E-cigs linked to lung cancer and bladder changes in mice
NIEHS grantees showed that mice exposed to e-cigarette smoke (ECS) were more likely to develop lung adenocarcinomas, a type of lung cancer. They also found that exposed mice had higher levels of bladder urothelial hyperplasia, an abnormal increase in epithelial cells that can precede development of bladder tumors.
The researchers exposed one group of mice to ECS aerosols generated from e-juice containing nicotine and compared them to a second group of mice exposed to a control aerosol without ECS. The mice were subjected to whole-body exposure for four hours per day, five days per week, for 54 weeks. A third group of mice was exposed only to filtered air. Of the mice exposed to ECS, 22.5% developed lung adenocarcinomas and 57.5% developed urothelial hyperplasia. These lesions were extremely rare in mice exposed to the control aerosol without ECS or filtered air.
Interestingly, mice with ECS-induced lung adenocarcinomas were not more prone to developing urothelial hyperplasia, suggesting that the two outcomes are divergent events and may involve different mechanisms.
Previous studies have linked nicotine and nicotine-derived products to effects on lung and bladder cells. According to the authors, the findings of this study show that ECS, including nicotine, may be a lung and bladder carcinogen and warrants further study in humans.
Citation: Tang MS, Wu XR, Lee HW, Xia Y, Deng FM, Moreira AL, Chen LC, Huang WC, Lepor H. 2019. Electronic-cigarette smoke induces lung adenocarcinoma and bladder urothelial hyperplasia in mice. Proc Natl Acad Sci U S A 116(43):21727–21731.