Are all normal diploid human cell strains alike?
The present results suggest that studies on the oncogenic potential of normal diploid human cells in vitro should be qualified with respect to the stage of development and genetic constitution. For example, cultured normal human embryo and foreskin cells are phenotypically distinct from normal adult cells (5-65 years). The former appear to grow in culture in a fashion similar to that seen with initiated human mutant cells. They also exhibit a proliferative response pattern to a tumor promoter (TPA) closely resembling that obtained with human tumor cells. Thus, normal embryo and foreskin cells presumably represent a state in development which is genetically unstable, rendering them considerably more susceptible to malignant transformation. This conclusion may hold true with respect to spontaneously occurring tumors as well.
