We conducted a genome wide SNP association study on 1,803 Urinary Bladder Cancer (UBC) cases and 34,336 controls from Iceland and the Netherlands and follow up studies in seven additional case control groups (2,165 cases and 3,800 controls). The strongest association was observed with allele T of rs9642880 on chromosome 8q24, 30kb upstream of the c-Myc gene (allele specific OR=1.22; P=9.34×10−12). Approximately 20% of individuals of European ancestry are homozygous for rs9642880 (T) and their estimated risk of developing UBC is 1.49 times that of non-carriers with population attributable risk (PAR) of 17%. No association was observed between UBC and the four 8q24 variants previously associated with prostate, colorectal and breast cancers, nor did rs9642880 associate with any of these three cancers. A weaker signal, but nonetheless of genome wide significance, was captured by rs710521 (A) located near the TP63 gene on chromosome 3q28 (allele specific OR=1.19; P=1. 15× 10−7).

Tobacco smoking and occupation are major risk factors of bladder cancer via exposure to polycyclic aromatic hydrocarbons (PAHs) and aromatic amines. Glutathione S-transferase (GST) M1, T1 and P1 are involved in the detoxification of PAH reactive metabolites. Two N-acetyltransferase isozymes, NAT2 and NAT1, have major roles in catalyzing the N-acetylation and O-acetylation of aromatic amines. Cytochrome P450 1B1 (CYP1B1) and sulfotransferase 1A1 (SULT1A1) are also involved in the metabolism of PAHs and aromatic amines. It is hypothesized that the genetic polymorphisms of these metabolic enzymes have an effect on the individual susceptibility to bladder cancer in particular by interacting with relevant environmental exposures. A hospital-based case-control study among men in Brescia, Northern Italy recruited 201 incidence cases and 214 controls from 1997-2000. Occupational exposures were blindly coded by occupational physicians. Genotyping of polymorphisms were carried out with PCR-RFLP method. Unconditional multivariate logistic regression was applied to model the association between genetic polymorphisms and bladder cancer risk. Effect modifications by age of onset, smoking and occupational exposures to PAHs and aromatic amines were evaluated. We also conducted an analysis of interaction between genetic factors. GSTM1 and GSTT1 null genotype were associated with an increased risk of bladder cancer with an odds ratio (OR) of 1.69 (95% confidence interval [CI] ‫؍‬ 1.11-2.56) and 1.74 (95% CI ‫؍‬ 1.02-2.95), respectively. The effect of GSTM1 null was seen particularly in heavy smokers, and there was a combined effect with occupational exposure of aromatic amines (OR ‫؍‬ 2.77, 95% CI ‫؍‬ 1.08 -7.10). We observed a trend (p-value < 0.01) of increasing cancer risk comparing subjects with normal GSTM1 and T1 activity to subjects with one (OR ‫؍‬ 1.82, 95% CI ‫؍‬ 1.16 -2.85) or both null genotypes (OR ‫؍‬ 2.58, 95% CI ‫؍‬ 1.27-5.23). NAT2 slow acetylator was associated with marginally increased risk of bladder cancer (OR ‫؍‬ 1.50, 95% CI ‫؍‬ 0.99 -2.27), and the OR for the joint effect with occupational exposure of aromatic amines was 3.26 (95% CI ‫؍‬ 1.06 -9.95). SULT1A1 Arg213His polymorphism showed a marginal protective effect. These findings suggest that individual susceptibility to bladder cancer may be modulated by GSTM1, GSTT1 and NAT2 polymorphisms.

