars) than for the best-case scenario (120,684 dollars). However, a greater proportion of the costs were attributable to complications with the worst-case scenario (43%, 42,290 dollars) compared with the best (28%, 34,169 dollars). CONCLUSIONS: The management of bladder cancer and its associated complications results in a major economic burden. More cost-effective surveillance strategies and approaches for preventing complications are crucial to minimizing the disease's clinical and economic consequences.

Aged↗

Bladder cancer risk as modified by family history and smoking.

BACKGROUND: The familial risk of bladder cancer (BC) is not well understood and, to date, little attention has been paid to the joint effect of smoking and family history in modifying the risk of BC. The authors investigated the role of family history in association with the risk of BC. METHODS: Case and control probands were identified as part of an on-going BC case-control study. The relative risk associated with a family history of BC was estimated. RESULTS: In total, 713 cases and 658 controls were included. In a case-control analysis, compared with individuals who never smoked and who had no family history of BC, probands who had smoked and who also had a positive family history were at 5.31-fold increased risk of BC (P for interaction = .04). The 713 case probands and the 658 controls reported 5160 and 4816 first-degree relatives, respectively. Compared with never-smoking relatives who had probands diagnosed with BC at an older age (age >65 years), ever-smoking relatives who had probands diagnosed at a younger age (ages 40-65 years) showed a 6.89-fold (95% confidence interval, from 2.25-fold to 21.12-fold) increased risk. Similar results were obtained for the joint effects of family history of BC and smoking. CONCLUSIONS. The current results indicated that a positive family history of BC may have interacted with smoking habits to increase the risk of BC in the study population.

Aged↗

Mutations within the kinase domain and truncations of the epidermal growth factor receptor are rare events in bladder cancer: implications for therapy.

PURPOSE: It has previously been reported that the patient response to gefitinib depends on the presence of mutations within the kinase domain of epidermal growth factor receptor (EGFR) or the expression of its truncated form, EGFR variant III (EGFRvIII). The focus of this study was to determine if these alterations are present within the tyrosine kinase and ligand-binding domain of EGFR in urothelial carcinoma. EXPERIMENTAL DESIGN: The kinase domain found within exons 18 to 21 of the EGFR from 11 bladder cancer cell lines and 75 patient tumors were subjected to automated sequencing. EGFRvIII expression was determined by immunohistochemistry using a urothelial carcinoma tissue microarray, and its expression was subsequently verified by reverse transcription PCR, real-time PCR, and Western blot analysis, using an EGFRvIII-transfected glioblastoma cell line and glioblastoma tumors as positive controls. RESULTS: Our analysis failed to detect mutations within the tyrosine kinase domain of EGFR in the 11 cell lines and 75 patients tested. The initial analysis of EGFRvIII expression by immunohistochemistry revealed that at least 50% of the patient tumors expressed EGFRvIII in a urothelial carcinoma tissue microarray. Conflicting reports exist, however, regarding the extent of EGFRvIII expression in tissues owing to the specificity of the antibodies and the methodologies used. Therefore, we sought to validate this observation by reverse transcription PCR, real-time PCR, and Western blot analysis. In these assays, none of the samples were positive for EGFRvIII except for control transfectants and glioblastomas. CONCLUSIONS: When our results are taken together, we conclude that alterations within the tyrosine kinase domain and expression of EGFRvIII are rare events in bladder cancer. The present study has clinical implications in selecting tyrosine kinase inhibitors for the therapy of urothelial carcinoma.

Blotting, Western↗

Bladder cancer predisposition: a multigenic approach to DNA-repair and cell-cycle-control genes.

