Imetelstat induces apoptosis of MF but not normal CD34⁺cells. (A,D) Representative FACS plots showing the percentage of CB (A) or MF (D) CD34⁺ cells that were undergoing apoptosis 2 days after the treatment with vehicle alone, MM, or Ime (7.5 μM). Both the percentage (B) and absolute number (C) of normal CB CD34⁺ cells that were annexin V⁺ and propidium iodide (PI)⁻ were similar in cultures under each treatment condition. However, both the percentage (E) and absolute number (F) of MF splenic CD34⁺ cells that were annexin V⁺ and PI⁻ were greater in cultures treated with cytokines plus Ime (7.5 μM) as compared with cells treated with cytokines plus MM (7.5 μM). *P < .05; **P < .01. MF and CB: n each = 4.