Chromosome Studies of Cell Lines and Tumors Derived from a Single Specimen of Human Leukemic Blood by Cell Culture and Heterotransplantation

Lymphoblasts isolated from the peripheral blood buffy coat of a pediatric patient and maintained in continuous suspension culture (CCRF-SB) have a diploid karyotype of 46 chromosomes. Tumors initiated and transplanted in hamsters from this cell line with the help of antilymphocytic serum showed a high degree of pseudodiploidy and aneuploidy without any consistent recognizable marker chromosomes. A serially transplantable tumor isolated directly in hamsters (H-SB-2) from the same sample of the buffy coat had a distinctive extra F-group chromosome. The H-SB-2 tumor cell population was near-diploid in the earlier serial passages, but by the 46th serial passage it had evolved into a predominantly near-tetraploid cell population which retained the extra F-group chromosomes. This extra chromosome was also seen in hamster tumor cells grown in suspension cultures and in i.p. transplants of hamster tumors in rats.