The candidate-gene approach in association studies of polygenic diseases has often yielded conflicting results. In this hospital-based case-control study with 696 white patients newly diagnosed with bladder cancer and 629 unaffected white controls, we applied a multigenic approach to examine the associations with bladder cancer risk of a comprehensive panel of 44 selected polymorphisms in two pathways, DNA repair and cell-cycle control, and to evaluate higher-order gene-gene interactions, using classification and regression tree (CART) analysis. Individually, only XPD Asp312Asn, RAG1 Lys820Arg, and a p53 intronic SNP exhibited statistically significant main effects. However, we found a significant gene-dosage effect for increasing numbers of potential high-risk alleles in DNA-repair and cell-cycle pathways separately and combined. For the nucleotide-excision repair pathway, compared with the referent group (fewer than four adverse alleles), individuals with four (odds ratio [OR] = 1.52, 95% CI 1.05-2.20), five to six (OR = 1.81, 95% CI 1.31-2.50), and seven or more adverse alleles (OR = 2.50, 95% CI 1.69-3.70) had increasingly elevated risks of bladder cancer (P for trend <.001). Each additional adverse allele was associated with a 1.21-fold increase in risk (95% CI 1.12-1.29). For the combined analysis of DNA-repair and cell-cycle SNPs, compared with the referent group (<13 adverse alleles), the ORs for individuals with 13-15, 16-17, and >or=18 adverse alleles were 1.22 (95% CI 0.84-1.76), 1.57 (95% CI 1.05-2.35), and 1.77 (95% CI 1.19-2.63), respectively (P for trend = .002). Each additional high-risk allele was associated with a 1.07-fold significant increase in risk. In addition, we found that smoking had a significant multiplicative interaction with SNPs in the combined DNA-repair and cell-cycle-control pathways (P<.01). All genetic effects were evident only in "ever smokers" (persons who had smoked >or=100 cigarettes) and not in "never smokers." A cross-validation statistical method developed in this study confirmed the above observations. CART analysis revealed potential higher-order gene-gene and gene-smoking interactions and categorized a few higher-risk subgroups for bladder cancer. Moreover, subgroups identified with higher cancer risk also exhibited higher levels of induced genetic damage than did subgroups with lower risk. There was a significant trend of higher numbers of bleomycin- and benzo[a]pyrene diol-epoxide (BPDE)-induced chromatid breaks (by mutagen-sensitivity assay) and DNA damage (by comet assay) for individuals in higher-risk subgroups among cases of bladder cancer in smokers. The P for the trend was .0348 for bleomycin-induced chromosome breaks, .0036 for BPDE-induced chromosome breaks, and .0397 for BPDE-induced DNA damage, indicating that these higher-order gene-gene and gene-smoking interactions included SNPs that modulated repair and resulted in diminished DNA-repair capacity. Thus, genotype/phenotype analyses support findings from CART analyses. This is the first comprehensive study to use a multigenic analysis for bladder cancer, and the data suggest that individuals with a higher number of genetic variations in DNA-repair and cell-cycle-control genes are at an increased risk for bladder cancer, confirming the importance of taking a multigenic pathway-based approach to risk assessment.

Aged↗

Neoadjuvant chemotherapy for bladder cancer.

The 30-45% failure rate after radical cystoprostatectomy mandates that we explore and optimize multimodal therapy to achieve better disease control in these patients. Cisplatin-based multi-agent combination chemotherapy has been used with success in metastatic disease and has therefore also been introduced in patients with high-risk but non-metastatic bladder cancer. There is now convincing evidence that chemotherapy given pre-operatively can improve survival in these patients. In this review we establish the need for peri-operative chemotherapy in bladder cancer patients and summarize the evidence for the efficacy of neoadjuvant chemotherapy. The advantages and disadvantages of neoadjuvant versus adjuvant chemotherapy are discussed, and the main shortcomings of both--treatment-related toxicity and the inability to prospectively identify likely responders--are presented. Finally, a risk-adapted approach to neoadjuvant chemotherapy is presented, whereby the highest risk patients are offered treatment while those unlikely to benefit are spared the treatment-related toxicity.

Chemotherapy, Adjuvant↗

Vitamins C and K3 sensitize human urothelial tumors to gemcitabine.

