Abstract
The rat liver oval cell line OC/CDE 22 was exposed to each of the four optically active fjord-region dihydrodiol epoxides of benzo[c]phenanthrene to investigate their capacity for malignant transformation of liver cells. All four configurational isomers malignantly transformed OC/CDE 22 cells, resulting in a similar colony-forming efficiency in soft agar. Inoculation of the transformed cells into newborn syngeneic rats produced an extremely high incidence of carcinomas with a short latency period. The induced carcinomas displayed cholangiocellular, adenoid and solid growing structures. Thus, the fjord-region dihydrodiol epoxides of benzo[c]phenanthrene are able to efficiently transform rat liver cells. Furthermore, experimental evidence is presented that proliferation plays a central role in liver cell transformation mediated by polycyclic aromatic hydrocarbons.