Tobacco smoking and occupational exposure are major risk factors of bladder cancer via exposure to polycyclic aromatic hydrocarbons (PAHs) and aromatic amines, which lead to oxidative stress and DNA damage. Several enzymes, which play key roles in oxidative stress are polymorphic in humans. Myeloperoxidase (MPO) produces a strong oxidant for microbicidal activity, and activates carcinogens in tobacco smoke. Catechol-O-methyltransferase (COMT) catalyzes the methylation of endo- and xenobiotics and prevents redox cycling. NAD(P)H:quinone oxidoreductase (NQO1) catalyzes the two-electron reduction of quinoid compounds, which also protects cells from redox cycling. Manganese superoxide dismutase (MnSOD) protects cells from free radical injury. To test the hypothesis that the risk of bladder cancer can be influenced by polymorphisms in the genes that modulate oxidative stress, in particular by interacting with environmental carcinogens, we conducted a hospital-based case-control study among men in Brescia, Northern Italy. We recruited and interviewed 201 incident cases and 214 controls from 1997 to 2000. Occupational exposures to PAHs and aromatic amines were coded blindly by occupational physicians. Unconditional multivariate logistic regression was applied to model the association between genetic polymorphisms and bladder cancer risk and the effect of modifications of smoking and occupational exposures were evaluated. MPO G-463A homozygous variant was associated with a reduced risk of bladder cancer with an OR of 0.31 (95% CI = 0.12-0.80). MnSOD Val/Val genotype increased the risk of bladder cancer with OR of 1.91 (95% CI = 1.20-3.04), and there was a combined effect with smoking (OR = 7.20, 95% CI = 3.23-16.1) and PAH (OR = 3.02, 95% CI = 1.35-6.74). We did not observe an effect of COMT Val108Met polymorphism. These findings suggest that individual susceptibility of bladder cancer may be modulated by MPO and MnSOD polymorphisms, and that the combination of genetic factors involved in oxidative stress response with environmental carcinogens may play an important role in bladder carcinogenesis.

Previously, we reported germline DNA variants associated with risk of urinary bladder cancer (UBC) in Dutch and Icelandic subjects. Here we expanded the Icelandic sample set and tested the top 20 markers from the combined analysis in several European case-control sample sets, with a total of 4,739 cases and 45,549 controls. The T allele of rs798766 on 4p16.3 was found to associate with UBC (odds ratio = 1.24, P = 9.9 x 10(-12)). rs798766 is located in an intron of TACC3, 70 kb from FGFR3, which often harbors activating somatic mutations in low-grade, noninvasive UBC. Notably, rs798766[T] shows stronger association with low-grade and low-stage UBC than with more aggressive forms of the disease and is associated with higher risk of recurrence in low-grade stage Ta tumors. The frequency of rs798766[T] is higher in Ta tumors that carry an activating mutation in FGFR3 than in Ta tumors with wild-type FGFR3. Our results show a link between germline variants, somatic mutations of FGFR3 and risk of UBC.

Tobacco smoking is the most important and well-established bladder cancer risk factor and a rich source of chemical carcinogens and reactive oxygen species that can induce damage to DNA in urothelial cells. Therefore, common variation in DNA repair genes might modify bladder cancer risk. In this study, we present results from meta-analyses and pooled analyses conducted as part of the International Consortium of Bladder Cancer. We included data on 10 single nucleotide polymorphisms corresponding to seven DNA repair genes from 13 studies. Pooled analyses and meta-analyses included 5,282 cases and 5,954 controls of non-Latino white origin. We found evidence for weak but consistent associations with ERCC2 D312N [rs1799793; per-allele odds ratio (OR), 1.10; 95% confidence interval (95% CI), 1.01-1.19; P = 0.021], NBN E185Q (rs1805794; per-allele OR, 1.09; 95% CI, 1.01-1.18; P = 0.028), and XPC A499V (rs2228000; per-allele OR, 1.10; 95% CI, 1.00-1.21; P = 0.044). The association with NBN E185Q was limited to ever smokers (interaction P = 0.002) and was strongest for the highest levels of smoking dose and smoking duration. Overall, our study provides the strongest evidence to date for a role of common variants in DNA repair genes in bladder carcinogenesis. [Cancer Res 2009;69(17):6857-64]