PURPOSE: We evaluated the antitumor effects of vitamins C and K3 for human urothelial carcinoma and the potential use of the combination of vitamins C plus K3 as a sensitizing agent for conventional chemotherapy for urothelial carcinoma. MATERIALS AND METHODS: The antiproliferative and apoptotic effects of vitamin C alone, vitamin K3 alone, vitamins C plus K3, gemcitabine alone and gemcitabine plus vitamins C plus K3 were assessed in vitro by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, propidium iodide staining and flow cytometry. For in vivo studies we implanted UMUC-14 tumorigenic urothelial carcinoma cells into the subcutis of nude mice. One week later we treated 10 mice each with saline (control), vitamins C plus K3, gemcitabine or gemcitabine plus vitamins C plus K3. Treatment was continued for 4 weeks, followed by necropsy. Tumor volume was measured and tumor kinetics were established. Apoptosis and proliferation were evaluated in tumor sections using immunohistochemistry and TUNEL assay. RESULTS: Vitamins C plus K3 induced cytostasis and caused apoptosis to a greater degree than either vitamin alone (p < 0.05). Vitamins C plus K3 also substantially augmented the effects of gemcitabine in vitro. There were 32.3% apoptosis with gemcitabine plus vitamins C plus K3, 5.3% with gemcitabine alone and 15.8% with vitamins C plus K3 alone (p < 0.05). In vivo tumor growth was substantially inhibited by gemcitabine plus vitamins C plus K3 compared with that in the control or for either agent alone. Mean tumor weight and growth rate in the gemcitabine plus vitamins C plus K3 group (237 mg and 11.3 mm3 daily) were decreased compared with those in the control (530 mg and 34.3 mm3 daily), and those for vitamins C plus K3 alone (490 mg and 25.2 mm3 daily) and gemcitabine alone (400 mg and 21.3 mm3 daily) (p < 0.05). CONCLUSIONS: Vitamins C and K3 have significant antiproliferative and apoptotic effects when used in combination. This combination enhances the efficacy of gemcitabine against bladder cancer in vivo.

Animals↗

Evaluation of the relevance of lymph node density in a contemporary series of patients undergoing radical cystectomy.

PURPOSE: Lymph node density, that is the ratio of positive nodes to the total number of nodes excised, has been suggested to better stratify patients with bladder cancer who have nodal metastasis. We evaluated its relevance in a contemporary series of patients treated with radical cystectomy and in the context of adjuvant chemotherapy. MATERIALS AND METHODS: From 1993 to 2003, 150 patients had pN+M0 disease at cystectomy, of whom 108 who did not receive neoadjuvant chemotherapy form the basis of this report. Statistical analyses were performed using standard methodology. RESULTS: Five-year overall, disease specific and recurrence-free survival rates were 30.9%, 45.5% and 29.7%, respectively. The median number of lymph nodes removed was 12 and the median number of positive nodes was 2. Of the patients 70% received adjuvant chemotherapy. Patients with a lymph node density of 25% or less had 5-year overall and recurrence-free survival rates of 37.3% and 38.1% compared with 18.7% and 10.6%, respectively in those with a lymph node density of greater than 25% (p = 0.02). In the context of adjuvant chemotherapy, which was associated with prolonged overall, disease specific and recurrence-free survival (p < or =0.01), lymph node density still remained prognostic for recurrence-free survival (HR 1.69, p = 0.047). The total number of nodes removed and the number of positive nodes were not prognostic. CONCLUSIONS: Our results support the relevance of lymph node density in a contemporary series of patients with bladder cancer treated with radical cystectomy. Lymph node density remains a significant prognostic factor for recurrence-free survival even when adjuvant chemotherapy is used.

Aged↗

Should cystectomy only be performed at high-volume hospitals by high-volume surgeons?

