Occupational exposures and genetic susceptibility to urinary tract cancers: a systematic review and meta-analysis

This study aims to summarize the current knowledge on the relationship between genetic polymorphisms, occupational exposures, and urinary tract cancers. We searched MEDLINE, ISI Web of science, and SCOPUS online databases for all articles published in English language up to September 2016. A meta-analysis was performed to provide summary estimates for the association between a certain genetic polymorphism, occupational exposure and bladder cancer (BC) or kidney cancer (KC), when appropriate. Fifteen studies on BC and six on KC were deemed eligible for the review. With regard to BC, an overall odds ratio (OR) of 2.07 [95% confidence interval (CI): 1.38–3.09] for those with GSTM1 and an OR of 2.07 (95% CI: 1.38–3.09) for those with GSTT1 null genotype were reported when exposed to polycyclic aromatic hydrocarbons (PAHs). NAT2 slow genotype carriers had an OR of 3.59 (95% CI: 2.62–4.93) for BC when exposed to aromatic amines and an OR of 2.07 (95% CI: 1.36–3.15) when exposed to PAHs. With regard to KC and pesticide exposure, the meta-analysis reported an OR of 4.38 (95% CI: 2.28–8.41) for GSTM1 present genotype, an OR of 2.59 (95% CI: 1.62–4.15) for GSTT1-present genotype and an OR of 6.51 (95% CI: 2.85–14.89) for combined effects of GSTM1 and GSTT1 active genotypes. This meta-analysis indicates a possible association between the variant genotypes of GSTM1, GSTT1, NAT2 and SULT1A1, occupational exposure to aromatic amines or PAHs, and development of BC. Our results suggest that polymorphisms in GSTM1 and GSTT1 genes could influence the risk for developing KC in individuals occupationally exposed to pesticides.