Variability of DNA content of murine fibrosarcoma cells

ANEUPLOIDY or heteroploidy and hyperploidy have been observed in tumours of experimental animals and of humans and seem to be a feature of most malignant cells1–9. DNA contents seem to correlate with karyotype in these changes or deviations from euploidy. Most tumours are hyperploid and higher in DNA content2,8,9. A rapid and reliable method of analysis of DNA content distribution of a cell population has recently become available with the development of flow microfluorometry (FMF)10. We report here the use of FMF analysis to measure DNA content of clones isolated from a fibrosarcoma. All the clones examined had a higher DNA content than did either the normal cells tested or the original fibrosarcoma. There is thus a variability of DNA content in fibrosarcoma cells. This suggests that variability, as well as increase in DNA content in malignant cells may relate to their neoplastic development.