SV40LT highly mutates and immortalizes two fibroblast strains from patients with Wilms' tumor

In order to analyze in detail the process of immortalization of human cells , SV40LT was introduced into two chromosome 11p- fibroblast strains from Wi lms' tumor patients. Both fibroblasts, hereafter referred to as CM1 and CM2 , displayed the mutant phenotype in the crisis stage of cellular aging. In comparison to a control fibroblast, the density of the CM1 strain was abnor mally high while the crisis period of the CM2 strain was abnormally long, T he CM1 immortalization was 7 times greater than the control and the CM2 str ain had the highest frequency of immortalization, 7 times greater than the CM1. These findings indicate that genes associated with chromosome 11p- may be involved in the immortalization of human cells. During their abnormal c risis periods, the cells derived from the patients with Wilms' tumor showed an extremely high frequency of chromosomal aberrations and mutations (6TG( s) --> 6TG(r)). These results indicate that when the growth-arrested cells from Wilms' patients are induced to grow with the introduction of SV40LT at the crisis stage they are highly mutable, resulting in their immortalizati on in vitro.