EXPRESSION OF SV40 T-ANTIGEN IN LIPOMA CELLS WITH A CHROMOSOMAL TRANSLOCATION T(3-12) IS NOT SUFFICIENT FOR DIRECT IMMORTALIZATION

12q13-15 changes are the most frequent cytogenetic abnormalities in human tumor cells. To test their biological significance we used an assay based on lipoma cells with a limited in vitro lifetime and this type of chromosomal aberration. Lipoma cells with a reciprocal translocation t(3;12)(q28;q14) were transformed by transfection with a plasmid containing the SV40 "early region". The transformed cells showed an altered morphology with loss of contact inhibition, formation of foci, and T-antigen expression. They were immortalized after a growth crisis. The karyotypic patterns before and after the crisis show that the translocation together with expression of SV40 T-antigen is not sufficient for direct immortalization. © 1992 Academic Press Ltd.