Chromosome instability in lymphocytes, fibroblasts, and colon epithelial-like cells from patients with familial polyposis coli.

Detailed chromosome studies on early-passage skin fibroblast cultures from 17 patients with familial polyposis coli (FPC) showed an increase in all classes of chromosome aberrations compared with controls. The most striking difference was in the number of cytogenetically abnormal clones, some of which reached 80-100% in early cultures, suggesting either presence in vivo or considerable proliferative advantage. The occasional occurrence of very high levels of tetraploidy in these cultures was thought to be a manifestation of clone formation. The same type of chromosome instability was found to extend to colon fibroblasts and lymphocytes but without evidence of clone formation, apart from high tetraploidy in the former. Chromosomes in colon epithelial-like cultures were remarkably stable initially, despite the time span of several months required to establish them. However, from the outset one of these cultures was composed of three abnormal clones. After approximately 18 months in culture, stable and unstable chromosome rearrangements clearly increased in all tested cultures, although the cells were not senescent, suggesting a possible shift toward malignancy.