Prevalidation study of the Syrian hamster embryo (SHE) cell transformation assay at pH 6.7 for assessment of carcinogenic potential of chemicals.

The Syrian hamster embryo (SHE) cell transformation assay (CTA) is an important in vitro method that is highly predictive of rodent carcinogenicity. It is a key method for reducing animal usage for carcinogenicity prediction. The SHE assay has been used for many years primarily to investigate and identify potential rodent carcinogens thereby reducing the number of 2-year bioassays performed in rodents. As for other assays with a long history of use, the SHE CTA has not undergone formal validation. To address this, the European Centre for the Validation of Alternative Methods (ECVAM) coordinated a prevalidation study. The aim of this study was to evaluate the within-laboratory reproducibility, test method transferability, and between-laboratory reproducibility and to develop a standardised state-of-the-art protocol for the SHE CTA at pH 6.7. Formal ECVAM principles for criteria on reproducibility (including the within-laboratory reproducibility, the transferability and the between-laboratories reproducibility) were applied. In addition to the assessment of reproducibility, this study helped define a standard protocol for use in developing an Organisation for Economic Co-operation and Development (OECD) test guideline for the SHE CTA. Six compounds were evaluated in this study: benzo(a)pyrene, 3-methylcholanthrene, o-toluidine HCl, 2,4-diaminotoluene, phthalic anhydride and anthracene. Results of this study demonstrate that a protocol is available that is transferable between laboratories, and that the SHE CTA at pH 6.7 is reproducible within- and between-laboratories.

Prevalidation study of the Syrian hamster embryo (SHE) cell transformation assay at pH 7.0 for assessment of carcinogenic potential of chemicals.

The European Centre for the Validation of Alternative Methods (ECVAM) has organised an interlaboratory prevalidation study on the Syrian hamster embryo (SHE) cell transformation assay (CTA) at pH 7.0 for the detection of rodent carcinogens. The SHE CTA at pH 7.0 has been evaluated for its within-laboratory reproducibility, transferability and between-laboratory reproducibility. Four laboratories using the same basic protocol with minor modifications participated in this study and tested a series of six coded-chemicals: four rodent carcinogens (benzo(a)pyrene, 3-methylcholanthrene, 2,4-diaminotoluene and o-toluidine HCl) and two non-carcinogens (anthracene and phthalic anhydride). All the laboratories found the expected results with coded chemicals except for phthalic anhydride which resulted in a different call in only one laboratory. Based on the outcome of this study, it can be concluded that a standardised protocol is available that should be the basis for future use. This protocol and the assay system itself are transferable between laboratories and the SHE CTA at pH 7.0 is reproducible within- and between-laboratories.