[Cytogenetic changes in an explanted mouse rhabdomyosarcoma during prolonged cultivation]

Quantitative and qualitative chromosome rearrangements, dynamics of distribution of double-minute chromosomes (DMs), and morphological characteristics of tumor rhabdomyoblasts MH-82 during explantation and following in vitro cultivation are analysed. Cells of the 13th and 27th passages of cultivation were characterized by the epithelial type of growth, although their form and size varied. Chromosome analysis of tumor rhabdomyoblasts was carried out on passages 4, 14, 20, 25 and 30 of in vitro cultivation. The modal class with 53-55 chromosomes was established within 20 passages. Heterogeneity of cell population in concern to the chromosome number and content of hypotetraploid cells (72-78) diminished during cultivation. Chromosome rearrangements (marker chromosomes) in hyperdiploid and hypotetraploid cell subpopulations differed. The number of cells with DMs and the number of DMs per cell decreased till the full disappearance by the 30th passage. It is concluded that the establishment of the MH-82 cell line was completed up to the 30th passage of cultivation.