PURPOSE OF REVIEW: Monitoring and improving the quality of healthcare is an evolving process that involves patients, physicians, and healthcare purchasers. Growing interest is seen in addressing quality concerns with policy changes. Surgeon and hospital volumes for specific high-risk procedures have been shown to be predictive of posttreatment outcome, but debate continues as to if the evidence justifies changes in practices. We reviewed the literature for robust evidence that surgeon and hospital volumes are markers of improved outcome of radical cystectomy. RECENT FINDINGS: Outcome can be measured by postoperative mortality, as well as complication rate, recurrence rate, and several other factors. Evidence suggests that outcome is improved after cystectomy performed at high-volume centers and by high-volume surgeons. The limitations of volume-based referral policies are discussed, and the use of alternative strategies is reviewed. SUMMARY: A significant regionalization of cystectomy has already been established. Owing to their limitations, however, volume-based referral systems have not been embraced by all parties. New strategies will continue to evolve, and validation of these strategies will be required before clinical implementation.

Cystectomy↗

Personal permanent hair dye use is not associated with bladder cancer risk: evidence from a case-control study.

Whether personal hair dye use is associated with an increased bladder cancer risk has been controversial and there are limited available data addressing this issue. We used a large case-control study of 712 incident bladder cancer cases and 712 age-, gender-, and ethnicity-matched controls to evaluate this association. After adjusting for confounding variables, the use of permanent hair dye was not associated with bladder cancer risk in all subjects [odds ratio (OR), 0.81; 95% confidence interval (95% CI), 0.50-1.30], in women (OR, 0.90; 95% CI, 0.41-1.96), or in men (OR, 0.68; 95% CI, 0.36-1.29). The lack of association was not modified by duration of use, frequency of use, lifetime use, age at first use, or color of use in subsequent stratified analyses. Our data do not support personal hair dye use as an important risk factor for bladder cancer.

Adult↗

Polymorphisms in inflammation genes and bladder cancer: from initiation to recurrence, progression, and survival.

PURPOSE: Since chronic inflammation contributes to tumorigenesis, we hypothesized that the risk and clinical outcome of bladder cancer (BC) might be modulated by genetic variations in inflammation genes. METHODS: Using the TaqMan method, we genotyped single nucleotide polymorphisms in interleukin (IL) -6 (-174 G-->C), IL-8 (-251 T-->A), tumor necrosis factor-alpha (TNF-alpha; -308 G-->A), and peroxisome proliferator-activated receptor gamma (PPARG; Pro12Ala), and determined their associations with BC initiation and clinical outcome. RESULTS: We found that the IL-6 variant genotype (C/C) was associated with an increased BC risk (OR, 1.77; 95% CI, 1.25 to 2.51). There were joint effects between the variant IL-6 genotypes and smoking status, and between the variant genotypes of IL-6 and other genes. To assess effect on recurrence, we grouped non-muscle-invasive BC patients according to intravesical Bacillus Calmette-Guerin (BCG) treatment status: no BCG, induction BCG (iBCG), and maintenance BCG (mBCG). In the Cox proportional hazards model, the variant IL-6 genotype was associated with an increased recurrence risk (hazard ratio [HR], 4.60; 95% CI, 1.24 to 17.09) in patients receiving mBCG. The variant PPARG genotype was associated with a reduced recurrence risk (HR, 0.41; 95% CI, 0.20 to 0.86) among untreated patients. In patients with non-muscle-invasive BC, the variant IL-6 genotype was associated with an increased progression risk (HR, 1.88; 95% CI, 0.80 to 4.11). In patients with invasive BC, variant IL-6 was associated with improved 5-year overall and disease-specific survival (HR, 0.43; 95% CI, 0.19 to 0.94 and HR, 0.39; 95% CI, 0.15 to 1.00, respectively). CONCLUSION: Inflammation gene polymorphisms are associated with modified BC risk, treatment response, and survival.

Aged↗

Roles of tumor suppressor and telomere maintenance genes in cancer and aging--an epidemiological study.

