Results showing that quiescent CML cells rarely contain detectable levels of IL-3 or G-CSF transcripts.

(A) RT-PCR detection of transcripts for BCR-ABL, IL-3, G-CSF, and actin (samples 3-5) or c-ABL (samples 7-9) in extracts of at least 10 initially quiescent (G₀) CD34⁺ cells or cycling (G₁/S/G₂/M [G₁]) cells. (B) Single-cell RT-PCR analyses for IL-3 and G-CSF expression in initially quiescent (G₀) CD34⁺BCR-ABL⁺ cells isolated from patients 3 to 5 and (C) for IL-3 expression in initially cycling (G₁/S/G₂/M) CD34⁺BCR-ABL⁺ cells isolated from patient 3 as a representative example confirming that more than 80% of such cells express IL-3.