Comparing the joint effect of arsenic exposure, cigarette smoking and risk genotypes of vascular endothelial growth factor on upper urinary tract urothelial carcinoma and bladder cancer

Abstract

Arsenic exposure and cigarette smoking are environmental risk factors for urothelial carcinoma (UC). Vascular endothelial growth factor (VEGF) is the key regulator of angiogenesis in various malignancies. This study investigates the joint effect of arsenic exposure, cigarette smoking, and VEGF polymorphisms on UC risk. This was a hospital-based case-control study consisting of 730 histopathologically confirmed UC cases, including 470 bladder cancers, 260 upper urinary tract UCs (UUTUCs), and 850 age-matched controls, recruited from September 1998 to December 2009. UC risk was estimated by odds ratios and 95% confidence intervals using unconditional logistic regression. Ever smokers with high arsenic exposure had significantly increased risks of 5.7 and 6.4 for bladder cancer and UUTUC, respectively. Moreover, ever smokers with high arsenic exposure carrying 1 or 2 risk genotypes of the VEGF gene had a significantly increased risk of 6.6 for bladder cancer and a strikingly higher risk of 9.9 for UUTUC. Additionally, UUTUC cases with high arsenic exposure carrying 1 or 2 risk genotypes of the VEGF gene had a non-significant increased risk of advanced tumor stage. Our findings suggest that arsenic exposure, cigarette smoking, and risk genotypes of VEGF contribute to a higher risk of UUTUC than of bladder cancer.

Keywords: 95% CI; 95% confidence interval; Arsenic; Bladder cancer; Cigarette smoking; HWE; Hardy–Weinberg equilibrium; LD; OR; PAHs; PCR-RFLP; ROS; SNP; UC; Upper urinary tract; Urothelial carcinoma; VEGF; Vascular endothelial growth factor; linkage disequilibrium; odds ratio; polycyclic aromatic hydrocarbons; polymerase chain reaction-restriction fragment length polymorphism; reactive oxygen species; single nucleotide polymorphism; urothelial carcinoma; vascular endothelial growth factor.