Presence of p210^BCR/ABL in normal CD34⁺ cells increases number of GM-CFU.

p210-eGFP– or eGFP-transduced GFP⁺ CD34⁺ cells (10³) from 4 umbilical cord blood samples were plated in methylcellulose assay with SCF, GM-CSF, and IL-3 each at a final concentration of 5 ng/mL and erythropoietin at 3 IU/mL. After 14 days, GM-CFU and BFU-E were enumerated separately, and the size of colonies was assessed visually. (A) Significantly greater numbers of GM-CFU in 10³ p210-eGFP– (▪) than eGFP-transduced (■) GFP⁺ CD34⁺ cells and similar numbers of BFU-E in either population. Comparison between GM-CFU in 10³p210-eGFP– and eGFP-transduced GFP⁺ CD34⁺cells (P = .001). (B) In addition, the size of GM-CFU was significantly greater in p210-eGFP– than in eGFP-transduced GFP⁺ CD34⁺ cells.