Posttransplantation follow-up of mice for engraftment and development of leukemia. All transplanted mice (as described under “Transplantation of murine bone marrow”) were followed at regular intervals of 10 days for the peripheral blood cell counts (Haemavet) and percentage of GFP-positive cells (flow cytometry). The mean values from each different group of mice were plotted as percentage GFP (A), WBC count (× 1000/μL; B), hemoglobin content (grams per deciliter; C) and platelet count (PLT; × 1000/μL; D) versus time in days after transplantation (*P < .05).