Reproducibility of and experiences with the BHK cell transformation assay

Transformation of BHK 21 C 13 cells was investigated using the ability of transformed cells to reproduce in semi solid agar (anchorage independent growth). A number of modifications to previously published methods have been made, our assays were carried out on 16 compounds, including both carcinogens and non-carcinogens as judged by in vivo bioassay. Reproducibility of test results within the laboratory and with data derived from literature could be shown. Experiences concerning the optimal growth of transformed cells and the threshold level to differentiate between positive and negative results are discussed.