title: An international validation study of a Bhas 42 cell transformation assay for the prediction of chemical carcinogenicity.
abstract: The Bhas 42 cell transformation assay is a sensitive short-term system for predicting chemical carcinogenicity. Bhas 42 cells were established from BALB/c 3T3 cells by the transfection of v-Ha-ras gene and postulated to have acquired an initiated state in the two-stage carcinogenesis theory. The Bhas 42 cell transformation assay is capable of detecting both tumor-initiating and tumor-promoting activities of chemical carcinogens. The full assay protocol consists of two components, the initiation assay and the promotion assay, to detect the initiating activity and the promoting activity, respectively. An international study was carried out to validate this cell transformation assay in which six laboratories from three countries participated. Twelve coded chemicals were examined in total and each chemical was tested by three laboratories. In the initiation assay, concordant results were obtained by three laboratories for eight out of ten chemicals and in the promotion assay, concordant results were achieved for ten of twelve chemicals. The positive results were obtained in all three laboratories with the following chemicals: 2-acetylaminofluorene was positive in both initiation and promotion assays; dibenz[a,h]anthracene was positive in the initiation assay; sodium arsenite, lithocholic acid, cadmium chloride, mezerein and methapyrilene hydrochloride were positive in the promotion assay. o-Toluidin hydrochloride was positive in the both assays in two of the three laboratories. d-Mannitol, caffeine and l-ascorbic acid were negative in both assays in all the laboratories, and anthracene was negative in both assays in two of the three laboratories except one laboratory obtaining positive result in the promotion assay. Consequently, the Bhas 42 cell transformation assay correctly discriminated all six carcinogens and two tumor promoters from four non-carcinogens. Thus, the present study demonstrated that the Bhas 42 cell transformation assay is transferable and reproducible between laboratories and applicable to the prediction of chemical carcinogenicity. In addition, by comparison of the present results with intra-laboratory data previously published, within-laboratory reproducibility using the Bhas 42 cell transformation assay was also confirmed.
authors.affiliation: Hatano Research Institute, Food and Drug Safety Center, Kanagawa, Japan. sakai.a@fdsc.or.jp
authors.forename: Ayako
authors.initials: A
authors.lastname: Sakai
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Sasaki
authors.forename: Kumiko
authors.initials: K
authors.lastname: Hayashi
authors.forename: Dai
authors.initials: D
authors.lastname: Muramatsu
authors.forename: Shoko
authors.initials: S
authors.lastname: Arai
authors.forename: Nobuko
authors.initials: N
authors.lastname: Endou
authors.forename: Sachiko
authors.initials: S
authors.lastname: Kuroda
authors.forename: Albrecht
authors.initials: A
authors.lastname: Poth
authors.forename: Susanne
authors.initials: S
authors.lastname: Bohnenberger
authors.forename: Thorsten
authors.initials: T
authors.lastname: Kunkelmann
authors.forename: Masumi
authors.initials: M
authors.lastname: Asakura
authors.forename: Hideki
authors.initials: H
authors.lastname: Hirose
authors.forename: Nana
authors.initials: N
authors.lastname: Ishii
authors.forename: Fukutaro
authors.initials: F
authors.lastname: Mizuhashi
authors.forename: Sawako
authors.initials: S
authors.lastname: Kasamoto
authors.forename: Miho
authors.initials: M
authors.lastname: Nagai
authors.forename: Kamala
authors.initials: K
authors.lastname: Pant
authors.forename: Shannon W
authors.initials: SW
authors.lastname: Bruce
authors.forename: Jamie E
authors.initials: JE
authors.lastname: Sly
authors.forename: Shojiro
authors.initials: S
authors.lastname: Yamazaki
authors.forename: Makoto
authors.initials: M
authors.lastname: Umeda
authors.forename: Noriho
authors.initials: N
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D041702:BALB 3T3 Cells; D015197:Carcinogenicity Tests / Q000379:methods*; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D011905:Genes, ras / Q000235:genetics; D051379:Mice; D015203:Reproducibility of Results