[Chromosomes and carcinogenesis. Study on the evolution of an epithelial cell line of porcine origin].

The PFT cell line was established in 1969 from diploid cells of the inner lining of a uterine tube of a 2 year-old sow and has been continuously subcultured more than 500 times over a decade. Three chromosomal rearrangements have occurred during this time. The first translocation was shown at the 100th passage with the concomitant and spontaneous release of an endogeneous type C virus. The second translocation was observed at the 290th passage along with the appearance of gap junctions and the induction of malignant tumors in athymic nude mice following the inoculation of PFT cells. The third translocation was found towards the 470th passage with the simultaneous appearance of annulate lamellae. Since the translocations were accompanied by the spontaneous release of a retrovirus and then by malignancy of PFT cells when inoculated in athymic nude mice, it is likely that the chromosomal abnormalities are associated with the viral carcinogenesis of the cell line. The third translocation appears to confirm the perenniality of the multistep evolution hypothesis of malignancy.