Advanced age is strikingly linked to increased incidence of cancer. To gain insight into the mechanism underlying the association between increased cancer incidence and aging in normal human physiological conditions, we used a case-control design and measured the mRNA expression levels of p53, ATM, hTERT and TRF2, the four major protectors of genomic integrity, in isolated peripheral blood lymphocytes from 202 confirmed bladder cancer (BC) patients and 199 healthy controls. Significant age effects on expression levels were observed. When we divided the study subjects into three age groups (<57, 57-65 and > or = 65), the expressions of p53, ATM and TRF2 significantly decreased with advancing age in cases (P for trend < or = 0.001, 0.01 and 0.01 for p53, ATM and TRF2, respectively). In controls, however, p53 expression significantly increased with advancing age (P for trend = 0.05). Among subjects > or = 65 years of age, the expressions of p53, ATM and TRF2 were significantly lower in cases than in controls (P = 0.003, 0.04 and 0.05 for p53, ATM and TRF2, respectively), suggesting that attenuated genomic maintenance mechanisms lead to increased cancer risk in older individuals. When we dichotomized our study population at the median age of study subjects (61 years old), low p53 expression was associated with a significantly increased BC risk in older people (OR = 2.27, 95% CI = 1.00-5.16). In addition, older subjects without detectable hTERT expression had a significantly reduced BC risk (OR = 0.41, 95% CI = 0.17-0.99). Our study provides the first epidemiologic evidence that the increased genomic instability resulting from the combination of telomere dysfunction, impaired ATM- and p53-mediated DNA damage, and/or telomere dysfunction response pathway contributes to increased cancer incidence in the elderly population.

Aged↗

Nucleotide excision repair gene polymorphisms and recurrence after treatment for superficial bladder cancer.

PURPOSE: Interindividual differences in DNA repair capacity not only modify individual susceptibility to carcinogenesis, but also affect individual response to cancer treatment. Nucleotide excision repair (NER) is one of the major DNA repair pathways in mammalian cells involved in the removal of a wide variety of DNA lesions. Polymorphisms in NER genes may influence DNA repair capacity and affect clinical outcome of bladder cancer treatment. EXPERIMENTAL DESIGN: To test the influence of NER gene polymorphisms on superficial bladder cancer outcome (recurrence and progression), we conducted a follow-up study of 288 patients with superficial bladder cancer. Median follow-up among patients who were recurrence-free at the end of observation was 21.7 months from diagnosis. The specific polymorphic loci examined include XPA [A/G at 5' untranslated region (UTR)], XPC (poly AT, Ala(499)Val, Lys(939)Gln), XPD (Asp(312)Asn, Lys(751)Gln), XPG (His(1104)Asp), ERCC 1 (G/T at 3' UTR), and ERCC6 (Met(1097)Val, Arg(1230)Pro). RESULTS: The ERCC6 (Met(1097)Val) polymorphism had a significant impact on recurrence: carriers of at least one variant allele (Val) had a significantly higher recurrence risk than carriers of the wild-type allele (Met/Met; hazard ratio, 1.54; 95% confidence interval, 1.02-2.33). There were no overall statistically significant differences in the distributions of the other polymorphisms between patients with and without recurrence. However, when we combined these variant genotypes, there was a significant trend for an increased recurrence risk with an increasing number of putative high-risk alleles. Using individuals with five or fewer putative high-risk alleles as the reference group, individuals with six to seven risk alleles and individuals with eight or more risk alleles had higher recurrence risks, with hazard ratios of 0.92 (0.54-1.57) and 2.53 (1.48-4.30), respectively (P for trend < 0.001). There was also a significant trend for shorter recurrence-free survival time with increasing number of variant alleles (log rank test, P = 0.0007). When we stratified the patients according to intravesical Bacillus Calmette-Guerin treatment, we found a significant trend for shorter recurrence-free survival time in patients with variant alleles of XPA or ERCC6 polymorphisms who received Bacillus Calmette-Guerin treatment (log rank test, P = 0.078 and 0.022, respectively). There were no significant individual or joint associations between these polymorphisms and progression. CONCLUSIONS: These data suggest that interindividual differences in DNA repair capacity may have an important impact on superficial bladder cancer recurrence. A pathway-based approach is preferred to study the effects of individual polymorphism on clinical outcomes.

Aged↗