[Oncogenes and tumor promotion].

We have studied the effects of 2 hepatic promoters: an exogenous one:phenobarbital, and an endogenous one biliverdin (a bile pigment) on the expression of 3 oncogenes c-Ki-ras, c-fos and c-myc involved in growth process, differentiation and tumorigenesis for the liver. This work was done: 1) in vitro using epithelial liver cell strains originated from 10-day old rats; 2) in vivo using regenerating liver after partial hepatectomy, as well as preneoplastic nodules obtained by the Solt and Farber procedure. In all cases we have shown an important overexpression of the oncogenes.