| Summary: | BACKGROUND: Bromodichloromethane is a by-product of water disinfection. We tested if bromodichloromethane could cause cancer in two different strains of genetically modified mice. METHODS: We exposed male and female Tg.AC mice to bromodichloromethane for 6 or 9 months in three different ways: by painting solutions of the chemical dissolved in acetone on their backs, by giving the animals drinking water containing the chemical, or by depositing solutions of the chemical dissolved in corn oil directly into their stomachs through a tube (gavage). We also exposed p53 haploinsufficient mice to bromodichloromethane dissolved in drinking water or by gavage. Animals given the same solvents (acetone, drinking water, or corn oil), but without bromodichloromethane, served as the control groups. Tissues from 15 sites were examined for every animal. RESULTS: Exposure to bromodichloromethane through the skin had no effect on male or female Tg.AC mice. Male Tg.AC and p53 mice given bromodichloromethane by drinking water or gavage had increased rates of kidney renal tubule degeneration, and male and female p53 mice exposed by those two means had increased rates of fatty changes in the liver. No increases in tumors were seen in males or females from either strain of mice exposed by any of these routes. CONCLUSIONS: We conclude that bromodichloromethane did not cause cancer in the genetically modified mice in these studies. This chemical did cause cancer in other studies with different rodents, and thus these genetically modified mice may not be as sensitive for detecting cancer-causing compounds
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