Generation of CFU-GM from 1,000 sorted cells from three CML patients in the pre-CFU assay over 28 days. Aliquots of cells for the CFU-GM assay were removed from the pre-CFU cultures at intervals. The total number of CFU generated (from 1,000 original cells) was calculated from the number of colonies derived and the proliferation of the remaining cells, ie (Number of Colonies/1,000 Cells) × (Number of Cells Generated [× 1,000]). ○, CD34⁺CD38⁻ in 4HGF; •, CD34⁺CD38⁻ in SCF; ▪, CD34⁺CD38⁺ in SCF; □, CD34⁺CD38⁺ in 4HGF.