Non-tumorigenic SV40T immortalized human buccal epithelial cells show aneuploidy and genetic instability

Cytogenetic and DNA flow cytometric analysis was carried out on four SV40T-transfected human buccal epithelial cells lines. One of these was immortalized and showed a nontumorigenic phenotype when tested in athymic nude mice. DNA flow cytometric ploidy values correlated well with cytogenetic ploidy values as calculated from chromosome length or DNA content, whereas the chromosome counts correlated poorly with the flow cytometric results. Gross ploidy changes were seen at early passages, while the immortalized cell line had a stabilized DNA content in the near diploid range. However, this cell line showed ongoing random chromosomal changes with the appearance of new marker chromosomes balancing chromosome losses. The chromosome losses were mainly found in the groups 12-16 and 18-23 and the gains in the group 1-6. This reflects, together with the stabilization of the DNA content, a nonrandom component in the overall random chromosomal changes. In conclusion, aneuploidy and genetic instability found in the immortalized cell line were not linked to malignant growth in nude mice.