ABSTRACT
To improve the usefulness of the Syrian hamster embryo (SHE) cell transformation system as a short-term test, it was investigated whether the variation in results due to serum variability could be reduced by the addition of epidermal growth factor (EGF). It was found that EGF-significantly (3-7-fold) enhanced the frequency of morphological transformation induced by N-ethyl-N-nitrosourea or benzo[a]pyrene if added to growth medium supplemented with a batch of serum which had a low ability to support transformation. Furthermore, addition of EGF to the assay medium enabled the demonstration of dose dependence of transformation with relatively small group sizes (up to 2000 colonies). Finally, it was observed that the transformed phenotype was easier to recognize in the presence of EGF. These data suggest that routine addition of EGF to the assay medium might reduce variability and enhance sensitivity of the SHE transformation assay.