Cytogenetic analysis and population study in P3HR-1 cell line derived from Burkitt's lymphoma.

P3HR-1 cell line derived from Burkitt's lymphoma was chosen as a model for studying the development of the cell population during long-term cultivation from the cytogenetic point of view. Fifty G-banded karyotypes at two different passage levels were analyzed, using also C-, Q- and Ag-staining. The modal chromosomal number at the 15th passage was 49, at the 75th passage 48. At the 15th passage considerable heterogeneity of karyotypes was found. Only four metaphases had an identical karyotype: 49, XY, +7, +21, +psu dic mar, dup(1) (q21q42), del(1) (p ter----q23:), t(8;14) (q24;q32), 16qh+. This clone turned out to be important in the further development of the cell population. At the 75th passage there was only one metaphase with this karyotype. Fifteen metaphases (30%) revealed a karyotype with only one difference from the karyotype mentioned above: deletion of a part of the short arm of one chromosome 7. Further 16 metaphases (32%) had 48 chromosomes, where one chromosome 7 was missing in comparison with the above mentioned karyotype, and 3 metaphases (6%) with 48 chromosomes, where the loss of chromosome 21 and deletion of a part of the short arm of one chromosome 7 were found. These three clones could have originated from the clone described at the 15th passage through loss of a whole or part of chromosome, or both; i.e. the clone forming 8% of the cell population at the 15th passage gave rise to 70% of the cell population during 60 passages in vitro (30 weeks of cultivation). Cytogenetic analysis at two different passages enables the observation of the dynamic changes in the cell population. A wide gamut of cell clones enables heterogenous selection influences in vitro.