[Intraclonal and interclonal differences of ploidy in transplantable rat rhabdomyosarcoma RA-2 detected using DNA flow cytometry]

DNA contents were determined using flow cytometry in cells of 71 clones of the rat transplantable rhabdomyosarcoma passed through more than 70 cycles of selection for increased malignancy. 58 clones (82%) consisted of cells with diploid DNA content, whereas 13 clones (18%) displayed not only diploid, but also near tetraploid cell subpopulations, the latter covering from 20 to 60% of the total number of cells measured. The data obtained show the existence of intra- and interclonal karyotypic heterogeneity in populations of tumor clonogenic cells.