[Karyotypic variability of human myeloma cell lines]

Cytogenetic analysis of human myeloma cell lines L363, Karpas 707, RPMI 8226 and U-266 has been performed. Chromosome numbers retained near-diploid (L363, Karpas 707 and U-266) or increased to hypotriploid (RPMI 8226) during many years of maintenance of the cell lines in vitro. Based on G-banding analysis, the complex karyotypes with abnormalities of virtually all chromosome pairs were found in these cell lines but common chromosome translocations were not observed. In addition, chromosome loci involved in structural rearrangements in these cell lines often overlapped with loci of DNA copy number imbalances revealed in myeloma cells in vivo. Besides, distinct types of karyotypic structure of cell populations were found in all of these cell lines which differed by combination of cells with main and additional structural variants of karyotype and cells with non-clonal chromosome aberrations. Taken together, it seems obvious that karyotypic variability of human myeloma cell lines corresponds to karyotypic progression of myeloma in vivo and, hence, has tumor specific pattern.