Editors' ChoiceBladder Cancer

The Haze Clears: Second-Hand Tobacco Smoke a Risk for Bladder Cancer

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Science Translational Medicine  15 Dec 2010:
Vol. 2, Issue 62, pp. 62ec195
DOI: 10.1126/scitranslmed.3002015

The association between the development of bladder cancer and smoking history has been well established: Inhalation of tobacco smoke is associated with intake of arylamines, which represent potent bladder carcinogens. However, the risk of bladder cancer in relation to second-hand smoke has remained unclear. A recent study by Tao et al. has found that environmental tobacco exposure (ETS) is associated with an increased risk for bladder cancer in lifelong nonsmokers.

Tao et al. investigated the association between ETS and the development of bladder cancer using a case-control study with lifelong nonsmoking patients identified through the Shanghai Cancer Registry. Using a questionnaire-based format, the authors examined a variety of environmental exposures in detail, including history of tobacco use, smoking history of relatives in the same household, and smoking history of coworkers in indoor work environments. In addition, study subjects were assessed for the phenotype of hepatic cytochrome P450 (CYP) 1A2 and N-acetyltransferase (NAT2), which respectively affect activation and detoxification of tobacco carcinogens. In all, 195 bladder cancer patients and 261 controls participated.

Increasing total ETS, including the number of cigarettes smoked by household members or more hours spent in a smoky work environment, was associated with an increasing risk of bladder cancer. An interesting component of the study was the evaluation of exposure during childhood: Participants who lived with smoking parents during childhood also appeared to have an increased risk of developing bladder cancer. However, environment didn’t appear to be the entire story; participants who had a CYP1A2 high efficiency and/or a NAT2 slow acetylation phenotype appeared to be principally at risk. The results from this study support the concerns of many regarding the risks of second-hand smoke, highlighting the intricate interplay between genes and environment that appears to affect the development of bladder cancer.

L. Tao et al., Environmental tobacco smoke in relation to bladder cancer risk – The Shanghai Bladder Cancer Study. Cancer Epidemiol. Biomarkers Prev. 15 October 2010 (10.1158/1055-9965.EPI-10-0823). [Abstract]

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