Comparative studies of in vitro transformation by ethylene oxide and gamma-radiation of C3H/10T1/2 cells.

A dose-dependent transforming ability of the direct-acting alkylating agent, ethylene oxide (EtO), was demonstrated in C3H/10T1/2 mouse embryo fibroblasts. Morphologically transformed colonies were observed 5-6 weeks after the treatment with EtO. The transforming effectiveness of EtO was compared with that of gamma-radiation, and the rad-equivalence of EtO was calculated to be approximately 90 rad/mMh. This value is consistent with earlier estimates based on induced mutation in various biological systems and thus indicates the applicability of the C3H/10T1/2 cell system in the risk estimation of human exposure to genotoxic compounds.