Proportion of human CD45⁺/GFP⁺ in the peripheral blood of ALL-11 engrafted mice at event. PB from mice engrafted with untransduced (A), empty vector (B), or AKR1C3 cDNA (C) ALL-11 cells was collected when mice reached event (hCD45⁺ population in blood reaches 25%). One representative mouse is shown from each. The hCD45⁺ population was gated by flow cytometry to determine the proportion of GFP⁺ cells circulating in the PR-104–treated (blue) or vehicle (red) groups. The numbers in panels A through C refer to the percentage of GFP⁻ and GFP⁺ cells in the PR-104–treated mice. (D) Quantification of the proportion of hCD45⁺/GFP⁺ cells in all groups.