Abstract
A comparative study has been made of fibroblasts obtained from patients with differing susceptibilities to malignant disease, both with respect to their chromosome complements and their transformation with SV40 virus. Fibroblasts from 2 Bloom's syndrome patients were found not to have raised SV40 transformation rates and no correlation was found between chromosome abnormality per se and transformation. Of 2 cell types with greatly increased rates, one was derived from a neurofibromatosis patient and the other from an A-T heterozygote. When SV40 DNA was employed as the transforming agent for the latter, the transformation rate was no longer raised.