title: Inhalation carcinogenicity of 1,1,1-trichloroethane in rats and mice.
abstract: Carcinogenicity of 1,1,1-trichloroethane (TCE) was examined by an inhalation exposure of F344 rats and BDF1 mice of both sexes to TCE at 0, 200, 800 or 3200 ppm for 6 h/d, 5 d/week for 104 weeks. In male rats, the incidences of bronchiolo-alveolar adenomas and peritoneal mesotheliomas were significantly increased in the 800 and 3200 ppm-exposed groups, respectively. The incidence of bronchiolo-alveolar adenomas in the 3200 ppm-exposed groups exceeded the range of historical control data in the Japan Bioassay Research Center. In female rats, the tumor incidences were not increased in any organs of the TCE-exposed groups. In male mice, a significant positive trend with dose was shown for incidences of bronchiolo-alveolar carcinomas, combined incidences of bronchiolo-alveolar adenomas/carcinomas and hepatocellular adenomas. The incidence of Harderian gland adenomas was significantly increased in the 3200 ppm-exposed group, and malignant lymphomas of spleen at this highest dose exceeded the range of historical control data. In female mice, the combined incidence of bronchiolo-alveolar adenomas/carcinomas was significantly increased in the 3200 ppm-exposed group, and the incidences of hepatocellular adenomas and combined incidences of hepatocellular adenomas/carcinomas were significantly increased in the 200, 800 and 3200 ppm-exposed groups with dose dependence except the combined incidence of hepatocellular adenomas/carcinomas in the 200 ppm-exposed group. The incidences of bronchiolo-alveolar adenomas in the 3200 ppm-exposed group and combined incidences of hepatocellular adenomas/carcinomas in the 200 ppm-exposed groups exceeded the ranges of historical control data. Thus, this study provided clear evidence of inhalation carcinogenicity for TCE in both rats and mice.
authors.affiliation: Japan Bioassay Research Center, Japan Industrial Safety and Health Association, Hadano, Kanagawa, Japan. m-onishi@jisha.or.jp
authors.forename: Makoto
authors.initials: M
authors.lastname: Ohnishi
authors.forename: Yumi
authors.initials: Y
authors.lastname: Umeda
authors.forename: Taku
authors.initials: T
authors.lastname: Katagiri
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kasai
authors.forename: Naoki
authors.initials: N
authors.lastname: Ikawa
authors.forename: Tomoshi
authors.initials: T
authors.lastname: Nishizawa
authors.forename: Shoji
authors.initials: S
authors.lastname: Fukushima
mesh_terms: D000236:Adenoma / Q000139:chemically induced / Q000473:pathology; D000280:Administration, Inhalation; D000818:Animals; D002273:Carcinogens / Q000008:administration & dosage / Q000633:toxicity*; D002277:Carcinoma / Q000139:chemically induced* / Q000473:pathology; D005260:Female; D006243:Harderian Gland / Q000187:drug effects / Q000473:pathology; D008113:Liver Neoplasms / Q000139:chemically induced* / Q000473:pathology; D008175:Lung Neoplasms / Q000139:chemically induced* / Q000473:pathology; D008223:Lymphoma / Q000139:chemically induced / Q000473:pathology; D008297:Male; D051379:Mice; D051381:Rats; D011916:Rats, Inbred F344; D013160:Splenic Neoplasms / Q000139:chemically induced* / Q000473:pathology; D036401:Toxicity Tests, Chronic; D014240:Trichloroethanes / Q000008:administration & dosage / Q000633:toxicity*
chemical_list: D002273:Carcinogens; D014240:Trichloroethanes; C024566:1,1,1-trichloroethane